جستجوی مقالات مرتبط با کلیدواژه « Pushdown Analysis » در نشریات گروه « عمران »

This research examines the effect of plan irregularities on the progressive collapse of steel structures. Firstly, the three structures, regular and irregular are designed. Secondly, the effect of the two plan irregularities on the progressive collapse of moment resisting frame assessed. The collapse patterns of the buildings are analyzed and compared under seven loading scenarios using non-linear dynamic and pushdown analyses. In the non-linear dynamic analyses, node displacements above the removed columns and the additional force on the columns adjacent to them are discussed. Furthermore, the strength and capacity of the columns are compared to determine their susceptibility to collapse. In the non-linear static analyses, the pushdown curve and yield load factor of the structures are obtained after column removal. The results indicate that an irregular structure collapses in most of the column removal scenarios. Moreover, when comparing regular and irregular structures, the demand force to capacity ratio (D/C) of the columns in the irregular structures is on average between 1.5 and 2 times that of the regular ones.

Progressive collapse can be caused by the failure and instability of a small part of the structure that gradually develops as a chain function and eventually leads to collapse of an important part of the structure. Progressive collapse may happen due to explosion, fire, earthquake, vehicle collision and errors in design and construction of building with any system type. Reinforced concrete (RC) load bearing wall system is one of the appropriate structural systems for average height buildings that Based on the number of walls in plan and reduction in lateral force contribution, this system in addition to its strength against earthquake, according to volume of construction materials is economic. It can be constructed with high speed, accuracy and quality. In this thesis, the effect of progressive collapse on RC load bearing wall system has been studied and its performance is compared to RC moment frame. For this purpose three-dimensional models of 10-story structures with the same plan in both systems, have been selected. The effects of geometric and material nonlinearity are considered and cross sections are modeled by fiber elements. To ensure the accuracy of modeling by fiber section method, the analysis results are validated by an experimental model of RC load bearing wall. .