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Structure 808 Webinar with Associated of Kerman University y ((Bahonar ) Of IRAN

Methods of Stability Analysis for the Design of Steel Frames (Evaluation of the ELM and the DAM Method according to AISC 360 360--2005 2005))

‫ﺳﺮﺧﻲ‬

‫ﻣﺠﺘﺒﻲ اﺻﻐﺮي‬

Mojtaba Asghari www.Saze808.com IRAN Kerman December 2010 IRAN,Kerman-December


‫آﻧﭽﻪ در اﻳﻦ دوره ﺗﺎﺑﺤﺎل اﺷﺎره ﺷﺪ‪:‬‬

‫™ ﺑﺮرﺳﻲ ﺗﻐﻴﻴﺮات ﺻﻮرت ﮔﺮﻓﺘﻪ در ﻣﺒﺤﺚ دﻫﻢ وﻳﺮاﻳﺶ ‪ 1387‬و ﻣﻘﺎﻳﺴﻪ ﺑﺎ ‪AISC360-05‬‬ ‫™ ﻧﺤﻮه اﻋﻤﺎل اﻟﺰاﻣﺎت ﻃﺮح ﻟﺮزه اي ﻣﺒﺤﺚ دﻫﻢ در دﻓﺘﺮﭼﻪ ﻣﺤﺎﺳﺒﺎت و ‪ETABS‬‬ ‫™ ﻃﺮاﺣﻲ ﺳﺎزه ﻫﺎي ﻓﻮﻻدي ﺑﻪ روش ﺣﺪي ‪LRFD‬ﺑﺮ اﺳﺎس ﺿﻮاﺑﻂ ﻣﺒﺤﺚ دﻫﻢ و ‪ AISC 360-05‬در ‪ETABS‬‬

‫ﺷﻮد‪::‬‬ ‫و آﻧﭽﻪ در اﻳﻦ ﺳﻤﻴﻨﺎر اﺷﺎره ﻣﻲ ﺷﻮد‬ ‫™ روش ﻫﺎي ﺑﻜﺎر ﮔﻴﺮي اﺛﺮ ﻣﺮﺗﺒﻪ دوم)ﻟﻨﮕﺮ ﺛﺎﻧﻮﻳﻪ(‬ ‫ﻣﻄﺎﺑﻖ ﻣﺒﺤﺚ دﻫﻢ و ‪AISC 360-05‬‬


(‫™روش ﻫﺎي ﺑﻜﺎر ﮔﻴﺮي اﺛﺮ ﻣﺮﺗﺒﻪ دوم)ﻟﻨﮕﺮ ﺛﺎﻧﻮﻳﻪ‬ ™Stability Analysis in Design of Steel Building In ETABS v.9.5 with AISC 360 360-05 05 Standard

‫روش اﻋﻤﺎل اﺛﺮ ﺛﺎﻧﻮﻳﻪ در دو ﮔﺰﻳﻨﻪ‬ Second ‫ و‬Design Analysis Method : ‫ﻗﺎﺑﻞ ﺗﺗﻌﻴﻴﻦ ااﺳﺖ‬ ‫ ﻗﺎ ﻞ‬Order Od M Method th d Direct Analysis ‫آﻧﺎﻟﻴﺰ ﻣﺴﺘﻘﻴﻢ‬ Effective Length ‫ﻃﻮل ﻣﻮﺛﺮ‬

Design Analysis Method

Stability Analysis in ETABS

Limited 1st Order‫ﻣﺮﺗﺒﻪ اول‬

General 2nd Order

P−Δ

‫آآﻧﺎﻟﻴﺰ ﻋﻤﻮﻣﻲ ﻣﺮﺗﺒﻪ دوم‬

Second Order Method

Amplified 1st Order

‫ﻣﺮﺗﺒﻪ اول ﺗﺸﺪﻳﺪ ﻳﺎﻓﺘﻪ‬


‫ﻣﻄﺎﺑﻖ ‪ AISC 360-05‬ﻫﻔﺖ روش ﺑﺮاي ﻟﺤﺎظ آﺛﺎر ﺛﺎﻧﻮﻳﻪ وﺟﻮد دارد‪:‬‬ ‫‪¾ 7 Method for Stability Analysis with AISC 360-05 :‬‬ ‫ﺿﺮﻳﺐ ﻛﺎﻫﺶ ﺳﺨﺘﻲ‬ ‫ﺗﺤﻠﻴﻞ ﻋﻤﻮﻣﻲ ﻣﺮﺗﺒﻪ دوم‬

‫‪P−Δ‬‬

‫آﻧﺎﻟﻴﺰ ﻣﺴﺘﻘﻴﻢ‬

‫‪Stability‬‬ ‫‪Analysis‬‬ ‫‪Methods‬‬

‫ﺿﺮﻳﺐ ﻛﺎﻫﺶ ﺳﺨﺘﻲ‬ ‫‪Fixed‬‬ ‫ﺳﺨﺘﻲ‬ ‫ﺿﺮﻳﺐ ﻛﺎﻫﺶ ﺨﺘ‬ ‫ﺿ‬

‫‪Direct Analysis‬‬

‫آﻧﺎﻟﻴﺰ ﭘﺎﻳﺪاري‬

‫‪Variable‬‬

‫ﺗﺤﻠﻴﻞ ﻣﺮﺗﺒﻪ اول ﺗﺸﺪﻳﺪ ﺷﺪه‬

‫‪Variable‬‬

‫‪Amplified 1st Order‬‬

‫ﺿﺮﻳﺐ ﻛﺎﻫﺶ ﺳﺨﺘﻲ‬ ‫‪Fixed‬‬

‫ﺗﺤﻠﻴﻞ ﻋﻤﻮﻣﻲ ﻣﺮﺗﺒﻪ دوم‬

‫‪P−Δ‬‬

‫ﺿﺮاﻳﺐ ﻃﻮل ﻣﻮﺛﺮ‬ ‫‪Effective Length‬‬

‫ﺗﺤﻠﻴﻞ ﻣﺮﺗﺒﻪ اول ﺗﺸﺪﻳﺪ ﺷﺪه‬ ‫‪Amplified 1st Order‬‬

‫ﺗﺤﻠﻴﻞ ﻣﺮﺗﺒﻪ اول ﻣﺤﺪود‬ ‫‪Limited 1st Order‬‬


‫‪Design Analysis Method :‬‬ ‫™ روش آﻧﺎﻟﻴﺰ ﻣﺴﺘﻘﻴﻢ ‪Direct Analysis‬‬ ‫روش ﺟﺪﻳﺪ آﻳﻴﻦ ﻧﺎﻣﻪ ‪ AISC‬اﺳﺖ و ﺗﺤﻠﻴﻞ اﺛﺮات ﺛﺎﻧﻮﻳﻪ ﺑﻪ ﺻﻮرت ﻣﺴﺘﻘﻴﻢ ﺑﺎ ﺗﺤﻠﻴﻞ ‪ P − Δ‬ﻳﺎ ﻏﻴﺮ ﻣﺴﺘﻘﻴﻢ‬ ‫ﭘﺴﻤﺎﻧﺪ‬ ‫ﻫﺎي ﺎ‬ ‫ﻛﺎﻫﺶ ﺳﺨﺘﻲ ﻣﺤﻮري و ﺧﻤﺸﻲ ﺎﻧﺎﺷﻲ ااز ﺗﻨﺶ ﺎ‬ ‫اﻋﻤﺎل ﻣﻲ ﺷﻮد‪ .‬ااﺛﺮ ﻛﺎ‬ ‫ﻟﻨﮕﺮ روي ااﻋﻀﺎﺎ ا ﺎل‬ ‫ﺿﺮاﻳﺐ ﺗﺸﺪﻳﺪ ﻟ ﮕ‬ ‫ﺎﺑﺎ ا‬ ‫ﺑﻪ ﺻﻮرت ﻣﺴﺘﻘﻴﻢ اﻋﻤﺎل ﻣﻲ ﺷﻮد‪ .‬در ﻣﺒﺤﺚ دﻫﻢ اﺷﺎره اي ﺑﻪ اﻳﻦ روش ﻧﺸﺪه اﺳﺖ‪.‬‬ ‫™ روش ﻃﻮل ﻣﻮﺛﺮ ‪Effective Length‬‬ ‫روش ﺳﻨﺘﻲ آﻳﻴﻦ ﻧﺎﻣﻪ ‪ AISC‬و روش اﺻﻠﻲ ﻣﻌﺮﻓﻲ ﺷﺪه در ﻣﺒﺤﺚ دﻫﻢ ﻣﻴﺒﺎﺷﺪ و در آن از ﺿﺮﻳﺐ ﻃﻮل ﻣﻮﺛﺮ‬ ‫ﺷﻮﻧﺪ‪.‬‬ ‫ﮔﺮﻓﺘﻪ ﻣﻲ ﺷ ﻧ‬ ‫ﻧﻈﺮ ﮔ ﻓ‬ ‫ﻟﻨﮕﺮ در ﻧﻈ‬ ‫ﺿﺮﻳﺐ ﺗﺸﺪﻳﺪ ﻟ ﮕ‬ ‫ﻣﺤﺎﺳﺒﻪ ﺿ‬ ‫ﻞ ﻳﺎﺎ ﺎ‬ ‫ﺗﺤﻠﻴﻞ‬ ‫اﻋﻤﺎل ﻠ‬ ‫ﺛﺎﻧﻮﻳﻪ ﺎﺑﺎ ا ﺎل‬ ‫اﺛﺮات ﺛﺎﻧ‬ ‫ﺷﻮد و اﺛ ا‬ ‫اﺳﺘﻔﺎده ﻣﻲ ﺷ‬ ‫‪ K‬ا ﻔﺎ‬ ‫™ روش ﻃﺮاﺣﻲ اﻋﻀﺎ ﺑﺪون ﻟﺤﺎظ ﻛﺮدن آﺛﺎر ﻣﺮﺗﺒﻪ دوم ‪Limited 1st Order‬‬

‫اﺳﺘﻔﺎده از اﻳﻦ روش ﻋﻼوه ﺑﺮ ﺗﺎﻣﻴﻦ ﺷﺮوط ﻣﺮﺑﻮﻃﻪ ﺑﻨﺪ ‪ 6-1-7-2-10‬ﻣﺒﺤﺚ دﻫﻢ ‪ ،‬داراي ﺗﻘﺮﻳﺐ ﻗﺎﺑﻞ ﺗﻮﺟﻬﻲ‬ ‫ﻫﻢ ﺧﻮاﻫﺪ ﺑﻮد ﻛﻪ ﺑﻪ ﺟﻬﺖ ﻣﺤﺪودﻳﺖ ﻫﺎي ﻣﻮﺟﻮد‪ ،‬اﺳﺘﻔﺎده از اﻳﻦ روش ﺑﻪ ﻃﻮر ﻛﻠﻲ ﺗﻮﺻﻴﻪ ﻧﻤﻲ ﺷﻮد‪.‬‬


‫‪Advanced analysis or‬‬ ‫‪second-order inelastic analysis for frame design:‬‬ ‫ƒﻟﺤﺎظ ﺧﻄﺎﻫﺎي اﺟﺮاﻳﻲ در ﺣﻴﻦ ﺑﺎرﻫﺎي ﺛﻘﻠﻲ ﭘﻴﺶ ﺑﻴﻨﻲ ﺷﺪه‬ ‫ﻫﻨﺪﺳﻲ‬ ‫ﻧﻮاﻗﺺ ﻫﻨﺪ‬ ‫ƒ اﺛاﺛﺮ ﻧ اﻗ‬ ‫ƒ ﺧﺎﺻﻴﺖ ﻏﻴﺮ اﻻﺳﺘﻴﻚ ﺑﻪ دﻟﻴﻞ ﻋﺪم ﺗﻮﺟﻪ ﺑﻪ ﺧﺮوج از ﻣﺤﻮرﻳﺖ‬ ‫ƒو ﻛﺎﻫﺶ ﺳﺨﺘﻲ ﻋﻀﻮ ﻧﺎﺷﻲ از ﺗﻨﺶ ﻫﺎي ﭘﺲ ﻣﺎﻧﺪ ﻛﻪ در‬ ‫ﺗﺤﻠﻴﻞ رخ ﻣﻲ دﻫﺪ‬

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AISC 2005 ‫ﻣﺰﻳﺖ روش ﻫﺎي ﺟﺪﻳﺪ ﺗﺤﻠﻴﻞ ﭘﺎﻳﺪاري در‬

: ‫در ﺗﺤﻠﻴﻞ ﻫﺎي ﻏﻴﺮ اﻻﺳﺘﻴﻚ‬

It is a state-of-the-art methodology for the structural engineering profession for the 21st century. 7


8


‫‪ AISC 360‬در ﻟﺤﺎظ اﺛﺮ ﻣﺮﺗﺒﻪ دوم ‪:‬‬ ‫‪360-05‬‬ ‫ﺗﻔﺎوت ﻋﻤﺪه ﻣﺒﺤﺚ دﻫﻢ ﺑﺎ ‪05‬‬ ‫ﻣﻄﺎﺑﻖ ‪ AISC 360-05‬ﺑﺮﺧﻼف ﻣﺒﺤﺚ دﻫﻢ اﻧﺘﺨﺎب روش ﻟﺤﺎظ آﺛﺎر ﻣﺮﺗﺒﻪ دوم واﺑﺴﺘﻪ ﺑﻪ‬ ‫ﻳﻜﻲ از ﺷﺮاﻳﻂ ‪ B2 = Δ2nd / Δ1st > 1.5‬ﻳﺎ ‪، B2 = Δ 2 nd / Δ1st ≤ 1.5‬ﻳﻜﻲ از ﺳﻪ روش آﻧﺎﻟﻴﺰ ﻣﺴﺘﻘﻴﻢ ‪،‬‬ ‫روش ﻃﻮل ﻣﻮﺛﺮ و ﻣﺮﺗﺒﻪ اول ﻣﻴﺒﺎﺷﺪ‪.‬‬ ‫در ﺣﺎﻟﻴﻜﻪ ﻣﺒﺤﺚ دﻫﻢ اﺳﺘﻔﺎده از روش ﻫﺎي ﻟﺤﺎظ آﺛﺎر ﻣﺮﺗﺒﻪ دوم را ﺗﻨﻬﺎ از ﻳﻜﻲ از دو روش ﻃﻮل‬ ‫ﻣﻮﺛﺮ و روش ﻣﺮﺗﺒﻪ اول ﻣﺠﺎز ﻣﻲ داﻧﺪ‪.‬‬ ‫ﻣﻄﺎﺑﻖ ‪ AISC 360-05‬در ﺣﺎﻟﺖ ‪ B2 = Δ2nd / Δ1st > 1.5‬از ﻣﻴﺎن ﺳﻪ روش ﻟﺤﺎظ اﺛﺮ ﻣﺮﺗﺒﻪ دوم ﺗﻨﻬﺎ‬ ‫روش آﻧﺎﻟﻴﺰ ﻣﺴﺘﻘﻴﻢ ﻗﺎﺑﻞ اﺳﺘﻔﺎده ﻣﻴﺒﺎﺷﺪ‪.‬‬


Design Analysis Method :

AISC 2005 Specification C2 2 Design C2.2 D i R Requirements i t

¾Effective Length Method (C2.2a) • Limited application pp • uses K>1.0

¾First-order analysis (C2.2b) • Limited application • Simplest approach

¾Direct Analysis Method (Appendix 7) • Applies to all buildings (K=1.0) • Preferred method


Effective Length MethodÆ ELM ¾ Applies pp when

‫روش ﻃﻮل ﻣﻮﺛﺮ‬

B2 = Δ 2 nd / Δ1st ≤ 1.5

¾ Notional Loads, Ni = 0.002Yi (gravity load combinations) ¾ Second-Order Analysis Nominal Geometry Nominal Stiffness ¾ K from a sidesway buckling analysis Δ 2 nd / Δ1st ≤ 1.1 then K=1.0

‫ )ﻧﺴـﺒﺖ ﺟﺎﺑﺠـﺎﻳﻲ ﺛﺎﻧﻮﻳـﻪ ﺑـﻪ‬B2 ≤ 1.5

‫ ﺗﻨﻬﺎ در ﺻﻮرت ﺑﺮﻗﺮاري ﺷﺮط‬AISC360-05 ‫ﻣﻄﺎﺑﻖ آﻳﻴﻦﻧﺎﻣﻪ‬ .‫ﺟﺎﺑﺠﺎﻳﻲ اوﻟﻴﻪ( ﻣﺠﺎز ﺑﻪ اﺳﺘﻔﺎده از روش ﻃﻮل ﻣﻮﺛﺮ ﺧﻮاﻫﻴﻢ ﺑﻮد‬


‫ﻣﻌﺎﻳﺐ روش ﻫﺎي ﺳﻨﺘﻲ آﻧﺎﻟﻴﺰ ﭘﺎﻳﺪاري ﺳﺎزه ﻫﺎي ﻓﻮﻻدي‪:‬‬ ‫روش ﻃﻮل ﻣﻮﺛﺮ ‪Effective Length‬‬ ‫™ ﻋﺪم ﻗﺎﺑﻠﻴﺖ اﻧﻌﻜﺎس ﺗﻮزﻳﻊ ﻏﻴﺮ اﻻﺳﺘﻴﻚ ﻧﻴﺮو ﻫﺎي داﺧﻠﻲ در ﺳﻴﺴﺘﻢ ﺳﺎزه اي‬ ‫™ ﻋﺪم ﺗﺸﺨﻴﺺ اﻃﻼﻋﺎت ﻣﻜﺎﻧﻴﺰم ﺷﻜﺴﺖ اﻋﻀﺎ در ﺳﻴﺴﺘﻢ ﺳﺎزه اي‬ ‫™ آﻧﺎﻟﻴﺰ ﭘﺎﻳﺪاري ﺑﺎ روش ﻃﻮل ﻣﻮﺛﺮ در ﻧﺮم اﻓﺰارﻫﺎي ﻣﺤﺎﺳﺒﺎﺗﻲ ﺑﻪ ﺟﻬﺖ ﻟﺰوم ﻣﺤﺎﺳﺒﻪ ‪ K‬ﺑﺮاي ﻫﺮ‬ ‫ﻲ ﺮ‬ ‫ﺳﺮﻋﺖ ﻛﻤﻲ‬ ‫ﭘﺎﻳﺪاري ﺑﺑﺎ ﺮ‬ ‫آﻧﺎﻟﻴﺰ ﭘ ﻳ ري‬ ‫ﺑﺮرﺳﻲ ﻴﺰ‬ ‫ﺳﭙﺲ ﺑﺮر ﻲ‬ ‫ﻋﻀﻮ و ﭙﺲ‬ ‫ﻮ‬ ‫ﻫﻤﺮاه اﺳﺖ‬ ‫™ و ﻣﻬﻢ ﺗﺮ اﻳﻨﻜﻪ ﻫﻤﻮاره در ﺗﻌﻴﻴﻦ ﺿﺮﻳﺐ ‪ K‬ﺑﺎ ﻣﺸﻜﻼت و ﭘﻴﭽﻴﺪﮔﻲ ﻫﺎﻳﻲ ﺑﺮاي ﻣﻮارد ﺧﺎص‬ ‫ﻣﻮاﺟﻪ ﺑﻮدﻳﻢ ﻛﻪ روﻧﺪ آﻧﺎﻟﻴﺰ را ﺑﺎ ﻣﺸﻜﻞ روﺑﺮو ﻣﻲ ﺳﺎزد ﻣﺎﻧﻨﺪ‪:‬‬

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First-Order First Order Method ¾ Applies when

‫روش ﻣﺮﺗﺒﻪ اول‬

B2 = Δ 2 nd / Δ1st ≤ 1.5

And aPr ≤ 0.5Py for all lateral members ⎛Δ⎞ N i = 2.1 ⎜ ⎟ Yi ≥ 0.0042Yi ¾ Notional Loads ⎝L⎠ ¾ First-Order First Order Analysis on Nominal Geometry using Nominal Stiffness ¾ Apply B1 to total member moments ¾ Use K=1.0 ‫ﻢ و روش ﺣﺎﻟـﺖ ﺣـﺪي‬ ‫ي‬ ‫ﻣﺒﺤـﺚ دﻫـﻢ‬ ‫ي ﺒ‬ ‫ول درر روش ﺣﺎﻟـﺖ ﺣـﺪي‬ ‫ﻣﺮﺗﺒﻪ اول‬ ‫ﻴﺰ ﺮ ﺒ‬ ‫ﺗﻔﺎوت اﺳﺘﻔﺎده زاز آﻧﺎﻟﻴﺰ‬ ‫ﻣﻬﻤﺘﺮﻳﻦ و‬ ‫ﻬ ﺮﻳﻦ‬ ‫ ﺑﺮاي اﺳـﺘﻔﺎده از روش‬AISC 360-05 ‫ در‬،6-1-7-2-10‫ در اﻳﻨﺴﺖ ﻛﻪ ﻋﻼوه ﺑﺮ ﺷﺮوط ﺑﻨﺪ‬AISC 360-05 .‫ ﻧﻴﺰ ﺑﺮﻗﺮار ﺑﺎﺷﺪ‬B2 ≤ 1.5 ً‫ﺗﺤﻠﻴﻞ ﻣﺮﺗﺒﻪ اول ﻣﻴﺒﺎﻳﺴﺖ ﻟﺰوﻣﺎ‬ 1 5 ‫ﻟﺰوﻣﺎ ﺷﺮط‬


Direct Analysis MethodÆ DAM 9Applies to all structures

‫روش آﻧﺎﻟﻴﺰ ﻣﺴﺘﻘﻴﻢ‬

B 2 < 1 . 5, B 2 ≥ 1 . 5

9 K=1.0 K=1 0 9 Straight-forward Analysis and Design 9 Improved Results & Less potential for error 9 Applies to all lateral systems or combination of systems w/o distinction 9 Most accurate determination of internal forces when combined with rigorous second-order analysis

:‫ﻣﺰاﻳﺎي روش آﻧﺎﻟﻴﺰ ﻣﺴﺘﻘﻴﻢ‬ .‫ ﻗﺎﺑﻞ اﺳﺘﻔﺎده اﺳﺖ‬B 2 < 1 .5, B 2 ≥ 1 .5 ‫•در ﻫﺮ دو ﺻﻮرت ﺑﺮﻗﺮاري ﺷﺮط‬

K

‫در اﻳﻦ روش ﺿﺮﻳﺐ‬.‫ ﻧﻴﺎزي ﺑﻪ ﻛﻨﺘﺮل ﻃﺒﻘﻪ ﻣﻬﺎر ﺷﺪه و ﻧﺸﺪه ﺑﺮاي ﺳﺎزه ﻫﺎ ﻧﻴﺴﺖ‬، ‫• در ﺻﻮرت اﻧﺠﺎم ﺗﺤﻠﻴﻞ آﻧﺎﻟﻴﺰ ﻣﺴﺘﻘﻴﻢ‬ .‫ اﻧﺘﺨﺎب ﻣﻲ ﺷﻮد‬1 ‫ﺑﺮاي ﻫﻤﻪ ﺳﺘﻮن ﻫﺎ ﺑﺮاﺑﺮ‬

‫ﻲ ﺑﺎﺷﺪ و ﻣﻨﺠﺮ ﺑﻪ ﻧﺘﺎﻳﺞ‬ ‫ﺞ‬ ‫ ﻣﻲ‬Effective Length ‫ﻊ ﺗﺮ از روش ﺿﺮﻳﺐ ﻃﻮل ﻣﻮﺛﺮ‬ ‫ﻣﺴﺘﻘﻴﻢ ﺗﻮﺳﻂ ﻛﺎرﺑﺮ ﺳﺎده ﺗﺮ و ﺳﺮﻳﻊ‬ ‫ﻢ‬ ‫اﻧﺠﺎم آﻧﺎﻟﻴﺰ‬ ‫• م‬ .‫واﻗﻌﻲ ﺗﺮ از ﺳﺎزه ﻣﻲ ﺷﻮد‬


‫)‪Stiffness Reductions (Inelasticity‬‬ ‫‪EA* = 0.8 EA‬‬

‫‪¾ Axial Stiffness‬‬

‫‪EI* = 0.8 τ b EI‬‬

‫‪¾ Flexural Stiffness‬‬

‫‪αPr ≤ 0.5‬‬ ‫‪⎧1.0‬‬ ‫⎫‬ ‫‪Py‬‬ ‫⎪⎪‬ ‫⎪⎪‬ ‫⎨ = ‪τb‬‬ ‫⎬‬ ‫⎪‪αPr > 0.5‬‬ ‫⎟⎞ ‪⎪4⎛⎜ αPr ⎞⎟⎛⎜1 − αPr‬‬ ‫⎝⎠ ‪Py‬‬ ‫⎠ ‪Py‬‬ ‫‪Py‬‬ ‫⎝ ⎩⎪‬ ‫⎭⎪‬ ‫‪α = 1(LRFD ),‬‬ ‫) ‪α = 1.6( ASD‬‬

‫‪¾Ultimately this allows for K=1.0‬‬ ‫‪¾ τ b =1.0 may be used for all members provided an additive notional load of‬‬ ‫‪0.001Yi is applied‬‬

‫ﺛﺎﺑﺖ و‬ ‫ﺻﻮرت ﺛﺎ ﺖ‬ ‫ﺑﻪ ﺻ ت‬ ‫ﺧﻤﺸﻲ ارا ﻪ‬ ‫ﺳﺨﺘﻲ ﺧ ﺸ‬ ‫ش ﻫﺎي ﻛﺎﻫﺶ ﺨﺘ‬ ‫ﻳﻜﻲ از روش‬ ‫ﻣﺴﺘﻘﻴﻢ‪ ،‬ﺎﺑﺎﻳﺪﺪ ﻜ‬ ‫ﺗﺤﻠﻴﻞ ﺘﻘ‬ ‫ش ﺗﺤﻠ ﻞ‬ ‫ددر روش‬ ‫ﻣﺘﻐﻴﺮ اﻧﺘﺨﺎب ﻛﺮد‪.‬‬ ‫در ﺣﺎﻟﺖ ﻣﺘﻐﻴﺮ ﺿﺮﻳﺐ ‪ τ b‬ﺗﺎﺑﻌﻲ از ﻧﻴﺮوي ﻣﺤﻮري ﺳﺘﻮن ﻫﺎ ﺧﻮاﻫﺪ ﺑﻮد‪.‬در ﺣﺎﻟﺖ ﺳﺨﺘﻲ ﺛﺎﺑﺖ‬ ‫ﺑﻮد‪.‬‬ ‫ﺧﻮاﻫﺪ د‬ ‫‪ 0.8‬ﺧ ا ﺪ‬ ‫ﺑﺮاﺑﺮ ‪0 8‬‬ ‫ﺧﻤﺸﻲ ا‬ ‫ﺳﺨﺘﻲ ﺧ ﺸ‬ ‫ﻛﺎﻫﺶ ﺨﺘ‬ ‫ﺑﻮده و ﻛﺎ ﺶ‬ ‫‪ 1.0‬د‬ ‫ﺑﺮاﺑﺮ ‪1 0‬‬ ‫ﺿﺮﻳﺐ ‪ τ b‬ا‬ ‫ﺿ‬


Stiffness Reduction Reduced flexural stiffness, 0.8 τ b EI Generally

τ b = 1.0 for the following :

¾ Beams moment frames (low axial load) Braced frames (flexural stiffness does not contribute) ¾ Braces (flexural stiffness does not contribute) ¾ Columns in braced frames (flexural stiffness does not contribute)

Can take τ b = 1.0 for all members if : ¾ apply additional notional load

Ni = 0.001Yi

¾ Eliminates iteration! ‫ﻣﻴﺒﺎﺷـﺪ اﻣـﺎ در ﺣﺎﻟـﺖ اﻧﺘﺨـﺎب ﺿـﺮﻳﺐ‬0.002 ‫در ﺣﺎﻟﺖ ﺿﺮﻳﺐ ﻛﺎﻫﺶ ﺳﺨﺘﻲ ﻣﺘﻐﻴﺮ ﺿﺮﻳﺐ ﺑﺎر ﻣﺠﺎزي ﺑﺮاﺑـﺮ‬ ‫ﺿـﺮﻳﺐ‬ ‫ﻣﻘـﺪار ﺿ‬ ‫اﻃﻤﻴﻨـﺎن ﻘ ﺪا‬ ‫ﺟﻬـﺖ اﻃ ﺎ‬ ‫ﭼﻨﺎﻧﭽـﻪ در ﺖ‬ ‫ ﻳﻌﻨـﻲ ﺎﻧ‬.‫ﺧﻮاﻫﺪ ﺑﻮد‬ ‫ ﺧ ا ﺪ‬0.0033 ‫ﻣﻘﺪار‬ ‫ﺿﺮﻳﺐ ﻘﺪا‬ ‫ﺖ ااﻳﻦ ﺿ‬ ‫ﺳﺨﺘﻲ ﺛﺎﺛﺎﺑﺖ‬ ‫ﺶ ﺨﺘ‬ ‫ﻛﺎﻫﺶ‬ ‫ﻛﺎ‬ .‫ ﺑﺎر ﻣﺠﺎزي ﺟﺎﻧﺒﻲ ﺑﻴﺸﺘﺮي ﺗﺤﻠﻴﻞ ﻛﺮد‬50% ‫ ﻓﺮض ﺷﻮد ﻣﻴﺒﺎﻳﺴﺖ ﺳﺎزه را ﺑﻪ ﻣﻴﺰان‬1 ‫ﻛﺎﻫﺶ ﺳﺨﺘﻲ ﺑﺮاﺑﺮ‬


Procedure Summary ¾Model the structure (no change) ¾Apply Notional Loads ¾Perform second-order second order analysis on nominal geometry with reduced stiffness ¾Design all members for resulting forces ¾Design compression members with K=1.0

Updates Stability Design Requirements ¾New requirements for analysis ¾Recognizes current analysis options ¾Addresses shortcomings of previous methods (K = ?) ¾Provides straight-forward methods

DAM is most general and accurate approach


‫‪Direct Analysis in CSI Programs:‬‬ ‫‪Direct Analysis using ETABS v.9.6 :‬‬

‫ﭼﻨﺎﻧﭽﻪ آﻧﺎﻟﻴﺰ ﻣﺴﺘﻘﻴﻢ ﺑﺎ ﻟﺤﺎظ ﺿﺮﻳﺐ ﻛﺎﻫﺶ ﺳﺨﺘﻲ ﻣﺘﻐﻴﺮ ﻣﺪﻧﻈﺮ ﺑﺎﺷﺪ از ﻛﺸﻮي ‪Stiffness‬‬ ‫‪ Reduction Method‬ﻋﺒﺎرت ‪ Tau-b Variable‬و ﺑﺮاي آﻧﻜﻪ ﺿﺮﻳﺐ ﻛﺎﻫﺶ ﺳﺨﺘﻲ ﺛﺎﺑﺖ درﻧﻈﺮ‬ ‫ﺟﺎﻧﺒﻲ ﺑﻪ‬ ‫ﻣﺠﺎزي ﺟﺎﻧ‬ ‫ﺷﺮﻃﻴﻜﻪ ﺑﺎﺑﺎر ﻫﺎي ﺠﺎزي‬ ‫ﺷﻮد )ﺑﻪ ﺷ ﻃ ﻜﻪ‬ ‫‪ Tau-b‬اﻧﺘﺨﺎب ﻣﻲ ﺷ د‬ ‫ﺷﻮدد ﮔﺰﻳﻨﻪ ‪Tau b Fixed‬‬ ‫ﻓﺘﻪ ﺷ‬ ‫ﮔﮔﺮﻓﺘﻪ‬ ‫ﻣﻴﺰان ‪ 0.001‬ﺑﻴﺸﺘﺮ ﻣﻨﻈﻮر ﺷﻮد(‬

‫‪Direct Analysis Method using‬‬ ‫‪SAP2000 v. 11.0.7 :‬‬


Second Order Analysis in ASD - AISC 360-05 :

他Carried out under 1.6 times ASD load combination 他Results divided by 1.6 to obtain required strengths

In Direct second order analysis , the method already includes 1.6 factor


Initial imperfections, either ¾Notional Loads at each level, or • Notional Loads at each level • Ni = 0.002Yi • Yi = total gravity load on a level • Applied to all load combinations Applied only in Gravity Combos, except for B2 ≤ 1.5 Gravity load combinations: Two orthogonal directions Positive and negative sense Same direction at all levels ¾Model with assumed out-of-plumbness

‫ﺑﺎر ﻫﺎي ﻣﺠﺎزي‬


‫رواﺑﻂ و ﺣﺎﻻت ﻣﻨﺪرج در ‪ AISC 360-05‬ﻣﻄﺎﺑﻖ ﺟﺪول ‪ 1-2‬از راﻫﻨﻤﺎي آﻳﻴﻦ ﻧﺎﻣﻪ‬ ‫‪ AISC360-05‬ﻣﻮﺟﻮد در ‪: ETABS‬‬


S Second dO Order d A Analysis l i:

General 2nd Order

P−Δ

‫ﻣﺮﺗﺒﻪ دوم‬ ‫آﻧﺎﻟﻴﺰ ﻋﻤﻮﻣﻲ ﺗ‬ ‫آﻧﺎﻟ‬

Amplified 1st Order ‫ﻣﺮﺗﺒﻪ اول ﺗﺸﺪﻳﺪ ﻳﺎﻓﺘﻪ‬

Second Order Method ‫روش ﻫﺎي ﻟﺤﺎظ اﺛﺮ ﻣﺮﺗﺒﻪ دوم‬


General 2nd Order ( P − Δ ‫روش ﻋﻤﻮﻣﻲ ﺗﺤﻠﻴﻞ ﻣﺮﺗﺒﻪ دوم )ﺗﺤﻠﻴﻞ ﻏﻴﺮﺧﻄﻲ ﻫﻨﺪﺳﻲ‬ P−Δ

‫•اﺛﺮ ﺛﺎﻧﻮﻳﻪ ﺑﺮاي ﺑﺎرﻫﺎي ﺟﺎﻧﺒﻲ‬

P −δ

‫• اﺛﺮ ﺛﺎﻧﻮﻳﻪ ﺑﺮاي ﺑﺎر ﻫﺎي ﺛﻘﻠﻲ‬

General Second-Order Analysis ¾ Free of limitations of amplified first-order method ¾ More accurate determination of internal forces and strength level deformations Complex geometry irregular lateral framing ¾ Structure Analyzed for Load Combinations (ASD with a 1.6 factor) ¾ Stable model required


‫ﺗﺤﻠﻴﻞ ‪ P − Δ‬در‪ETABS‬‬ ‫‪AISC 360-05‬‬

‫‪P-Delta Combination in LRFD‬‬ ‫ﻣﺒﺤﺚ دﻫﻢ ﺣﺎﻟﺖ ﺣﺪي‬

‫ﺗﺤﻠﻴﻞ ‪ P − δ‬در‪ETABS‬‬ ‫اﺛﺮات ﺛﺎﻧﻮﻳﻪ ﺗﺸﺪﻳﺪ ﻟﻨﮕﺮ ﻣﺮﺑﻮط ﺑﻪ ﺑﺎر ﻫﺎي ﺛﻘﻠﻲ در اﻛﺜﺮ ﻣﻮارد ﻧﺴﺒﺖ ﺑﻪ ‪ P − Δ‬ﻧﺎﭼﻴﺰ ﻣﻲ‬ ‫ﺑﺤﺮاﻧﻲ ﺧﻮاﻫﺪ ﺷﺪ‪.‬‬ ‫ﺑﺎﺷﻨﺪ و ﺗﻨﻬﺎ ﺑﺮاي ﺳﺘﻮن ﻫﺎي ﺑﺎ ﻃﻮل ﺑﻠﻨﺪ و ﻣﻘﻄﻊ ﻛﻮﭼﻚ ﺑﺤﺮاﻧ‬ ‫ﺑﺮاي اﻳﻦ ﺗﺤﻠﻴﻞ ﻻزم اﺳﺖ ﺳﺘﻮن ﻫﺎ در ﻃﻮل ﺧﻮد ﺗﻘﺴﻴﻢ ﺑﻨﺪي ﺷﻮﻧﺪ‬


‫روش ﺗﺸﺪﻳﺪ ﻟﻨﮕﺮ ﻫﺎي ﺧﻤﺸﻲ‬

‫)‪(Amplified 1st Order‬‬


Li it ti Limitations off Amplified A lifi d Fi First-Order tOd A Analysis l i : ¾ Have to separate translation and no-translation moments ¾ Engineering g g jjudgment g often required q Distribution of moments where B2 factors vary at a joint ¾ Complex geometry cause difficulties Sloping beams and columns Floor levels not readily identifiable :‫ﺗﻮﺟﻪ ﻣﻬﻢ‬ ‫ ﻧﻴﺴﺖ و اﻳﻦ‬B2 ‫ ﻓﻌﻼً ﻗﺎدر ﺑﻪ ﻣﺤﺎﺳﺒﻪ ﺿﺮﻳﺐ‬،‫ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﺗﻮﺿﻴﺤﺎت ﻣﻨﺪرج در راﻫﻨﻤﺎي ﺑﺮﻧﺎﻣﻪ‬ETABS ‫ﺿﺮﻳﺐ را ﺑﻪ ﻃﻮر ﭘﻴﺶ ﻓﺮض ﻳﻚ در ﻧﻈﺮ ﻣﻲﮔﻴﺮد‬ ‫ﺑﺮ اﻳﻦ اﺳﺎس ﺟﺪا از ﻣﺸﻜﻠﻲ ﻛﻪ در ﺗﺸﺪﻳﺪ ﻟﻨﮕﺮ و ﺑﺎر ﻣﺤﻮري در ﻗﺎبﻫﺎي ﻣﻬﺎر ﻧﺸﺪه ﭘﻴﺶ ﻣﻲآﻳﺪ در ﻗﺎبﻫﺎي‬ .‫ﻛﻤﺘﺮ ﺑﻪ دﺳﺖ ﻣﻣﻲآﻳﺪ‬ ‫ﻧﺎﻣﻪ اﺳﺖ ﻛﻤﺘ‬ ‫ﻦﻧﺎﻣﻪ‬ ‫ﻧﻈﺮ آﻳآﻳﻴﻦ‬ ‫ﻣﻮرد ﻧﻈ‬ ‫ﻟﻨﮕﺮ ﺗﺸﺪﻳﺪ ﺷﺪه از آﻧﭽﻪ ﻛﻪ ﻣﻮ د‬ ‫ﻣﻘﺪار ﻟﻨﮕ‬ ‫ﻣﻬﺎر ﺷﺪه ﻣﻘﺪا‬ ‫ﻣﻬﺎ‬


‫ﺑﻨﺎﺑﺮاﻳﻦ ﻣﻄﺎﺑﻖ ﻣﺒﺤﺚ دﻫﻢ‪:‬‬ ‫‪Design Analysis‬‬ ‫‪Method‬‬

‫ﻧﺤﻮه اﻋﻤﺎل اﺛﺮ ﻣﺮﺗﺒﻪ‬ ‫دوم ﺣﺎﻟﺖ ﺣﺪي در‬ ‫‪ETABS‬‬

‫ﻃﻮل ﻣﻮﺛﺮ ‪Effective Length‬‬

‫‪General 2nd Order‬‬ ‫آﻧﺎﻟﻴﺰ ﻋﻤﻮﻣﻲ ﻣﺮﺗﺒﻪ دوم‬

‫‪Second Order‬‬ ‫‪Method‬‬ ‫‪Amplified 1st Order‬‬

‫ﻣﺮﺗﺒﻪ اول ﺗﺸﺪﻳﺪ ﻳﺎﻓﺘﻪ‬

‫در ﻣﺒﺤﺚ دﻫﻢ ﻣﻄﺎﺑﻖ ﺑﻨﺪ ‪ 5-1-7-2-10‬ﺑﻪ ﻃﻮر ﻛﻠﻲ ﺟﻬﺖ ﻟﺤﺎظ اﺛﺮ ﻣﺮﺗﺒﻪ دوم ﻣﻴﺒﺎﻳﺴﺖ از دو‬ ‫ﺷﻮد‪.‬‬ ‫اﻋﻤﺎل ﺷ‬ ‫اﻧﺘﺨﺎب و ا ﺎل‬ ‫ش اﻧﺘﺨﺎ‬ ‫ﻚ روش‬ ‫ﻟﻨﮕﺮ ﻳﻚ‬ ‫ﺗﺸﺪﻳﺪ ﻟ ﮕ‬ ‫ﺿﺮاﻳﺐ ﺗﺸ‬ ‫روش ﺿ ا‬ ‫ﻏﻴﺮﺧﻄﻲ ﻫﻨﺪﺳﻲ و ش‬ ‫ﺗﺤﻠﻴﻞ ﻏ ﺧﻄ‬ ‫ش ﻋﻤﻮﻣﻲ ﺗ ﻠ ﻞ‬ ‫روش‬ ‫روش ﻋﻤﻮﻣﻲ ﺗﺤﻠﻴﻞ ﻣﺮﺗﺒﻪ دوم )ﺗﺤﻠﻴﻞ ﻏﻴﺮﺧﻄﻲ ﻫﻨﺪﺳﻲ ‪ (P − Δ‬در ‪ETABS‬‬

‫روش ﺗﺸﺪﻳﺪ ﻟﻨﮕﺮ ﻫﺎي ﺧﻤﺸﻲ )‪ (Amplified 1st Order‬در‪ETABS‬‬


‫‪Changes in AISC 2010‬‬ ‫‪¾ The next AISC specification comes out in 2010‬‬ ‫‪¾DAM will be default method in body of code‬‬ ‫‪¾ Several Clarifications included in Specification‬‬ ‫در ‪ AISC 2010‬روش آﻧﺎﻟﻴﺰ ﻣﺴﺘﻘﻴﻢ ﻛﻪ ﻫﻢ اﻳﻨﻚ ﺑﻪ ﻋﻨﻮان ﭘﻴﻮﺳﺖ ‪ 7‬از آﻳﻴﻦ ﻧﺎﻣﻪ ‪AISC 360-05‬در دﺳﺘﺮس ﻣﻴﺒﺎﺷﺪ‬ ‫آﻳﻴﻦ ﻧﺎﻣﻪ ﺟﻬﺖ‬ ‫اﺻﻠﻲ آﻳ ﻦ‬ ‫ض و اﺻﻠ‬ ‫ﺶ ﻓﻓﺮض‬ ‫وش ﭘﭘﻴﺶ‬ ‫ﻓﺖ وﺑﻪ ﻋﻨﻮان روش‬ ‫ﻣﻮﺛﺮ ارا ددر ‪ Chapter C‬ﺧﻮاﻫﺪ ﮔﮔﺮﻓﺖ‬ ‫اﻳﺐ ﻃﻮل ﻣﻮﺛ‬ ‫ﺿﺮاﻳﺐ‬ ‫ﺳﻨﺘﻲ ﺿ‬ ‫وش ﺳﻨﺘ‬ ‫ﺟﺎي روش‬ ‫ﻟﺤﺎظ اﺛﺮ ﻣﺮﺗﺒﻪ دوم ﺳﺎزه ﻫﺎي ﻓﻠﺰي ﺗﺒﺪﻳﻞ ﺧﻮاﻫﺪ ﮔﺸﺖ‪.‬‬ ‫ﺑﻨﺎﺑﺮاﻳﻦ ﮔﺮﭼﻪ اﻳﻦ روش در آﺧﺮﻳﻦ وﻳﺮاﻳﺶ از ﻣﺒﺤﺚ دﻫﻢ )وﻳﺮاﻳﺶ ‪ (1387‬ﮔﻨﺠﺎﻧﺪه ﻧﺸﺪه اﺳﺖ اﻣﺎ ﺑﻪ ﺟﻬﺖ ﺳﻬﻮﻟﺖ‬ ‫ﻃﺮاﺣﻲ و ﻣﺰاﻳﺎي آﻧﺎﻟﻴﺰ ﻣﺴﺘﻘﻴﻢ در ﻧﺮم اﻓﺰار ‪ ETABS‬آﺷﻨﺎﻳﻲ ﻣﻬﻨﺪﺳﻴﻦ ﺑﺎ اﻳﻦ روش ﻣﻬﻢ و ﺿﺮوري ﻣﻴﺒﺎﺷﺪ‪.‬‬


Refrences

: ‫ﻣﺮاﺟﻊ‬ 1387 ‫ ﻣﻘﺮرات ﻣﻠﻲ ﺳﺎﺧﺘﻤﺎن وﻳﺮاﻳﺶ ﺳﺎل‬10 ‫ﻣﺒﺤﺚ‬-

- AISC-360-2005 - AISC 2010-Draft -ETABS AISC360-05 Manual -Jason R Ericksen, CSC ,”How To Guide for the Direct Analysis Method”, 2010 -Christopher p m. Hewitt ,”Stability , y Analysis y It’s not as Hard as You Think”,2008 , -CSI DAM Guide Manual


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‫راﻫﻨﻤﺎي ﻃﺮاﺣﻲ ﺳﺎزهﻫﺎي ﻓﻮﻻدي ﺑﻪ روش ﺣﺎﻟﺖ ﺣﺪي ‪ LRFD‬و ﺗﻨﺶ ﻣﺠﺎز ‪ASD‬‬ ‫ﺑﺎ در ﻧﻈﺮ ﮔﺮﻓﺘﻦ اﻟﺰاﻣﺎت‪ :‬ﻣﺒﺤﺚ دﻫﻢ ﻣﻘﺮرات ﻣﻠﻲ ﺳﺎﺧﺘﻤﺎن وﻳﺮاﻳﺶ ‪ 1387‬و آﻳﻴﻦﻧﺎﻣﻪ ‪AISC 2005‬‬

‫ﺟﻌﻔﺮي”‬ ‫ﺿﺎ ﻔ‬ ‫اﺣﻤﺪرﺿﺎ‬ ‫ﺳﺮﺧﻲ ‪ ،‬ا ﺪ‬ ‫اﺻﻐﺮي ﺧ‬ ‫ﻣﺠﺘﺒﻲ ا ﻐ‬ ‫ﺗﺎﻟﻴﻒ‪ “ :‬ﺘ‬ ‫ﺗﺎﻟ ﻒ‬ ‫اﻧﺘﺸﺎرات ﻋﻠﻢ ﻋﻤﺮان‪-‬ﭘﺎﻳﻴﺰ ‪89‬‬

Saze808-Kerman%20Presentation4  

http://www.saze808.com/DL/Saze808-Kerman%20Presentation4.pdf

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