单层楼阁式木架动力与耗能性能试验研究

中国传统楼阁式木构由柱基层、柱架层、铺作层和屋架层组成，地震作用下各结构层间出现的非线性响应表明了楼阁式木构是一个高度非线性的结构体系，其中蕴含了丰富的减隔震机理，而整体楼阁式木架的抗震机理复杂且各结构层协调工作机制、动力及耗能性能尚未被完全揭示。为了探究楼阁式木架的动力及耗能性能，基于先前研究内容对1/16缩尺的观音阁单层木架简化模型进行了振动台试验。将三条地震波缩尺并调整地震动峰值加速度（PGA）后输入，分析木架在单向地震激励下的动力响应。试验结果表明，当输入地震动加速度较小时，三条地震波作用下木架响应都较小，当输入地震动加速度较大时，三条地震波作用下木架均会出现柱摇摆、柱脚滑移和柱脚提离等结构响应；木架层间位移角主要由柱架层提供，且随着PGA增大，铺作层层间位移占比减小，柱架层层间位移占比增大。基于试件位移响应和加速度响应，进而分析木架表现出的滞回特性，结果表明在柱摇摆前滞回曲线呈现较大初始刚度，在柱摇摆后滞回曲线呈现二阶刚度，在柱脚提离后滞回曲线呈现负刚度；同时对不同地震激励下的木架累积耗能及耗能占比进行了分析，结果表明，随PGA增大，柱脚摩擦滑移耗能占比越大，且PGA越大，柱架层摇摆耗能占比越大，铺作层耗能占比越小。

Dynamic and Energy Dissipation Performance of Single-story Pavilion-type Timber Frame

Traditional Chinese pavilion-type timber structure consists of column base layer, column frame layer, paving layer and roof truss layer, of which the response of each layers under seismic waves indicates that the pavilion-type timber frame is a highly non-linear structural system, which contains a wealth of seismic mitigation and isolation mechanism. The seismic mechanism of the overall pavilion-type timber frame is sophisticated and the coordinated working mechanism, dynamic and energy dissipation performance have not been fully revealed. To investigate the dynamic and energy dissipation performance of the pavilion-type timber frame, a shaking table test of a 1/16 scaled simplified Guanyin Pavilion timber frame was carried out based on the previous study. Three seismic waves were scaled down and adjusted for peak ground acceleration (PGA) to analyze the dynamic response of the timber frame under unidirectional seismic excitation. The test results show that the response of the timber frame is small with small input acceleration, and the structural response, such as column rocking, column base sliding and column base uplifting will occur with large input acceleration. The inter-story drift is mainly provided by the column frame layer, the inter-story displacement of the column frame layer decreases and the inter-story displacement of the paving layer increases as the PGA increases. Based on the displacement and acceleration responses of the specimen, the hysteresis characteristics of the timber frame were then analyzed. Hysteretic curves of the timber frame present large initial stiffness before column rocking, as well as small positive second-stiffness after column rocking and negative stiffness when column base uplifting occurs. At the same time, cumulative energy dissipation and energy dissipation proportion of each part of the specimen under different seismic excitations are analyzed. With an increasing PGA, the column base sliding becomes the main energy dissipation mode, and the greater the PGA, the more energy dissipation proportion of the column rocking of the column frame layer and the less energy dissipation proportion of the paving layer are.