高位弱连接连体桁架竖向地震作用系数研究

采用谐波合成理论,合成了与《建筑抗震设计规范》相吻合的空间相关地震波,采用空间相关地震波对某大跨度高位弱连接连体桁架进行竖向一致、行波激励下地震响应时程分析,结果表明:一致地震动激励下,大跨度高位连体桁架竖向地震作用系数比现行《建筑抗震设计规范》推荐的系数明显偏大,平均增幅达60%左右。另外,竖向行波激励能减小连体桁架的动力响应,设计时不需考虑竖向地震行波效应。

Study on the vertical seismic action coefficient of large-span weak connected truss in high position

Based on superposition of harmonic waves, spatially variable ground motions being compatible with response spectrum of national code for seismic design of buildings are simulated. Large-span weak connected trusses in high position are analyzed by using the time history analysis method, considering vertical uniform and wave-passage earthquake excitations. The results show that the coefficients of vertical earthquake action of large-span truss in high position are larger than the coefficients provided by national code for seismic design of buildings, and the amplitudes of the coefficients of vertical earthquake action may be increased by 60% in average. The axial forces of members of large-span truss have been decreased when considering the wave-passage effect, so the vertical wave-passage effect can be ignored in structure design.