预应力钢带加固震后混凝土框架抗震性能试验研究

Experimental study on seismic performance of post-earthquake reinforced concrete frame structure retrofitted by prestressing steel strips

提出采用预应力钢带加固技术对处于"可修"性能水准状态的钢筋混凝土框架进行快速抢救加固,以有效提高历经大震的混凝土框架抵抗余震的能力,并为震后全面加固提供条件.首先对一榀三层单跨1:2比例的钢筋混凝土框架进行低周反复拟静力试验,并加载至试件承载能力下降至极限荷载的85%时停止试验.然后采用预应力钢带加固技术对该框架试件的柱端、梁端和节点核心区进行加固,并重新进行低周反复拟静力,以考察加固后框架试件的抗震性能,通过详细对比加固前试件和加固后试件的承载能力、刚度、延性、层间位移角、耗能能力等性能指标,发现采用预应力钢带加固的震后框架试件基本上能达到震前框架的抗震性能,初步表明,采用预应力钢带加固技术可以实现对震后混凝土框架的有效加固,非常适用于对震后混凝土的快速抢救加固.

In order to improve the reinforced concrete frame＇s resistance ability of aftershocks and provide conditions for comprehensive post-earthquake strengthening,the strengthening technology with prestressing steel strips was adopted to retrofit reinforced concrete frame that remains stable and erect under strong earthquakes.In this paper,low-cyclic pseudo static test of the reinforced concrete frame with single span and three stories was conducted and was halted when the specimen＇s carrying capacity decreased to85%of the ultimate load bearing capacity.Then,the prestressing steel strips reitrofitted technology was adopted to retrofit the beam end,the column end and the core area of frame joints.The low-cyclic pseudo static test was conducted again in order to study the seismic performance of the frame after it was retrofitted.A series of seismic performance indexes such as the bearing capacity,stiffness,ductility and energy dissipation capacity were contrasted in details between preshock and retrofitted specimen.It can be concluded that the seismic performance of post-earthquake reinforced concrete frame which was retrofitted by prestressing steel strips was almost similar to intact specimen＇s.The results showed that the post-earthquake structure retrofitted methods was suitable for strengthening post-earthquake reinforced concrete frame rapidly.