雀替型阻尼器加固箍头榫木框架结构的抗震性能

为研究广府古建筑木结构的抗震性能及加固方法,采用菠萝格木材,设计并制作了两榀不同结构形式的典型广府木祠堂箍头榫框架,提出并制作了用于木结构榫卯节点加固的雀替型阻尼器,对雀替型阻尼器加固前后的木框架进行低周往复荷载试验,研究结构的抗震性能及阻尼器的加固效果。研究结果表明：阻尼器可以弥补初次加载产生的损伤,在转角不大时给残损的榫卯节点提供较高的初始刚度,并在榫卯节点自身开始闭合时与之协同受力,提高节点刚度、极限承载能力和耗能能力,使得加固试件的极限承载能力高于未加固试件;未加固试件经过加载,出现了榫卯脱离、榫卯局部压屈现象,加固试件的破坏形式主要为榫卯脱离、榫卯局部压屈和竖向顺纹劈裂裂缝;各节点的滞回曲线呈现明显的“捏缩”现象,榫卯节点强度退化系数均大于0.83,在循环荷载作用下表现出稳定的承载性能,随节点转角的增大,各节点的环线刚度、等效粘滞阻尼系数呈现逐渐减小并趋于稳定的趋势;边跨框架试件节点的等效粘滞阻尼系数逐渐稳定于0.1～0.2,而中跨框架试件节点的等效粘滞阻尼系数逐渐稳定于0.05～0.1,且经过阻尼器加固,边跨框架与中跨框架试件的总滞回耗能分别提高了67%和19%。

Seismic Performance of Hoop Head Tenon Frame Structure Reinforced by Sparrow Brace Type Damper

In order to study the seismic performance and reinforcement method of the wooden structure of Guangfu ancient building, two typical hoop tenon frames of Guangfu wooden ancestral halls with different structural forms were designed and manufactured by using merbau wood. A sparrow brace type damper for strengthening the tenon and mortise joints of the wooden structure was proposed and manufactured. Cyclic loading tests were carried out on the wooden frames before and after strengthening using the sparrow damper and the seismic performance of the structure and the reinforcement effect of dampers were studied. The results show that the damper can repair the damage caused by the cyclic loads, and provide higher initial stiffness in small rotation angle for the damaged mortise joint. It cooperates with the mortise joints well, so as to improve the joint stiffness, ultimate bearing capacity and energy consumption capacity, so that the ultimate bearing capacity of the reinforced specimens is higher than that of the unreinforced specimens. The unreinforced specimen show the phenomena of mortise and tenon separation and local compression buckling of mortise and tenon joints after loading, while the failure modes of the reinforced specimen are mainly mortise and tenon separation, local compression buckling of mortise and tenon joints, and vertical splitting cracks along the grain. The hysteresis curves of each joint show obvious pinching phenomenon. The strength degradation coefficients of all tenon joints are greater than 0.83, which shows stable bearing capacity under cyclic load. The ring stiffness and the equivalent viscous damping coefficient of each joint gradually decrease and tend to be stable with the increase of rotation angle. Equivalent viscous damping coefficients of the side-span frame specimen joints gradually stabilize from 0.1 to 0.2, while those of the mid-span frame specimen joints gradually stabilize from 0.05 to 0.1. With the reinforcement of damper, the total energy consumption of the mid-span frame specimen and the side-span frame specimen increases by 67% and 19%, respectively.