本文对直接刚度法进行了改进，用于识别基于以弯曲变形为主的结构的截面刚度，此法可根据截面刚度在地震前后的变化情况进行结构的损伤评估。改进后的方法简单实用，按照该方法开发的OpenSees系统识别工具箱有望应用于实际工程。本文对同济大学土工程防灾国家重点实验室在2003年进行的12层钢筋混凝土标准框架的振动台试验后的动力性能测试结果进行了数值模拟和试验对比，然后应用OpenSees系统识别工具箱进行地震损伤评估，结果表明改进的直接刚度方法及其工具箱对受弯曲变形为主的结构进行初步评估是有效和可行的。

An improvement to the Direct Stiffness Calculation (DSC) method for bending-type frame structures, which can be used to carry out damage assessment, and corresponding System Identification toolbox in platform of OpenSees is proposed in this paper. The proposed improvement is a simple, but apparently quite effective, the modification of the DSC method for damage detection, and the System Identification toolbox could be applicable to practical bending-type frame structures. Research on the benchmark test of a 12-story reinforced concrete frame model on shaking table in Tongji University, a simulation model for the benchmark test under excitation of several seismic waves was evaluated to verify the modified DSC technique and the System Identification toolbox. The results show that the preliminary assessment using the improved direct stiffness method and the corresponding System Identification toolbox are feasible and efficient in the damage detection of bending-type structures.