基于结构频响函数的再生混凝土框架地震作用损伤评估

结构遭受地震作用时，其内部损伤的累积会导致该结构频响函数曲线的变化，这可为评估结构损伤程度提供依据。利用ABAQUS有限元软件，对1榀2层单跨平面再生混凝土框架拟动力试验进行有限元分析，计算结果与试验值吻合良好。通过对再生混凝土框架频响函数曲线的分析可知，结构1阶和2阶自振频率分别在2.5Hz和6.0Hz附近变化，随着地震峰值加速度的不断增大，结构自振频率不断降低，反映损伤累积导致结构刚度的不断退化。基于结构的频响函数，提出可用于评判框架结构在地震作用下损伤程度的指标。分析结果表明：该损伤评估方法能有效评判再生混凝土框架在不同强度地震作用下的损伤程度。

Seismic damage assessment for recycled concrete frame based on structure frequency response function

The accumulation of damage in a structure during an earthquake leads to changes in frequency response function (FRF) of the structure, and it can be used as the basis for evaluating the seismic damage condition of this structure. The finite element software ABAQUS was adopted to simulate a series of pseudo-dynamic test for a one-bay, two-story plane recycled aggregate concrete (RAC) frame. It is found that the analytical results agree well with the experimental results. Analysis of the FRFs of the RAC fame indicates that the natural frequencies for the 1st and 2nd mode are around 2.5Hz and 6.0 Hz, respectively. The natural frequency of the tested frame decreases continuously as peak ground acceleration (PGA) increases, which indicates the accumulated damages in the frame lead to a decrease of stiffness. A damage index based on FRF was proposed for assessing the damage condition of the frame. Analytical results indicate that the damage index performs well in evaluating damage conditions for the frame subjected to different PGAs.