上下盘断层参数对RC框架结构地震响应研究(Ⅱ:隔震)

Effects of hanging wall/footwall fault parameters on seismic responses of RC frame structures(Ⅱ: isolated structures)

为研究上下盘断层参数对隔震钢筋混凝土框架结构地震动响应的影响,对四种不同高度的框架结构进行了隔震设计,从隔震层抗风性能、偏心率、支座压应力三个方面验证了隔震设计的合理性,在160条上下盘地震作用下以验证的隔震结构模型为基础,进一步研究了震级、土体剪切波速、断层倾角、上界埋置深度等断层参数对其动力响应的影响规律。结果表明:隔震框架结构在上盘地震动作用下的控制效果优于下盘地震动,结构水平向减震系数和隔震层位移随下盘场地距离的变化基本保持不变,随上盘场地距离呈现"下凹型"变化趋势,以上盘20~30 km场地范围内结构的隔震效果最优;隔震结构的控制效果随震级、结构高度的增大而降低,随土体剪切波速的增大而增大,随断层倾角和上界埋置深度的增大在下盘保持不变、在上盘逐渐减小。

Seismic isolation designs for four RC frame structures with different heights were conducted with Etabs platform to investigate effects of hanging wall/footwall fault parameters on dynamic responses of the isolated RC structures.The rationality of seismic isolation design models for the four buildings was verified from three aspects including wind resistance performance of isolation layer,eccentricity and compressive stress of isolation bearing.Based on the verified isolated structure models,effects of fault parameters,such as,earthquake magnitude,soil body shear wave velocity,fault dip angle and upper bound embedded depth on structural dynamic responses were investigated in detail under the action of160hanging wall/footwall earthquake samples.The results showed that the control effect of the isolated structures under hanging wall earthquakes is better than that under footwall earthquakes;the structural vibration reduction coefficient in horizontal direction and displacement of isolation layer are basically unchanged with variation of footwall site distance,while they have a concave shape changing tendency with variation of hanging wall site distance;the seismic isolation effect is the best within footwall site distance range of20-30km;the control effect of the isolated structures decreases with increase in earthquake magnitude and structural height and increases with increase in soil body shear wave velocity;the control effect keeps unchanged under footwall earthquakes and decreases under hanging wall earthquakes with increase in fault dip angle and upper bound embedded depth.