土结相互作用对质量不规则钢框架抗地震倒塌性能的影响

对4种钢结构体系进行振动台实时动态子结构试验研究，包括规则钢框架(R-SMRF)、不规则钢框架(Ir-SMRF)、 土结规则钢框架(R-SMRF-SSI)和土结不规则钢框架(Ir-SMRF-SSI)。研究发现，附加的设备质量和地基土会对低层钢框架结构抗地震倒塌性能产生影响，结构的倒塌模式为侧移性倒塌。在小震作用下，设备鞭梢效应导致结构顶层的加速度响应增大；在中震作用下，结构中损伤发展，因此设备质量甚至会降低结构的加速度响应；相比之下，地基土增大的自振周期总是降低结构的加速度响应。随着震级增加，结构的位移响应增强，结构的损伤和残余变形增大，最终大震结构发生底层侧移性倒塌。地基土减小上部结构的位移响应，具有减震作用；而设备质量增大结构的位移反应，对结构抗地震倒塌不利。

Effects of soil-structure interaction on seismic collapse resistance of#br#mass-irregular steel frames

The real-time dynamic substructure tests of the shaking table are performed, including four structural systems: regular steel moment-resisting frame (R-SMRF), irregular steel moment-resisting frame (Ir-SMRF), regular steel moment-resisting frame considering soil structure interaction (R-SMRF-SSI), and irregular steel moment-resisting frame considering soil structure interaction (Ir-SMRF-SSI). The influence of mass irregularity and soil-structure interaction on the seismic collapse resistance of low-rise steel frame structure is evaluated. It is noted that whiplash effect leads to increase of acceleration response of the top story in minor earthquake. In contrast, medium earthquake cause structural damage, so the equipped-mass reduces the acceleration response. The foundation significantly reduces acceleration response of structure because the natural period of structure system increases. As the seismic intensity increases, displacement response of structure increases. Damage and residual deformation of structure occurs during medium earthquake, and structure eventually collapses due to lateral displacement of the first storey in the rare earthquake. The foundation has a damping effect, but the equipped-mass is not conducive to for the seismic resistance of the structure.