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在大多建筑抗震规范中,都是通过结构自振周期计算设计地震加速度。设计规范给出了结构基本自振周期的经验公式。研究了一系列沿高度方向属性不变的钢板剪力墙结构。采用三维几何线性有限元分析确定这些结构的基本自振周期,并与规范给出的经验值进行比较,结果表明,经验公式并不准确。提出一个简化方法用于估算结构的基本自振周期,该方法将钢板剪力墙看成竖向悬臂结构,这样就可简化求解过程。考虑剪力墙的抗剪和抗弯刚度,在框架剪力墙结构中,这种简化方法可以进一步应用到具有钢板墙和抗弯框架的双系统结构中。将采用此方法计算的自振周期与有限元分析结果比较,可知两者非常吻合。研究了几何非线性和材料非线性对基本周期的影响。在不同的侧移水平下,计算钢板墙的基本周期。基于数值分析,给出由填充板屈曲和屈服带来的周期增大值。
In most of the building seismic codes, the seismic acceleration is calculated through the period of structural natural vibration. The design specification gives the empirical formula of the fundamental natural period of the structure. A series of steel plate shear wall structures with constant property along the height direction were studied. The fundamental natural periods of these structures were determined by three-dimensional geometric linear finite element analysis and compared with the empirical values given in the specifications. The results showed that the empirical formulas were not accurate. A simplified method is proposed to estimate the fundamental free vibration period of the structure. This method takes the steel plate shear wall as a vertical cantilever structure, thus simplifying the solution process. Considering shear and flexural stiffness of shear walls, this simplified method can be further applied to dual-system structures with steel walls and flexural frames in frame-shear wall structures. Comparing the natural period and the finite element analysis calculated by this method shows that the two are in good agreement. The effects of geometric nonlinearity and material nonlinearity on the fundamental period are studied. Under different lateral displacement levels, the basic period of the steel wall is calculated. Based on the numerical analysis, the increase of period due to the buckling and yielding of the filler plate is given.