ارزيابي تأثير تقويت ساختمان هاي بتن مسلح چند طبقه با FRP بر خواص عملكرد لرزه اي ديناميكي

The Evaluation of Strengthening Effect Reinforced Concrete Structures with FRP on Seismic Dynamic Performance of the Structures

اﻣﺮوزه ﺗﻘﻮﯾﺖ ﺳﺎزه ﻫﺎي ﻣﻮﺟﻮد ﺑﻪ ﻣﻨﻈﻮر اﻓﺰاﯾﺶ ﻇﺮﻓﯿﺖ ﺑﺎرﺑﺮي ﺷﮑﻞﭘﺬﯾﺮي ﺑﻪ وﺳﯿﻠﻪ ﺻﻔﺤﺎت FRP ﮐﻪ ﻣﺎﻧﻨﺪ ﻣﯿﻠﮕﺮدﻫﺎي ﻋﺮﺿﯽ ﻋﻤﻞ ﻧﻤﻮده و ﺑﺎﻋﺚ اﯾﺠﺎد ﻓﺸﺎر ﻣﺤﺼﻮر ﺷﺪﮔﯽ در ﺑﺘﻦ و اﻓﺰاﯾﺶ ﻣﻘﺎوﻣﺖ ﻣﯽﮔﺮدد در ﮐﺸﻮر اﯾﺮان ﻣﺘﺪاول ﺷﺪه اﺳﺖ در اﯾﻦ ﭘﮋوﻫﺶ ﺳﺎﺧﺘﻤﺎنﻫﺎي ﺑﺘﻦ ﻣﺴﻠﺢ ﺗﻘﻮﯾﺖ ﻧﺸﺪه و ﺷﺪه ﺑﺎ ورق ﻫﺎيCFRP ﺑﺎ ﺗﻌﺪاد ﻃﺒﻘﺎت 10 ،5 ،3 و 15 ﻃﺒﻘﻪ و دﻫﺎﻧﻪﻫﺎي 1 اﻟﯽ 5، در ﻧﻈﺮ ﮔﺮﻓﺘﻪ ﺷﺪهاﻧﺪ. ﺑﺎ اﻧﺠﺎم آﻧﺎﻟﯿﺰ اﺳﺘﺎﺗﯿﮑﯽ ﺧﻄﯽ و ﻏﯿﺮﺧﻄﯽ ﺑﺮ روي ﺳﺎزهﻫﺎي ﺑﺘﻦ ﻣﺴﻠﺢ ﻣﺬﮐﻮر، ﺗﺎﺛﯿﺮ ﭘﺎراﻣﺘﺮﻫﺎي ﻣﺨﺘﻠﻔﯽ از ﺟﻤﻠﻪ ﺷﺘﺎب و ﺟﺎﺑﺠﺎﯾﯽ ﻃﯿﻔﯽ، ﻣﯿﺮاﯾﯽ و زﻣﺎن ﺗﻨﺎوب ﻣﺆﺛﺮ در ﻧﻘﻄﻪ ﻋﻤﻠﮑﺮد ﺳﺎزه، ﻣﻨﺤﻨﯽ ﻇﺮﻓﯿﺖ ﻧﺎﺷﯽ از ﺗﻘﻮﯾﺖ و اﺛﺮ ﺗﻘﻮﯾﺖ ﺳﺎزه ﺑﺎCFRP ﻫﻤﺮاه ﺑﺎ اﻓﺰاﯾﺶ ﺗﻌﺪاد ﻃﺒﻘﺎت، ﺗﻌﺪاد دﻫﺎﻧﻪﻫﺎي ﺳﺎﺧﺘﻤﺎن ﺑﺮ ﺳﻄﺢ ﻋﻤﻠﮑﺮد و رﻓﺘﺎر ﻟﺮزهاي ﺳﺎزهﻫﺎ ﺑﺮرﺳﯽ ﮔﺮدﯾﺪ. ﻧﺘﺎﯾﺞ ﺑﺪﺳﺖ آﻣﺪه ﻧﺸﺎن داد ﮐﻪ ﻣﺤﺼﻮرﺳﺎزي ﺗﯿﺮ و ﺳﺘﻮن ﺳﺎزه ﺑﺘﻦ ﻣﺴﻠﺢ ﺑﺎ ﻻﯾﻪﻫﺎي CFRP ﻣﻮﺟﺐ اﻓﺰاﯾﺶ ﺗﻮاﻧﺎﯾﯽ ﺳﺎزه در ﺟﺬب و اﺳﺘﻬﻼك اﻧﺮژي ﺷﺪه و اﻓﺰاﯾﺶ ﺳﺨﺘﯽ و ﺷﯿﺐ اوﻟﯿﻪ ﺣﺪود 1/5 اﻟﯽ 2/5 ﺑﺮاﺑﺮﺳﺎزه ﺗﻘﻮﯾﺖ ﻧﺸﺪه ﺑﻮد. ﺗﻘﻮﯾﺖ ﺳﺎزه ﺗﻮﺳﻂ ورقﻫﺎي CFRP ﺑﺎﻋﺚ اﻓﺰاﯾﺶ ﻣﯿﺰان ﺷﺘﺎب ﻃﯿﻔﯽ و ﮐﺎﻫﺶ ﺟﺎﺑﺠﺎﯾﯽ ﻃﯿﻔﯽ و ﻣﯿﺰان ﻣﯿﺮاﯾﯽ و زﻣﺎن ﺗﻨﺎوب ﻣﺆﺛﺮ ﺷﺪه ﮐﻪ ﻧﺘﯿﺠﺘﺎ ﻣﻨﺠﺮ ﺑﻪ اﻓﺰاﯾﺶ ﻇﺮﻓﯿﺖ ﺑﺎر ﻟﺮزهاي ﻗﺎب ﻣﻘﺎوم ﻣﯽ-ﮔﺮدد ﺿﻤﻨﺎً، اﺛﺮ ﺗﻘﻮﯾﺖ ﺳﺎزه ﺑﺎ CFRP در ﺳﺎزه 3 ﻃﺒﻘﻪ 4 دﻫﺎﻧﻪ ﻣﻄﻠﻮبﺗﺮﯾﻦ ﻋﻤﻠﮑﺮد را از ﻧﻈﺮ ﺳﺨﺘﯽ و ﺷﺘﺎب ﻃﯿﻔﯽ ﺑﯿﺸﺘﺮ و ﺟﺎﺑﺠﺎﯾﯽ ﻃﯿﻔﯽ و زﻣﺎن ﺗﻨﺎوب ﻣﺆﺛﺮ ﮐﻤﺘﺮ اﯾﺠﺎد ﮐﺮده، از ﻃﺮﻓﯽ ﺑﻬﺘﺮﯾﻦ رﻓﺘﺎر را از ﻧﻈﺮ ﻣﯿﺮاﯾﯽ و ﺟﺬب اﻧﺮژي ﺑﻪ ازاي ﺗﻘﻮﯾﺖ، ﺳﺎزهي 10 ﻃﺒﻘﻪ 4 دﻫﺎﻧﻪ ﻧﺸﺎن ﻣﯽدﻫﺪ.

Nowadays, Strengthening of existing structures was conducted by FRP wrapping in Iran in order to increase capacity and ductility particularly for columns resulting in an increase in the strength of concrete and improve structure behaviour. In this study, RC strengthened (with FRP) and un-strengthened buildings with 3, 5, 10 & 15 stories and 1 to 5 bay were considered. By performing linear and non-linear static analyses, seismic parameters such as acceleration and spectral displacement, damping and effective period of structure in performance points and capacity curves were discussed. The results indicated that the confinement of beams and columns of RC structures with CFRP sheets will improve the absorption and dissipation energy of structure and the stiffness and initial gradient of retrofitted structure with CFRP were about 1.5 to 2.5 times of those of original un-strengthened structure. an‎d also via strengthening of structure with CFRP sheets, the spectral acceleration was increased and the spectral displacement, damping ratio and effective period were decreased, resulting in increasing seismic loading capacity. However, the structure retrofitted by CFRP with 3-stories, 4 bays showed the best performance in the term of stiffness, more spectral acceleration and spectral displacement and less effective period, but in the term of damping and energy absorption the best performance was for the structure with 10-stories, 4 bays.