ﺑﺮرﺳﯽ رﻓﺘﺎر ﻟﺮزهاي ﺳﺎﺧﺘﻤﺎنﻫﺎي ﺑﻠﻨﺪ ﻟﻮﻟﻪاي ﺑﺎ درﻧﻈﺮﮔﺮﻓﺘﻦ اﺛﺮات اﻧﺪرﮐﻨﺶ ﺧﺎك و ﺳﺎزه

Investigation of the Seismic Behavior of Framed Tube Buildings Considering Soil Structure Interaction

در ﺳﺎﺧﺘﻤﺎنﻫﺎي ﺑﻠﻨﺪ ﺑﺎ ﺳﯿﺴﺘﻢ ﻟﻮﻟﻪاي ﺳﺘﻮنﻫﺎ و ﺗﯿﺮﻫﺎي اﻃﺮاف ﺳﺎزه وﻇﯿﻔﻪ ﺗﺤﻤﻞ ﺑﺎرﻫﺎي ﺟﺎﻧﺒﯽ را ﺑﻪ ﻋﻬﺪه دارﻧﺪ. در اﯾﻦ ﺳﯿﺴﺘﻢ ﺳﺎزهاي در ﺣﺎﻟﺖ اﯾﺪهال ﮐﻞ ﺳﺎزه ﺑﻪ ﺻﻮرت ﯾﮏ ﺗﯿﺮ ﻃﺮه رﻓﺘﺎر ﮐﺮده و ﺳﺘﻮنﻫﺎي ﺳﺎزه در دو وﺟﻪ ﻣﻘﺎﺑﻞ ﻫﻢ ﺑﻪﻃﻮرﯾﮑﻨﻮاﺧﺖ ﺑﻪ ﮐﺸﺶ و ﻓﺸﺎر ﺑﺎرﺑﺮي ﻣﯽﻧﻤﺎﯾﻨﺪ وﻟﯽ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﺗﻐﯿﯿﺮﺷﮑﻞ اﯾﺠﺎدﺷﺪه در ﺗﯿﺮﻫﺎي ﻣﺤﯿﻄﯽ ﺳﺎزه، ﯾﮑﻨﻮاﺧﺘﯽ ﺗﻨﺶ در ﺳﺘﻮنﻫﺎي ﻣﺤﯿﻄﯽ دﭼﺎر ﺧﻠﻞ ﺷﺪه و ﭘﺪﯾﺪه ﻟﻨﮕﯽﺑﺮﺷﯽ اﯾﺠﺎد ﻣﯽﮔﺮدد. ﻣﯿﺰان اﺛﺮ ﭘﺪﯾﺪه ﻟﻨﮕﯽﺑﺮﺷﯽ ﺑﻪ ﻋﻮاﻣﻠﯽ ﻣﺎﻧﻨﺪ اﻧﻌﻄﺎفﭘﺬﯾﺮي ﺗﯿﺮﻫﺎي ﺟﺎﻧﺒﯽ، ﻓﺎﺻﻠﻪ و اﺑﻌﺎد ﺳﺘﻮنﻫﺎي ﺟﺎﻧﺒﯽ، ارﺗﻔﺎع ﺳﺎزه و دﯾﮕﺮ ﻣﺸﺨﺼﺎت ﺳﺎزه ﺑﺴﺘﮕﯽ دارد. ﺗﻌﯿﯿﻦ اﺛﺮ ﭘﺪﯾﺪه ﻟﻨﮕﯽﺑﺮﺷﯽ ﺑﺮ ﺗﻮزﯾﻊ ﻧﯿﺮوي ﺟﺎﻧﺒﯽ ﺑﯿﻦ اﻟﻤﺎنﻫﺎي ﺳﺎزهاي اﻫﻤﯿﺖ زﯾﺎدي دارد. در اﯾﻦ ﺗﺤﻘﯿﻖ ﻣﯿﺰان ﺗﺎﺛﯿﺮ اﻧﺪرﮐﻨﺶﺧﺎكوﺳﺎزه ﺑﺮ ﭘﺪﯾﺪه ﻟﻨﮕﯽﺑﺮﺷﯽ، ﺗﻐﯿﯿﺮﺷﮑﻞﻫﺎ، ﻧﺤﻮه ﺗﻮزﯾﻊ ﻧﯿﺮوﻫﺎي ﺟﺎﻧﺒﯽ ﺑﯿﻦ ﺳﺘﻮنﻫﺎي ﻣﺤﯿﻄﯽ ﺳﺎﺧﺘﻤﺎن و روﻧﺪ ﺗﺸﮑﯿﻞ ﻣﻔﺼﻞﻫﺎي ﭘﻼﺳﺘﯿﮏ در ﺳﺎزهﻫﺎي ﻟﻮﻟﻪاي ﺑﺘﻦآرﻣﻪ ﺑﺮرﺳﯽ ﻣﯽﺷﻮد. ﻫﻤﭽﻨﯿﻦ ﻣﻘﺎﯾﺴﻪاي ﺑﯿﻦ ﻧﺘﺎﯾﺞ ﺗﺤﻠﯿﻞ ﺧﻄﯽ و ﻏﯿﺮﺧﻄﯽ ﺻﻮرت ﮔﺮﻓﺘﻪ و اﺛﺮات ﺗﺸﮑﯿﻞ ﻣﻔﺼﻞﻫﺎي ﭘﻼﺳﺘﯿﮏ ﺑﺎ در ﻧﻈﺮ ﮔﺮﻓﺘﻦ ﺗﺎﺛﯿﺮات ﺛﺎﻧﻮﯾﻪ -P Delta ﺑﺮ ﺗﻐﯿﯿﺮﺷﮑﻞﻫﺎ و رﻓﺘﺎر ﮐﻠﯽ ﺳﺎزه ﺑﺮرﺳﯽ ﺷﺪهاﺳﺖ. در اﯾﻦ ﺗﺤﻘﯿﻖ ﺑﺎ ﻣﺪل ﮐﺮدن ﯾﮏ ﺳﺎﺧﺘﻤﺎن ﺑﺘﻨﯽ 50 ﻃﺒﻘﻪ ﺑﺎ ﺳﯿﺴﺘﻢ ﻟﻮﻟﻪاي و ﺗﺤﻠﯿﻞ رﻓﺘﺎر ﻟﺮزهاي ﺳﺎزه ﺗﺤﺖ اﻋﻤﺎل ﺑﺎرﻫﺎي ﺟﺎﻧﺒﯽ ﻧﺎﺷﯽ از زﻟﺰﻟﻪ در دو ﺣﺎﻟﺖ ﺑﺎ و ﺑﺪون درﻧﻈﺮﮔﺮﻓﺘﻦ اﺛﺮ اﻧﺪرﮐﻨﺶﺧﺎكوﺳﺎزه ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن ﻣﯽدﻫﺪ ﮐﻪ ﺑﻪﻃﻮرﮐﻠﯽ وﺟﻮد اﻧﺪرﮐﻨﺶﺧﺎكوﺳﺎزه ﺑﺎﻋﺚ ﮐﺎﻫﺶ ﭘﺪﯾﺪه ﻟﻨﮕﯽﺑﺮﺷﯽ و اﻓﺰاﯾﺶ ﺗﻐﯿﯿﺮﺷﮑﻞ ﻣﯽﺷﻮد ﻫﻤﭽﻨﯿﻦ ﺗﺸﮑﯿﻞ ﻣﻔﺼﻞﻫﺎي ﭘﻼﺳﺘﯿﮏ اﺛﺮ زﯾﺎدي ﺑﺮ رﻓﺘﺎرﮐﻠﯽ و ﺗﻐﯿﯿﺮ ﺷﮑﻞ ﺳﺎزه ﻟﻮﻟﻪاي ﺧﻮاﻫﺪ داﺷﺖ.

In recent years, the framed tube system has been known as the most efficient structural system for the high-rise buildings. The entire lateral resistance in the framed tube structures is provided by closely spaced exterior columns and deep spandrel beams. A framed tube building suffers from the shear lag effects, which cause a nonlinear distribution of axial stresses along the face of the building so that the axial stress in the corner columns increases while it decreases in the interior columns. Shear lag depends on the perimeter columns size and spacing and flexibility of the spandrel beams. In this study, the influence of soil structure interaction (SSI) on shear lag phenomenon and deformation of reinforced concrete framed tube structures have been investigated and the results of linear and nonlinear analyses have been compared. In addition, P-Delta effects on some of the nonlinear static analyses have been considered and the sequence of plastic hinges formation has been investigated. The influence of SSI, the formation of plastic hinges and P-Delta effects have been determined by analyzing a 50-story reinforced concrete framed tube structure under seismic loading. The results show that SSI decreases shear lag and increases deformations of the structure. It also indicates that the formation of plastic hinges is so effective in deformation of the top stories and distribution of axial stresses in the top half of the building, and how P-Delta effects are important in deformation and strength of the framed tube structures