预应力装配式混凝土框架-屈曲约束支撑体系参数分析

Parametric Analysis of Prestressed Precast Concrete Frames with Buckling-Restrained Braces

为了促进装配式混凝土框架在强震区的应用,针对一种新型预应力装配式混凝土框架-屈曲约束支撑体系(BRB-PPCF),进行了20条地震波作用下6、9和12层BRB-PPCF算例的动力时程分析。结果表明:在罕遇地震烈度和极罕遇地震烈度下,BRB-PPCFs的最大层间位移角(θ_(max))平均值均远小于2.0%,最大残余层间位移角(θ_(r))均小于0.5%。随BRB-PPCF中抗弯子框架(MSF)与抗侧子桁架(TSS)的层间初始刚度比αc的减少,BRB-PPCFs的θ_(max)和θ_(r)均逐渐减少,可有效提升其抗震能力和震后可恢复性能。在线性极限状态下MSF的层间剪力与在屈服时TSS的层间剪力的比值ψ增加,BRB-PPCFs的θ_(max)和θ_(r)均表现出先减少后增加,但影响相对较小。预应力筋的初张应力与其比例极限强度的比值σ_(pi)/σ_(pl)对BRB-PPCF的θ_(max)和θ_(r)的影响可以忽略。

To promote the application of precast concrete frames in earthquake hazard areas,a new prestressed precast concrete frame with buckling-restrained braces(BRB-PPCF)was proposed,and the nonlinear dynamic time-history analysis of 6-story,9-story and 12-story BRB-PPCF cases under 20 earthquake waves were carried out.The results showed that the average maximum inter-story drift ratiosθ_(max)of BRBPPCFs were less than 2.0%and the maximum residual inter-story drift ratiosθ_(r)were less than 0.5%under both rare and extremely rare seismic intensity.Theθ_(max)andθ_(r)values of BRB-PPCFs gradually decreased with the decrease of the initial stiffness ratioαc between the moment-resistant sub-frame(MSF)and the truss sub-system(TSS).Reducing theαc value of BRB-PPCF effectively improved its seismic performance and post-earthquake recoverability.Theθ_(max)andθ_(r)values of BRB-PPCFs decreased first and then increased with the increase of the ratioψof the MSF inter-story shear force at linear limit state and the TSS shear force at yield state,and the influence of theψwas relatively small.The effects of the ratioσ_(pi)/σ_(pl)between the initial tensile stress and the proportional ultimate strength on theθ_(max)andθ_(r)values of the BRB-PPCF could be ignored.