【作者】 陆海燕；

【导师】 李刚；

【作者基本信息】 大连理工大学 ， 力学， 2009， 博士

【摘要】 高层建筑设计不仅要满足结构安全、功能适用等要求,还应做到结构体系受力合理、材料用量尽可能少。现行的“试算-验证-修改”设计方法,得到的设计方案不一定是满足规范要求的所有方案中最好的(或较好的),需要耗费大量的人力资源和设计时间。结构优化设计是结构设计理论的重要发展,其思想内涵不仅仅是追求体积最小或重量最轻,更重要的是要达到一种资源合理的优化配置。结构优化理论的研究历史悠久,在很多领域得到了成功应用,并且开发了许多具有优化功能的大型有限元软件。然而,针对建筑结构的优化算法研究及应用还相对比较匮乏。这一方面是由于建筑结构的优化设计是多工况、多变量、多约束和多目标的复杂的离散变量优化问题,且存在大量的不确定性(如荷载、构件材料与尺寸、分析模型等);另一方面建筑结构体系复杂,规范构造要求繁多,结构形式和构件形式丰富,这些都给建立全面而实用的建筑结构优化设计算法带来了挑战。本文针对高层建筑优化设计的一系列问题,包括梁多目标选筋优化问题,构件截面尺寸的优化、多目标结构方案拓扑优化、多目标分灾抗震设计等问题,以遗传算法和准则法为工具,开展了优化混合算法的研究,并基于现有分析及设计软件进行了二次开发。本文的主要工作概括如下:1.通过对设计规范相关条款的深入领会,并充分考虑到设计和施工的可行性,结合以往的设计经验和标准图集,提出了梁截面选筋模板。通过建立配筋模板数据库,将梁柱的计算配筋面积转换成最优的且满足规范和施工要求的实际配筋形式。建立了梁选筋目标评价体系,采用模糊分析的方法求得方案对优的相对隶属度。在此基础上,对框架梁多目标选筋优化问题进行了研究,提出了一种求解多目标优化问题的基于模糊综合评价技术的遗传算法(FMOGA)。2.结合我国现行的建筑结构设计规范,对承受多工况荷载作用下的钢筋混凝土框架结构离散变量的优化设计问题,提出了两级混合优化算法。将结构的优化设计分为单元优化和整体刚度优化两级,先以整体刚度优化结果作为下限,用遗传算法完成结构的强度优化设计,再以单元优化的结果作为下限,用经过严密推导的准则法完成整体刚度优化设计,重复上述两级优化到目标函数收敛为止。根据建筑结构的特点,在遗传算法中提出了自适应设计域技术,提高了算法的效率。将上述优化算法在大型有限元软件ANSYS和建筑结构设计专用软件SATWE软件上进行了程序实现。对两个30层的高层建筑结构进行了优化设计,结果表明本文提出的方法是有效的和可操作的。3.结构的变形控制抗震设计方法是实现基于结构性能设计理论的重要途径。钢筋混凝土框架结构中,梁柱的变形能力及其变形是度量结构位移水平的重要指标。针对影响梁柱变形能力的轴压比、配筋率和配箍特征值等重要因素,根据约束混凝土的本构关系,建立了梁柱塑性铰转动能力与配筋率、配箍特征值和轴压比之间的函数关系。通过虚功原理,得到了结构的层间位移与梁柱的截面尺寸和构造配筋之间显式表达式。提出了钢筋混凝土框架结构基于性能的两层次抗震优化设计方法,并给出了采用两级混合算法和基于非线性分析的准则法进行优化设计的基本过程。4.在专家调查和文献资料收集整理的基础上,建立了结构方案优化设计影响因素层次关系图,采用模糊技术对多目标的建筑结构方案进行综合评定。根据建筑结构设计专业和建筑设计专业的关系,提出了建筑结构设计模板,并以结构元件的组合替代结构方案设计,为建筑结构方案的优化设计提供了一种定量的数学描述方法。在此基础上,对多目标的建筑结构方案的拓扑优化设计问题进行研究。5.详细论述了复杂结构分灾设计方法的设计思想、优化模型和基本原则以及相关的问题。指出分灾元件布置方案是一个多目标决策问题,并根据投资—效益准则,建立了分灾元件布置方案的目标评价体系。分别以结构方案综合经济造价和灾害引起的损失最小、结构的安全性最大为目标构造两种目标函数,基于相关的设计规范,给出了分灾元件布置方案优化问题的一种合理提法,并给出了采用FMOGA求解的具体流程图。更多还原

【Abstract】 The design of tall buildings not only needs to satisfy the requirements of structural safety and building functions,but also should achieve the reasonable structural system with the minimum material.The present design method of trial-verification-modification always results in the acceptable design project that satisfies the regulations of the design codes, however,it may be an unoptimal design and the design is time-consuming.Structural optimization dsign is an important development of the structural design,whose inherent aim is not only to pursue the minimum cost or material volume,but also the rational distribution of the resourses.The research on structural optimization had a long history,and there were a lot of successful applications in many fields and some available commercial FEM softwares with optimization modules.However,there has been few research and application of the structural optimization for building structures.In general,the optimization problem for building structures is an complex discrete optimization one with multi-load,multi-variable, multi-constraint and multi-objective,and there exsits a lof of uncertainties(loads,materials, analsys models,and etc.).Moreover,the structural system and form and the component type of buildings are quite complex and with numerical regulations of the design codes.These difficulities make it much challenging to establish a comprehensive and practical optimum algorithm.This paper uses the genetic algorithm and the criterion method as a tool for the optimum design of building structures,and focuses on the multi-objective optimization of beam bars, size optimization of the component sections,multi-objective optimization of structural scheme and topology,multi-objective damage-reduction seismic design.Some optimization modules were integrated to the commercial softwares of structural analysis and design.The main contents of this paper are listed as follow:1.Based on the deep understanding of the relevant provisions of the design codes,this paper proposes the template of beam reinforcement,which not only accounts for the feasibility of the design and the construction convenience,but also the design experiences and standard atlas.The optimum reinforcement detailing,which satisfies the strength,serviceability, ductility and other constraints related to the user specified rules and regulations in design codes,is achieved by constructing the data sets containing different available reinforcement bar diameter in a pre-specified pattern.A target evaluation system of beam reinforcement is given.Fuzzy analysis method is used to obtain the relative membership to the optimum design.At last,a genetic algorithm(FMOGA) with fuzzy analytic decision for solving the multi-objective optimization problems is presented.2.Based on the current Chinese design codes,a 2-level hybrid method of optimum design for structural optimum design of reinforced concrete(RC) tall buildings under multi-load cases is proposed.The entire optimum design procedure is divided into two levels:element optimum design and system optimum design,A genetic algorithm is used to perform the discrete optimization of tall buildings under the strength constraints with the results of system optimum design as the lower bounds of member size,then the system optimum design is conducted using optimality criteria method with the results of element optimum design as the lower bounds of member size.This procedure is repeated until convergence is obtained.An adaptive feasible region technique is developed to improve the efficiency of genetic algorithm.The proposed optimum design method is integrated to the large-scale finite-element software ANSYS and the specialized design softwrae for building structures, SATWE.Finally,a practical frame-shear-wall structure(30-story) is optimized to illustrate the effectiveness and practicality of the proposed optimum design method.3 The structural displacement based seismic design is an important approach to realize the performance-based seismic design.For the RC frame structure,the story drift is descided by the deformation of beams and columns,which is influenced by the axial compression ratio, the reinfoecement ratio and the characteristic value of the confining reinforcement.According to the stress-strain relation of confined concrete,the formulation of plastic hinge deformation capacity of beams and columns is established,and this formulation creates the relationship among the axial compression ratio,the characteristic value of the confining reinforcement and the ultimate plastic hinge rotation of beams and columns.The relationship between the story drift and the deformation of beams and column is determined by the virtual work.A 2-1evel hybrid method of optimum design is proposed for performance-based seismic design of RC frame structure,and a flow chart of the proposed criteria method based on the ineleastic analysis is given.4 Based on the literatures,the design experiences and the experts’ suggestions,the relation between the influence factors and the structural scheme design is established,and the fuzzy evaluation technology is used to make multi-objective decision.According to the relationship between the structural design and the architectural design,the design template of building structures is proposed with the combination of structural elements,which provide a quantitive description for the scheme optimum design of building structures.Then,the multi-objective topology optimum design of the structural scheme of building is studied. 5.The basic concept,principle and optimization model of the damage-reduction seismic design of the complex structure are discussbed.It is suggest that the arrangement scheme of the damage-reduction elements should be considered as a multi-objective decision problem, and the target evaluation system of the arrangement of the damage-reduction elements is established according to the cost-benefit criterion.The multi-objective optimum design problem of damage-reduction element is studied,and a flow chart of the proposed method is given.更多还原