【摘要】 对一座采用柱下独立基础的钢筋混凝土4层框架结构进行了随着层数增加的4种工况模态实验,用脉冲锤击法测试得到了各种工况的整体模态频率和振型。考虑地基-基础-上部结构动力相互作用,上部框架结构采用缩聚得到的弯剪结构模型,下部基础利用Pais等人提出的弹性地基上埋置矩形板的地基阻抗函数进行简化处理得到的计算模型。在满足地基动剪模量和各层混凝土的弹性模量随框架层数的增加而增加的原则下,建立了4种工况下的多目标优化准则。将基于频率数据识别欠定问题的灵敏度方法进行了结构物理参数以及地基参数同时识别,识别得到的模态实验值与测试值符合良好。识别结果能够反应地基基础对结构的影响并为进一步损伤诊断提供了依据。更多还原

【Abstract】 Four cases of experimental modal analyses,with variation of the number of stories,were conducted for a four-story reinforced concrete frame structure with independent footing under the columns.The hammer impulse method was employed to measure the global modal frequencies and the mode shapes of each case.Considering the dynamic interaction of the soil-base-structure,a shear-bending frame model is employed for the superstructure,and the simplified embedded square slab’s impedance function proposed by Pais et al.is employed as for the infrastructure.Using the criterion that the foundation’s dynamic shear modulus and story’s elastic modulus will increase with the increase in stories,a multi-objective optimization criterion is formulated.A sensitivity method for under-determined problems,using frequencies,is employed to identify the physical parameters and foundation parameters simultaneously.The identified modes match well with the measured ones.The identified parameters can reflect the influence of foundation on the structure and provide the basis for damage identification.更多还原