偏心结构在双向地震作用下扭转反应之影响因素  

Factors Affecting Torsional Response of Eccentric System under Bidirectional Earthquake Motions

作　　者：刘畅[1] 邹银生[1] 

机构地区：[1]湖南大学结构工程研究所,长沙410082

出　　处：《防灾减灾工程学报》2007年第1期23-28,共6页Journal of Disaster Prevention and Mitigation Engineering

摘　　要：对偏心结构在双向地震作用下的弹塑性扭转反应进行了研究。以纤维模型模拟双向地震作用下混凝土柱的双轴弯曲,考查刚度偏心es、强度偏心ep和自振周期T等因素对结构扭转的影响。通过弹塑性时程分析得到的结果表明,在双向地震作用下,随着刚度偏心的增大刚性边和柔性边表现出不同的反应特点,前者“延性需求”变大,后者滞回耗能增加;单双向地震作用下,结构弹塑性扭转随强度偏心的变化趋势相同,当0<ep<es时能得到使弹塑性扭转最小的强度分布方案;随着自振周期的增大,质心处最大扭转角也随之增大,但扭转产生的附加变形对侧向变形贡献逐渐减小。The inelastic response of asymmetric structure subjected to bidirectional earthquake motion is studied in this paper. Fiber model is used to calculate the interaction of biaxial bending deformation in reinforced concrete columns. The effect of the system parameters on inelastic torsional response is evaluated： stiffness eccentricity es, yield strength eccentricity ep and lateral period T. The ensemble of earthquake records used consists of 6 two-component strong ground motions. The result of inelastic time-history analysis shows that： subjected to bidirectional excitation, different response occurs in stiff-side and flexible- side, with the increase of stiffness eccentricity es, the ＂ductility demand＂ of the stiff-side increase while the hysteretic energy reduces, the ＂ductility demand＂ of the flexible-side also increases with less degree than the former while the hysteretic energy increases ; with the increase of strength eccentricity ep, the system subjected to bi-and uni-directional excitation response in the same trend, 0〈ep〈es can result the best case to reduce inelastic torsion; with the increase of lateral period T, the absolute value of maximum rotation at the mass center increases, while the ratio of rotation to lateral deformation at the mass center reduces, which indicates that long-period system is slightly sensitive to bidirectional earthquake action.

关 键 词：双向地震作用 扭转 偏心结构 刚度偏心 强度偏心 

分 类 号：TU352.1[建筑科学—结构工程]