不同方式加固的榫卯节点木框架抗震性能试验研究

Experimental study on seismic behavior of timber frames with mortise-tenon joints under different strengthening methods

设计了竹斜撑、钢箍和钢支撑3种榫卯节点木框架加固方法,完成了4榀足尺单层单跨平面木框架拟静力试验。研究了不同加固方式对榫卯节点木框架抗震性能的加固效果,分析了未加固木框架和不同加固方式木框架的破坏特征、水平承载力、延性、刚度及承载力退化性能、耗能能力和榫头应变。结果表明:竹斜撑加固、钢箍加固和钢支撑加固木框架的正向峰值荷载较未加固木框架分别提高了105.2%、246.6%和68.1%,而反向峰值荷载仅分别提高了-8.7%、57.7%和12.4%;与未加固木框架相比,竹斜撑加固木框架和钢支撑加固木框架的初始刚度分别提高了82.4%和38.3%,钢箍加固木框架提高有限,仅为3.3%;在水平反复荷载作用下,各加固木框架的整体刚度均随位移及循环次数的增加而逐步下降,进入塑性阶段后,各加固木框架刚度下降较为平缓且与对比木框架差异较小;钢箍加固木框架的耗能能力显著大于未加固木框架,竹斜撑加固木框架和钢支撑加固木框架正向加载时的耗能较未加固木框架提高明显,但反向加载时基本没有增加。

Three strengthening methods including bamboo brace,steel hoop and steel brace were designed to improve the seismic behavior of traditional Chinese timber frames,and quasi-static tests were carried out on four full-scale onestory and one-bay plane timber frames. The effectiveness of different strengthening methods for improving the seismic behavior of timber frames was investigated. The failure characteristic,horizontal load bearing capacity,ductility,degradation of bearing capacity and stiffness,energy dissipation capacity and strain distribution in the mortise joint were analyzed. Compared to the unstrengthened timber frame,the increase of peak load in the positive direction were105. 2%,246. 6% and 68. 1% respectively for timber frames strengthened with bamboo brace,steel hoop and steel brace,and the increase of peak load in the negative direction were- 8. 7%,57. 7% and 12. 4% respectively.Timber frames strengthened with bamboo brace and steel brace show 82. 4% and 38. 3% increase in initial stiffness respectively compared to unstrengthened timber frame, while this increase was only 3. 3% for timber frame strengthened with steel hoop. Under the horizontal cyclic loading,the integral stiffness of strengthened timber frames is observed to decrease with the increase of displacement and cyclic times. After entering plastic stage,the stiffness decrease slowly and is similar to that of unstrengthened timber frame. A large improvement of energy dissipation capacity is observed for timber frame strengthened with steel hoop compared to unstrengthened timber frame,while for timber frames strengthened with bamboo brace and steel brace,only the energy dissipation capacity during the loading in the positive direction is improved obviously but the energy dissipation capacity during the loading in the negative direction is similar to that of unstrengthened timber frame.