高层筒体结构地震动输入能的计算

Evaluation of Seismic Input Energy in Tall Tube Structures

通过理论推导,获得了线性多自由度体系输入能与其等效单自由度体系输入能之间的关系,并以高层框架筒体结构为对象,研究了线性多自由度体系输入能的简化计算方法,以及非线性多自由度体系输入能与线性多自由度体系输入能之间的差异,探讨了地震波以及结构特征对这一差异的影响.研究表明,对于筒体结构而言,采用前3阶等效单自由度输入能之和即能对结构的弹性输入能作比较准确的估计.对于周期小于1 s的短周期结构,塑性的发展所导致的周期变大将使得输入能趋于增加;而对于周期较长的高层结构,塑性的发展与自振周期的变大会使得输入能趋向于降低.

The relationships between the input energy of elastic multi-degree-of-freedom systems and that of equivalent single-degree-of-freedom systems were derived. Based on the energy responses of 3 frame tube structures to 12 ground motion records, a simple calculation method for the input energy of elastic multi - degree- of - freedom system was proposed. The input energy difference between inelastic multi-degree-of-freedom system and elastic multi - degree - of - freedom system was discussed, and the effects of ground motions and characteristics of structures on the input energy difference were analyzed. It was shown that the summation of the first 3 orders input energies of the equivalent single-degree-of-freedom systems was enough to calculate the input energy of elastic multi-degree-of-freedom system. The inelastic input energy was greater than the corresponding elastic input energy for the structure of short period （ T〈 1.0 s） and less than that for the long period structure. Also, a simple formula for calculating input energy of inelastic MDOF system based on that of equivalent single-degree-of-freedom systems was proposed.