水平双向地震动记录选取及其敏感性分析

Selection and sensitivity analysis of horizontal bidirectional ground motion records

摘要:

为研究水平双向地震动记录选取中不同地震动参数间的差异性,以中国GB 50011—2010《建筑抗震设计规范》为例,对比选取记录的地震动特性和结构响应的差异。本文通过线性调幅和全周期谱匹配法,在两种工况下按照误差排序分别进行记录选取,并输入到4层和12层混凝土框架结构中,对比研究结构层间位移角和层间剪力,同时对比选取记录的地震动特性并分析其敏感性。结果表明:与均方根谱和几何平均谱相比,最大方向谱选取记录的结构响应、放缩系数、地震动特性离散性更小；与目标谱相比,最大方向谱选取的记录在中短周期偏保守,均方根谱和几何平均选取的记录在中长周期偏保守；采用最大方向谱选波时,选取结果的有效加速度和有效速度的敏感性偏高,而均方根谱和几何平均谱的敏感性偏低。在实际工程应用中,不应以偏概全,在保证经济性和实用性的前提下,建议依据不同的工程需求采用不同的地震动参数进行地震动记录的选取。

Abstract:

To study the differences of various ground motion parameters in the selection of horizontal bidirectional ground motion records, by taking the “Code for Seismic Design of Buildings” (GB 50011—2010) as an example, the differences of ground motion characteristics and structural responses of selected records were compared. The records were selected in order of error by linear amplitude and full period spectrum matching method under two working conditions, which were then input to 4-story and 12-story concrete frame structures to analyze the story displacement angle and story shear force. Meanwhile, the characteristics and sensitivity of the selected ground motion records were compared. Results show that the structural response, scaling coefficient, and ground motion characteristics of the records selected by the maximum direction spectrum have less discreteness in comparison with those of sum of mean square spectrum and geometric average spectrum. Compared with the target spectrum, the records selected by the maximum direction spectrum are more conservative in medium and short periods, and those selected by sum of mean square spectrum and geometric average spectrum are more conservative in medium and long periods. When using maximum direction spectrum for ground motion selection, the sensitivity of effective peak acceleration (EPA) and effective peak velocity (EPV) of the selection results are higher, while those of sum of mean square spectrum and geometric average spectrum are lower. In practical engineering application, it is suggested that different ground motion parameters should be selected according to different engineering requirements under the premise of ensuring economy and practicability.