Seismic Torsional Effects In Multistory Buildings

这项研究是一个学术研究单位和一个专业设计室合作进行的，目的是研究多层建筑的地震扭转效应。两个项目(BCS 9020394和BCS 9116089)被合并为参考主题领域的联合合作研究，作为一个单一的研究努力。通过分析模型和概率方法，本研究对扭转不平衡结构的弹塑性地震反应进行了评估，以期发展更合理的设计方法。关于地震响应的知识，由归一化真实和合成加速度图的集合定义的地震运动计算，用于在广泛的基于弹性的程序的检查中获得物理洞察力，这些程序广泛应用于当前的抗震设计扭转效应规范中。这些程序的有效性是通过首先根据基于弹性的“静态”和模态叠加规则来设计结构模型来评估的，然后对这些模型的非弹性响应进行了显式评估。如果地震反应参数(楼层位移或构件延性需求)超过的概率不超过，则判定扭转不平衡结构已被正确设计。相应的平衡(对称)系统。建立的标准将有助于识别当前实践中的缺陷，并将提供一种方法，用于系统地测试和修改不同的设计规则，直到获得令人满意的概率。该项目的研究结果为多层建筑在地震力作用下的扭转效应提供了至关重要的数据。

This research study is a joint collaborative research effort between an academic research unit and a professional design office to investigate seismic torsional effects in multistory buildings. Two projects (BCS 9020394 and BCS 9116089) are combined into a joint cooperative study of the referenced topic area as a single research effort. By means of analytical models and a probabilistic approach, this research study evaluates the inelastic seismic response of torsionally unbalanced structures, with a view towards developing more rational methods of design. Knowledge of the seismic response, calculated for seismic motions defined by ensembles of normalized real and synthetic accelerograms, are used to gain physical insight in the examination of a wide range of elastically-based procedures widely used in current codes for torsional effects in seismic design. The validity of these procedures are assessed by first designing the structural models according to the elastically-based "static" and modal superposition rules, followed by an explicit evaluation of the inelastic response of these models. A torsionally unbalanced structure will be judged to have been properly designed if the probability of exceedance of a seismic response parameter (story drift or component ductility demand) does not exceed that for the corresponding balanced (symmetric) system. Criterion established will help identify deficiencies in current practice and will provide a method for testing and modifying systematically different design rules until satisfactory probabilities are obtained. Results from this project provide critically important data on the torsional effects in multistory buildings induced by seismic forces.