足尺带斗拱木结构水平滞回性能试验研究

Experimental study on horizontal hysteretic behavior of full-scale timber frame with dou-gong sets

在不同竖向荷载下对七等材、八等材足尺模型进行水平拟静力试验,分析滞回曲线、骨架曲线、变形及刚度变化规律.结果表明:木构架的变形主要表现为摇摆柱的转动、摩擦滑移及如嵌压等的塑性变形,并由此导致刚度的退化,而构件间的约束力则延缓了刚度退化的速率;在水平往复侧移中,木构架体现出良好的变形能力和自复位能力;竖向荷载的增加提高了极限承载能力,且与弹性段、屈服点的最大荷载和刚度均呈正线性关系.相对于七等材模型,八等材模型的滞回耗能和延性较高,但极限承载力较低,刚度退化更快;木构架的滞回性能与模型比例的关系与竖向荷载的区域有关.

The hysteresis curves,envelope curves,deformation capacity,and change in stiffness under different vertical loads were analyzed by conducting the horizontal pseudo-static experiments for two full-scale models according to the requirements of a seventh-grade and eighth-grade material system.Results indicate that the deformation of the timber frame is mainly caused by the column rotation,frictional sliding,and plastic deformation like embedment,and thus the stiffness is decreased,however,the constraining forces among components decelerate the rate of stiffness degradation.Besides,the timber frame exhibits obvious self-restoring and favorable deformation capacity during reciprocating horizontal motions.The increase in vertical loads improves the ultimate bearing capacity,and shows positive linear relationships with the maximum forces and stiffness in elastic stage and yield point.Lastly,the seventh-grade model is higher for hysteretic energy dissipation and ductility than the eighth-grade model,but shows lower ultimate bearing capacity and faster stiffness degradation.The relationship between the hysteresis behaviors and the timber frame scale is also related to the areas of vertical load.