西藏坚塞颇章宫的结构计算分析

本研究以全国重点文物保护单位西藏罗布林卡三大宫殿之一的坚塞颇章宫为实例,分析藏式古建筑的结构特点,探讨计算分析方法,并针对静力荷载工况和地震组合工况下的结构性能进行了讨论。本研究区别于以往藏式结构的研究方法,主要在于:在计算分析中将墙体建入整体结构模型,考虑墙体对结构的影响;考虑墙体和木柱的“收分”造型的影响;将楼板和屋面的密布木檩等刚度转化为单向板考虑;同时考虑构件已存的变形缺陷影响。计算结果表明:西藏坚塞颇章宫在静力荷载工况作用下,整体状态良好,梁柱墙及节点均满足承载力要求;在地震组合工况作用下,部分柱和墙不满足抗震承载力要求。在地震作用下,该建筑刚度较小的木结构构件首先发生振动。结构薄弱部位是中部四根二层通高木柱。这四根通高木柱长细比较大,刚度较小,一旦发生较大的变形,将直接影响整体结构安全。木柱与墙体之间的变形差异较大,两者变形协调性较差。此外,存在变形缺陷的中部通高木柱所在梁柱节点的抗震承载力不满足要求,应注意加强防护。研究涉及的计算分析方法及相关计算结论对藏式建筑结构的深入研究具有重要的参考价值。

Structural analysis and calculation of Jansal Palace in Tibet

The structural characteristics of Jansal Palace in Tibet and its method of analysis are discussed in this paper. The responses of the structure under static load and under earthquake action are also shown. The methodology in this research is different from that of other studies mainly in that 1) the walls are considered in the calculation model; 2) the shapes of columns and walls are considered; 3) the timber purlins are transferred into slabs and 4) defects of members are considered. The results show that Jansal Palace in Tibet is stable under the static loads, but many of its members could not withstand earthquake action. In an earthquake, the wooden members with insufficient stiffness would vibrate first. The weakest part of the structure is the four-column portion in the center. These columns have a large slenderness ratio, thus a large deformation of these columns may destroy the whole structure. The difference in displacement between the columns and the walls is obvious, as they do not coordinate with each other. Additionally, the beam-column joints cannot withstand earthquake action, in the case of columns with deformation defects, which is important in ensuring protection of the building.