基于Info-Gap决策的结构抗震稳健性优化设计

Info-Gap Decision for the Robust Seismic Design Optimization of Structures

针对结构抗震设计中存在严重不确定性问题,基于Info-Gap理论建立一种考虑地震设计谱参数不确定的结构抗震稳健性优化设计方法.该设计方法采用Info-Gap模型来描述地震设计谱中反映地面运动强度的水平地震影响系数最大值αmax和场地特征周期Tg的不确定,通过嵌套优化使结构设计满足结构的临界性能要求的同时实现最大化不确定的稳健性.通过对一个6层3跨的钢框架的抗震稳健性优化设计验证分析表明:这种基于满足性能的结构抗震设计需在满足结构性能需求和提高不确定稳健性之间进行权衡取舍;同时也证实该方法为在不易得到不确定性因素足够信息情况下的基于性能结构抗震可靠性设计提供了一条新思路.

Seismic design for buildings is usually subject to various uncertainties,often severe,which have the potential to undermine engineering decisions.It is crucial that these uncertainties be accounted for in seismic design.We formulated a performancebased seismic design model that takes into account uncer-tainty in the seismic design spectrum of theαmax and Tg .We used info-gap theory for satisfying the critical performance requirements,while at the same time maximized the robustness to uncertainty through nested optimization.The design implications of this robust-satisfying approach were demonstrated with a three-span six-floor steel frame design example.It is shown that design preferences depend upon the performance requirements considering the trade-off between robustness to uncertainty.Also,the result reveals that the proposed method provides a novel tool for the performance-based seismic reliability design under the lack of knowledge.