بررسی تاثیر خصوصیت جهت پذیری پیش رونده و جابجایی ماندگار رکوردهای نزدیک گسل بر رفتار لرزه ای قاب های خمشی فولادی بلند مرتبه با مهار بند برون محور و تعیین نقطه آستانه فروریزش

اﻫﺪاف اﺻﻠﯽ اﯾﻦ ﭘﮋوﻫﺶ ﺷﺎﻣﻞ ﺑﺪﺳﺖ آوردن ﻧﻘﻄﻪ آﺳﺘﺎﻧﻪ ﻓﺮورﯾﺰش (cp) ﻗﺎب ﻫﺎی ﺧﻤﺸﯽ ﻓﻮﻻدی ﺑﻠﻨﺪ ﻣﺮﺗﺒﻪ ﺗﺤﺖ ﺗﺄﺛﯿﺮ زﻟﺰﻟﻪ ﻫﺎی ﻧﺰدﯾﮏ ﮔﺴﻞ و ﺑﺮرﺳﯽ ﺗﺄﺛﯿﺮ وﯾﮋﮔﯽ ﻫﺎی ﺟﻬﺖ ﭘﺬﯾﺮی ﭘﯿﺶ روﻧﺪه و ﺟﺎﺑﻪ ﺟﺎﯾﯽ ﻣﺎﻧﺪﮔﺎر زﻟﺰﻟﻪ ﻫﺎ ﺑﺮ رﻓﺘﺎر ﻗﺎب ﻫﺎ ﺑﺎ اﺳﺘﻔﺎده از روش ﻫﺎی ﺗﺤﻠﯿﻞ دﯾﻨﺎﻣﯿﮑﯽ ﻏﯿﺮﺧﻄﯽ ﻓﺰاﯾﻨﺪه (ida) و ﻃﯿﻒ ﻇﺮﻓﯿﺖ و ﺗﻌﯿﯿﻦ ﻣﻘﺪار ﺷﺘﺎب ﻃﯿﻔﯽ در زﻣﺎﻧﯽ ﮐﻪ ﻗﺎب در آﺳﺘﺎﻧﻪ ﻓﺮورﯾﺰش ﻗﺮار ﻣﯽ ﮔﯿﺮد، اﺳﺖ. ﺑﺮای رﺳﯿﺪن ﺑﻪ اﯾﻦ اﻫﺪاف، 6 ﻗﺎب ﺧﻤﺸﯽ ﺳﻪ دﻫﺎﻧﻪ ﺑﺮون ﻣﺤﻮر ﺳﻪ دﻫﺎﻧﻪ ﺑﺎ 20،15 و 25 ﻃﺒﻘﻪ و ﺑﺎ دو ﻣﻘﺪار ﺑﺮون ﻣﺤﻮری 1 و 2 ﻃﺮاﺣﯽ ﺷﺪﻧﺪ. ﺳﭙﺲ 22 رﮐﻮرد زﻟﺰﻟﻪ ﻣﺘﻨﺎﺳﺐ ﺑﺎ ﭘﯿﺸﻨﻬﺎدﻫﺎی femap695 در دو دﺳﺘﻪ ﺷﺎﻣﻞ رﮐﻮردﻫﺎی دارای وﯾﮋﮔﯽ ﻫﺎی ﺟﻬﺖ ﭘﺬﯾﺮی ﭘﯿﺶ روﻧﺪه و رﮐﻮردﻫﺎی دارای وﯾﮋﮔﯽ ﺟﺎﺑﻪ ﺟﺎﯾﯽ ﻣﺎﻧﺪﮔﺎر اﻧﺘﺨﺎب ﺷﺪﻧﺪ. ﻧﻘﺎط ﻋﻤﻠﮑﺮدی ﺣﺎﻻت ﺣﺪی اﺳﺘﻔﺎده ﺑﯽ وﻗﻔﻪ (io)، اﯾﻤﻨﯽ ﺟﺎﻧﯽ (ls) و آﺳﺘﺎﻧﻪ ﻓﺮورﯾﺰش (cp) ﺑﺎ اﺳﺘﻔﺎده از ﻣﻨﺤﻨﯽ ﻫﺎی ﺧﻼﺻﻪ ﺷﺪه ida ﺑﺮای ﻫﻤﻪ رﮐﻮردﻫﺎی ﻧﺰدﯾﮏ ﮔﺴﻞ ﺑﺪﺳﺖ آﻣﺪﻧﺪ. در روش ﻃﯿﻒ ﻇﺮﻓﯿﺖ، ﻃﯿﻒ ﻫﺎی ﺗﻘﺎﺿﺎ ﺑﺮای ﻫﺮ دو دﺳﺘﻪ از رﮐﻮردﻫﺎ و ﺳﭙﺲ ﻃﯿﻒ ﻣﯿﺎﻧﮕﯿﻦ آﻧﻬﺎ رﺳﻢ ﺷﺪﻧﺪ. ﻧﻘﻄﻪ ﻋﻤﻠﮑﺮد cp ﺑﻪ ﺻﻮرت ﻧﻘﻄﻪ ﺗﻼﻗﯽ دو ﻣﻨﺤﻨﯽ ﻃﯿﻒ ﺗﻘﺎﺿﺎ ﺑﺎ ﻣﯿﺮاﯾﯽ ﻣﺆﺛﺮ و ﻃﯿﻒ ﻇﺮﻓﯿﺖ ﺑﺪﺳﺖ آﻣﺪﻧﺪ. ﻧﺘﺎﯾﺞ ﺗﺤﻠﯿﻞ ﻫﺎی ida ﻧﺸﺎن ﻣﯽ دﻫﺪ ﮐﻪ وﯾﮋﮔﯽ ﻫﺎی ﺟﻬﺖ ﭘﺬﯾﺮی ﭘﯿﺶ روﻧﺪه و ﺟﺎﺑﻪ ﺟﺎﯾﯽ ﻣﺎﻧﺪﮔﺎر ﺗﺄﺛﯿﺮ ﮐﻤﺘﺮی ﺑﺮ ﻣﻘﺪار ﻇﺮﻓﯿﺖ ﺗﻐﯿﯿﺮ ﻣﮑﺎن ﻧﺴﺒﯽ ﻧﻘﻄﻪ آﺳﺘﺎﻧﻪ ﻓﺮورﯾﺰش درﻣﻘﺎﯾﺴﻪ ﺑﺎ ﺗﺄﺛﯿﺮ ﺑﺮ ﻣﻘﺪار ﺷﺘﺎب ﻃﯿﻔﯽ ﻗﺎب ﻫﺎ دارﻧﺪ. ﻗﺎب ﻫﺎ ﺗﺤﺖ ﺗﺄﺛﯿﺮ رﮐﻮردﻫﺎی ﻧﺰدﯾﮏ ﮔﺴﻞ ﺑﺎ وﯾﮋﮔﯽ ﺟﺎﺑﻪ ﺟﺎﯾﯽ ﻣﺎﻧﺪﮔﺎر، در ﺷﺘﺎب ﻃﯿﻔﯽ ﭘﺎﯾﯿﻦ ﺗﺮی ﻧﺴﺒﺖ ﺑﻪ رﮐﻮردﻫﺎی ﻧﺰدﯾﮏ ﮔﺴﻞ ﺑﺎ وﯾﮋﮔﯽ ﺟﻬﺖ ﭘﺬﯾﺮی ﭘﯿﺶ روﻧﺪه ﺑﻪ ﻧﻘﻄﻪ آﺳﺘﺎﻧﻪ ﻓﺮورﯾﺰش ﻣﯽ رﺳﻨﺪ و ﺷﺘﺎب ﻃﯿﻔﯽ ﻣﺤﺪوده io و ls ﺑﺮای رﮐﻮردﻫﺎی ﻧﺰدﯾﮏ ﮔﺴﻞ ﺑﺎ اﺛﺮ ﺟﻬﺖ ﭘﺬﯾﺮی ﭘﯿﺶ روﻧﺪه ﺑﯿﺸﺘﺮ از رﮐﻮردﻫﺎی ﻧﺰدﯾﮏ ﮔﺴﻞ ﺑﺎ وﯾﮋﮔﯽ ﺟﺎﺑﻪ ﺟﺎﯾﯽ ﻣﺎﻧﺪﮔﺎر اﺳﺖ. ﺑﺮرﺳﯽ ﻧﻮع ﺳﺎزوﮐﺎر ﻧﯿﺰ ﻧﺸﺎن ﻣﯽ دﻫﺪ ﮐﻪ درﻗﺎب 15 ﻃﺒﻘﻪ، ﺳﺎزوﮐﺎر ﺷﮑﺴﺖ در اﺛﺮ ﺳﺎزوﮐﺎر ﯾﮏ ﻃﺒﻘﻪ ﻣﯿﺎﻧﯽ و ﺑﺮای ﻗﺎب ﻫﺎی 20 و 25 ﻃﺒﻘﻪ در اﺛﺮ اﯾﺠﺎد ﻣﻔﺎﺻﻞ در ﺗﯿﺮﻫﺎ و ﺳﺘﻮن ﻫﺎی ﭼﻨﺪ ﻃﺒﻘﻪ ﻓﻮﻗﺎﻧﯽ اﺳﺖ. ﻧﺘﺎﯾﺞ ﺑﻪ دﺳﺖ آﻣﺪه از روش ﻃﯿﻒ ﻇﺮﻓﯿﺖ ﻧﯿﺰ ﻧﺸﺎن ﻣﯿﺪﻫﺪ ﮐﻪ روش ﻃﯿﻒ ﻇﺮﻓﯿﺖ ﻣﻘﺎدﯾﺮ ﮐﻤﺘﺮی ﺑﺮای ﻧﻘﻄﻪ آﺳﺘﺎﻧﻪ ﻓﺮورﯾﺰش cp در ﻣﻘﺎﯾﺴﻪ ﺑﺎ روش ida اراﺋﻪ ﻣﯽ دﻫﺪ.

The effect of fling step and forward directivity the near-fault earthquake on the seismic behavior of high-rise steel moment frames by EBF and determine the point collapse preventation performanced

This paper focuses on the interstory drift ratio (IDR) demands of building structures subjected to nearfault ground motions having different impulsive characteristics based on generalized interstory drift spectral analysis. The nearfault ground motions considered include the idealized simple pulses and three groups of nearfault ground motions with forward directivity pulses, flingstep pulses and without velocity pulse. Meanwhile, the building systems are equivalently taken as shearflexural beams with representative lateral stiffness ratios. The IDR distribution of continuous beams subjected to three groups of nearfault ground motions is acquired. It is illustrated that the maximum IDR shifts from the upper half to the lower half of buildings with an increase in lateral stiffness ratio. For longperiod systems, the average IDR under impulsive ground motions is significantly greater than that under nonpulse motions. Finally, for momentresisting frame buildings the forward directivity pulses amplify the drift response of higher modes, while the flingstep pulses excite primarily their contribution in the first mode and generate large deformation in the lower stories. The essential reason for this phenomenon is revealed according to the distinct property of nearfault impulsive ground motions and generalizedmdrift spectral analysis. Highrise buildings behavior subjected to nearfault records is different than the farfault records. Because of this difference, the characteristics of nearfault records that alters the behavior of the structure in the nearfault records. The effect of the characteristics of nearfault earthquakes on seismic behavior of steel moment frames with eccentricity brace and determine the collapse prevention. The aim of this study was to analyze the IDA tall buildings and obtain the point of collapse prevention (CP) of the curve by IDA under the nearfault records, the effect of height and weight stories on the point of collapse prevention , to obtain the Immediate Occupancy performance level (IO) and life safety (LS) of the curve IDA, determining the impact feature nearfault records (forward directivity, backward directivity, fling step) at the time of forming the point collapse prevention and determine the amount of spectral acceleration records at the time of forming the point collapse prevention , To obtain the point of collapse prevention (CP) by capacity spectrum method (determining the performance level CP) and compare the result with the result of IDA and the reasons for the difference in results of these two methods and proposals for closer results in future research. To achieve these goals, 6 frames 15, 20 and 25 floors with two extraaxial value of 1 and 2 m were designed. Then, 30 nearfault records to determine the point of collapse prevention with IDA and capacity spectra. To evaluate the effect of the characteristics of nearfault records to determine the point of collapse prevention, nearfault records of the three categories including feature a forward directivity, backward directivity, fling step, was divided. The frame is designed for IDA analysis was performed and the results for of these records have been examined individually. In order to characterize the structural response over the nearfault records showed that nearfault records with the fling step in spectral acceleration lower than the nearfault records with the forward directivity the point collapse prevention arrive. Structural response to nearfault records with backward directivity was also very similar to farfault records. The comparison between the response of structures to analyze the IDA and NSP analysis to determine the point collapse prevention became clear answers obtained by NSP smaller amounts of IDA method show.