基于模糊可靠度的 SRC 框架结构优化设计研究

摘要

Based on “investment-benefit”rule,the optimization mathematical model of SRC frame structures was established.Optimization objectives included the initial cost minimization and the structural failure loss minimization,and the weighed coefficient was used to adjust the importance of the both.In order to obtain the structural loss expectation, firstly,the failure probability of structures was calculated.In order to obtain the failure probability more close to reality, the fuzzy reliability analysis of SRC frame structures was performed.The main contents of fuzzy reliability analysis included determining the aseismic performance level quantification value of SRC frame structures,establishing structural fuzzy function,and presenting Monte Carlo method considering the fuzziness.The SRC frame structure optimization process was adjusted to a two-level iteration process with the outer layer for optimization design and the inner layer for the structural reliability analysis.Aiming at too many design variables and constraint conditions and the higher nonlinear level of constraint conditions and objective function,the phase-in optimization calculation method for SRC frame structures was put forward.Finally,the optimization design of a one-bay-three-story SRC frame is implemented.The optimization results showed that the optimization method proposed here can obtain ideal and reliable design results.%基于“投资－效益”准则，建立 SRC 框架结构的优化数学模型，优化目标包括初始造价及结构失效损失期望最小化两部分。利用加权系数调整两者重要程度。为获得结构失效损失期望值计算结构失效概率；为获得接近实际的失效概率，对 SRC 框架结构进行模糊可靠度分析，主要内容包括：确定 SRC 框架结构抗震目标性能水平量化值，建立结构模糊功能函数，提出考虑模糊性 Monte Carlo 法。将 SRC 框架结构优化过程调整为含内外两层的迭代过程，外层对优化模型进行计算，内层对结构进行模糊可靠度分析。考虑优化模型中设计变量、约束条件过多、目标函数非线性程度较高等特点，提出适用于 SRC 框架结构的分阶段优化计算方法。通过对一榀单跨三层 SRC 框架结构优化设计，表明所提优化方法可获得理想、可靠的设计效果。