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Research paper Vol. 1 [issue 1] February, 2014

FDI in Retail Sector in India: Challenges and Opportunities *Kahkashan Khan MBA Department of Deen Dayal Upadhyay Gorakhpur University Gorakhpur, India Email: kahkashan17@gmail.com ABSTRACT: The Retail Sector of India is very vast, and has capability for development, as the majority of its constitutes are un-organized. The retail sector of India contributes of about 15% to the national GDP, and employs a huge workforce of it, after the agriculture sector. The retail sector of India handles about $250 billion every year, and is expected by veteran economists to reach to $660 billion by the year 2015.The business in the organized retail sector of India is expected to grow at the rate of 15-20% every year, and reach the level of $100 billion by the year 2015.Despite the recent furore, FDI in retail sector will boost the Indian economy, creating job opportunities in the next few years. Driven by an increasing disposable income, purchasing power and now the much awaited FDI, retail has emerged as one of the fastest growing sectors in India. Moving towards modernisation, India's retail sector, currently growing at 30%, and is expected to generate 54,000 jobs over the next five years — a variety of opportunities from the entry level to senior management level, for fresher’s as well as for professionals[8]. From the employment point of view, jobs will be created not only in retail sector area, but also in areas such as front-end sales, facility management, security management, inventory, merchandising, customer relationship and visual merchandising, among others. In smaller towns, knowing the local language will be an asset because it will help one connect with the masses. Keywords: FDI, GDP, Retail Sectors. 1. INTRODUCTION The recent clamour about opening up the retail sector to Foreign Direct Investment (FDI) becomes a very sensitive issue, the most important factor against FDI driven “modern retailing” is that it is labour displacing to the extent that it can only expand by destroying the traditional retail sector. This is because the primary task of government in India is still to provide livelihoods and not create so called efficiencies of scale by creating redundancies [12]. As per present regulations, no FDI is permitted in retail trade in India. Allowing 49% or 26% FDI (which have been the proposed figures till date) will have immediate and direct consequences. Entry of foreign players now will most definitely disrupt the current balance of the economy; will render millions of small retailers jobless by closing the small slit of opportunity available to them. Retailing is not an activity that can boost GDP by itself. It is only an intermediate value-adding process. If there aren’t any goods being manufactured, then there will not be many goods to be retailed. This

underlines the importance of manufacturing in a developing economy[1]. Global retailers have already been sourcing from India; the opening up of the retail sector to the FDI has been a political challenges. With politicians arguing that the global retailers will put thousands of small local players and fledging domestic chains out of business. The only opening in the retail sector so far has been to allow 51% foreign stakes in single brand consumer stores, private labels, high tech items/ items requiring specialized after sales service, medical and diagnostic items and items sourced from Indian small sector (manufactured with technology provided by the foreign collaborations)[2]. Parties supporting the FDI suggest that the FDI in retail sectors should be opened in a gradual manner, such that it can promote competition and contribute to the growth of the Indian economy. The impact of the FDI would benefit the end user of the consumer to a great extent and will help to generate a decent amount of employment as more and more entrepreneurs would be coming forward to invest and taste the new generation

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in retail marketing[3]. The opening of FDI should be designed in such a way that many sectors – including agriculture, food processing, manufacturing, packaging and logistics would gain benefits. FDI in retail sector is an economic reform, which would allow global chains like Wal-Mart Stores Inc and Carrefour to own up to 51 percent of retail ventures. The policy would let foreign retailers own up to 51 percent of supermarkets and 100 percent of single-brand stores[4]. The policy doesn't require parliamentary approval, but foreign retailers must get prior approval from the state governments where stores will be opened or located. The government, as a measure to protect themselves, has said foreign retailers would have to source 30 percent of their goods from small industries. A Citi report says $15-20 billion in FDI could flow into the country over the next 10 years as a result of FDI in multi-brand retail. The report also says the move into retail sector would help enhance the share of organised players in the overall retail sector, which currently account for about 6 % of India's $470billion retail market [5]. Multi-brand retail in India is largely in the unorganised sector is dominated by neighbourhood kirana stores and there is a concern among the political parties and the traders that these stores would be affected by the entry of global retailers. The Indian Retail Sector Can Be Broadly Classified Into:Food Retailers Health and beauty Products Clothing and Footwear Home Furniture & Household goods Durable goods Leisure & Personal Goods Of these above segment Food and beverage and clothing segment is expected to grow exponentially. 2 HOW WILL FDI (Foreign Direct Investment) HELP INDIAN RETAIL SECTORS Future Group and Spencer’s Retail Executives are of the views that FDI in Indian Retail will help Indian Economy. The entry of global retailers in the form of joint venture / partners will help Indian retailers, as foreign retailers will bring with them international experience and best practices[7].

Research paper Vol. 1 [issue 1] February, 2014

Successful retailing involves support from ancillaries that specialise in setting up distribution centres, training of staff, managing supply chain processes et al. The experts felt large investments from foreign retailers will draw specialized global players in the space (ancillary activities) to India. This will help improve overall processes and supply chain network, leading to improved efficiency and better profitability for Indian retail. Large international retailers have superior platform in terms of IT infrastructure and have much deeper understanding of their consumers[17]. This will lead to better operational management in the Indian retail sector, especially when the Indian retail sector is looking for expansion. FMCG companies in India have several stock keeping units (SKUs) in their portfolio; only ~20-25% of this is aggressively marketed or made available to consumers [9]. Thus, Indian retailers had no choice but to come up with their own private labels rather than focus on sales of existing companies. However, with the advent of foreign partner and his strong relationship with global FMCG companies, Indian retailers can get better product line, which can help to drive sales growth and improve sales per sq. ft, which currently stands at almost half that of their global counterparts. 3 FDI IN RETAIL TO TAKE INDIA’S CONSUMERISM TO A NEW GROWTH TRAJECTORY Any process of change is a dialectic process. Change is the only truth which prevails at the end if it brings wellbeing to the masses. We believe sooner or later opposition to the FDI in retail will end and new era will begin[6]. 4 FDI IN RETAIL –THE PRESENT STATUS 51% FDI in multi brand Retail and 100% in single brand is put on hold till the consensus is reached between the political parties. There is stiff opposition being seen within the UPA allies in context of FDI in retail. Also the opposition party is seeing this as an opportunity to get the political mileage[8]. 5 FINE POINTS PROPOSED IN FDI IN RETAIL SECTORS Govt allowed 51 percent FDI in multi brand retail and increased FDI limit in single brand retail from 49 percent to 100 percent. Right now this is put on the back burner due to

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Research paper Vol. 1 [issue 1] February, 2014

opposition from the political parties. Followings are the fine points of the FDI in retail.

Investments and improvement in the supply chains and warehousing.

1) FDI is not likely under the automatic route implying that FIPB approval on case by case basis. 2) Minimum Investment to be done is $100 million. 3) 50% of the investment should be done in improving the back end infrastructure. 4) 30% of all raw materials have to be procured from the small and medium enterprises. 5) Permission to set up retail stores only in cities with a minimum population of 10 lakhs. 6) Govt has the first right to procure or purchase materials from the farmers.

Franchising opportunities entrepreneurs.

Growth of infrastructure.

Increased efficiency.

Cost reduction.

Implementation of Technology in retail.

Stimulate infant industries and other supporting industries [12].

6 GLOBAL RETAILING SCENARIOS Retail Sectors has been playing a major role in improving the productivity of the whole economy at large. The positive impact of organized retailing could be seen in USA, UK, and Mexico and also in China. Retail is the second largest industry in US. It is also one of the largest employment generators sectors [10]. It is also important to understand that Argentina, China, Brazil, Chile, Indonesia, Malaysia, Russia, Singapore and Thailand have allowed 100% FDI in multi brand retail. These countries have been benefited immensely from it. Also small retailers co-exist. The quality of services they are providing has increased. China permitted FDI in retail in 1992 and has seen huge investment flowing into the sector. It has not affected the small or domestic retail chains and on the contrary small retailers have increased since 2004 from 1.9 million to over 2.5 million. We can take the example Indonesia where still 90% of the business still remains in the hand of small traders [11]. 7 OPPORTUNITIES OF FDI IN INDIAN RETAIL 

Inflow of investment and funds retail sectors.

Improvement employment.

in

Generating opportunities.

more

Increased local sourcing.

Provide better consumers.

the

quality

of

for

local

Information

8 CHALLENGES OF FDI IN INDIAN RETAIL 

Would give rise to cut-throat competition rather than promoting incremental business.

Promote cartels monopoly.

Increase in the real estate prices.

Marginalize domestic entrepreneurs.

The financial strength of foreign players would displace the unorganized players.

Absence of proper regulatory provisions and guidelines would induce unfair trade practices like Predatory pricing [12].

and

will

create

Despite the above challenges there are certain other problem relating to foreign direct investment (FDI) in retail in India is that it does not provide a level playing field to other players of the domestic and small sort. In addition, it appears to take a rather naive and simplistic view on certain aspects, which like myths being repeated, tend to become urban legends. On the other hand, no country can afford to take on an isolationist approach. 9 HOW FARMERS TO GET BENEFITED

value

employment

to

the

end

Farmers in India get only 10% to 12% of the price the consumer pays for the agricultural products which they produce. Coming of organized retailing will benefit farmers in big way. Big retailers sell their product at very competitive prices. So, they source it directly from the farmers. Thus Middleman get eliminated or does not have any place or role in this format of retailing. This will not only

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Research paper Vol. 1 [issue 1] February, 2014

benefit the farmers but also help in checking the food inflation. Thus the farmers will get benefited up to a large extent. Also India has very inadequate facilities to store the food grains and vegetables. As the investment will flow into back end infrastructure, supply chain will get strengthened. Storage is a major problem area and 20% to 25% of the agricultural products get wasted due to improper storage[10].

Knowledge about different products through different mediums like Internet, Television etc. Also knowledge about the latest trend and fashion.

47% of the India’s population is under the age of 30. This category is driving the consumption story.

Emergence of new retailing format.

PRODUCT

WASTAGE

Easy availability of Credit Facilities.

TOMATOES

35%

MANGOES

30%

POTATOES

25%

12 FDI COULD BENEFIT STRESSED COMPANIES FDI in multi brand will stimulate investment in the sector. There are companies in the retail sector that are reeling under debt. These companies could get fresh lease of life[14].

Another area which is also the cause of concern is, movement of vegetables and other perishable agricultural items from one place to another. Due to lack of proper transportation facilities farmers sell their produce in local market. This results in the lower realization on the produce.

Company

Debt Crore)

(Rs Market Cap

Pantaloon

4,200

3, 867

Vishal Retail

700

42

Provogue

400

275

10 IMMENSE GROWTH OPPORTUNITY FOR RETAILERS India is Asia’s third largest retail market after China and Japan. Organized retailing has a very virgin space in India. It provides immense growth opportunity. Only 5% of the total sales are being done by organized retailer. Currently Indian Retail sector have sales of around $500 billion. Retail sector is expected to have sales of $900 billion by 2014. It is still far behind China, whose retail sales by 2014 are expected to cross $4500 billion[13].

12.1 Beneficiary of FDI in Multi Brand Retail:-

Purchasing power of the Indian urban consumer is growing and branded merchandise in categories like Apparels, Cosmetics, Shoes, Watches, Beverages, Food and even Jewellery, are slowly becoming lifestyle products that are widely accepted by the urban Indian consumer.

12.1.2 Single Brand Retail: 100% FDI in Single Brand Retail. Archies Cantabil VIP Ind Titan IFB Industries

11 GROWTH DRIVERS OF INDIAN RETAIL SECTOR: 

Rising Income and increase in convergence of consumer taste and preferences.

Dual family Income.

12.1.1 Multi Brand Retail Stores: 51% in Multi brand retail [16]. Pantaloon Retail Vishal Retail Shoppers Stop Koutons Trent

12.1.3 Real Estate: Especially mall developers. Retailers like Wal-Mart; Tesco operates in large area of 50,000 – 60,000 sq.ft. They generally pay to the builders certain percentage of the total revenue. Real Estate companies into retailing space to be benefitted. Unitech DLF Sobha Developers

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Research paper Vol. 1 [issue 1] February, 2014

12.1.4 FMCG Companies: Big retailers generally sources from the producers, FMCG companies are going to be benefited. HUL GSK Godrej Consumer Dabur Marico

[6] Guruswamy, M., K. Sharma, J. P. Mohanty, and T. J. Korah. (2005). FDI in India’s Retail Sector: More Bad than Good? Economic and Political Weekly, 40(7), pp. 619-623

13 SIDE EFFECTS OF THE FDI AND SOLUTION Nevertheless the good thing that FDI in retail is that it will bring growth and opportunities in this sector but argument will not be justified if we do not take into account the grey areas. Some of the grey areas are:

[8] Mukherjee, A., D. Satija, T. M. Goyal, M. K. Mantrala, and S. Zou (2011). Impact of the Retail FDI Policy on Indian Consumers and the Way Forward, ICRIER Policy Series No. 5

[7] Kalhan, A. (2007). Impact of Malls on Small Shops and Hawkers, Economic and Political Weekly, 42 (22), pp. 2063 – 2066.

1-Predatory pricing could strangulate the domestic retailers. 2-It has been seen MNCs retailers uses there big size to kill competitors. 3-In order to bring goods at lowest possible price for customers they squeeze the margins of their suppliers. So as claimed by thousand that suppliers will benefit, it still doubted. In order to correct these grey areas, India need to have strong regulator for the sector. And at the same time strengthen the Competition Commission of India before these Big Retailers prowls into the Indian Territory [15]. 14. CONCLUSIONS We wish row over FDI in retail gets over soon and India should embrace new era of retailing. And Govt makes right kind of body to vigil these giants. Indian consumers are waiting to splurge. Indian consumers’ balance sheet is still clean, which provide much of room to consumption related debt. 15 REFERENCES

[9] Patibandla, M. (2012). Foreign Direct Investment in India’s Retail Sector: Some Issues, Working Paper No. 366, Indian Institute of Management Bangalore. [10] www.slideshare.net/dpdas3/impact-of-fdiin-retail-sector [11]www.indiainsouthafrica.com/InvestinIndia /ppts/4%20FDI%20Policy.ppt [12] Bhattacharyya, R. (2012). The Opportunities and Challenges of FDI in Retail in India, IOSR Journal of Humanities and Social Science, 5(5), pp. 99 – 109 [13] Coe, N. M. and M. Hess (2005). The internationalization of retailing: implications for supply network restructuring in East Asia and Eastern Europe, Journal of Economic Geography, 5, pp. 449 – 473 [14]Department of Industrial Policy and Promotion (2010). Foreign Direct Investment (FDI) in Multi-brand Retail Trading. Discussion Paper. [15]www.iosrjournals.org/ccount/click.php?id =5897 [16]http://karkuvelraj1987.blogspot.in/2013/ 02/fdi-in-multi-brand-retail-challenges.html

[1]www.allbankingsolutions.com/BankingTutor/FDI-in-India.htm [2]www.spaceandculture.in/index.php/spacean dculture article view 7

[17] www.pbr.co.in/Vol-5%20Iss-5/3.pdf

[3]www.legalindia.in/foreign-directinvestment-in-indian-retail-sector [4]www.thehindubusinessline.com/.../fdi-inretail-is-30.../article5225758 [5] Gupta, R. (2012). FDI in Indian Retail Sector: Analysis of Competition in Agri-Food Sector, Internship Project Report, Competition Commission of India. © Virtu and Foi

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Research paper Vol. 1 [issue 1] February, 2014

Shredded Scrap Tires as Drainage Materials in Landfill Cover System *1Ajay Kumar Verma

2Dr. S.M. Ali Jawid

Department of Civil Engineering M.M.M. Engineering College Gorakhpur, India Email: smaj@rediffmail.com

Department of Civil Engineering M.M.M. Engineering College Gorakhpur, India Email: Ajaycrazy100@gmail.com

ABSTRACT: Shredded Scrap tire serve as good drainage material and have durability since tires are made up of such material that are indestructible. Over 280 million use, bikes, truck and automobiles tire discarded each year nationwide. Disposal of whole tires in landfills was the common practice in many countries for many years. However whole tire tend to float to the surface. Breaking the landfill cover and causing increased leachate production which can contaminate groundwater. Because of this many states have banned the disposal of tires in landfills. This paper provides the evaluation of the feasibility of using shredded scrap tires in civil engineering applications. Laboratory test were done to characterize the permeability values for different mix ratio of soils and shredded scrap tires. Using scrap tires structure needs data on engineering properties of tires derived material Key words: Engineering.

Scrap tires; Recycling; Protective covers, Shreds; Land fill; Drainage material, Civil

1. INTRODUCTION A scrap tire is a type of solid waste that includes any unwanted or discarded tire regardless of size that has been removed from its original use. A scrap tire is any tire that has been removed from its original use and includes all whole scrap tires and pieces of scrap tires which are readily identifiable as scrap tires by visual inspection and still contain wire .Over 280 million used automobiles, truck and especially tire discarded each year nationwide disposal of whole tires in landfills was the common practice for many years. The state of Illinois requires tires to be shredded before being placed in landfills. Currently 2,4 billion tires are stockpiled nationwide. Shredded scrap tires have been used in leachate collection system for landfill drainage material solely based on their high hydraulic conductivity.(Ahmed and Lovell, 1991; Duffy, 1996; Hall, 1991; Edil et al.,1992) The purpose of the drainage layer is to allow infiltrated water to drain from the overlying cover soil layer so that it is prevented from seeping into the underlying barrier layer and the waste. The drainage layer minimizes the generation of leachate in the landfill and also prevents build-up of a hydraulic head within the cover. This is critical because a large hydraulic

head may cause the slopes to become unstable. Thus the most important engineering property for the use of shredded scrap tires as the drainage material in landfill cover is the hydraulic conductivity. 2 PROBLEM DUE TO SCRAP DEPOSITION IN NATIONWISE

TIRE

Scrap tire the most problematic source of waste that covering the large volume and their life long durability consequently

  

Scrap tire have good resident for mosquito and other insects that can spreads diseases such as encephalitis, dengue, malaria and west nile virus. These tire provide good breeding groups for rat, snakes, ticks and other vectors. Critical problems occurs presenting fire hazards when stored improperly. When these tires burned illegally creates dangerous oils and shoots into air.

These characteristics which make waste tires such a problem also make them one of the most re-used waste materials as the rubber is very

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resilient and can be reused in other products. Approximately one tire is discarded as per person per year. Tires are also often recycled for use on basketball courts and new shoe products. However material recovered from waste tires also known as crumb which is generally only a cheap filler material and is rarely used in high volumes.

Research paper Vol. 1 [issue 1] February, 2014

3.2 Tire chips characterization The tire chips used in this study were obtained from automobile shop in Gorakhpur. The tires were shredded in the range from (1.5-2.0) inches excluding wire mesh. These chips were randomly mixed with soil sample. Tire chips and

3. EXPERIMENTISATION

tire shreds are non-reactive under normal 3.1 Soil Sampling 

environmental conditions.

The soil used for this experiment is taken from field of village Narhi apart 15 Kilometer from M.M.M. .Engineering College Gorakhpur.-Uttar Pradesh. The soil samples were collected from a depth of about 0.3 to 0.4 m below the ground surface.

The engineering, and grain size distribution curve of the soil is given in Table 1

Fig : 1

Shredded Scrap Tires

3.3 Test procedure

Table 1 Compact the soil into the mould at a given dry density and moisture content by a suitable static or dynamic device for remolded sample. Place the specimen centrally over the bottom porous disc and filter paper. Fill the annular space between the mould and the specimen with an impervious material such as cement slurry or bentonite slurry to provide sealing against leakage from the sides. Place a filter paper, porous stone and washer on top of the soil sample and fix the top collar. Connect the stand pipe to the inlet of the top plate. Fill the stand pipe with water. Connect the reservoir with water to the outlet at the bottom of the mould and allow the water to flow through and ensure complete saturation of the sample. 3.4 Observations and calculations Calculate the coefficient of permeability of soil using the following equations.... KT = 2.303 aL/(At) Log 10 (h1/h2) (variable head method) Where KT = coefficient of permeability at test temperature T O C (cm/sec)

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Research paper Vol. 1 [issue 1] February, 2014

Different percentage at which SST was mixed with soil and its permeability is given in Table 2 and Fig 3 from the table and graph it is clear that permeability decreases when tire aggregate increases to the soil.

a = cross section area of stand pipe (cm2) L = effective length of the soil sample (cm) A = cross sectional area of soil sample (cm2) T = time required for the head to fall from h1 to h2 (sec) h1 = initial head of water in the stand pipe above the water level in the reservoir (cm) h2 = final head of water in the stand pipe above the water level in the reservoir (cm) KT = QL/(Aht) (constant head method) Where KT = coefficient of permeability at test temperature T O C (cm/sec)

Fig. 3 permeability vs. mix% of tire chips

Q = quantity of water collected in time t (cc) L = effective length of the soil sample (cm) A = cross sectional area of soil sample (cm2) h = constant hydraulic head (cm)

5 CONCLUSIONS AND ANALYSIS This paper provides the evaluation the feasibility of using shredded scraps in civil engineering application. Shredded tire used as drainage material in cover system for landfill as the tire aggregate increases to the soil, the permeability of soil tire decreases significantly.

Fig. 2 Permeability Test Apparatus

4. PERMEABILITY PERFORMANCE ASSESMENT

The purpose of this document is to provide Municipal Solid Waste Landfill owners/operators with guidance in the use of tire chips in the design and construction of leach ate collection systems at municipal solid waste landfills. The tire chip size can ranges from 1.5-2 inches can posses’ satisfactory properties for drainage material in landfill covers system However, site specific testing using the actual tire chips size is recommended for different-different soil for particular purpose. I believe that for better result each kind of soil sample require particular size of tire chip size. Therefore , future experiment include narrowing down the scope of result up to 25% increment of tire aggregate to less than 5%tire aggregate in soil. It is the greatest challenges of this century that no country can develop without sustainable development. The use of scrap tire shreds in civil engineering would reduce the magnitude of

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Research paper Vol. 1 [issue 1] February, 2014

the current tire disposal problem by converting a waste into a beneficial material. REFERENCE 1.

Edil, T. B., Fox, P. J., and Ahl, S. W. _1992_. “Hydraulic conductivity and compressibility of waste tire chips.” Proc., 15th Annual Madison Waste Conf., Madison, Wis., 49–61.

2.

McIsaac, R., and Rowe, R. K. _2005_. “Change in leachate chemistry and porosity as leachate permeates through tire shreds and gravel.” Can. Geotech. J., 42_4_, 1173–1188.

3.

Rubber Manufacturers Association _2004_. “U.S. Scrap tire markets.” _http://www.rma.org/scrap_tires_.

4.

Warith, M. A., Evgin, E., and Benson, P. A. S. _2004_. “Suitability of shredded tires for use in landfill leachate collection systems.” Waste Manage., 24, 967–979.

5.

Hall, T. J. _1991_. “Reuse of shredded tire material for leachate collection systems.” Proc., 14th Annual Madison Waste Conf., Madison, Wis., 367–376.

6.

Ahmed, I., and Lovell, C.W., “Tire Chips as Permeable Aggregate in Landfills.” Proc. First Annual Great Lakes Geotechnical / Geoenvironmental Conference, University of Toledo, 1993, pp.83-90.

7.

Duffy, D.P., “The Potential for Use of Shredded Tire Chips as a Leachate Drainage and Collection Medium: Design, Construction and Performance Consideration -n,” Waste Age, Vol.26, No.9, 1995

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Review paper Vol. 1 [issue 1] February, 2014

Comparison of Different Traffic Noise Prediction Models *1Swati Tiwari

2Dr. R.K. Shukla

Department of Civil Engineering M.M.M. Engineering College Gorakhpur, India Email: drshukla_gkp@rediffmail.com

Department of Civil Engineering M.M.M. Engineering College Gorakhpur, India Email: swati.tiwari2012@gmail.com

ABSTRACT: The incessant growth in the number of vehicles and the ever expanding road network, results in the increase of road traffic noise, which has led to the gradual degradation in the quality of the environment. Also, the management of road traffic noise is a challenging task for environmental managers and urban planners. For the assessment of traffic noise, urban planners often have to rely on road traffic noise prediction models. A review of various traffic noise studies and the number of traffic noise prediction models cited in literature reveals that they describe the temporal and spatial distribution of traffic noise. Most of these models are either deterministic or statistical in nature. This paper presents a critical review of some of these models. Keywords: ASJ model and GIS model, CoRTN model, FHWA model, FHWA TNM model, RLS90, Stop-andgo model. 1 INTRODUCTION Road traffic noise has become a major concern of communities living in the vicinity of major highway corridors. It is causing more disturbances to people than any other sources. Moreover, this menace to health and quality of life has been increasing over the last two decades for number of reasons [1]. The most important cause is of the number of road vehicles, and consequently, increases in the density of road Traffic. The construction of multi-lane motorways is going on at increasing rates in most developed countries and even in many developing nations during last few decades, allowing large volume of traffic to travel at a sustained speed. The next most important cause of noise on the roads is the speed of traffic. As a general rule, faster the traffic moves, greater is the volume of noise [2]. Surveys conducted in many countries have shown that traffic noise is one of the principal environmental nuisances in urban areas, and most of the countries have their own traffic noise prediction model according to the traffic and environmental conditions.

Traffic noise prediction models are required as aids in the design of highways and other roads and sometimes in the assessment of existing or envisaged changes in traffic noise conditions. They are commonly needed to assess noise levels set by government authorities. Environmental laws require the Environmental Impact Statement (EIS) to take into account the effect of the proposed noise on all existing and potential elements of the environment, besides statutory criteria. This calls for a variety of descriptors and criteria. Special descriptors are sometimes required for the assessment of complaints about road traffic noise [3]. Traffic noise prediction models are required for use by five main groups, viz., • Roadway engineers, who check designs for compliance with statutory noise constraints and determine any need for screens or additional spacing between road and buildings. • Acoustical engineers for fi ne work such as architectural and more general applications. • Expert witnesses in civil or criminal courts or other officials enquiries, whose opinion is usually required in addition to an assessment of any statutory requirements.

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• Acoustic specialists, who prepare the acoustic section of EISs. • Acoustic consultants engaged by clients perhaps adversely affected by road Traffic noise. Such cases preliminarily require remedies and recommendations. Models may be used to ascertain whether measured noise is consistent with appropriate design or, in a few cases, statutory conditions. As per reviewed literature, it is observed that various traffic noise studies were reported and a number of traffic noise prediction models have been developed. To the best knowledge of the authors, the more popular ones include the CoRTN model in UK, the Federal Highway Administration (FHWA) model in USA, the RLS90 model in Germany, the OAL model in Austria, the Statens Planverk 48 model in Scandinavia, the EMPA model in Switzerland, the ASJ model in Japan and the GIS model in China. A critical review of some of these models is discussed in this article. 2 Traffic Noise Prediction models The prediction models considered here represent national responses to the noise pollution concerns, which arose from the great increase in automobile ownership after World War II and also from the current interest in environmental matters generally [3]. The FHWA Traffic Noise Model Version 1.0 is a development of the earlier FHWA Traffic Noise Model. With that exception, the models considered here had parallel independent development, albeit with some theoretical interaction. Most current models assume point sources, although some assume line sources. Rathe [4] found an analytical solution of the problem for incoherent point sources in a line with given spacing and given angle of view. The Japanese model (the ASJ Model, 1993) adopts this form. Steele [5] gave a more general solution. This solution admits of roads of any shape with either line or multiple point sources, but with time and not distance-determined spacing. This allows for acceleration and braking as well as steady flow. Directivity may be accommodated in several models. Recent models incorporate a propagation section, even though there is a current international standard [6] for

Review paper Vol. 1 [issue 1] February, 2014

calculation of outdoor sound attenuations. Although individual in their detail, these propagation equations are generally similar to that of Maekawa [7]. A number of European models incorporate sub models for the prediction of traffic flow itself, whereas American and British models assume that such inputs are to be had from other sources [3]. In developing countries, traffic noise studies are relatively less when compared to the developed nations. Among the developing countries, China is in progress in conducting traffic noise studies. Recently, it has developed its own traffic noise prediction model with GIS applications [2]. India has now slowly started its efforts in developing its own traffic noise prediction model [8]. 2.1 The FHWA model In response to the widely recognized shortcomings of existing highway noise prediction methodologies, Barry and Reagan of the US FHWA developed an in-house model in 1979 [9] by considering those areas that had not been addressed by the National Cooperative High-way Research Program (NCHRP) and Transportation Systems Centre (TSC) models of USA. The model was published in\ the report FHWA-RD-77-108 which included a programmable calculator program. This program was further developed separately under the title STAMINA in several successive versions. The FHWA model calculates noise level through a series of adjustments to a reference sound level. The reference sound level is the energy mean emission level which is determined through field measurements of individual vehicle. Adjustment are then made to this level to account for traffic flow, distance of receivers from the roadways, finite length roadways, ground cover, and shielding effects. The model assumes point source traveling at constant speed. The authors compared predicted A-weighted sound pressure levels with data collected in a program known as the Four State Noise Inventory [10]. The accuracy of the method was found to depend on the distance of the receiver from the source, and also on vehicle composition. In comparing some Florida traffic with the national noise emission levels [10], the mean errors were found to be –0.05, – 0.95, and –1.3 dB (A) at horizontal distances of

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15, 30, and 60 m, respectively. The corresponding standard deviations were 1.64, 1.82, and 2.39 dB (A). However, comparison made with noise emission levels of Florida only gave mean errors of +0.58, –2.3, and 0.57 dB (A) with slightly smaller standard deviations. They gave some examples of insertion loss calculations for a barrier. In one case, the predicted loss was 7.2 dB (A), whereas the measured was 10 dB (A). The STAMINA program allows a convenient adjustment to the reference emission levels. Junf et al. [11] reported an adaptation for Ontario with fair success, and those about 4% of trucks were excessively noisy and caused an upward increase of 0.5–1.0 dB (A) in the reference level. The authors thought this comparable with observations made elsewhere. This procedure is strictly applicable to straight roads and vehicles of constant speed, but methods are incorporated for the use of segments to simulate curved roads and multiple lanes. Three major assumptions were made in this model, viz., 1. The vehicles are adequately represented by acoustic point sources. 2. Emissions levels within groups (automobile, medium, and heavy trucks) are normally distributed (although they are skewed to the high side). 3. Propagation losses are adequately represented by distance effects. In the original FHWA-RD-77-108 format, standardized reference energy mean emission levels (REMEL) for three classes – automobile, medium trucks (MT), and heavy trucks (HT) – were employed. They are expressed as sound pressure levels at 15 m from the sources as functions of the speed of the vehicle. In addition to the mean levels, account was taken of the statistical distribution at each speed for each class. All of these adjustments are related by the following equation.

where Leq(h)i is the hourly equivalent sound pressure level for ith class of vehicle, L0 is the hourly mean sound pressure level at the

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reference distance, Ni is the vehicles volume for ith class of vehicle in passenger car unit per hour, Si is the mean speed of ith class of vehicle in km per hour, D is the perpendicular distance from the center line of the traffic lane to the receiver, Do is the reference distance from the center line of road to the observer, T is the time period over which Leq is computed (1 h), α is a site parameter (0 < α < 1), ø1 and ø2 are the angles from the perpendicular of the limits of the observer’s view of a section of the road way, and Δs is the excess attenuation due to barriers, buildings, wood, etc. Attenuation due to shielding is an important mechanism by which road traffic noise levels are lowered. Shielding can be provided by different types of noise barriers such as berms, walls, large buildings, etc. Barriers affect sound propagation by interrupting the sound waves and creating an acoustic shadow zone. The FHWA model expresses the attenuation by noise barriers as a function of the Fresnel number, the barrier shape, and the barrier length. The acoustic phenomenon governing barrier attenuation is known as Fresnel diffraction which analytically defines the amount of the acoustic energy loss encountered when sound waves are required to travel over and around a barrier. The proposed equation for calculating noise attenuation due to thin barriers is given by:

where ΔLS is the attenuation for the ith class of vehicle, and øR and øL are the angles measured from the perpendicular to the right and left ends of the barriers, respectively. The total noise due to all types of vehicles can be calculated by:

where LeqT is the total equivalent traffic noise due to all class of vehicles, C is the equivalent noise for car, MT is the equivalent noise for medium trucks, and HT is the equivalent noise for heavy trucks. As mentioned before, the FHWA model computes predicted sound levels

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through a series of adjustments to a reference sound level. These adjustments depend on traffic patterns, topography, and roadway geometry, and are available from different figures and tables. Various procedures have been developed for implementing the FHWA model. These include a manual method, nomographs, handled calculators, and computer programming. A more powerful version of the model evolved in the form of STAMINA 1.0 (FHWA, 1979) program. This program was coordinate-based and could simultaneously consider Leq values for multiple receivers and complex roadway barrier geometry. Enhancements to this program resulted in the latest program for highway noise analysis, STAMINA 2.0. This version of FHWA model is used almost exclusively for highway noise analysis in USA and in many other countries as well. 2.2 The CoRTN model This model was published by the Department of the Environment and Welsh Office in UK in 1975 by Delany et al. [13]. It is used as an aid to road design, and also for the determination of entitlements to the sound insulation of private dwellings at public expense under the British Land Compensation Act. This latter influenced the choice of L10 as the index of noise. CoRTN is distinguished by its extensive use of curve fitting between empirical data, even when this was known not to conform to theory. This model assumes a line source and constant speed traffic, and in Britain, it is the sole instrument for the assessment of road traffic environmental impacts by road authorities. Calculation of Road Traffic Noise [14] (CoRTN) was replaced by a more convenient Predicting Road Traffic Noise [15] which followed Delany et al. [13] rationale for the procedure. These authors reported that for the range 50–54.9 dB (A), the mean difference between their predicted and measured levels was +1.4 dB (A). On the other hand, between 80 and 84.9 dB (A), the mean error was –1.2 dB (A). That is, CoRTN underestimated high levels and overestimated low levels. Samuels & Saunders [16] observed significant differences in the model with Australian vehicles, depending upon the

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prevailing conditions. The mean overestimation was 0.7 dB (A) for free field conditions and 1.7 dB (A), in front of facades with corresponding standard deviations 1.8 and 2.5 dB (A). Some users came to depend on CoRTN for applications for which it was not strictly valid, for which Steele [5] found even greater under or overestimates by as much as +12.5 dB (A) in one case. Computer programs based on CoRTN were written for various authorities, for example, in Weatherall [17]. This model has applicability to long line of free flowing rush hour traffic or train at a distance from the observer. It is less suitable for situations where the distance is not great in relation to the inter-vehicular spacing, or when the spacing is very even or uneven. First, the basic noise level at a reference distance of 10 m away from the nearside carriageway edge is obtained from the traffic flow, the speed of traffic, the composition of the traffic, the gradient of the road, and the road surface. The noise emission level equation for L10 is given as: L10 = L0 + AHV + AD + AG + AGC + Aa + AB, (6) Where L0 is the basic noise emission level and, L0 = 42.2 + 10 log10 q. (7) AHV is the adjustment for mean traffic speed and percentage of heavy vehicles: AHV = 33 log10 (V + 40 + 500/V) + 10 log10 (1 + 5P/V) – 68.8, (8) Where V is the traffic speed that depends upon the road classification as specified by CoRTN model, and P is the percentage of heavy vehicles. P = 100 f/q. Where f is the hourly flow of heavy vehicles, q is the hourly flow of all vehicles, and AD is the distance adjustment. AD = –10 log10 (d*/13.5), (9) Where d* is the shortest slant distance from the effective source position, in m. d* = [(d + 3.5)2 + h2]1/2, (10) Where d is the shortest horizontal distance from the edge of the nearside carriageway to the reception point, h is the height of reception point relative to the source line at the point where the slant line intersects the source line at the effective source position, S. AG is the adjustment for gradient G: AG = [0.73 + (2.3 – 1.15P/100) P/100] × G, (11) Where G is the gradient of roadway. AGC is the adjustment for ground cover:

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AGC = 5.2 I log10 (6H – 1.5/d + 3.5) for 0.75 ≤ H < (d + 5)/6, (12) AGC = 0 for H ≥ (d + 5)/6, (13) AGC = 5.2 I log10 (3/d + 3.5) for H < 0.75, (14) Where H is the mean height of propagation, I is the proportion of absorbing ground between the edge of the nearside carriageway and the segment boundaries leading to the reception point R. Aa is the correction for angle of view: Aa = 10 log10 (q/180), (15) where q is the angle of view. CoRTN also contains a calculation of the attenuation due to thin barriers. Instead of calculating the attenuations frequency by frequency, an A-weighted attenuation is attempted. No allowance is made for differences between spectra. The potential barrier correction is calculated as a function of path difference (δ). CoRTN model gives a polynomial expression for potential barrier correction as: AB = a0 + a1 X + a2 X2 + a3 X3 + … + an Xn, (16) Where X = log10 S, (17) in which S is the path length difference, in meters, between the direct and diffracted rays, and a0 to an are constants. 2.3 The stop-and-go model This model was developed for central part of Bangkok by Urban Transport Department in 1997 by Pamanikabud and Tharasawatpipat [18]. The research focuses toward formulating an empirical model of interrupted traffic flow in Bangkok using two analytical approaches. The first being the single model analysis, and the second, the separated model or dual model analysis. In this study, several parameters that are considered to have possible influences on the interrupted traffic flow noises were measured at the study sites. Then, these were tested for their correlation with traffic noise levels. The parameters consisted of vehicle volume which is classified into different vehicle types appearing on the Bangkok roadways, average spot speed of vehicles in the traffic stream, road width, distance from curb to building façade, and distance to the nearest intersections. In the analysis of data, these parameters also were separated into nearside and far side roadway parameters. In this study,

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the distances to building facade were applied by two parameters. The first was the distance from observer to nearside building facade, and second, the distance from observer to far side building facade. Geometric mean of the roadway cross-section was introduced as one of the parameters in the analysis of the stop-and-go traffic noise model. Tests were conducted to determine the correlation of various parameters with the traffic noise level in Leq as well as the co-linearity among these parameters if they existed. The sets of parameters which correlated highly with Leq were used further as input in multiple regression analysis. Stepwise analysis technique was adopted in the multiple regression analysis processes of the study. Individual noise characteristics at an overall mean vehicle speed was used to identify the proportional weighting scale of the noise levels generated per unit of each vehicle type in relation to an automobile unit. The overall spot speed range obtained from the field survey data of this research together with the value for overall mean vehicle speed (of 33 km/h) were superimposed onto the vehicle noise characteristics. As there are many vehicle types that are in use in Bangkok, these were classified into seven groups based on the similarities in their noise level characteristics within the speed range that was observed in this study. From this analysis, the proportional weighting scale of the noise levels generated by each vehicle class was calculated. With this information, the traffic of traffic used in the model then could be described in terms of the noise generating ratio of each vehicle type in comparison with automobiles in Bangkok’s urban traffic. The equation for traffic volume can be given as follows:

Where AU stands for automobile; HT, heavy truck; LT, light truck; MC, motorcycles; MT, medium truck; BU, bus, and TT for tuk-tuk. In order to validate the model, another set of data was collected from 10 new locations in the central part of Bangkok. The results indicated that the mean differences between measured and predicted values of 0.09192 dB (A) and

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0.02219 dB (A) occur in the goodness-of-fi t test with 127 data sets for acceleration and deceleration lanes, respectively. 2.3.1 The single model analysis This approach was applied first to build a single stop-and-go traffic flow model. This can be applied to both sides of an urban roadway. The model developed in this study is given as: Leq = 71.05 + 0.10 Sn + 0.95 log Vn + 0.04 Sf + 0.015 log Vf – 0.111 Dg, Where Leq is the equivalent traffic noise level in one hour in dB (A), Sn and Sf are the mean speed of traffic on nearside and far side of observer in km/h, and Vn and Vf are the volume of traffic for nearside and far side of traffic in vehicles per hour. Dg is the geometric mean of roadside section:

where Dn and Df are the distance from the observer to center line of nearside and far side road way, in m. 2.3.2 The separate lane model analysis This approach acknowledges the difference in traffic noise characteristics between acceleration lane and deceleration lane of both sides of the urban road when vehicles leave and intersect on a green traffic light and come to stop on red traffic light. The acceleration lane model was built using data generated from the noise level meter placed on the sidewalk near the acceleration lane on the roadway when the traffic leaves the intersection. These models for accelerated and decelerated situations are as follows. Acceleration lane interrupted traffic noise model: Leq = 56.91 + 0.09 Sn(a) + 5.22 log Vn(a) + 0.04 Sf(a) + 0.02 log Vf (a) – 0.061 Dg (a). Deceleration lane interrupted traffic noise model: Leq = 71.12 + 0.07 Sn (b) + 0.42 log Vn (b) + 0.08 Sf (b) + 0.44 log Vf (b) – 0.061 Dg(b). 2.4 The ERTC model This model was developed by the Environmental Research and Training Centre (ERTC) of Thailand for environmental impact

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assessment [19]. In this model, vehicles were classified into two groups and the average stationary noise level of each group was then determined by measurement of many vehicles. The power level of each group was determined by measuring the noise level of running vehicles. The equivalent sound level ‘Leq’ observed at a certain receiving point is given by, Leq = PWL – 10 log 2ld + Ld + Lg, Where PWL is A-weighted energy average power level of vehicle, dB (A), l is the distance from a traffic line to receiving point, m, Ld and Lg are the correction value for distance and diffraction attenuation, dB (A), and d is the average distance between front of vehicles, m. d = 1000 × V/Q Where V is the average speed of vehicles, km/h and Q is the traffic volume, Vehicles/h. The energy power level of vehicles is given by: For large vehicle group: PWL= 75.1 + 20.4 log V. For small vehicle group: PWL = 67.8 + 20.4 log V. The average noise level of large group of vehicles is about 7.3 dB (A) higher than that of small group of vehicles and the average power level for a number of vehicles of mixed type is given as follows: PWL = 67.8 + 20.4 log V + 10 log [(1–a) + 5.37 a] – 10 log 2ld + Ld + Lg, Where a is the ratio of the large number of vehicles to the total number vehicles. The study concluded that the accuracy of the model is sufficient for practical use and will be used for environmental impact assessment in Thailand. It has been shown that the model can be used for 2, 4, 6, 8, and 10 lane highways in cases where speed is between 30 and 140 km/h. The accuracy of the model has been shown to be within ±3 dB (A) range about 92.3% of the time and that it can predict the road traffic noise level at a distance of 1–80 m, and at a height of 1–12 m from the ground. 2.5 The RLS 90 model Richtlinien fur den Larmschutz an Stra en (RLS90) (Guidelines for Noise Protection on Streets) is an anonymous legal standard for noise prediction in Germany [3]. The current 1990 issue replaced the original 1981 issue. It incorporates traffic flow design data where the

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actual flow is not known. The assessed sound pressure level for a street is given by: LT = Lm + K, Where Lm is the mean A-weighted level, and K is the addition for increased effect of traffic light controlled intersections and other intersections. The mean A-weighted level is given by: Lm = 10 log [100.1Lm.n + 100.1Lm.f], Where n and f represent the nearer and further lanes, respectively. For long, straight traffic streams: The mean noise level for each lane is calculated from, Lm = Lm.E + Ds_ + DBM + DB, Where Lm.E is the emission level, Ds_ is the attenuation due to distance and air absorption, DBM is the attenuation due to ground and atmospheric effects, and DB is the attenuation due to the topography and building dimensions. The emission level is calculated by, Lm.E = Lm+ Dv + DStrO + DStg + DE, (25) Where Lm is the A-weighted mean level, Dv is a correction for speed limits, DStrO is a correction for road surfaces, DStg is a correction for rises and falls, and DE is a correction for the absorption characteristics of building surfaces. Lm = 37.3 + 10 log [M (1 + 0.082 p)], Where M is the standardized traffic flow according to whether the road is a Federal, State, District, or Municipal connecting roads, and p is the percentage of heavy vehicles. The value of each parameter that depends upon whether day (6.00–22.0 h) or night (22.0–6.00 h) is under consideration.

Where vPkw is the speed limit in the range of 30–130 km/h for light vehicles, vLkw is the speed limit in the range of 30–80 km/h for heavy vehicles; LPkw and LLkw are the corresponding mean noise levels, Lm, and DStrO is the correction for road surface given in a table and depends upon the kind of surface and vehicle speed. It ranges from 0 to 6 dB (A). DStg = 0.6 [G] – 3 for [G] > 5%,

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DStg = 0 for [G] 5%. RLS 90 is unique, among the programs considered here, in having an algorithm for parking lots. The calculations are similar to those for roads. The sound emission level is calculated from, L*m.E = 37 + 10 log (N, n) + DP Where N is the number of vehicle movements per hour by parking spot, N is the number of such parking spots, and DP is a correction for the type of car park. Attenuation is calculated with usual ray tracing methods. Barriers, elevated and depressed roads are treated in usual way for incoherent line sources. 2.6 The ASJ model In 1975, the Acoustical Society of Japan published a method of predicting a pseudo-L50 resulting from freely flowing road traffic. It was reported by Koyasu in 1978 [20] and up-dated by Takagi & Yamamoto in 1993 [21]. The updated version contains a direct method of calculating Leq. This is termed as A-method. The ASJ model also includes an empirical method called the B-method which is valid only far from the line source. The sound power levels for traffic stream can be calculated by: For two classes of vehicle: LW = 65.1 + 20 log V + 10 log (a1 + 4.4 a2), Where a1 and a2 are the proportions of light and heavy vehicles. For three classes of vehicles: LW = 64.7 + 20 log V + 10 log (b1 + 1.5 b2 + b3), Where b1, b2, and b3 are constants corresponding to light, medium, and heavy vehicles. The ASJ method admits of a precise, A-method and an empirical B-method. A-method: This method calculates the octave band spectra. These are derived from the band center frequencies from 63 to 4,000 Hz according to the equation: L(f) = –10 log {1 + (f/2,000)} ± 2.5 log (f/1,000). B-method:

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Where, Ui is the ith subinterval of U(f), the range of the propagation function at the receiver, N is the traffic volume, and T is the time equal to 3,600 s. Δt = Δd/v, Where Δd is the spacing between the vehicles. The basic propagation equation is based on Rayleigh [22], but modified to incorporate the A-weighting.

Where LWi is A-weighted and ø is the velocity potential. The pseudo L50 may be found from: L50 = Leq + ad/1 + b, Where d is the vehicle spacing and l is the distance from the road center to the receiver, a and b are constants depending on the relative elevation of the road. 2.7 The GIS model of China This GIS based road traffic noise prediction model has been developed for China in 2002 [2]. The model is developed based on local environmental conditions, vehicle types and traffic conditions in China. An integrated noiseGIS system was developed to provide general functions for noise modeling and an additional tool for noise barrier design, where a new interaction mode in ‘WHAT IF Question/Explanation’ format was used. Application of this system offered improvements in the efficiency and accuracy of traffic noise assessment and noise barrier design. In this study, vehicles have been classified into three types, namely, light cars (LC), medium trucks (MT), and heavy trucks (HT). A composite relationship was developed based on factor of acoustic equivalence between different vehicle classes. The final form of the traffic noise prediction model of the study is given by:

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Where Leq is the equivalent noise level, dB (A), VE is the equivalent speed of traffic flow, km/h, QE is the equivalent traffic flow, Veh/h, Do is the measurement distance for the reference noise emission level = 7.5 m, D is the equivalent distance from road segment to the reception point, m, a is the site parameter whose value depends on site conditions, P is the percentage of soft ground cover within the segment, Δø is the angle subtended by road segment relative to the receiver, degree, and ΔLs is the shielding adjustment for noise barrier, dB (A). The model evaluation results indicated that noise prediction is more accurate at locations closer to the road carriageway where the environment of sound propagation is less complex. The model has an accuracy of 0.8 dB (A) for traffic noise prediction at locations nearer to the road, and was accurate to 2.1 dB (A) for locations within housing estate. Further, there were no errors in the prediction results observed in either set of conditions. The accuracy in predictive results of the adjusted model for China is comparable to those of the FHWA model whose predictive accuracy is 2.0 dB (A). 3 COMPARISON OF MODELS AND THE IDEAL MODEL In order to know the differences among the above models, comparison is made with respect to some salient attributes. Table 1 shows the comparison of models. There is a practical need for a model like the ideal one shown in the last column in meeting a range of needs. Capability is especially wanted for interrupted and complex flow, for predicting the effects of various traffic light cycles, traffic routings, pedestrian crossing locations, and other controls. The ideal model in

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comparison of models (Table 1) incorporates these attributes. Table 1.Comparison of different traffic noise models Particulars

FHWA STAMINA

FHWA TNM version 1.0

CoRTN

Stop-and-go model

RLS 90

Government users USA, Canada, Japan, Mexico

USA, Canada

UK, Australia, Hong Kong, New Zealand

Bangkok

Germany

Applications

Highway (Leq), not architectural Grid Road networks

Highway (Leq), not architectural Grid, excellent source base Road networks

Highways (quasi L10) Point Single traffic streams only

Urban road network where interrupted traffic flows (Leq)

Predicts traffic volumes?

No

No

No

No

Highways and car parks (Leq), not architectural Point Good propagation Simple streams only Yes

Traffic conditions

Constant speed, grades

Constant speed, acceleration, grades, and interruption

Constant speed, grades

Constant speed

Input data

Traffic speed, flow, road and environmental data Local characteristics

Traffic type, flow, speed, whether interrupted, road and environmental data Local characteristics

Heavy/light ratio, flow, speed, road and environmental data

Type

Hybrid, consistent/ inconsistent

Mathematical/hybrid Hybrid inconsistent

Mathematical

Hybrid consistent

Noise descriptor

Leq/quasi-L10

Leq

Quasi-L10 (18 h)

Leq

Leq

Type of mapping

Point → grid

Multiple dual Point → grid

Line → point

Line → point

Line → point

Source

Simple stream

Simple stream

Simple stream

Simple stream

Simple stream

Propagation

Energy by type

Energy by type

Energy by type

Energy by type

Energy by type

Vehicle types

Automobile/medium Optional spectra for trucks/heavy trucks automobile/medium trucks/heavy trucks/buses motor cycles

Light vehicles/heavy vehicles

Automobile, heavy truck, light truck, motorcycles, medium truck, bus and tuk-tuk

Light vehicles/heavy vehicles/car parks

Validation

Contingent; 0.58–1.3 Not readily available dB(A) @ 15–60 m

+1.4 @ 50–54.9 dB(A) (Delany): –1.2 @ 80–84.9 dB(A) +1.7 @ facades (saunders)

0.1165 dB(A) within central part of Bangkok

Not readily available

Constant speed, grades, quasiintersections, interruptions Traffic type, Traffic type, interrupted flow, flow, park or speed, and road road data, and geometry environmental data

4 RECENT DEVELOPMENTS The FHWA TNM model is an example of the trends toward more accurate physics in models and toward more realistic representations of the actual traffic flows. Another approach, by Cammarata et al. [23], was to use a neural network scheme as a substitute for the linear regression in earlier models. He compared his results with Burgess [24], Josse [25], and Bertoni et al. [26], and found significant improvements for the neural network. In 1982, Samuels [27] developed an air pumping theory of tyre/road noise. His model comprised of four simple sources at both front and back of every tyre (32 sources) for an automobile. 5 CONCLUSIONS Based on the critical review of the models, it can be concluded that within the range of validity, the models reviewed here meet the requirements of government regulations and

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many designers. Some models allow for other road vehicles as well as automobiles and trucks, and one includes car parks. All the models discussed here have acoustic energy descriptions usually explicit as Leq or in two cases as a pseudo-L10. The Leq models admit of easy corrections for interrupted flow, multiple streams, and multiple roads. The eight models reviewed here are designed to meet the requirements of roadway engineers. However, they do not meet the requirements of other users of traffic noise models. The ideal model is proposed to supply all the deficiency. Therefore, there is a need to develop an ideal model which satisfies all the constraints. REFERENCES [1] Nirjar, R.S., Jain, S.S., Parida, M. & Katiyar, V.S., Study of transport related noise pollution in Delhi. J. Institution of Engineers (India), Environmental Engineering Division, 84, pp. 6– 15, 2003. [2] Bengang, Li., Shu-Tao & Dawson, W., A GIS based road traffic noise prediction model. Applied Acoustics, 63(6), pp .679–691, 2002. [3] Campbell, S., A critical review of some traffic noise prediction models. Journal of Applied Acoustics, 62, pp. 271 -287, 2001. [4] Rathe, E.J., Note on two common problems of sound propagation. Journal of Sound and Vibration, 10, pp. 472-479, 1969. [5] Steele, C.M., Report to the New South Wales Department of Public Works, CM. Steels & Associates, 1985. [6] Anon., Acoustics – Attenuation of Sound during Propagation Outdoors. Part 2: General Method of Calculation, ISO 9613-2, 1996. [7] Maekawa, Z. Noise reduction by screens. Applied Acoustics, 1, pp. 57–73, 1968. [8] Jain, S.S., Parida, M. & Bhattacharya, C.C., Development of comprehensive highway noise model for Indian conditions. J. Indian Road Congress, 62(3), pp. 453–488, 2000.

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[9] Barry, T.M. & Reagan, J.A., FHWA Highway Traffic Noise Prediction Model, Report No. FHWA-RD-77-108, US DOT, FHWA, Offi ce of Research, Offi ce of Environmental Policy: Washington DC, USA. [10] Anon., Highway Noise Measurements for Verifi cation of Prediction Models (DOT-TSCOST78-2/DOT-TSC-FHWA-78-1), Federal Highway Administration: Washington, 1978. [11] Junf, F.W., Blaney, C.T. & Kazakov, A.L., Noise Emission Levels for Vehicles in Ontario, Transportation Research Record 105, 1996. [12] Anderson, G.S., Menge, C.W., Rossano, C.F., Armstrong, R.E., Ronning, S.A., Flemming, G.G. & Lee, C.S.Y., FHWA traffic noise model, version 1.0: introduction to its capacities and screen components. The Wall Journal, 22, pp. 14–17, 1996. [13] Delany, M.E., Harland, D.G., Hood, R.A. & Scholes, W.E., The prediction of noise levels L10 due to road traffic. Journal of Sound and Vibration, 48(3), pp. 305–325, 1976. [14] Anon., Calculation of Road Traffic Noise, United Kingdom Department of the Environment and Welsh Offi ce Joint Publication/HMSO: London, 1975. [15] Anon., Predicting Road Traffic Noise, United Kingdom Department of the Enivornment/HMSO: London. [16] Samuels, S.E. & Saunders, R.E., The Australian performance of the UK DoE traffic noise prediction method. Australian Road Research Board Conference, 1982. [17] Weatherall, F., A Program for a programmable calculator for estimation of traffic noise by UK CoRTN procedure. Australian Acoustical Society 1985 Conference, 1985. [18] Pamanikabud, P. & Tharasawatpipat, C., Modeling of urban area stop-and-go model. Journal of Transportation Engineering, 125(2), 1999. [19] Suksaard, T. & Sukasem, P., Road traffic noise prediction model in Thailand. Applied Acoustics, 58(2), pp. 123–130, 1999.

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[20] Koyasu, M., Method of Prediction and Control of Road Traffic Noise in Japan, Internoise 78: San Francisco, 1978. [21] Takagi, K. & Yamamota, K. Calculation Methods for Road Traffic Noise Propagation Proposed by ASJ, Inter-noise: Yokohama, 1994. [22] Rayleigh Baron (John William Strutt), The Theory of Sound, Dover Publications: New York, 1945 (work originally published in 1896). [23] Cammarata, G., Cavalieri, S. & Fichera, A., A neural network architecture for noise prediction. Neural Networks, 8(6), 1995. [24] Burgess, M.A., Noise prediction for urban traffic conditions – related to measurements in the Sydney Metropolitan Area. Applied Acoustics, 10, pp. 1–7, 1977. [25] Josse, R., Notions d’acoustique, ed. Eyrolles, Paris, France [26] Bertoni, D., Franchini, A. & Magnoni, M., Centre Scientifi que et Technique des Batiments,1987. [27] Samuels, S.E., The generation of tyre/road noise. Australian Road Research Board ResearchReport ARR 12, 1982., 1972.

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Research paper Vol. 1 [issue 1] February, 2014

Behavior of Reinforced Concrete Skew Slab under Different Loading Conditions *Kanhaiya Lal Pandey

Dept. of Civil Engineering MMM. Engineering College Gorakhpur, India Email: pandeystr@gmail.com ABSTRACT- Behavior of reinforced concrete skew slab under different loading condition is reported in this paper a total of three slabs were tested in structure and concrete laboratory of Madan Mohan Malviya Engineering College Gorakhpur, Uttar Pradesh, India. All the test slabs were full scale model of prototype skew slab having opposite edges simply supported. For all the slabs same steel arrangement was used, Main steel was parallel to free edge and distribution steel was parallel to support line. Aspect ratios 0.625 were selected for study. Centrally and +300 and -300 eccentrically located four point load test with reference to IRC Class B loading were studied, and uniformly distributed load test also carried out. For study skew angle 30° is selected for slab. The experimental observation were limited to observation of vertical displacement at various nodal point, and crack pattern and observing the cracking and ultimate loads Keywords: Skew, Reinforced Concrete, Slabs, Four point loads, Uniformly Distributed load. Ultimate load. Crack pattern INTRODUCTION Skew slab can be defined as a four-sided slab having equal opposite angles other than 90°. Skew angle α is usually measured clockwise from the vertical line perpendicular to the support line of the skew slab. Aspect ratio (r) is defined as the ratio of span to width of the supports. Due to skewness of the structure, the stress and deflection characteristics are quite different from those observed in right bridge deck slabs. Laboratory test facility prescribe that a full scale model be selected which was also found be adequate from dimensional analysis of the model with respect to the prototype The constitutive relation of the model materials was geometrically similar to the one of the prototype, which is important for taking into account the material similitude. For the purpose of geometric similitude between the prototype and the model, all the linear dimensions of the model were scaled from the corresponding dimensions of the prototype by a constant ratio. The four point load was applied on the model through a 20mm thick steel plate to spread the load over an area of 11250mm2 (75×150) at four points with reference to IRC Class B loading. This was done to approximate the tyre effect of the vehicles wheel on prototype with reference to IRC Class B loading. Reinforced concrete skew slabs are widely used in bridge construction when the roads cross the streams and canals at angles other than 90 degrees. They are also used in floor system of reinforced concrete building as well as load

bearing brick buildings where the floors and roofs are skewed for architectural reasons or space limitations. [1] Due to increasing population in India, the demand for more roads and highways are increasing and more of them would require more intersections of roads and highways. To maintain steady flow of traffic in these intersections it will be necessary that they be designed with grade separation, which indicates that more skew slab and deck bridges will be constructed in future. This investigation is an attempt to study the physical behavior of skew slabs more closely and characterize the response observed.

Figure 1; Skew Slab with Four Point Loading Arrangement

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Research paper Vol. 1 [issue 1] February, 2014

2. REVIEW OF PREVIOUS WORK In 1965 a paper is published by A. COULL, Dept. of Civil Engineering the University of Southampton, England. In this paper a method is presented for the direct stress analysis of orthotropic skew bridge slabs. The method of analysis employs the Principle of Least Work, in conjunction with the assumption that the stress resultants may be expressed as Fourier series in the chord wise coordinate, the coefficients being functions of the span wise position only. A system of oblique co-ordinates is used to simplify the analysis. A paper published By Baidar Bakht In 1988 in ASCE he analyzed a skew bridge of less than 20° skew angle. By the method of bridge analysis that are developed basically for right bridges. He give the procedure for obtaining longitudinal moments with good accuracy in skew slab-ongirder bridges. He obtained that the errors in analyzing skew slab-on-girder bridges as right are not characterized by the angle of skew but by two dimensionless parameters, which depend upon the angle of skew, the spacing and span of girders, and their flexural rigidities relative to the flexural rigidity of the deck slab. He proposed that bridges having (S tan α/L,) less than 0.05 can be analyzed as equivalent right bridges, where S, L, and α are the girder spacing, bridge span, and angle of skew, respectively.[2] In 1990 a paper is presented by Mohammad A. Khaleel and Rafik Y. Itani, Member, ASCE In This paper they presents a method for determining moments in continuous normal and skew slab-and-girder bridges due to live loads. Using the finite element method, 112 continuous bridges are analyzed, each having five pretensions I- girders. The spans vary between 24.4 and 36.6 m (80 and 120 ft.), and are spaced between 1.8 and 2.7 m (6 and 9 ft.) on center. The angle of skew α varies between 0 and 60°. A convergence study is also performed on a control bridge to ensure reliable results. Design parameters are identified and their influence on the load distributions studied. For a skew angle of 60°, maximum moment in the interior girder is approximately 71% of that in a normal bridge; and reduction in maximum bending moment is 20% in the exterior girders, which control the design for a bridge with long span, small girder spacing, and small relative stiffness of girders to slab. It is concluded that the AASHTO distribution of wheel loads for exterior girders in normal bridges underestimates the bending moments by as much as 28%. In august 2001 a paper is presented by A Kabir, S M Nizamud-Doulah, and M Kamruzzaman at 27th Conference on OUR WORLD IN CONCRETE & STRUCTURES Singapore. In this paper he presents empirical formulae for the determination of deflections and design moments in reinforced concrete skew slabs. The formulae are derived from numerical results of finite element analysis based on layered Mindlin plate element formulations. An eight-node isoperimetric Mindlin plate

element that accounts for transverse shear deformations is used to develop the numerical model. The layered technique is adopted to allow for the progressive development of cracks through the thickness at different sampling points. The non-linear effects due to cracking and crushing of concrete and yielding of steel reinforcement are included in the numerical model. However, the empirical relations are derived on the basis of numerical results up to about 50% of the ultimate loads. This means that the proposed formulae represent the serviceability limit state values during which the overall response is somewhat linear except for the non-linearity effects due to the cracking of concrete. A Kabir, S M Nizamud-Doulah, and M Kamruzzaman presented a paper at 27th Conference on OUR WORLD IN CONCRETE & STRUCTURES Singapore. In this paper both experimental and numerical study has been carried out to investigate the effects of reinforcement arrangements on the ultimate behavior of skew slabs. A total of four skew slabs were experimentally tested in the laboratory. All the slabs were identical in dimension except the reinforcement arrangements. Three types of reinforcement style were used. The reinforcing bars for three slabs were hooked at the ends except in the case of the fourth slab. The main bars for this slab ending at the free edges were welded to an extra bar provided and laid parallel to the two free edges of the slab. The load displacement behavior of these slabs were carefully studied both numerically and experimentally to determine effective reinforcement scheme for skew slabs. Finite element layered Mindlin plate formulation was used to study the numerical response of these slabs. In august 2002 a paper is published by S M NizamudDoulah, A Kabir, Md Kamruzzaman at 27th Conference on OUR WORLD IN CONCRETE & STRUCTURES Singapore on “Behavior of RC skew slabs - finite element model and validation”. And in this paper Numerical material models incorporated in finite element method for the nonlinear analysis of reinforced concrete slabs are briefly described. The model is based on a layered Mindlin plate formulation in which the crosssection is divided into steel and concrete layers with nonlinear properties. Mindlin plate element is used to account for transverse shear deformations. Concrete and steel layers are simulated with eight-node quadrilateral plane stress element. The non-linear effects due to cracking and crushing of concrete and yielding of steel reinforcement are included Experiments on reinforced concrete skew slabs are carried out for validation of the numerical models. Comparison with experimental results indicates good performance of the numerical model. In December 2005 Md. Khasro Miah and Ahsanul Kabir from BUET present a paper in journal of civil engineering. IEB. And they present about the behavior of reinforced concrete skew slabs under vertical

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Research paper Vol. 1 [issue 1] February, 2014

concentrated loads. A total of six slabs were tested in the Concrete Laboratory of Bangladesh University of Engineering and Technology (BUET), Dhaka. All the test slabs were 1/6th scale models of prototype skew slabs having opposite edges simply supported. The same steel arrangement was used for all the slabs. Main steel was parallel to free edges and distribution steel was parallel to support line. Two aspect ratio viz., 0.85 and 1.50 were selected for the study. Centrally located single concentrated load and four point loads equally spaced across the mid-span were the two types of loading condition studied. Two different skew angles viz., = α 25° and 45° were the other parameters of study. The experimental observations were limited to measurement of deflection at different nodal points, concrete fiber strains at some top and bottom points of the slabs, steel strains, cracking patterns and observing the cracking and ultimate loads. Numerical analysis was also carried out for the test slabs to verify the experimental results. In august 2006 a paper is published by S. N. Tande in 31st Conference on OUR WORLD IN CONCRETE & STRUCTURES Singapore. This paper presents a critical analysis of reinforced concrete skew slabs with clamped edges under different types of loads such as uniformly distributed, concentrated and patch loads. A simplified finite strip approach with higher order function for better accuracy has been used to develop the results for skew slabs in bending. The results are presented both numerically and graphically in the form of distribution coefficients for deflections and bending moments, for aspect ratios 1, 1.5, and 2. The effect of skew has been investigated on behavior of skewed slab subjected to various types of loads. The slabs having skew angles 0 to 60 with increment of 150 are considered. Hence the motivation herein was to find results, which would still yield reasonable accuracy, and find immediate applications. In 2007 a bulletin is published by The University of Illinois named as “Engineering Experiment Station Bulletin Series’’ on the “STUDIES OF HIGHWAY SKEW SLAB-BRIDGES WITH CURBS’’. This bulletin contains studies being made of highway slab- bridges with curbs. Designs, and analyses, based on a difference equation method made for a range of bridges. Normal span lengths range up to about 30 ft., skew angles up to 60 deg. Only a single standard curb and handrail detail is considered in all designs. Tables and curves are given which show the variation of design moments with the bridge dimensions. These moments are compared with the corresponding moments in similar right slab- bridges with curbs. And their test result contains: Maximum Dead Load Moment at Center of Slab, Minimum Dead Load Moment at Center of Slab , Maximum Live Load Moment at Center of Slab ,Secondary Live Load Moment at Center of Slab , Maximum Dead Load Moment in Curb ,.

Maximum Live Load Moment in Curb. Moments at the centers of skew Slab-bridges of short span. A. Vasseghi, F. Nateghi and M. Pournadaf Haghi In May 2008 published a paper in IJE In this paper Highway bridges are frequently constructed as simple span structures with steel or concrete girders and a cast-inplace concrete deck, spanning from one pier to another. At each end of the simple span deck, a joint is provided for deck movement due to temperature, shrinkage, and creep Bridge deck joints are expensive and pose many problems with regard to bridge maintenance. Elimination of deck joints at the support of multi-span bridges has been the subject of recent studies. Recent researches have led to the development of a design concept and approach for joint less bridges where the expansion joints are replaced with continuous link slabs. Further studies have indicated the proper performance of such bridges under service loading conditions. This paper presents analytical study of seismic behavior and response of a two span bridge connected by link slabs. Three dimensional finite element analyses of straight and skew bridges with skew angles varying from 15 to 60 degrees is performed. Both linear time history and response spectrum analyses method are carried 60 degrees is performed. Both linear time history and response spectrum analyses method are carried displacement demands of the interior bent maybe reduced considerably, if link slab is used in the middle of the bridge instead of an expansion joint. In 2012 Patrick Théoret ; Bruno Massicotte; and David Conciatori present a paper in journal of bridge engineering, ASCE and they aimed to determine bending moments and shear forces, required to design skewed concrete slab bridges using the equivalent-beam method. Straight and skewed slab bridges were modeled using grillage and finite-element models to characterize their behavior under uniform and moving loads with the objective of determining the most appropriate modeling approach for design. A parametric study was carried out on 390 simply supported slabs with geometries covering one to four lane bridges of 3- to 20-m spans and with skew angles ranging from 0 to 60°. The analysis showed that no orthogonal grillages satisfactorily predict the amplitude and the transverse distribution of longitudinal bending moments and shear forces, and can be used for the analysis of skewed slab bridges. Results of the parametric study indicated that shear forces and secondary bending moments increase with increasing skew angle while longitudinal bending moments diminish. Equations are proposed to include, as part of the equivalent-beam method for skew angles up to 60°, the increase of shear forces and the reduction of longitudinal bending moments. Equations are also given for computing secondary bending moments. A simplified approach aimed at determining the corner forces for straight and skewed bridges is proposed as an alternative to a more-refined analysis. The analyses indicated the presence of high vertical shear stresses in the

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Research paper Vol. 1 [issue 1] February, 2014

vicinity of free edges that justifies suggesting to provide shear reinforcement along the slab free edges. 3. EXPERIMENTAL WORK Three model skew slabs have been experimentally tested in the Concrete and structure Laboratory of Madan Mohan Malviya Engineering College Gorakhpur Uttar Pradesh, India. These investigations have been carried out to study the behavior of reinforced concrete skew slabs subject to four point load with reference to IRC Class B Loading The test slabs are designated as slab SS01 through slab SS03.skew slabs first tested with uniformly distributed load up to the elastic limit and then the same slab were tested with four point loading arrangement with centrally applied load and +300mm and -300mm eccentrically applies load. All the slab which is tested was a constant skew angle of 30ツー. The size and specification of the slab is given below and the slab thickness was 100 mm for all the test slabs. Skew span of the slab = 1600mm Right span of the slab = 1385.6mm Skew angle = 30ツー 3.1 Casting of slabs The test slabs were cast using Ordinary Portland Cement, Fine aggregate (F. M. = 2.85) and stone chips 20-mm and 10mm mixed by a constant ratio of 6:4 as coarse aggregate. The aggregate gradation conforms to the zone窶的II recommendations [IS 546-2000]. The flexural reinforcements used in the test slabs were Fe 5000D and diameter 06 mm. properties viz. actual

the formwork. Fresh concrete was prepared manually. Immediately after mixing of fresh concrete, the fresh concrete was placed in the form and compacted manually. The top surface was leveled using a wooden float. A total of nine cubes and three prisms of standard size were cast simultaneously as a control specimen for determining the compressive and tensile strength of slab concrete. [3] 3.2 Testing of Slabs Three reinforced concrete skew slabs were tested, each of which was loaded with either uniformly distributed load or four concentrated loads. All the slabs were simply supported on two opposite edges. The test slab was placed on its supports. After checking for any possible damage, all the deflection dial gauges are placed at various nodal points for checking deflection precisely. After all the primary checks, initial zero load readings for the load cell, deflection dial gauges and strain gauges were taken. The test was then continued applying the load at suitable increments, so as to reach the ultimate load in about twelve installments. Loading arrangement for the application of four point loads is shown in Fig. 3 The readings of the load cell, deflection dial gauges were simultaneously read and printed out at 500 kg (5 KN) interval as indicated by dial reading of the testing machine. The process was repeated until the failure load was reached. The ultimate stage was assumed to have been reached when the deflection readings continuously moved on without any significant change in the applied load. The crack widths of some of the prominent cracks were measured at failure. An optical crack measuring device was used for such measurements with accuracy of up to 0.02 mm

The water cement ratio of concrete mix was 0.48 and the concrete mix ratio was 1: 2.30: 2.65 (by weight) of Cement: Sand: Stone Chips. The form works for the test slabs were made of brick wall and boundaries formed with cement, fine sand mixed paste. Boundary angle is precisely formed by the cement paste to make the desired skew slab dimensions. Steel reinforcement was calculated for 1.6 m span prototype slab. Steel for the 1.6 m span models were then appropriately scaled. Typical reinforcement layout of the Slab SS01 is given in Fig. 2. The reinforcement assembly was placed on the base of the prepared formwork for the respective model. Wooden block 20 mm thick were used between the form base and the reinforcement to maintain desired clear cover. The slab models were cast in the concrete laboratory. The formwork for casting was placed on the floor of the laboratory with proper arrangement. Lubricating oil was used to smear the bottom and side of the shutter for its easy removal after hardening of the concrete. The reinforcement mesh was then properly positioned inside

Figure 2. Reinforcement Layout of Skew Slab At the end of every slab test, the accompanying cube cast as control specimens were tested to assess the compressive strengths of concrete respectively. Nine cubes were tested for compression and three prism for flexural

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Research paper Vol. 1 [issue 1] February, 2014

strength and their respective average value was considered as the representative value of slab concrete strengths. The average test results of the control cube specimens are summarized in Table.1 for the test slabs. Table. 1. Crushing Strength of Cubes

S.

Crushing

Crushing

Remark

No.

Load

Strength

(KN)

(MPa)

1.

790

35.11

2.

800

35.55

All values

3.

710

31.55

greater

4.

738

32.80

than

5.

725

32.22

The

6.

706

31.37

target

7.

730

32.44

mean

8.

718

31.91

strength

9.

714

31.73

31.37 MPa

4. OBSERVATION AND DISCUSSION ON TEST RESULTS Some basic behavioral observations of the test slabs as noticed and recorded during the experimental investigations are briefly discussed and presented in the following articles: 4.1 Deflection The deflections were measured at some selected location for all the test slabs with the help of deflection dial gauges. The load-deflection response at the central point and +300mm and -300mm eccentric point of all the test slabs for the entire loading history up to failure is shown in Fig. 4-6. This includes slabs supporting both uniformly distributed and four point loads. As expected, the deflection recorded at central nodal point is found to be more in slabs as compared to the other nodal point. Slab thickness remaining constant. Comparing the two types of loading, it was observed that skew slabs supporting four point loads across the mid span deflected less at the centre span than the slabs supporting than slab supporting four points at eccentricity. This is expected as the four point load at centre are somewhat distributed over a central band line compared to the four point load at some eccentricity, thus reducing the point deflection at the centre. The maximum deflection of slabs SS01, SS022, SS03 having identical aspect ratio was found to depend on the loading type. As can be observed from Table 2-4, the deflections at obtuse zones were found to be more than acute zones in slabs SS01, SS02 and SS03 all having aspect ratios less than unity this indicates that the aspect ratio of skew slabs influences the flexibility of acute and obtuse angled zones . 4.1.1. Load Displacement tables Table .2 Load Deflection Table In Case Of Uniformly Distributed Load D/ L

D1

D2

D3

D4

D5

D6

D7

D8

D9

0

8.79

3.55

14.3 1

3.8 3

4.00

1.7 5

5.25

4.10

0.1 3

3.80

8.74

3.85

14.1 0

4.0 1

4.20

2.2 0

5.42

4.20

0.3 5

7.6

8.60

3.94

13.9 0

4.6 3

4.58

2.6 0

5.60

4.45

0.5 0

11.40

8.52

4.11

13.7 6

4.8 6

4.84

2.8 2

5.65

4.60

0.7 2

Figure 3. Load Position -300mm Eccentric

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Table 4. Load Deflection Table In Case of Four Point Load Test (Load Position Is Centric)

Table .3 Load Deflection Table In Case of Four Point Load Test (Load Position Is -300mm Eccentric) D

D1

D2

D3

D4

D5

D6

D7

D8

D9

5.11

8.48

6.17

0.79

10.1

3.53

1.32

1.50

8.68

/L 0

0 5

5.00

8.48

6.24

0.75

10.2

3.68

1.43

1.65

4.90

8.48

6.34

0.70

10.2

4.63

1.45

1.70

4.76

8.48

6.45

0.65

10.5

5.74

1.67

1.90

9.58

5.82

1.88

2.55

9.76

5.98

2.06

2.80

9.93

6.05

2.45

2.90

10.0

0 20

4.64

8.47

6.55

0.60

10.8 5

25

4.61

8.46

6.65

0.56

11.2 1

30

4.58

8.45

6.76

0.50

11.3 0

35

4.53

8.45

6.90

0.48

12.0

4.51

8.45

7.06

0.42

12.9

6.57

2.56

3.70

4.45

8.44

7.26

0.38

13.1

7.03

4.69

4.80

4.30

8.43

7.54

0.28

55

4.20

8.43

7.78

0.24

60

4.11

8.42

7.94

0.21

13.6

D5

D6

D7

D8

D9

0

11.69

3.92

14.15

1.83

4.00

2.40

11.33

5.6

0.77

5

11.65

3.83

14.11

1.84

4.5

2.70

11.40

5.8

1.00

10

11.59

3.79

14.07

1.83

4.55

3.00

11.70

6.00

1.25

15

11.48

3.75

14.06

1.83

4.80

3.20

11.70

6.40

1.43

20

11.39

3.72

14.06

1.83

5.60

3.50

11.70

6.66

1.65

25

11.27

3.70

14.06

1.83

6.25

4.77

12.20

6.90

1.80

30

11.18

3.60

14.04

1.83

6.40

4.80

12.50

7.15

2.00

35

11.07

3.60

14.01

1.83

7.10

4.85

12.90

7.80

3.00

10.6

40

11.04

3.60

13.98

1.83

8.50

4.97

13.55

9.25

3.65

11.8

45

10.84

3.60

13.95

1.86

9.95

5.00

14.22

9.80

4.30

50

10.69

3.57

13.93

1.86

10.70

5.90

14.60

10.30

5.05

55

10.59

3.57

14.01

1.88

11.40

6.30

14.85

10.35

5.25

60

10.35

3.57

14.10

1.88

12.30

6.50

16.10

10.20

7.00

3 7.55

5.67

4.95

5 50

D4

3

0 45

D3

6

0 40

D2

9.10

0 15

D1

8.86

5 10

D/ L

12.9 2

8.52

7.19

4.98

17.7

10.4

8.96

8.98

0

4

22.1

15.0

17.6

14.5

23.5

5

2

5

5

3

0

12.9 6 14.7 8

Figure 5. Load Position +300mm Eccentric Figure 4. Load Position -Centric

These tables show the displacement in vertical direction with respect to the incremental load,

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Research paper Vol. 1 [issue 1] February, 2014

First of all layer of cube is placed on the skew slab for checking the deflection at uniformly distributed load three layers of cubes is placed on the slab in three steps for checking deflection under uniformly distributed load,

4.1.2. Load displacement curve

Four point centric load

After that all the cubes is unloaded and four point load testing arrangement is placed on slab as shown in figure 3 for applying load. Manually operated hydraulic jack is used to apply incremental load.

18

DEFLECTION(mm)

16

Load is applied at an increment of 5KN. Table 5. Load Deflection Table In Case Of Four Point Load Test (Load Position Is +300mm eccentric)

14 12 10 8 6 4 2

D/ L

0

D1

D2

D3

D4

D5

D6

D7

D8

D9

0.00

11.40

5.41

1.29

8.55

6.55

5.65

10.35

3.80

0

10

20

30

40

50

D5

60

Load()KN 0

5

0.10

11.44

5.40

1.30

8.68

7.75

5.70

10.40

3.95

10

0.50

11.47

5.39

1.32

8.70

8.15

5.81

10.45

4.20

15

0.60

11.48

5.16

1.33

8.75

8.45

5.90

11.47

5.00

20

0.70

11.48

4.54

1.34

8.78

8.70

6.14

11.50

5.40

25

0.72

11.49

3.95

1.34

8.85

8.85

6.20

12.15

5.55

D1

D2

D3

D4

D6

D7

D8

D9

Figure 6. Load Deflection Curve for U.D.L

Four point load test , eccentricity -300mm 25

30

35

0.75

0.75

11.49

11.50

3.90

3.89

1.35

1.36

9.10

1025

9.00

10.10

6.50

7.00

12.50

13.40

6.00

7.05

40

0.77

11.52

3.85

1.36

12.15

10.40

8.03

13.80

8.55

45

0.78

11.53

3.80

1.40

14.05

11.95

10.55

15.60

10.18

50

1.05

11.53

3.72

1.49

14.15

27.85

11.50

16.95

12.55

55

1.50

11.60

3.65

1.50

16.68

29.45

13.40

17.65

12.95

Deflectiodn(mm)

20

15

10

5

0 0

10

20

30

40

50

D6

60

Load(KN)

60

2.05

11.70

3.50

1.65

16.98

30.64

14.50

29.15

16.25

D1

D2

D3

D4

D7

D8

D9

D5

Figure 7. Four Point Load Test Eccentricity -300mmm

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Tables 6.Cracking Load for Skew Slabs for Four Point Loading

Load deflection curve for UDL

Load position/ Slab designation SS01 SS02 SS03

25

Axis Title

20 15 10 5

centric

Eccentric -300mm

Eccentric +300mm

37 40 38

33 32 35

32 35 34

0 0

2

4

6

8

10

12

Axis Title D1

D2

D3

D4

D6

D7

D8

D9

The load at failure condition recorded for each test slab is defined as the ultimate load shown in Table

D5

7.The ultimate loads of the slabs with centric loading were also higher compared to slabs with eccentric loading for the same skew angle

Figure 8. Four Point Load Test -Centric

Tables 7. Ultimate Load for Skew Slabs for Four Point Loading

Four point load test .eccentricity +300mm

Load position/ Slab designation SS01 SS02 SS03

25

20

Deflection (mm)

4.3 Ultimate Load Carrying Capacity

15

centric

Eccentric -300mm

Eccentric +300mm

77 75 79

71 74 70

69 72 74

4.4 Cracking patterns

10

5

0 0

10

20

30

40

50

D5

60

Load(KN) D1

D2

D3

D4

D6

D7

D8

D9

Figure 9. Four Point Load Test Eccentricity +300mmm 4.2 cracking load The load at the first visible crack termed as cracking load was recorded for each test slab and are furnished in Table 6... Cracks were observed in the test slabs between 40-50 percent of the respective ultimate loads. For the same skew angle, the cracking load of the slabs with centric four point loading were higher compared to slabs with eccentric four point loading.

The cracking patterns of all the test slabs were observed and photograph taken after test. Loading system on the skew slabs appears to have significant influence on the crack patterns. The first crack was always observed at concrete bottom surface near the mid span. For four point loading, a number of cracks originated from the bottom of mid span area and propagated nearly parallel to the support lines towards the free edges like a mesh crack. In case of four-point loading representing an area load at four points, the cracks were limited within a narrow band of centre span. The widths of the major cracks were measured at failure load by an optical crack-measuring device. The cracking patterns at the bottom surface of two test slabs are shown in Fig. 8 and Fig. 9. The crack widths of the prominently visible cracks at failure were measured. Crack width as large as 7 mm was recorded for slabs SS03 and SS02 and 6mm for SS01.It may be noted that relatively wider cracks were observed in case of four-point loading representing knife-edge loading.

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(ii)

The deflection at obtuse zone is more than acute zone in slabs with lower aspect ratio (r = 0...625) uplift of acute corners also occurred when aspect ratio is low as in this case.

(iii)

Cracks propagate toward free edges like a mesh crack and somewhat parallel to support line in case of a four point loading condition.

(iv)

Cracks are limited within a small bandwidth parallel to support line along centre span for multiple point loads placed across the centre span. REFERENCES

1.

AASHTO (1983). ″Standard Specification for Highway the

Figure 10.Crack at Mid-Point Parallel to the Supports

Figure 11.Failure at Mid-Point Parallel to the Supports 5. CONCLUSIONS The following conclusions may be drawn based on the observations of the present experimental study: (i)

For the same aspect ratio and skew angle, the ultimate (total) load carrying capacity of skew slabs are higher in case when the loads are distributed across the width like that of four point centric loads as compared to the four point eccentric loading.

Bridges″ 13 edition, American Association of State Highway and Transportation Officials, Washington. 2. ASTM C 136 (1988). Test method for Sieve Analysis of Fine and Course Aggregates, Vol. 04.02, Section-4, American Society of Testing Materials, Philadelphia, pp. 76. 3. Cope, R. J. and Rao, P. V. (1983). Moment Redistribution in Skewed Slab Bridge, Proc. Instn. Of Civil Engineers, Part 2, Vol. 75, September, pp. 419451. 4. Desayi, P. and Probhakara, A. (1981). load Deflection Behavior of Restrained R/C Skew Slabs, Journal of the Structural Division ASCE, 107, No. ST5, May, pp. 873 – 887. 5. Doullah, Sk. Md. Nizam-ud and Kabir A. (1997). Analysis of Reinforced Concrete Skew Slabs using Layered Mindlin Plate Element, J. of Inst. of Engineers (India), 78, pp. 97-102, Nov. 6. Doullah, Sk. Md. Nizam-ud (2000). Nonlinear Finite Element Analysis of Reinforced Concrete Skew Slabs, Ph. D. Thesis, Department of Civil Engineering, BUET, Dhaka. 7. El-Hafez, L.M.A., (1986). Direct Design of Reinforced Concrete Skew Slabs, Ph.D. Thesis, University of Glasgow, UK. 8. Islam, N. M. (1996). Ultimate Load Behaviour of Skew Slab Bridge Deck, M. Sc. Engineering Thesis, Department of Civil Engineering, BUET, Dhaka. 9. Engineering Thesis, Department of Civil Engineering, BUET, Dhaka. 10. Zia, P., White, R. N. and Vanhorn, D. A. (1970). Principles of Model Analysis, ACI Special Publication SP-24, American Concrete Institute, Detroit, Michigan, pp. 19-39 11. Jahan, S. M. (1989). Investigation of Skew Slab Bridge, M. Sc. Engineering Thesis, Department of Civil Engineering, BUET, Dhaka. 12. Miah, M. K. (2000). Behavior of Reinforced Concrete Skew Slab under Vertical Loads, M. Sc.

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13. Jeanty, P.R. et al. 1988. Investigation of ‘‘Top Bar’’ Effects in Beams. ACI Structural Journal, Proceedings Vol. 85, No. 3, Detroit, Michigan, February 1988. 14. ECP 203-2007. Egyptian Building Code for Structural Concrete Design and Construction. Ministry of Housing, 2007. 15. ACI 318-05, 2005. Building Code Requirements for Structural Concrete and Commentary. American Concrete Institute, Michigan, 2005.

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IMPROVING THE BEHAVIOR OF REINFORCED CONCRETE BEAM WITH VARYING LAP SPLICES LENGTH *Ashish Singh

Dept. of Civil Engineering MMM. Engineering College Gorakhpur, India Email: mech.ashish.2011@gmail.com ABSTRACT- The main objective of this paper is to study the behaviour of lap splice of steel reinforcement in tension zones in reinforced concrete beams. An experimental program is conducted on fifteen simply supported concrete beams. The main studied variable is splices length in the splice zone. There is an increase in ductility of beams when transverse reinforcement was used. Key words: Development Length, Yield Stress, Ultimate Stress, Splice Length, D1 Dial Gauges.

INTRODUCTION When reinforcement is spliced together within a concrete beam, it is necessary to overlap the bars long enough for tensile stresses in one bar to be fully transferred to other bars without inducing a pull-out failure in the concrete. Most design codes allow the use of bars with lap splice and specify minimum length of the lap as well as the required transverse reinforcement. According to ACI 318-05, the minimum length of lap for tension lap splices for Class A=1.0 Ld and =1.3 Ld for class B. Stirrup area in excess of that required for shear and torsion is provided along each terminated bar or wire over a distance from the termination point equal to three-fourths the effective depth of member. Most of design codes do not specify a specific shape of transverse reinforcement required for spliced bars. Ferguson and breen (1965) studied thirty five beams focusing on bar diameter, stirrups and concrete strength. From these tests, they concluded that stirrups increased splice strength, minimum stirrups as much as 20%, heavy stirrups up to 50%. The splitting prior to failure gradually developed over the full splice lengths seemed almost to stabilize with a substantial centre length remaining unsplit until a final catastrophic failure occurred.

reinforcement crossing the plane of splitting , the top bar factor was found to be 1.22 , which means that the required lap splices length must be increased by 22% for spliced top tension bars . The presence of transverse reinforcement across the plane of potential splitting reduce significantly the require development length for both bottom- cast and top cast bars. Hamad et al (2006) investigated eighteen full scale beam specimens. In this study, the amounts of transverse reinforcement, bar size and bar type (black or galvanized) were considered. They concluded that in beams without transverse reinforcement in the splice region, surface of black and galvanized bars were relatively clean with limited signs of concrete crushing in the vicinity of very few bar lugs. In beams with transverse reinforcement in the splice region. however , there were relatively more signs of concrete crushing adjacent to the bar lugs indicating the positive role of confinements by transverse reinforcement in mobilizing more bar lugs in the stress transfer mechanism between the steel bars and the surrounding concrete. OBJECTIVE

Jeanty et al. (1988) tested thirteen specimens to the effect of transverse reinforcement on the bond performance among other variables. [1] The main conclusion of this research were that for beams with and without transverse

A) To study the behaviour of reinforced concrete simply-supported beams with lap splice of tension steel reinforcement zones with different lap splice lengths.

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B) To obtain a spliced beam that can achieve at least the same strength and ductility of the same Beam without any splices using transverse reinforcement with different shapes.

Table1.Details of Tested Beam Specimens

EXPERIMENTAL PROGRAM Fifteen simply supported reinforced concrete beams of dimension 150mm x 250mm x 2500mm were tested in Structural Engineering Lab, Madan Mohan Malaviya Engineering College. All specimens had the same concrete strength and the same longitudinal reinforcement. 2, 10 mm-diameter 500 high strength steel were used in tension reinforcement. Stirrups of 6mm-diameter of 420 grade were used . The rest set up of the studied beam is shown in figure 1. Figure 2 shows reinforcement details of some of the

test

beams.

TEST PROCEDURE AND INSTRUMENTATION Figure 1 shows the details of the test rig. The load applied using a calibrated hydraulic jack of 100 KN capacity. A strong spreader I-beam was used to transfer the vertical load to the tested beam through two concentrated loads 800 mm apart. 5 dial gauges of .01mm accuracy were used to record deflection at the centre of the beams as well as under position of two loads. The load is applied in increment equal to 5KN. Figure 1.Testing Frame

TEST GROUP The tested beams are divided in to five groups. According to different lap splices length. 1.

Group 1 no lap splices

2.

Group 2 lap splice of 300mm

3.

Group 3 lap splice of 600mm

4.

Group 4 lap splice of 900mm

5.

Group 5 lap splice of 1200mm

Figure 2.Detail of Tested Specimen

Figure 3. Sections

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Figure 4. Spreader I- Beam Used To Perform 2 Point Loading

Figure 6. Crack pattern of beam B-2 in centre at bottom layer of tension zone.

TEST RESULT AND DISCUSSIONS The main obtained results are given in table- 1. All group are tested as the control beam group 1 the beam B-1 with no lap flexure test starts as the test progress the readings are taken after every 5 KN , as the control beam is being designed for 44 KN. After 46 kn the hair line cracks are visible first which visible at the bottom near 800 mm and 1600 mm as on when load is on 50 kn the hair line begins in the centre in flexure zone.

For beam B-3 which had lap length equals to Ld that is 600 mm. As the loading on this beam propagates the hair line are start appears at the load of 28 KN and soon after 48 KN hair line cracks converted in to large cracks. Firstly the cracks are visible at the end of splices bars where the overlapping of the bars ended. Means 300 mm away from the centre to its right and left. As shown in figure 6. The cracks propagates and end in compression zone.

For beam B-2 with lap splice length 300mm flexure crack propagated upward to the compression zone at a load 44 KN, a horizontal splitting crack along the lap splice length appeared and a bond failure occurred at a load of 47.5 KN. As shown in figure 5. Bottom fibber cracks of tension zone in beam. Table 2. Main test results.

Figure 6. Bottom crack pattern of beam B-3 For beam B-4 which had lap length equals to 1.5 L d shows better behaviour than previous group beam. In these group beams hair line cracks are start from 34 KN and its ultimate failure too is 73 KN which is better than the entire group and its ductility to be better than all groups. Its ultimate load deflection by yield load deflection is 2.4 which are nearly equals to the control beam. For beam B-5 which had lap length equals to 2 Ld. this beam shows almost same result as previous group except in this beam hair line cracks starts at 39 kN. In this beam crack start from 400 mm and 2000 mm which are near the end point of spliced bars and cracks propagates towards the loading point as shown in figure 7. Below.

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lengths. From the results of the studied beams, the following conclusion were obtained: 1.

The use of a lap splice with 100% cut off ratio, with length of 300 mm resulted in much earlier failure then required.

2.

As the beam have same transverse reinforcement but if the transverse reinforcement is not there in spliced zone then there will be more severe failure like brittle bond failure can be occurred.

Figure 7. Crack propagation shown with black paint B5.

3.

All the beams with spliced bars shows large deflection with respect to the no lap beam.

The relationship between load and mid-span deflection for the tested beams .B-3A, B-4A, B-5A reached an ultimate load of that of the reference beam B-1A. It is clear that beam B-2A, with a lap length of 300 mm did not reach the ultimate load. Figure shows that after cracking B-1A and B5A shows nearly the same behaviour up to the sudden failure. Beam B-4A shows lower deformation as compared to other lapped beams. More deflection shown in B-3A, B5A group beams. These results indicate that the use of lap splice length equals to the recommended by the Indian code (600 mm) or greater (900 mm, 1200 mm) increased the maximum deflection at ultimate load. The ratio between the maximum deflection at ultimate load and the deflection at yield load : u/y was 1.91 , 2.6 , 2.4 , 2.48 for beams B-1A , B-3A , B-4A , B-5A respectively . This shows B-4A was most ductile beam.

4.

The behaviour of a beam without any spliced beam can be achieved in a spliced beam of lap length 2Ld and for the economical and nearly achieving the same strength as control beam the value 1.5 Ld can as spliced length.

Figure 8. Load and deflection curve Summary and Conclusion Fifteen concrete beams were tested to study the effect of lap splice of tension reinforcement with different splice

REFERENCES

1.

ACI 318-05, 2005. Building Code Requirements for Structural Concrete and Commentary. American Concrete Institute, Michigan, 2005.

2.

Diab A.M. 2008. Lap Splices in Reinforced Concrete Beams Subjected to Bending, Master thesis. University of Alexandria, Egypt, December 2008.

3.

ECP 203-2007. Egyptian Building Code for Structural Concrete Design and Construction. Ministry of Housing, 2007.

4.

Eurocode 2 1992-1. Design of Concrete Structures-Part 1: General Rules and Rules for Buildings, European Standard, European Committee for Standardization, October 2001.

5.

Ferguson, P.M. and Breen, J.E. 1965. Lapped Spliced For High Strength Reinforcing Bars. ACI Structural Journal, Proceedings Vol. 62, No. 9, Detroit, Michigan, September 1965.

6.

Hamad, B.S. and Fakhran, M.F. 2008. Effect of Confinement on Bond Strength of Hot-Dip Galvanized Lap Splices in High-Strength Concrete. ACI Structural Journal, Proceedings Vol. 103, No. 1, Detroit, Michigan, January 2006.

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7.

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Jeanty, P.R. et al. 1988. Investigation of ‘‘Top Bar’’ Effects in Beams. ACI Structural Journal, Proceedings Vol. 85, No. 3, Detroit, Michigan, February 1988.

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Study on the Behavior of Pile Cap Model with Various Type Failure of Concrete Cap *Ambareesh

Kumar Dept. of Civil Engineering M.M.M. Engineering College Gorakhpur, India Email: ambar006@gmail.com

ABSTRACT: The ability of pile caps to resist vertical loads is often neglected in the design of pile groups to support buildings and bridges, although these caps are often massive and deeply buried. Neglecting cap resistance can result in excessively conservative estimates of pile group deflections and bending moments, exceeding the actual deflections and bending moments by 100% or more of pile cap failure. This paper present the result of pile cap failure of deferent type cracks and the show cracking load and failure load of concrete pile caps. It is clear that the behavior of pile groups subjected to vertical loads can be reflected more accurately in design if the lateral-load resistance of pile caps is better understood. The pile cap design of three batches at (one batches 3 sample) nine samples. There are define at PC-1, PC-2 and PC-3. In addition to the samples shown in the section, the whole report of crack distributions at the failure steps for all the samples in Batch 1 and 2 and the crack characteristics and types discussed below are shown and annotated in paper. The terminologies of the six surfaces of the cap are shown in Figure (1). Key words: failure load, cracking load and cracking pattern

INTRODUCTION In total, three batches of samples were tested (Table 1). In order to clarify the identity of all pile caps, samples in different batches were numbered in an efficient way, generalized as: ‘PC-NA’. The first ‘PC-1’ represented ‘Batch’ followed by ‘PC-1A to PC-1C’ representing batch number (from 1 to 3). The third ‘PC-2’ was the cap series being either PC-2A to PC-2C. The final ‘PC-3’ was the sample number within each cap series. For example, PC-3A to PC3C meant the 3rd sample in Batch 3 Series A. The design strategy for sample dimensions is sketched in Figure (1). [1] As mentioned in Section, the key parameters influencing between IS 2911 are the loading and depth of pile cap. The dimensions of the pile cap samples were designed to obtain a range of values of design vertical load on the pile cap. A constant by varying the longitudinal pile spacing and keeping the transverse pile spacing constant.

Figure-1 Terminologies for describing the crack distribution and propagation

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Table: 1â&#x20AC;&#x201C; Sample dimensions and reinforcement arrangement

beginning of the maturing of the critical shear crack or the central bending crack on the front or back surfaces. The deflection could be very large in the yield stage before the structure finally failed, implying the failure was rather ductile. This could either be because of the yield behavior of the longitudinal reinforcement in bending failure or a gradual softening of the compressive concrete strut in the shear failure. This proved that in structures of short shear span, even in the absence of shear reinforcement, shear cracking does not necessarily result in immediate failure. The ductile behavior in pile caps with large transverse pile spacing may also be because of the capâ&#x20AC;&#x2122;s transverse behavior i.e. the ductile behavior of the transverse reinforcement which caused the cap to remain ductile even when the shear crack on the cap front and back surfaces appeared. Table: 2- Pile cap testing on cracking load and failure load

Crack distributions at failure step The first characteristic of the concrete pile cap crack distributions discussed in the following paragraphs was that under vertical loading, for caps with small transverse pile spacing, the crack distributions on front and back surfaces at failure were similar to those expected for 1way shear failure, and the cap behaved close to 1-way shear behavior. Result and discussion Crack propagations In all samples, cracks initiated with the bending cracks from the cap mid-span. The occurrence of the cracks in the experiments is a debatable point. In relatively deep caps as in the experiments, the cracks were less apparent and less densely distributed, but still did occur, in a form shorter and steeper than in a shallow pile. The cracks started at the cap soffit near the first bending crack and then extending upwards at an angle towards the edge of the vertical loading e.g. on PC-1A back surface (Figure-5). [6]This propagation normally occurred for a while and then stopped, being superseded by the propagation of the compressive splitting shear crack. This was because the short span constrained them from fully maturing, and the formation of the concrete compressive strut preceded the appearance of arch action which is deemed as a result of maturing cracks.

A compressive splitting crack also appeared and was fully developed on the back surface left side in PC-3A (Figure-2) and on the front surface right side in PC-1A and PC-2A. These cracks initiated near the middle of the inclined crack. It was only on PC-3C front (Figure-10) and back surfaces and on PC-2C front surface right side (Figure-8) that the widely opened compressive splitting crack initiated from the huge crushing of the concrete under vertical loading where the concrete severely spelled off. In most samples, the central bending crack linked the front and back surfaces of the cap on the cap soffit (Figure-4).

Cap deflection The early bending and shear cracks appearing in the cap in the elastic stage did not change the initial stiffness of the cap. The deflection of the center of the cap soffit increased linearly and remained in a small range, not more than 5. The deflection suddenly increased after the onset of the yield stage, the point that was normally marked by the

Concrete being crushed under vertical loading Figure-2 Crack distribution on PC-3A front surface at failure step

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As shown in Figure, for PC-2B, Crack (a) was definitely a bending crack induced by bending moment in the transverse direction. This was ensured by its shape on the right surface (Figure-3) which was vertically upwards rather than inclined. Crack (b) indicated the behavior around as individual corner pile. Its shape of the right and left surfaces was inclined and short. It might be a potential punching shear crack caused by the individual pile. A similar crack also appeared in PC-2C (Figure-8) and PC-3C. However, no pile cap finally failed by the punching shear failure of the corner pile. The type of Crack (c) is between a bending crack and punching shear crack.

Figure-5 Crack distribution on PC-1A cap soffit at failure step

Figure-3 Crack distribution on PC-2B back surface at failure step

For experiment, as can be seen of the back surface of PC1A and PC-2A, and the front surface of PC-1C (Figure-4, 5) caps failed in shear but with significant central bending cracks propagating widely and upwards deeply. On the other hand, the back surface of PC-3A (Figure-2) showed a bending failure with significant critical shear cracks.

Take pile cap 1-A is front surface as an example (Figure-4). The front surface shows a standard crack distribution in a shear failure similar to a 1-way spanning of pile cap, i.e. the bending crack propagated a long way into the region under the vertical loading, and the critical compressive splitting crack developed linking the loaded area and the area above the pile head. The concrete near the tip of the shear crack was crushed. [3] The inclined compressive stress was expected to dominate in the inclined strut confined by the surrounding concrete.

Concrete being crushed under vertical loading Figure-4 Front surface PC-1A

Figure-6 Crack distribution on PC-1C cap soffit at failure step

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Compressive splitting shear cracks along the concrete strut usually initiated at the mid height of the cap and then propagated in both directions towards the pile head and the vertical loading e.g. on the front surface of PC-1A, PC1C and back surface of PC-2A (Figure 4, 5, 6 and 9). A compressive splitting crack can also initiate because of crushing of the concrete immediately under the vertical loading, such as on the front and back surfaces of PC-2B (Figure-3) and front surface of PC-1B

Figure-7 Crack distribution on PC-1B back surface at failure step The crack distributions was that with the increasing pile transverse spacing, the cracking on the cap soffit became more 2-way, indicated mainly by the cracks occurring perpendicular to the main bending cracks on the soffit such as in PC-1B, PC-2C (Figure-7, 8) and PC-2B. This implied that the larger, the more possible that the reinforcement in the transverse direction took part in the shear resistance, and the bigger role the 2-way behavior of the cap and the behavior of an individual corner pile played relative to the normal shear behavior in a 1-way spanning beam.[4]

Figure-8 Crack distribution on PC-2C back surface at failure step

Figure-9 Crack distribution on PC-2A front surface at failure step The bending crack and the critical shear crack matured rapidly one after the other with both opening widely, but one finally overwhelming the other. Apart from PC-1C (shear failure without any significant bending crack on front surface (Figure-6) and PC-3C (bending failure without any significant shear crack on back surface (Figure-10), bending failure and shear failure were always very close at the failure step.

Figure-10 Crack distribution on PC-3C back surface at failure step

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Figure-11 Crack distribution from experiment at the onset of the yield stage

Figure-12 Observed crack pattern in experiment Conclusion So far, all results have been for pile caps subject to the vertical loading. It is expected that the shear capacity and mechanism may vary with the load pattern, and so in order to study its crack pattern the shear behaviors of pile cap experimental samples under a concentrated vertical load, and a model in the parametric study under a vertical loading with depth increased were investigated. The design of three batch samples, and testing of pile cap at study and the behavior of shear failure, punching failure and crack pattern at concrete cap. It is clear from the above discussion that the failure mechanism of pile cap under the vertical loading with reduced depth is neither the punching shear failure as under concentrated load.

Figure-10 Observed crack pattern Reference Failure load â&#x20AC;&#x201C; 205 KN PC-1A

1.

Indian standard code of practice for design and construction of pile foundations bureau of indian standards IS 2911-1979 and IS 2911-1984.

2.

Code of practice for road and bridges of indian road congress IRC 112-2011.

3.

Indian standard code of practice for design and construction of pile foundation bureau of indian standard IS 2911 part-4 1985.

4.

Reinforced concrete design of pile cap BS 8110.

5.

British standard code of practice and design for foundation BS 8004-1986 (formerly CP-2004).

6.

Indian standard code of practice. (1979). "Design and construction of pile foundation, IS 2911 (part 1/sec. 3)." New Delhi, India.

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7.

ACI Committee 445 (1998). "ACI Committee 445 on Shear and Torsion Recent Approaches to Shear Design of Structural Concrete." Journal of Structural Engineering ASCE, 1375-1417.

8.

Adebar, P., Kuchma, D., and Collins, M. P. (1990). "Strut-and-tie Models for the Design of Pile Caps: an Experimental Study." ACI Structural Journal, 87(1), 8192.

9.

Adebar, P., and Zhou, L. (1996). "Design of Deep Pile Caps by Strut-and-Tie Models." ACI Structural Journal, 93(1), 56-64.

10. Ashour, A. F. (2000). "Shear Capacity of Reinforced Concrete Deep Beams." Journal of Structural Engineering ASCE, 1045-1052. 11. Ashour, A. F., and Morley, C. T. (1994). "The Numerical Determination of Shear Failure Mechanisms in Reinforced-concrete Beams." The Structural Engineer, 72(24), 395- 400. 12. Ashour, A. F., and Morley, C. T. (1996). "Effectiveness Factor of Concrete in Continuous Deep Beams." Journal of Structural Engineering ASCE, 169-178. 13. Bazant, Z. P. (1983). "Crack Band Theory for Fracture of Concrete." Materials et Constructions, 16, 155-177.

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ANALYSIS OF FINITE ELEMENT MESH SPACING INFLUENCE ON MODELING RESULTS *Rohit Rai

Dept. of Civil Engineering M.M.M. Engineering College Gorakhpur, India Email: rohit.rai2609@gmail.com

ABSTRACT- In the present work the modeling of curved deck slab was done with computer program which was done with the help of finite element method .In model the mesh spacing was varied and its influenced on various properties i.e. deflection, bending moments, and torsional moments are discussed. In this only quadrilateral meshing is taken. And it was found that the mesh spacing changes the results of FE Analysis. However, it also was found out that after certain value of mesh divisions the results start to converge. Key words: Deflection, Bending Moment, Transverse Moment and Torsional Moment.

OVERVIEW OF FINITE ELEMENT ANALYSIS The finite element is a technique for analyzing complicated structures by notionally cutting up the continuum of the prototype into a number of small elements which are connected at discrete joints called nodes. For each element approximate stiffness equations are derived relating displacements of the nodes to node forces between elements and in the same way the slope –deflection equation can be solved for joints in a continuous beam, an electronic computer is used to solve the very large number of simultaneous equations that relate node force and displacements. Since the basic principle of subdivision of structure into simple elements can be applied to structures of all forms and complexity, there is no logical limit to the type of structure that can be analyzed if the computer program is written in the appropriate form. Consequently finite elements provide the more versatile method of analysis at present, and for some structures only practical method .However the quantity of computation can be enormous and expensive so that the cost cannot be justified for run of mill structures. Furthermore, the numerous different theoretical formulations of element stiffness characteristics all require approximations in different ways affect the accuracy and applicability of the method .Further research and development is required before the method will have the ease of use and reliability of the simple methods of bridge deck analysis. The technique was pioneered for two dimensional elastic structures by Turner et al and Clough during the1950s.The whole structure is divided into component elements, such as straight beams, curved beams, triangular or rectangular

plate elements, which are joined at the nodes. When this method is applied to a slab, the slab is divided into triangular, rectangular or quadrilateral elements. Thus, the corners of the elements become nodes usually; the vertical deflections of the plate element are expressed in a polynomial of the coordinates of the vertices of the element. This polynomial satisfies the conditions at the corners but may violate the continuity condition along the sides of the element. During recent years, several research workers have attempted to analyze curved bridge decks by the finite element method. Jenkins and Siddall used a stiffness matrix approach and represented the deck slab with finite elements in the form of annular segments, while Cheung adopted the triangular elements. In addition, a horizontal curved box-beam highway bridge was investigated in a three dimensional sense by Aneja and Roll. MODELING OF SLABS USING FINITE ELEMENTS If the finite element method is to be a useful tool in the design of reinforced concrete flat plate structures, accurate modeling is a prerequisite. Accurate modeling involves understanding the important relationships between the physical world and the analytical simulation. As Clough states, “Depending on the validity of the assumptions made in reducing the physical problem to a numerical algorithm, the computer output may provide a detailed picture of the true physical behavior or it may not even remotely resemble it”. The following sections attempt to expose the gap between physical and analytical behavior.

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Table 2: Result obtained for mesh division 05 ANALYSIS FOR MESH SPACING For the mesh analysis we selected a model of curved deck slab which has a radius of 1.27m ,outer arc length 2m and width if .90m . For the analysis we have taken a UDL loading which is kept constant for all the cases and there results are discussed and the results of longitudinal moments and torsional moments are compared with the moment obtained by analytical method. And the finite element program we selected STAAD Pro.In STAAD Pro we have two type of meshing polygonal and quadrilateral meshing .For our present study we had taken only the quadrilateral meshing in this the mesh is created by selecting the node and after selection we need to give the number of small divisions which we want to give that also would be in quadrilateral shape.

Maxim um displac ement (mm) 28.477

Maximu m Absolut e stress (N/mm 2) 125.932

Longitu dinal Moment (kNm/ m)

Transverse Moment (kNm/m)

Torsion al Moment (kNm/ m)

88.50

87.166

36.69

Case 3:Mesh Division=10

Case 1: Mesh Division = 01

Fig 1: Mesh Diagram with Division 01 Table 1: Result obtained for mesh division 01 Maximum displacem ent(mm)

30.166

Maximu m Absolute stress (N/mm2) 52.97

Longit udinal Moment (kNm/ m) 56.48

Transv e-rse Mome nt (kNm/ m) 38.719

Torsion al Momen t (kNm/ m) 27.52

Case 2: Mesh Division = 05

Fig 3: Mesh Diagram with division 10 Table 3: Result obtained for mesh division 10

Maximu m displace ment (mm)

Maximu m Absolute stress (N/mm2)

Longitud -inal Moment (kNm/m )

Transverse Moment (kNm/m)

Torsional Moment (kNm/m)

28.806

243.469

195.16

86.152

105.83

Fig 2: Mesh Diagram with division 05

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Research paper Vol. 1 [issue 1] February, 2014

Case 4: Mesh Division = 15

Table 5: Result obtained for mesh division 20 Maxim um displac ement (mm)

Maximu m Abosolu te stress (N/mm2 )

Longitu dinal Moment (kNm/ m)

Transve rse Moment (kNm/ m)

Torsio nal Momen t(kNm/ m)

27.829

324.71

287.183

81.05

123.80 3

DISCUSSION ON RESULTâ&#x20AC;&#x2122;S

Fig 4: Mesh Diagram with division 15

Maxi mum displa ceme nt (mm)

Maximu m Absolut e stress (N/mm2 )

Longitu dinal Momen t (kNm/ m)

Transver se Moment (kNm/m)

Torsion al Moment (kNm/ m)

28.22 5

253.48

232.794

81.36

94.63

Table 4: Result obtained for mesh division 15

Case 5: Mesh Division = 20

The finite element method is an approximate technique, and as such, results computed using the finite element method must be critically evaluated before relied upon in a design application. This process of critical evaluation involves several steps for any structure being analyzed. The number of elements used in a model can greatly affect the accuracy of the solution. In general, as the number of elements, or the fineness of the mesh, is increased, the accuracy of the model increases as well. As multiple models are created with an increasingly finer mesh, the results should converge to the correct numerical solution such that a significant increase in the number of elements produces an insignificant change in a particular response quantity. Not all response quantities will converge at the same rate, however. Displacements will generally be the most accurate response quantity computed and will converge faster than stresses, with the exception of some elements derived with hybrid stress formulations, in which case the stresses can converge at the same rate or higher than the displacements.

Displacement(mm) Displacement(mm)

30.5

30 29.5 29 Displacement (mm)

28.5 28 27.5 0

10

20

30

Divisions Fig 5: Mesh Diagram with division 20

Fig 6: Displacement Vs. Divisions

44 Š Virtu and Foi


Global Journal of Engineering and Scientific Research

Research paper Vol. 1 [issue 1] February, 2014

As far the case of transverse moment goes the value of moment starts to converge at about 10 divisions.

Torsional Moment(kNm/m)

400 Max. Absolute Stress(N/mm 2)

200 0 0

10

20

Torsional Moment(kNm/m)

Absolute Stress(N/mm2)

Max. Absolute Stress(N/mm2)

30

Divisions

150 100

Torsional Moment(kNm /m)

50 0 0

Fig 7: Absolute stress Vs. Divisions Above fig shows that the variation of absolute stress with respect to division shows that the results to converge at about divisions is about 10.

Longitudinal Moment(kNm/m)

Longitudinal Moment(kNm/m)

30

Fig 10: Torsional Moment Vs. Divisions For torsional moment the convergence is achieved only at about 10 division and further increase in division only refines the value .The comparisons with the Results obtained by FE Analysis at about 20 divisions is much close to that obtained by analytical methods CONCLUSION

400

1. The modeling should be done in a very proper way.

200 0 0

20

40

Longitudinal Moment(kN m/m)

2. More the fineness of the meshing more are the chances of getting accurate results. 3. But if we continue to increase the fineness of mesh that will make our program more bulky and which will slow the processing speed.

Divisions

Fig 8: Longitudinal Moment Vs. Divisions

4. The storage requirement also increases with meshing.

From above fig. (8) the longitudinal moment with respect to divisions it starts to converge at division about 20.The result of longitudinal was to much agreement when the number of divisions were 20.

Transverse Moment(kNm/m) Transverse Moment(kNm/m0

10 20 Divisions

100 50 0 0

20

40

Transverse Moment(kN m/m)

REFERENCE 1.Turner,M.J.,Clough,R.W.,Martin,H.C.and Topp,L.J(1956)Stiffness and deflection ana;ysis of complex structures,J.Aero.Sci.23,805-23. 2.Clough,R.W.(1960) ‘The finite element in plane stress analysis’,Proc.2nd A.S.C.E conf.on Electronic Computation,Pittsburg,Pa.,Sept. 3.Burnett,D.S(1987)Finite wesley,Reading ,Mass.

Element

Analysis,Addison-

4. Bentley Systems (2010), ‘STAAD Pro. Lab manual: Getting Started and Tutorials.

Divisions

Fig 9: Transverse moment Vs. Division

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Issue 1