高宽比对剪切型配筋砌块砌体剪力墙耗能能力的影响

Effect of aspect ratio on energy dissipation capacity of reinforced-block masonry shear walls with shear-dominated failure mode

为了研究高宽比对配筋砌块砌体剪力墙耗能能力的影响,确定墙体的耗能参数。利用6片高宽比H/h为1.57、1.14和0.71的足尺全灌芯配筋砌块砌体剪力墙拟静力试验,通过计算墙体的耗散能(累积和单圈)、等效粘滞阻尼比ζeq、能量耗散系数ψ和功比指数I w四个参数,来分析发生剪切型破坏模式墙体的耗能能力。研究结果表明:H/h对墙体的耗能能力影响较大,随着墙体变形的增大,H/h越小墙体的耗散能增长越迅速,墙体的延性越差;当H/h=1.14时,能量耗散系数ψ较低,等效粘滞阻尼比ζeq较小,约为7%~10%,墙体的耗能能力较差;当H/h=0.71时,ψ较高,ζeq较大,约为14%~15%,墙体的耗能能力较好;随着位移的增大,功比指数I w逐渐增大,当位移较小时I w几乎呈线性增长,当位移较大时I w呈非线性增长,H/h=1.14墙体的I w增长相对缓慢。可见:对于发生剪切型破坏模式的配筋砌块砌体剪力墙,H/h接近1时耗能能力较差,在工程中尽量避免采用。

The energy dissipation parameters are determined for studying the influence of the aspect ratio on the energy dissipation capacity of reinforced-block masonry shear walls.Six full-scale fully grouted sample models with the aspect ratio H/h of 1.57,1.14 and 0.71 are tested subjected to the low cyclic reversed lateral loads.The energy dissipation capacity of the walls with the shear-dominated failure mode is analyzed through calculating four parameters including dissipated energy(accumulation and single circle),equivalent viscous damping ratioζeq,energy dissipation coefficientψand power ratio index Iw.The results indicate that H/h has a great influence on the energy dissipation capacity of the wall.As the deformation of the wall increases,the smaller the H/h is,the faster the dissipated energy of the wall grows,and the worse the ductility of the wall becomes.When H/h=1.14,the energy dissipation coefficientψis low with a small equivalent viscous damping ratioζeq of about 7%-10%,and the energy dissipation capacity of the wall is poor.When H/h=0.71,ψis higher with a largerζeq of about 14%-15%,and the energy dissipation capacity of the wall is better.As the displacement increases,the power ratio index Iw gradually increases.Iw shows a linear increasing trend when the displacement is small,however,Iw increases nonlinearly when the displacement is relatively large.When H/h=1.14,Iw of the wall increases relatively slowly.It is concluded that the energy dissipation capacity of the reinforced-block masonry shear walls with the shear-dominated failure modeis poor when H/h is close to 1,which is not recommended for engineering applications.