多目标遗传算法用于给水管网优化设计的研究

建立了一个基于经济性和可靠性的多目标数学模型用于给水管网优化设计。利用惩罚函数法对遗传算法进行改进后,应用其对多目标数学模型进行求解,并将该优化方法运用于实际工程。结果表明,采用多目标遗传算法得出的结果优于常规优化方法。     

遗传算法在钢结构截面优化设计中的应用

将遗传算法应用于钢结构截面优化设计问题的求解;并在此基础上建立了钢结构截面优化数学模型库,通过调用不同的钢结构截面数学模型,可方便地对各种钢结构截面进行优化设计.算例结果表明,该优化算法用于钢结构截面优化设计是有效可行的.     

基于约束多目标优化算法的盾构隧道设计方法

当前盾构隧道的设计仍主要依托于经验确定设计参数,然后对其安全性进行校核,难以定量的考虑成本和控制指标(收敛变形等)的关系。以衬砌厚度、截面配筋率、横向接头螺栓直径为设计参数,以成本及结构的水平收敛变形为优化目标,结合多目标优化的算法,进行了盾构隧道的横断面设计。采用非支配原理,通过引入约束违反函数,实现了基于NSGA-Ⅱ算法的复杂约束条件处理。最后通过具体算例,完成了满足截面安全性要求的限制条件下,完整Pareto前沿面的获取工作,并与无约束优化结果进行了分析对比,说明了迭代过程的收敛性,阐述了所得Pareto前沿面的价值意义,得到了不同设计条件下的最优解。     

基于遗传算法的建设工程风险决策多目标优化研究

在建设工程风险决策过程中,只考虑单个目标因素的决策并不能满足实际工程的要求。为了使决策更加科学、合理,在风险识别和风险评价的基础上,综合考虑包括风险管理成本在内的多个目标因素对决策结果的影响,建立了工程风险多目标决策优化模型,通过多目标遗传算法NSGA-Ⅱ,实现了工程风险决策方案的优化。最后,对优化结果的分析和评价,证明了所建立的模型在解决工程风险决策问题上的有效性和实用性。     

水泥土墙支护结构遗传进化优化设计方法

探讨了水泥土墙支护结构优化设计方法,建立了以水泥土墙的有效宽度、嵌固深度和置换率为决策变量的优化设计模型,提出了水泥土墙支护结构参数遗传进化优化设计计算方法,讨论了设计计算参数对优化计算结果的影响。并给出了两个工程计算实例,计算结果表明本文方法可得到既安全可靠又经济合理的最优设计方案。     

A multi-objective design method for seismic retrofitting of existing reinforced concrete frames using pin-supported rocking walls

Over the past several decades, a variety of technical ways have been developed in seismic retrofitting of existing reinforced concrete frames (RFs). Among them, pin-supported rocking walls (PWs) have received much attentions to researchers recently. However, it is still a challenge that how to determine the stiffness demand of PWs and assign the value of the drift concentration factor (DCF) for entire systems rationally and efficiently. In this paper, a design method has been exploited for seismic retrofitting of existing RFs using PWs (RF-PWs) via a multi-objective evolutionary algorithm. Then, the method has been investigated and verified through a practical project. Finally, a parametric analysis was executed to exhibit the strengths and working mechanism of the multi-objective design method. To sum up, the findings of this investigation show that the method furnished in this paper is feasible, functional and can provide adequate information for determining the stiffness demand and the value of the DCFfor PWs. Furthermore, it can be applied for the preliminary design of these kinds of structures.     

Shape optimization of a corner-recessed square tall building to reduce mean wind pressure using a multi-objective genetic algorithm

The current study aims to determine how the corner recession affects tall buildings with square plans. A series of numerical simulations have been conducted to find the parametric models' wind pressure. Visualization tools, such as contour plots and streamlines, present the wind flow near the buildings. Numerical simulations are conducted using RANS k-ℇ turbulence models considering a length scale of 1:300. Subsequently, a shape optimization study has been carried out to propose a suitable percentage of corner recession, which should minimize the wind pressure on different faces of the building. As design factors, the amount of corner recession (S) and the wind incidence angle (Ø) are taken, along with the mean pressure coefficients (C_p) on the various building faces. Due to the eight axes symmetry of the building configuration, the random sampling technique is used for the Design of Experiment while accounting for the 0°–45° wind angle of attack. The Response Surface Approximation (RSA) is used to construct surrogate models of the objective functions. The RSA models are validated with wind tunnel test results presented in previously published articles. The optimization study is carried out using the multi-objective genetic algorithm technique.     

A generative facade design method based on daylighting performance goals

Successful daylighting design is a complex task which requires the designer to consider numerous design elements and their effects on multiple performance criteria. Facades, in particular, include many variables which may dramatically impact daylighting performance. Genetic algorithms (GAs) are optimization methods which are suitable for searching large solution spaces, such as those presented by design problems. This article presents a GA-based tool which facilitates the exploration of facade designs generated based on illuminance and/or glare objectives. The method allows the user to input an original 3d massing model and performance goals. The overall building form remains the same while facade elements may change. Ten parameters are considered, including materials and geometry of apertures and shading devices. A simple building data model is used to automatically generate a 3d model of each solution. Results from single- and multi-objective case studies are presented to demonstrate a successful goal-driven design exploration process.     

隧道支护结构体系协同优化设计方法及其应用

隧道支护结构体系的设计方法是隧道围岩稳定性控制的基本需求,如何确定合理的支护参数是保证隧道施工安全的关键问题.为此,首先将协同学原理引入隧道支护设计,构建了隧道围岩协同支护系统,阐明了其系统组成、研究层次及表征参数;隧道围岩协同支护的核心为充分发挥支护—围岩系统、构件和要素的工作性能,从而产生协同增强效应,其特点为时机...     

基于遗传算法的市政管网优化设计的开发应用

介绍了遗传算法的原理及其在管网优化设计中的适用性,对遗传算法在管网优化设计中的应用进行了阐述,从而节约了大量的建设资金,改善了供水系统的工作效率。     

A nonlinear projection method for constrained optimization

An algorithm is presented for the solution of nonlinear optimization problems involving locally differentiable functions with known analytical expressions. The algorithm is based on perturbation methods of system analysis and develops from a set of easy to implement procedures designed to detect and solve the activation and deactivation of constraints while selecting the steepest feasible trajectory and the largest step length. Numerical applications are presented to illustrate the performance of the algorithm.     

Simultaneous size and topology optimization of 3D outrigger‐braced tall buildings with inclined belt truss using genetic algorithm

To investigate the optimum location of the outrigger system, a metaheuristic‐based size and topology optimization of the outrigger‐braced tall buildings is carried out by various three‐dimensional structural frames with different shapes of belt trusses. By considering the elastic behavior, the whole elements of the structural models such as beams, columns, core, and trusses are optimized simultaneously in conjunction with the location of the outrigger. Furthermore, to reach more optimality, several novel types of belt truss are proposed having inclined and inverse‐inclined belt trusses with better structural and architectural features and optimum performance in comparison with the horizontal one. Different models with 25 to 40 stories having various span numbers are optimized using the genetic algorithm, and the results are compared with each other. In the modeling process, the exact wind load distribution is applied to the structure based on the ASCE7‐16 rather than the uniform or triangular ones. According to the results, the optimum cross‐sectional size and outrigger locations of different models are obtained, and it is indicated that the proposed novel belt trusses are optimal solution for the problem.     

A parametric natural fire model for the structural fire design of multi-storey buildings

A parametric natural fire model is presented, which is derived on the basis of simulations with heat balance models for realistic natural design fires, taking into account the boundary conditions of typical compartments in residential and office buildings. These so-called iBMB parametric fire curves are formulated with the help of simplified empirical equations which can easily be used for structural fire design as part of a performance-based natural fire design concept. The iBMB parametric fire curves are checked and validated by comparison with results of different heat balance models and with published fire tests from different fire research laboratories. In addition, a natural fire test in a test room with ordinary office room furnishings has been performed which supports the parametric natural fire model presented here. The application of the iBMB parametric fire curves is demonstrated by means of an example.     

高层建筑地基基础概念设计的思考

基于高层建筑箱、筏、桩筏基础变形、反力等实测资料的分析指出,按传统理念设计的箱基、筏基、桩筏基础有两个缺陷:一是呈现明显的碟形沉降引起上部结构的较大次应力;二是基底马鞍形反力分布导致基础板或承台冲剪力和弯矩显著增大。为使差异沉降和箱、筏承台的内力减至最小并改善上部结构受力性状,提出变刚度调平概念设计。对于框筒、框剪结构,应强化核心筒区的桩土刚度(调整桩长、桩径或桩数),相对弱化外围刚度;对于主裙连体建筑,应强化主体,弱化裙房(采用天然地基、复合地基和疏短桩基);对于箱、筏基础,可局部强化核心筒区(采用桩基或刚性桩复合地基)。对于上述变刚度调平概念设计,进行上部结构—基础—桩—土共同作用分析,进一步优化布桩和承台配筋。通过大比例现场模型试验对上述优化设计理念进行了验证,并应用于10余项工程,取得了良好的技术经济效果。     

基于鲁棒性的索穹顶结构截面优化设计

针对索穹顶结构缺乏有效的基于鲁棒性能的截面优化设计理论现状,基于H∞范数极小控制方法,利用非线性系统运动方程构建输入变量到输出响应的系统传递函数,通过引入L2性能准则并结合随机理论建立索穹顶结构非线性鲁棒性定量评价指标IR,在此基础上,利用MATLAB和ANSYS软件交互算法给出基于遗传算法的截面优化设计的具体步骤,并...     

悬臂式挡土墙结构优化设计的复形法

将单位长度墙体造价最低作为最优目标函数，采用复形法作为优化算法的数学手段对悬臂式挡土墙结构进行优化设计。讨论了基底摩擦系数对悬臂武挡土墙的系列优化设计影响。     

A combined tuned damper and an optimal design method for wind‐induced vibration control for super tall buildings

The wind‐induced vibrations of super tall buildings become excessive due to strong wind loads, super building height and high flexibility. Tuned mass dampers (TMDs) and tuned liquid column dampers (TLCDs) have been widely used to control vibrations for actual super tall buildings for decades. To fully use both the economic advantage of the TLCD system and the high efficiency of the TMD system, an innovative supplemental damping system including both TLCD and TMD and called combined tuned damper (CTD), which can substantially decrease the cost of the damper, was proposed to control the wind‐induced vibrations of tall buildings. The governing equations are generated for the motion of both the primary structure and the CTD and solved to anticipate the dynamic response of the CTD‐structure system. Moreover, an optimal design method of human comfort performance is proposed, in which the life cycle cost of the damper‐structure system is considered as the quantitative index of the performance. The life cycle cost includes the initial cost, the maintenance cost and the failure cost. The failure cost can be calculated using the vibration‐sensation rate model, which is based on the Japanese code AIJES‐V001‐2004. Copyright © 2016 John Wiley & Sons, Ltd.     

城市狭窄地形条件地铁风亭设计优化实践

以狭窄街道、高边坡条件下在建的某深圳地铁车站风亭设计方案的优化比选过程为实例,提出了复杂地形下地铁附属建筑布置的设计思路和实施方法,可为类似工程条件下的地铁工程提供一定指导。     

An optics inspired optimization method for optimal design of truss structures

This paper presents optics inspired optimization (OIO) as a new optimization technique for optimum design of truss structures with continuous variables. In OIO, the physical laws that govern the image formation in spherical mirrors are artificially modeled to develop a new metaheuristic method. In OIO, the surface of the objective function to be minimized is considered as the reflecting wavy mirror consisting of peaks and valleys. In the reflecting surface, each peak is assumed to reflect as a convex mirror and each valley to reflect as a concave one. By assuming each solution candidate as an artificial object (or light point) that is artificially glittered ray is reflected back by the function surface, the artificial image (new solution) is formed based on the governing equations in physics of optics. Compared with the other existing optimization techniques, OIO seems to be a promising alternative approach for solving truss optimum design problems.