eva‎luation of Performance Based Design of steel structures with irregularity in plan using push-over and time history analysis

2/11/2025 12:00:00 AM

One of the key aspects that draw public attention to structures is their visual appeal. A common technique used to achieve this is structures with irregularity in plan. These structures, due to improper distribution of mass and stiffness, have a high potential for seismic vulnerability. Seismic performance of Irregular plan of structures have been eva‎luated by nonlinear static analysis (Push-over) and Dynamic time history analysis due to this problem. For this purpose, two structures three and nine-story with irregular plan were modeled in Perform3D corresponding with their regular plan structures. First of all, these structures were analyzed through loads such as dead and live loads and then experienced different mode vibrations. Nonlinear static analysis (Push-over analysis) consists of two methods of lateral load distribution such as triangular and rectangular load distribution. Also, nonlinear time history analysis containing one far-field Northridge record and two near-field records containing Duzce (Turkey) and Kobe (Japan) have been applied for all buildings and all of their behaviors were eva‎luated. Performance-Based design of structures corresponding with code 360 which is based on FEMA356 has been conducted in three levels of performance. The first level is Immediate Occupation (IO), the second level is Life Safety (LS) and the third is Collapse Prevention (CP). By code 360, the first level of performance which is IO, is far higher than two LS and CP levels. So, this study has focused on the first level performance. The base shear coefficient using push-over analysis calculated in three and nine story irregular plan building is far higher than that in regular plan building by conditions of IO level with 1% target drift. The maximum drift of three and nine story irregular plan building by using time history analysis through three records of far-field such as Northridge in United States, Duzce in Turkey and Kobe in Japan were more than that parameter in regular plan building. The axial force in corner column located in structures with irregular plan was much higher than that in building with regular plan using nonlinear time history analysis and three above records.

سازه نامنظم در پلان، تحليل استاتيكي غير خطي، تحليل تاريخچه زماني غير خطي، طراحي عملكردي، شتابنگاشت

Irregular structure in plan, Nonlinear static analysis, Nonlinear time history analysis, Performance-Based design, Record

reza ghannadi

dr.mohsenali shayanfar