كليدواژه :
ﺷﮑﻞﭘﺬﯾﺮي , ﺿﺮﯾﺐ ﮐﺎﻫﺶ ﺷﮑﻞﭘﺬﯾﺮي , ﻣﻬﺎرﺑﻨﺪﻫﺎي ﺷﻮرن , ﺗﺤﻠﯿﻞ ﭘﻮشاور , ﺗﻐﯿﯿﺮﻣﮑﺎن ﻫﺪف
چكيده فارسي :
در اﯾﻦ ﺗﺤﻘﯿﻖ ﺗﻼش ﺷﺪه اﺳﺖ ﺿﺮﯾﺐ ﮐﺎﻫﺶ ﺷﮑﻞﭘﺬﯾﺮي ﻗﺎبﻫﺎي ﺳﺎﺧﺘﻤﺎﻧﯽ ﺳﺎده ﺗﻮأم ﺑﺎ ﻣﻬﺎرﺑﻨﺪﻫﺎي ﺑﻪ ﺷﮑﻞ 8 ﻣﻌﻤﻮﻟﯽ و وﯾﮋه، ﻣﻮرد ارزﯾﺎﺑﯽ ﻗﺮار ﮔﯿﺮد. ﺑﺮاﺳﺎس ﻧﺘﺎﯾﺞ ﺑﻪدﺳﺖآﻣﺪه از اﯾﻦ ﺗﺤﻘﯿﻖ ﺣﺪاﮐﺜﺮ ارﺗﻔﺎع ﻣﺠﺎز ﻗﺎبﻫﺎي ﻣﻬﺎرﺑﻨﺪيﺷﺪة ﻣﻌﻤﻮﻟﯽ ﺑﺎ ﻣﻬﺎرﺑﻨﺪﻫﺎي ﺑﻪ ﺷﮑﻞ 8 ﻣﯽﺗﻮاﻧﺪ از ﻣﻘﺪار ﻣﻮردﻧﻈﺮ آﺋﯿﻦﻧﺎﻣﮥ ASCE7 )10/7 ﻣﺘﺮ( ﺑﯿﺸﺘﺮ در ﻧﻈﺮ ﮔﺮﻓﺘﻪ ﺷﻮد. ﻧﺘﺎﯾﺞ اﯾﻦ ﺑﺮرﺳﯽ ﻧﺸﺎن ﻣﯽدﻫﺪ ﮐﻪ ارﺗﻔﺎع ﻗﺎبﻫﺎي ﻣﻬﺎرﺑﻨﺪيﺷﺪة ﻣﻌﻤﻮﻟﯽ ﺑﺎ ﻣﻬﺎرﺑﻨﺪﻫﺎي ﺑﻪ ﺷﮑﻞ 8 ﻣﯽﺗﻮاﻧﺪ ﺗﺎ ﺷﺶ ﻃﺒﻘﻪ )ﺣﺪوداً 20 ﻣﺘﺮ( اﻓﺰاﯾﺶ ﯾﺎﺑﺪ. ﺑﻪ ﻟﺤﺎظ ﻣﯿﺰان ﻣﺼﺎﻟﺢ ﻣﺼﺮﻓﯽ، ﻗﺎبﻫﺎي ﻣﻬﺎرﺑﻨﺪيﺷﺪة وﯾﮋه ﺑﺎ ﻣﻬﺎرﺑﻨﺪﻫﺎي ﺑﻪ ﺷﮑﻞ 8 ﻧﺴﺒﺖ ﺑﻪ ﻗﺎبﻫﺎي ﻣﻬﺎرﺑﻨﺪيﺷﺪة ﻣﻌﻤﻮﻟﯽ ﺑﺎ ﻣﻬﺎرﺑﻨﺪﻫﺎي ﺑﻪ ﺷﮑﻞ 8ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﺮاي ﻗﺎبﻫﺎي از ﯾﮏ ﺗﺎ ﺷﺎﻧﺰده ﻃﺒﻘﻪ، ﺻﻔﺮ اﻟﯽ 30 درﺻﺪ ﻣﻘﺮونﺑﻪﺻﺮﻓﻪﺗﺮ اﺳﺖ. ﻣﻄﺎﺑﻖ ﻧﺘﺎﯾﺞ اﯾﻦ ﺗﺤﻘﯿﻖ، ﺿﺮﯾﺐ رﻓﺘﺎر ﭘﯿﺸﻨﻬﺎدﺷﺪه در ﭘﯿﺶﻧﻮﯾﺲ وﯾﺮاﯾﺶ ﭼﻬﺎرم اﺳﺘﺎﻧﺪارد 2800 اﯾﺮان R=5.5)( ﺑﺮاي ﻗﺎبﻫﺎي ﻣﻬﺎرﺑﻨﺪيﺷﺪة ﻫﻤﮕﺮاي وﯾﮋه ﻣﻨﻄﻘﯽﺗﺮ از ﺿﺮﯾﺐ رﻓﺘﺎر ﭘﯿﺶﺑﯿﻨﯽﺷﺪه در آﺋﯿﻦﻧﺎﻣﮥ R=6) ASCE7( ﻫﺴﺖ. ﻣﺘﺄﺳﻔﺎﻧﻪ در ﻗﺎبﻫﺎي ﻣﻬﺎرﺑﻨﺪيﺷﺪة وﯾﮋه ﺑﺎ ﻣﻬﺎرﺑﻨﺪﻫﺎي ﺑﻪ ﺷﮑﻞ 8 در ﻗﺎبﻫﺎي ﺣﺪوداً ﺑﺎﻻي دوازده ﻃﺒﻘﻪ ﺷﮑﻞﭘﺬﯾﺮي ﻣﻮردﻧﯿﺎز ﺗﺄﻣﯿﻦ ﻧﻤﯽﺷﻮد. ﺑﺮاﺳﺎس ﻧﺘﺎﯾﺞ ﺑﻪدﺳﺖآﻣﺪه از اﯾﻦ ﺗﺤﻘﯿﻖ ﺑﺮاي ﻗﺎبﻫﺎي ﺑﺎﻻي دوازده ﻃﺒﻘﻪ ﺑﺎﯾﺪ از ﺿﺮﯾﺐ رﻓﺘﺎر ﮐﻤﺘﺮي اﺳﺘﻔﺎده ﺷﻮد. ﻫﻤﭽﻨﯿﻦ در ﻗﺎبﻫﺎي ﺑﺎﻻي دوازده ﻃﺒﻘﻪ ﺳﺎزه ﻋﻤﻮﻣﺎً ﺗﻐﯿﯿﺮﻣﮑﺎن ﻫﺪف را ﺗﺠﺮﺑﻪ ﻧﻤﯽﻧﻤﺎﯾﺪ و ﻗﺒﻞ از رﺳﯿﺪن ﺑﻪ آن ﺑﻪ ﺣﺎﻟﺖ ﻣﮑﺎﻧﯿﺰم رﺳﯿﺪه و ﻓﺮوﻣﯽرﯾﺰد و اﯾﻦ ﻣﺴﺌﻠﻪ ﻧﺸﺎندﻫﻨﺪة ﻟﺰوم ﺗﺠﺪﯾﺪﻧﻈﺮ در اراﺋﮥ ﺿﺮﯾﺐ رﻓﺘﺎر ﻗﺎبﻫﺎي ﺑﺎﻻي دوازده ﻃﺒﻘﻪ از اﯾﻦ ﻧﻮع ﻗﺎبﻫﺎي ﺳﺎﺧﺘﻤﺎﻧﯽ را ﺗﺄﯾﯿﺪ ﻣﯽﻧﻤﺎﯾﺪ.
چكيده لاتين :
The current design philosophy for buildings located in zones with high seismic risks is that the buildings must have sufficient strength and stiffness to remain elastic and serviceable under moderate but frequently occurring earthquakes and to have sufficient ductility to prevent collapse under extreme earthquake loading. Conventional structural steel framing systems such as moment resisting frames (MRFs), concentrically braced frames (CBFs), and eccentrically braced frames (EBFs), are extensively used in seismically active areas. Each of the previously mentioned structural systems has different advantages and disadvantages. In this study, response modification factor of ordinary inverted V-braced frames and specially inverted V-braced frames are evaluated, result confirm that the proposed height for buildings with ordinary inverted braced frames in the ASCE7, can be increased up to 10.7 meter. In addition, results indicate that by using ordinary inverted V-bracing systems in buildings their height can be increased up to 6 stories or 20 meters. Using special inverted V-braced systems can have saving about 0 to 30 present on used materials for frames from 1 story to 16 stories. According to the results of this study, the response modification factor proposed by Iranian seismic design code (2800 standard fourth edition), (R=5.5), is more logical than the one which is proposed by ASCE7, (R=6). Unfortunately, in special inverted V-braced frames, and when the story of the frames increases up to 12 stories, expected ductility demand cannot be achieved, so as a result, for frames that are more than 12 stories tall, lower response modification factor should be used. In addition, frames taller than 12 story height don’t experience specified target displacement and collapse before getting to preferred mechanism. This phenomenon shows the necessity of using different response modification factor for frames taller than 12 stories.
