高轴压比下钢管混凝土矮墙抗震性能试验研究

Experimental study on seismic behavior of concrete-filled steel tube squat wall under high axial compression ratio

为了提高矮墙的轴向稳定性以及侧向变形能力,在墙体中部布置多根钢管,形成钢管混凝土矮墙的形式。通过对5片剪跨比为0.95的矮墙试件在高轴压比(0.5)下的拟静力试验,研究了其承载力、变形能力、破坏形态、滞回耗能等抗震性能,并给出了内部钢筋与钢管应变。主要设计参数为钢管布置、轴压比、抗剪件类型以及钢管间连接。试验结果表明:钢管混凝土矮墙在峰值荷载之前呈现明显的剪切受力状态,腹板上布满大量剪切裂缝;峰值荷载之后损伤集中于钢管部位,形成开缝墙的受力模式,侧向变形能力得到明显提升;加载结束时墙体腹板混凝土剥落,但墙体仍然具有很好的竖向与侧向稳定性。墙体的峰值位移角约为1/290~1/106,极限位移角达到1/70,并且滞回性能明显改善,表明钢管混凝土矮墙具有良好的抗震性能和抗倒塌能力。

In order to improve the axial stability and the lateral deformability of the squat wall,the concrete-filled steel tube squat wall was proposed.Quasi-static tests of five concrete-filled steel tube squat walls with shear-span ratio 0.95 and high axial ratio(0.5)were carried out.The bearing capacity,deformability,failure modes and energy dissipation were studied.The strains of the reinforcement and steel tube were obtained.The main design parameters included the layout of steel tubes,axial compression ratio,shear connector type and braces between steel tubes.The test results indicate that before the peak load,the concrete-filled steel tube squat wall shows an obvious shear mode with a large number of shear diagonal cracks distributed along the web.After reaching the peak load,the damage tends to concentrate around the steel tubes.The failure mode of the slit wall is gradually formed,and the lateral deformability is obviously improved.When the test is finished,the concrete of the web has serious spalling.However,the concretefilled steel tube squat wall still has favorable vertical and lateral stability.The drift ratio at the peak load is about 1/290-1/106,and the ultimate drift ratio reaches 1/70.The hysteretic behavior of the concrete-filled steel tube squat wall specimens is improved significantly.It can be concluded that the concrete-filled steel tube squat wall designed here have an excellent seismic performance and collapse prevention capacity.