Overcoming construction site challenges

Figure 3. Soil nailing in progress with two steep slopes connected by a valley at the base, creating a river crossing for the pipeline installation.

Figure 4. Working on a steep slope requires winching, which is a process of using cables to move equipment up and down the hillside. Sometimes it is necessary to create a daisy chain, meaning multiple pieces of equipment winched together down the steep slope.

Figure 5. Seeding and mulching is more challenging through mountainous terrain and must be completed using less conventional means, such as by helicopter. Skilled pilots maneouvre these nimble aircrafts along the right-of-way to effectively spread ground cover crops from a spreading bucket. with the different types of slopes and terrain, and how this affects the operation of the equipment.

Constructing pipelines through steep slopes requires a special skillset of the entire crew. Operating heavy equipment with winching processes requires the confidence and experience of the operator and spotter. Pipe stringing and welding activities change based on load size and the equipment’s maximum slope capability, and labour tasks need to be completed with special attention to the effects high altitude may have on the person. Completing competency checks to confirm everyone understands – and is capable of performing – their assigned tasks is critical for safety. “We all have our limits as to what conditions we are comfortable working in and construction through mountainous terrain is not for everyone,” says Mike Lillie, Vice President of Health, Safety and Environment with PPL. “If someone feels uncomfortable with their task and decides to leave the project, I respect that. Knowing yourself and your own capabilities is a priority.”

Equipment and winching Installing infrastructure through mountainous locations uses traditional pipeline construction equipment that has been adapted to the unique challenges of the terrain. Hoisting and rigging configurations are decided and specialised tracks are chosen, typically single grouser pad cleats for enhanced traction. Heavy equipment has additional features added with a focus on winching activities, such as welding specific anchor points and connection systems to each piece to form secure attachment points for the winch cable and a redundancy in safety supports.

Once configured for the specialised task of winching, operators can safely move equipment up and down steep slopes. Communication is critical during this process. Winching involves attaching equipment to a secured tractor, secured winch or fixed pole at the top of the hill so the working equipment can be safely lowered down as well as pulled back to the top. This is done by connecting a steel cable between a winch and a piece of equipment using the reinforced anchor points and support systems, sometimes creating a daisy chain of heavy machinery where multiple pieces of equipment are connected to each other.

This high-stakes type of construction requires dependable equipment built for the task. Materials used to winch, such as steel cable and shackles, as well as the way they are attached to equipment, is all taken into consideration. The production standards, quality, specifications and composition of materials is evaluated and the best performer chosen to be used across the entire project. “Our largest project through steep slopes required us to assess every process and procedure. We researched new materials available in the market as well as implemented the new technologies available,” says Fenton. “We created approved material lists and didn’t allow any substitutions. With 100% support from our

leadership team, we had what we needed to get the job done and the necessary plans to do it safely before it even began.”

Once work begins, communication between crew members is essential. Finding a reliable method can be difficult as many radios have limited reception in mountainous terrain (since these frequencies work by line of sight and steep hills can block signals). Choosing the right radio for the job, and testing prior to work beginning, will ensure everyone is able to communicate throughout the project; again, communication is critical.

In addition, completing daily equipment and material inspections ensures work can begin safely, every day. Crews also address potential hazards and terrain evaluations by participating in safety meetings daily and anytime the scope of work or conditions change. The crew’s confidence in their equipment, coupled with the knowledge that a safe work environment is supported from the Leadership Team, allows for intentional operations throughout the project and final construction of a quality product. Environmental and restoration A successful project also depends on thorough review and complete understanding of the environmental risks and sensitivities posed by each phase of construction, and how to appropriately control and mitigate each activity. Hilly or mountainous terrain must be assessed to identify the most effective controls throughout the entire course of the project and ensure that conditions are restored to enable appropriate restoration as work is completed. Critical factors include slope stability issues, which can occur due to pop-up storms and precipitation events, hillside water, saturation, water pressure in critical joints and unfavorable stratification of rock. Strategic planning and constant monitoring is required to ensure that effective water management is in place, minimising potential erosion. Erosion, extraordinary effects, such as slips/landslides, and external loads can change the geometry of the slope, causing construction plans to change.

Erosion control methods such as temporary and permanent water bars, end treatments and clean water diversions assist to divert runoff from disturbed areas into stable, vegetated areas, are critical in maintaining the slope stability and help mitigate the effects of surface runoff during active construction. “On our extreme mountainous project, building water bars before work ended for the day was part of the construction plan,” says Evanto. “This additional daily task ensured we had a safe worksite in the event of a rain event that night as well as protected the slope while we were still actively constructing in that area.” Typical erosion and sedimentation controls such as silt fence, filter sock, hay bales and other water filtering mechanisms must be evaluated on a site-specific basis to ensure upgraded controls are designed and installed to withstand expected channelised and/or sheet flow off steep slopes.

Figure 6. Mechanical slope stabilisation and proper seeding techniques are used to maintain the hillside and ensure vegetation takes root. On steep slopes, mechanical slope stabilisation and proper seeding techniques is required to maintain the hillside upon completion. Soil nailing is one technique used to ensure the slope is maintained while the vegetation takes root. This technique uses high tensile wire mesh and erosion matting held down with spike plates attached to hollow bar soil nails driven and grouted into bedrock. Each component of soil nailing is designed and tested to work together as an overall system that protects the slope from erosion while also allowing seed mixes to take root. “We test and evaluate every material used in mechanical stabilisation to ensure the desired results for the location where they will be used,” says Schwartzbauer. “For instance, pullout tests of the nails were conducted by applying a load against the nail in tension to verify the planned bond strength and high tensile mesh was evaluated based on durability and performance reports from the manufacturer.” Additional items, such as spacing and grouting of the nails, also play a large role in the success of soil nailing on steep slopes. Once hillsides are secured, seeding takes place to restore the vegetation and provide natural erosion control. In many cases, traditional seeding equipment is unable to traverse up and down the restored hillside when winching activities cease. Because of this, seeding and mulching is more challenging and must be completed using less conventional means such as manual application, far reaching hydroseeders or by helicopter. Using a helicopter and bucket, pilots are able to access all areas of the jobsite and spread the required coverage of approved seed mixes and hydro mulch. Project completion Successfully installing crucial infrastructure through mountainous terrain requires a team of experts, working together from the beginning at preconstruction planning throughout the entire project. “We need everyone on the same page with the same construction plan,” says Evanto. “We make choices based on what is best for safety and the project. Knowing that we are all following the same plan on every spread consistently produces a high-quality product of which everyone can be proud.”

ncreasingly extreme and unpredictable weather conditions, unprecedented pressures on health services caused by the COVID-19 pandemic, and a pressurised employee recruitment and retention funnel are all issues putting strain on the health and safety provision for the pipeline construction industry.

For such inherently challenging and high-risk work, it is vital that pipeline companies consider both the short and long-term safeguarding measures required to protect their workers in the current conditions, with capacity in-built to manage further disruptions and challenges when they arise.

With the difficult terrain, extreme weather conditions and long hours, pipeline construction projects are often located in remote locations, meaning that medical services can be limited. Workers are therefore more vulnerable to onsite injury, especially if they are not used to the work or are simply

Figure 1. RMI Mobile Treatment Centre at a pipeline construction site.

Natalie Henley, Remote Medical International (RMI), USA, outlines how RMI is meeting the increasingly demanding health and safety needs of the trade.