砌体结构体外预应力抗震加固计算方法研究

利用砌体剪-压复合受力的相关性所带来的抗剪潜力,提出了采用体外预应力法对砌体结构进行抗震加固。通过整体张拉通长设于砌体墙外部两侧全高范围内的预应力筋对墙体施压,改善了结构自身内在的抗震性能。据库仑强度理论,以典型的四层砌体教学楼结构为例,讨论了该种抗震加固设计的简化计算方法。同时,考虑到结构各楼层各位置墙体受压状况的不同,提出了采用＂预应力分级键＂对预应力筋进行分级张拉的策略,实现了按照各墙体所需来施加对应大小的压应力,从而将原结构的有利因素充分调动起来为抗震加固服务,必要时还需设置柔性斜拉杆。

Seismic Retrofit Method with External Prestressed Tendons for Masonry Structures

According to the shear strength increase of the masonry material due to the correlation of shear-compression of masonry structures,seismic retrofit method with external prestressed tendons for masonry structures is put forward for the first time.After exerting the compression on the masonry walls by stretching prestressed tendons located on both sides of the entire walls in the vertical direction from bottom to the top,the internal seismic resistant performance of masonry structures is improved.Based on the classic Coluomb friction law,a typical four floors masonry school building is adopted as an example to present the accurate calculating process for this kind of seismic retrofit method.The result shows that different seismic retrofit methods should be applied to the masonry walls under different stress states,for some prestressed tendons should be stretched step by step to satisfy the seismic requirement,while some walls should be equipped with cross flexible members to hold the remaining earthquake loads.