钢筋混凝土框架核心筒高层建筑结构中美规范设计对比

Comparison between Chinese and US codes for design of high-rise reinforced concrete frame-core structures

为研究中美两国规范设计理念的不同,依照中国规范规定确定抗震设防烈度、设计地震分组、场地类别,按50年超越概率为2%的地表峰值加速度基本相当的原则,确定了美国规范地震作用的对应参数,选择两栋相同的钢筋混凝土框架核心筒高层建筑结构进行了设计。建立了空间弹性分析模型,采用振型分解反应谱法计算了结构的弹性地震响应,对结构的动力特性、结构位移、构件尺寸及配筋等进行对比分析。分析结果表明:按照美国规范设计的结构自振周期比中国规范的长;结构侧移更大;梁、柱截面尺寸比中国规范设计的小,楼板厚度比中国规范设计的大;按两国规范设计的结构总体用钢量基本相当。分别按两国规范选取10组地震波进行了动力弹塑性分析和结构倒塌概率分析。分析对比结果表明:按照中国规范设计的结构有8条波的计算结果超过规范限值,而按照美国规范设计的结构只有3条波的计算结果超限。

In order to study the differences between Chinese and American normative design concepts,two identical high-rise reinforced concrete frame-core structures were designed based on the corresponding codes in China and the United States. Seismic precautionary intensity, site classification and design earthquake effects were determined according to the Chinese code. The American standard seismic action were determined according to the principle that the peak ground acceleration is basically the same with the exceedance probability of 2% in 50 years. Models of these structures were built for spacial elastic analysis, and the corresponding seismic reactions were calculated based on the response spectrum method. The dynamic behavior, displacement, element dimension and reinforcement were compared. The results show that the natural vibration period of the structure designed by the American code is longer; the lateral movement of the structure designed by the American code is greater; the section sizes of beams and columns of the structure designed by the American code are smaller and the thicknesses of the floors are larger; and the total amount of steel is about the same. The dynamic elastic-plastic analysis was conducted using ten sets of earthquake waves to analyze the probability of failure of collapse. The results of analysis and comparison show that the results of eight waves in the structure designed according to the code of China exceed the standard limit while only the results of three waves are over the limit of the standard in the structure designed according to the American code.