再生混凝土框架梁抗震性能试验

Experimental Study on Seismic Behavior of Recycled Concrete Beams

目的研究再生混凝土框架梁在反复荷载作用下的破坏形态、滞回耗能特性、承载性能、延性以及刚度退化,探讨梁端塑性铰区的配箍要求.方法采用荷载与位移混合控制加载,对剪跨比为3的2根再生混凝土框架梁和2根普通混凝土框架梁进行低周反复荷载试验.结果再生混凝土框架梁与普通混凝土框架梁具有相近的承载性能,延性系数均大于4.0.当加密区箍筋间距为100 mm时,再生混凝土梁与普通混凝土梁的延性相近,但前者的极限位移角为后者的1.04倍;当箍筋间距为70 mm时,再生混凝土试件的延性低于普通混凝土试件4%,极限位移角低于普通混凝土试件9%.与箍筋间距为100 mm时的结果相比,箍筋间距为70 mm的再生混凝土试件的延性系数提高15%,极限位移角提高6%;普通混凝土试件的延性系数提高20%,极限位移角提高23%.结论再生混凝土框架梁的骨架曲线与普通混凝土框架梁类似,正截面受弯承载力可采用普通混凝土梁的计算方法,计算值与实测值吻合;再生混凝土框架梁与普通混凝土框架梁的抗震性能差异不大,可应用于工程中.

In order to study the failure pattern,hysteresis loops,load-carrying capacity,ductility,stiffness degradation and determine the confinement requirement in potential plastic hinge region of recycled concrete beams under cyclic loading,two recycled concrete beams and two normal concrete beams with a shear span ratio of 3 are tested. In the loading process,force and displacement control are used. It is found that recycled concrete beams and normal concrete beams have similar load-carrying capacity,and both of them achieve a ductility factor of more than 4. 0. When the stirrup reinforcement in plastic hinge region is provided with a spacing of 100 mm,the ductility fac-tors of recycled concrete beam and normal concrete beam are very close. However,the ultimate drift ratio of recycled concrete is 1. 04 times that of the normal one. When the spacing of stirrup reinforcement is 70 mm,the ductility factor of recycled concrete beam is 4% lower than that of normal concrete beam,and the ultimate drift ratio of recycled concrete is 9% lower than that of the normal one. Compare with the 100 mm spacing,the ductility factor and ultimate drift ratio of recycled concrete beam with the 70 mm spacing increase 15% and 6%,and those of normal concrete beam increase 20% and 23%,respectively. M oreover,the skeleton curves of recycled and normal concrete specimens are close,and the calculating method for flexural capacity of normal concrete beam is applicable to recycled concrete specimens,the predicted capacities are close to the test results. Based on this study,it is thought that the difference between the seismic behavior of recycled concrete beam and normal concrete beam are small,and it is suggested that the recycled concrete can be used in beams.