高层钢框架考虑损伤累积效应的地震倒塌分析方法

摘要

Considering the collapse uncertainty of structures, a numerical approach is proposed for simulating the collapse process of steel frame structures under severe earthquakes. This approach includes a structure damage index in story level using modified K＆K model in order to describe the degradation of structure strength and stiffness due to earthquakes, with the form of explicit integration based on the central difference method. Study of the failure path and the collapse process of a 20-storey benchmark steel frame structure under earthquake, using the proposed approach, was conducted, and the results indicate that the numerical approach can determine the failure ultimate loading of the high- rise steel frame precisely with consideration of damage accumulation. Without knowing the failure mode of the structures, the approach can better simulate the failure path, the collapse process of structures and the collapse mechanism of the structures.%针对结构倒塌破坏的不确定性，提出一种用于高层钢框架结构在强震作用下结构倒塌全过程模拟的数值方法，该方法采用基于中心差分法的显式积分格式，通过定义结构的层损伤，将修正的K＆K模型应用到结构中，以考虑结构在地震作用下强度和刚度的退化规律。通过编制有限元程序将该方法用于分析20层benchmark模型结构倒塌全过程和倒塌机理。分析表明，该考虑材料损伤累积效应的方法能更精确地确定高层钢框架结构的失效极限荷载，且在未知结构的失效破坏模式前提下，可较好地模拟在地震作用下结构的失效路径以及倒塌全过程和揭示结构的倒塌机理。