木结构古塔的动力特性分析

研究木结构古建筑的力学特性对保护和开发我国古建筑遗产具有重要意义。以山西北部释迦塔为研究对象,用有限元数值方法,通过引入梁单元组模拟斗拱连接,建立了具有木塔较细致结构的有限元计算模型,并通过木塔的实测模态结果方便地确定了斗拱这种复杂连接的刚度。对木塔进行了地震作用计算,计算结果与木塔现实残损变形集中在第二三层的现象一致。计算结果可为古塔的维护和修缮提供理论依据。

DYNAMIC STRUCTURAL CHARACTERISTICS OF AN ANCIENT TIMBER TOWER

As a typical example of ancient timber architectures, the dynamic characteristics of a Sakyamuni tower are investigated numerically by means of finite-element-method (FEM) in this paper. The tower is rebuilt by a delicate finite element model. The mortise and tenon joint in the structure is simulated by a special beam-element group in the model. The stiffness of the element-group joint is determined by modal analyses. Numerical simulation of the seismic response of the tower shows that the second and third floors of the tower must be damaged more seriously than other floors for their severe stresses when acted by seismic loadings. The present analysis of the tower shows the same phenomena. The results provide basis for repairing and reinforcing the ancient timber tower.