ارزيابي روش تحليل ايستاتيكي فزاينده‌ي غيرخطي مودي براي قاب‌هاي خمشي فولادي با اتصالات نيمه‌صلب

EVALUATION OF MODAL PUSHOVER ANALYSIS PROCEDURE USING MOMENT RESIST FRAMES WITH SEMI-RIGID CONNECTIONS

روش تحليل ايستاتيكي فزاينده غيرخطي مودي (MPA) كه به‌تازگي براي تخمين عملكرد سازه ها در هنگام زلزله ارايه شده در مقايسه با روش هاي تحليل ديناميكي غيرخطي بسيار ساده تر است. با توجه به اينكه در سازه هاي فولادي اتصالات درصدي لنگر انتقال داده و اتصالات صلب نيز كاملاٌ صلب عمل نمي‌كنند، و مي‌توان اين اتصالات را نيمه‌صلب با درصدهاي گيرداري گوناگون در نظر گرفت. از آنجا كه دقت و درستي روش MPA براي قاب‌هاي خمشي فولادي با اتصالات نيمه‌صلب بررسي نشده است، در اين نوشتار با انجام روش MPA بر روي قاب هاي فولادي صلب و نيمه‌صلب با درصدهاي گيرداري مختلف و مقايسه آن با تحليل‌ ديناميكي غير خطي تاريخچه‌ي پاسخ (NL-RHA) به‌عنوان روش دقيق به اين موضوع پرداخته مي شود براساس بررسي نتايج اين روش دقت قابل قبولي در تخمين تقاضاهاي لرزه يي دارد.

The recently developed nonlinear static analysis procedures have been shown to be a significant improvement over analysis procedures currently used in structural engineering practices. Nonlinear static analysis procedures in estimating the seismic demands of structures are much simpler and faster than nonlinear dynamic analysis procedures. Among these procedures, modal pushover analysis (MPA) will present a very good approximation of nonlinear response history analysis (NLRHA). There are two kinds of connection, pinned and rigid, which have some flexibility. Therefore, these connections, with different rigidity, can be considered as semi-rigid connections. Since the accuracy of MPA procedures has not been verified for steel moment resist frames with semi-rigid connections, in this study, we investigate this subject. For this purpose, MPA (approximate) and NLRHA (exact) are used for frames with different rigidity percentiles of connections. It seems that the procedure accuracy tends to decrease by increasing the number of stories and decreasing the rigidity percentiles of semi-rigid connections. Finally, the MPA procedure is simplified to facilitate its implementation in engineering practices and the accuracy of this simplified procedure is documented, especially for bottom and mid stories.