普拍枋对古建筑木柱侧向性能影响

Influence of Pu-pai Fang on lateral performance of columns in ancient timber structures

合理评估古建筑木结构抗震性能需要研究木柱的侧向性能。为此,开展了柱底不同支承条件古建筑木柱及木构架侧向加载试验,获取了设置及不设置普拍枋木柱的滞回曲线,评估了普拍枋对木柱力学性能的影响,提出考虑和不考虑普拍枋作用的古建筑木柱荷载-位移简化模型,基于简化模型开展了参数分析。研究表明:设置普拍枋,可使古建筑木柱至少提高140%侧向刚度以及97%侧向承载力,且能增加木柱约170%峰值荷载对应位移;普拍枋对浮搁础石木柱的承载力退化现象影响不明显,但显著改善了木枋支承木柱的承载力退化现象,对浮搁础石木柱和木枋支承木柱分别增加了19%和29%的累积耗能。所提荷载-位移简化模型与试验结果吻合良好,可用于古建筑木结构抗震分析;参数分析进一步表明,随着荷载的增加或木柱直径的减小,普拍枋对浮搁础石木柱的侧向刚度增强作用越显著;相对浮搁础石木柱,普拍枋对木枋支承木柱最大荷载的增强效果越显著。

To rationally evaluate the seismic performance of ancient timber structures,the lateral performance of timber columns is required.Considering different support boundaries,this paper presented lateral loading tests on columns and frames in ancient timber structures.Hysteretic curves of the columns with/without Pu-pai Fang were obtained and the influence of Pu-pai Fang on the mechanical properties of the columns was evaluated.A simplified model capable of describing the load-displacement relationship of the columns with or without consideration of the influence of Pu-pai Fang was proposed,and parametric study was further conducted based on the proposed model.The research indicates that Pu-pai Fang increases the lateral stiffness and load-resisting capacities of the columns by more than 140%and 97%,respectively,and increases the displacement corresponding to peak load by about 170%.Pu-pai Fang has a minor influence on the strength degradation of the columns resting on stone base,but considerably alleviate the strength degradation of the columns on timber beams.Pu-pai Fang increases 19%and 29%of the cumulative energy of the columns resting on stone base and timber beams,respectively.The proposed simplified model agrees well with experimental curves,and could be utilized in structural analysis.Parametric study further indicates that with the increase of vertical compression load or the decrease of column diameter,the enhancement on the lateral stiffness of the columns by Pu-pai Fang increases.The enhancement effect from Pu-pai Fang on the maximum load of the columns resting on timber beams is more remarkable than that on the columns resting on stone base.