Comparing the Seismic Collapse Capacity of Steel Moment Resisting Frames with Inclined Columns

Due to some constructional and architectural issues, the columns of the structure, which play the main load-bearing role in it to transfer imposed loads to foundation, may be forced out of their upright position and run obliquely, or it may even be determined due to a defect in the construction that the column is placed in an inclined manner. As a result, it is necessary to evaluate the effect of the column inclination against seismic excitations. In this research, a ۵-story steel moment resisting frame with three spans and considering six scenarios of the column inclination is investigated in OpenSees software by using incremental dynamic analysis (IDA) and plotting fragility curves. The rotation of the columns around the supports is assumed ۱ degree. Also, the influence of deteriorations of stiffness and strength is considered for modeling the studied samples exactly. Finally, the collapse capacity of the mentioned steel frames is assessed under the influence of far-fault ground motions probabilistically. Findings of this paper show that the M۶I۲۵ model has more collapse capacity than other samples under the studied records, and it is determined that at the statistical level of ۵۰%, the aforementioned collapse capacity is increased ۱۴% in comparison with the main model. Also, based on the spectral acceleration of ۰.۷ g, the collapse probability of the M۶I۲۵ model is ۵۰.۸%.

کلیدواژه ها:

Steel moment frame ، Deterioration ، Inclined column ، Incremental dynamic analysis (IDA) ، Fragility curve