بررسي اثرات بهره گيري از سيستم حركت گهواره اي در بهسازي لرزه اي ساختمان هاي فولادي بلند مرتبه

The investigation of the effects of using rocking systems on the seismic retrofit of high-rise steel building

در اين مقاله به منظور بررسي اثرات سيستم گهواره اي بر روي پاسخ لرزه اي ساختمان هاي فولادي بلند مرتبه منظم، يك سازه 15 طبقه فولادي با سيستم باربر جانبي قاب خمشي ويژه همراه با مهاربند همگراي ضربدري مطابق ويرايش چهارم استاندارد 2800 و آخرين ويرايش هاي مباحث ششم و دهم مقررات ملي ساختمان در نرم افزار ETABS2015 طراحي شده است. سپس هفت زلزله مطابق استاندارد 2800 انتخاب و مقياس شدند و با استفاده از تحليل تاريخچه زماني غير خطي به بررسي و مقايسه پاسخ لرزه اي ساختمان مورد مطالعه در حالت هاي با و بدون بهره گيري از سيستم گهواره اي پرداخته شده است. نتايج مطالعات( نظير برش پايه، دريفت، تغييرمكان ها و شتاب هاي جانبي و قائم سقف و ...) حاكي از آن است كه بهره گيري از سيستم حركت گهواره اي در ساختمان هاي بلند مرتبه فولادي مي تواند سبب كاهش قابل ملاحظه ي پاسخ لرزه اي سازه شود.

In this paper, a 15-story steel building was designed based on Iranian code No.2800 in order to study the effects of rocking systems on the seismic response of high-rise steel buildings. The selected accelerograms were related to the Chi Chi, Landers, Loma Prieta, Northridge, Parkfield, San Fernando and Tabas earthquakes which were selected and scaled according to Iranian Standard No. 2800. These accelerograms were related to the stations which were registered at the distance of 20 to 60 kilometers from the fault and did not have the near-fault earthquakes characteristics such as forward directivity and fling step and etc. Furthermore, the magnitude of all the selected earthquakes was between 6.5 and 7.5 Richter. Then, nonlinear time history analysis was used to investigate and compare the seismic response of the studied building in cases with and without using the rocking system. The results of studies (including base shear, drift, displacement of roof, acceleration of roof and etc.) indicated that using rocking system in the high-rise steel buildings could cause significantly reduce the seismic response of high-rise steel buildings.