考虑损伤退化的钢框架结构多自由度模型

A MULTI-DEGREE-OF-FREEDOM MODEL FOR STEEL FRAME STRUCTURES INCORPORATING DAMAGE AND DETERIORATION

  • 摘要: 为评估建筑震后维持与恢复原有建筑功能的能力,基于弹塑性时程分析的建筑抗震韧性评估技术近年来得到快速发展。其中,多自由度模型凭借其高效计算能力,在区域震害模拟、数据驱动评估等大规模计算任务中展现出广泛的应用潜力。尽管现有研究普遍认为钢框架结构具有良好延性,但震害调查和大比例尺振动台试验结果表明,底层柱底部发生局部屈曲,引发承载力退化,加剧二阶效应,是钢框架结构倒塌的重要原因。为了准确、高效地模拟钢框架结构损伤退化行为,平衡大规模计算问题中强震下韧性评估的精度与效率,提出了考虑损伤退化的钢框架结构多自由度模型。基于日本E-Defense振动台试验结果,剖析了钢框架结构的损伤退化机制。采用骨架曲线移位模型,构建了考虑损伤退化的钢框架层恢复力模型。利用E-Defense振动台18层钢框架倒塌试验数据,对比了所提出的多自由模型与常用平面框架模型的模拟精度与效率。结果表明:在建筑抗震韧性评价所考虑的地震水准下,所提出的考虑损伤退化的钢框架结构多自由度模型能够准确且高效地获取层间位移角、楼面加速度等关键工程需求参数,预测误差小于15%,计算效率提升了10倍以上,为大规模计算问题提供了高效高精度的计算模型。

     

    Abstract: In order to evaluate the ability of a building to maintain and to recover its original functionality after an earthquake, the seismic resilience assessment based on nonlinear time-history analysis has undergone a rapid development in recent years. Multi-degree-of-freedom (MDOF) models, featured high computational efficiency, have demonstrated a wide application potential in large-scale computational tasks such as regional seismic damage simulation and data-driven assessments. Although existing research generally acknowledges the good ductility of steel frame structures, the results of post-earthquake reconnaissance and of large-scale shaking table tests have shown that local buckling at the base of the low-storey columns can lead to strength deterioration and exacerbate second-order effects, which are significant contributors to the collapse of steel frame structures. To accurately and efficiently simulate the damage and deterioration behavior of steel frame structures, and to balance the accuracy and efficiency of resilience assessment under strong earthquakes in large-scale computational problems, an MDOF model for steel frame structures incorporating damage and deterioration is proposed. The damage and deterioration mechanisms of steel frame structures are analyzed upon the Japan’s E-Defense shaking table test results. A storey hysteretic model incorporating damage and deterioration is developed using the skeleton shift model. The accuracy and efficiency of the MDOF model proposed are compared with two commonly used planar frame models using data from the collapse test of 18-storey steel frame on the E-Defense shaking table. The research results indicate that, under the earthquake levels considered for seismic resilience assessment of buildings, the MDOF model proposed for steel frame structures incorporating damage and degradation can accurately and efficiently obtain key engineering demand parameters such as inter-storey drift ratios and floor accelerations, with a prediction error of less than 15% and a computational efficiency improvement of over 10 times, providing a highly efficient and accurate computational model for large-scale computational problems.

     

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