远场地震作用下长周期结构的基底剪重比

1)深圳大学土木工程学院,广东深圳518060; 2)广州大学工程抗震研究中心,广东广州 510405

建筑科学; 地下建筑; 远场地震动; 近场地震动; 长周期结构; 基底剪重比

Seismic base shear coefficients of long-period structures subjected to far-field ground motions
Guan Minsheng1, Du Hongbiao1, Zeng Qingli1, Cai Wei1, and Cui Jie2

1)College of Civil Engineering, Shenzhen University, Shenzhen 518060, Guangdong Province, P.R.China 2)Earthquake Engineering Research & Test Center, Guangzhou University, Guangzhou 510405, Guangdong Province, P.R.China

building science; substructure; far-field ground motion; near-field ground motion; long-period structure; seismic base shear coefficient

DOI: 10.3724/SP.J.1249.2017.05488

备注

为研究在峰值加速度与峰值速度调幅方式下,远场地震作用对长周期结构基底剪重比的影响. 选取了3条远场地震波和1条近场地震波,建立了6个规则型钢混凝土框架-核心筒结构模型,按照2种调幅方式分别进行设防水准下的动力时程分析. 结果表明,峰值加速度调幅方式下,远场地震作用下结构的剪重比明显大于近场地震,但两者差异在峰值速度调幅方式下较小; 两种调幅方式下,相比较近场地震,远场地震对长周期结构位移反应的影响更为明显. 长周期结构在峰值速度调幅方式下的顶点位移和基底剪力均大于峰值加速度调幅下的结果,说明长周期结构对于速度谱的敏感性要大于加速度谱. 建议长周期结构时程分析采用峰值速度调幅方式.

The paper aims to investigate the effect of far-field ground motions with two amplitude modulation means, i.e. peak ground acceleration(PGA)and peak ground velocity(PGV), on seismic base shear coefficients of long-period structures. Three far-field earthquake records and one typical near-field accelerogram are chosen as input ground motions. Six steel reinforced concrete frame-core wall structures are designed and studied through dynamic time history analyses with a set of four selected ground motions scaled to the fortification earthquake level. Numerical results show that, by scaling PGA, the seismic base shear coefficients under far-field ground motions are significantly larger than those of the near-field ground motion. However, in the way of scaling PGV, the difference between two types of earthquake records is minor. The structural top displacements are more effected by the far-field ground motions in comparison with those of the near-field ground motion under the two scaling methods. It is also found that the two structural responses, the top displacement and the seismic base shear coefficient in the way of scaling PGV are larger than those of scaling PGA, which indicates that the long-period structures is more sensitive to the velocity spectrum than the acceleration spectrum. As a result, the time history analysis is suggested to be used as the PGV amplitude modulation manner for long-period structures.

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