The application of the ant colony optimization algorithm to the construction site layout planning problem

A good site layout is vital to ensure the safety of the working environment, and for effective and efficient operations. Moreover, it minimizes travel distance, decreases materials handling, and avoids the obstruction of materials and plant movement. Based on studies in the manufacturing industry, the cost of materials handling could be reduced by 20–60% if an appropriate facility layout is adopted. In designing a site layout, a planner will first position the key facilities that influence the method and sequence of construction, and then assign the remaining facilities in the available space that is left over. This process is similar to the positioning of facilities in the ant colony optimization (ACO) algorithm. The general principle of the ACO algorithm is to assign facilities to a location one by one, and the occupied locations are deleted from the location scope in the next assignment. In the study, ACO algorithm is employed to resolve the construction site layout planning problem in a hypothetical medium‐sized construction project. By applying fuzzy reasoning and the entropy technique, the study calculates the closeness relationship between facilities, in which the optimal site layout is affected by the mutual interaction of facilities.     

Mathematical programming models for construction site layout problems

We address the construction site layout problem that determines the locations of temporary facilities. Mathematical programming models for the site layout problem are proposed, which can be solved by state-of-the-art solvers to optimality. A number of safety, health and environmental concerns, such as falling objects, dusts, and noise, are incorporated in the extensions of the mathematical models. We demonstrate, using numerical experiments, the superiority of our proposed mathematical programming model over existing heuristics in terms of solution optimality and the wide applicability in terms of handling practical considerations. Based on the results of conducted experiments, the proposed method achieved a 3–19% improvement on optimality over those of the existing heuristics methods. The contribution of this research work includes the advanced development of a mathematical programming model incorporating extended concerns and solving site layout problems within reasonable time.     

A hybrid simulation approach for quantitatively analyzing the impact of facility size on construction projects

Sizing temporary facilities is a crucial task in construction site layout planning due to its significant impact on project productivity and cost. This paper describes a simulation-based approach for modeling the size of facilities that temporarily contain materials in construction projects. Different methods have been introduced for estimating the required size of this kind of facility; however, space limitations, particularly on congested sites, may not allow the planner to allocate the estimated space to the facilities. This study aims at quantitatively analyzing the impact of facility size on the project and modeling the managerial corrective actions to remedy the space shortage in facilities. To this end, a hybrid discrete-continuous simulation technique is adopted. Simulation is superior in modeling dynamic interactions between variables as well as modeling construction processes with inherent uncertainties. The combination of discrete and continuous simulation is used to enhance accuracy and model the project at both operational level (i.e., activity level with higher level of detail) to estimate production rate, and strategic level (i.e., macro level with lower level of detail) to account for some construction planning decisions such as material management variables. The novelty of this study is analyzing the impact of facility size on the project time and cost, while managerial actions taken to resolve space shortages are modeled, and interdependent influencing parameters of the different disciplines, such as site layout, material management, logistics, and construction process planning are integrated in a unified model. The applicability and suitability of the proposed approach is demonstrated in layout planning of a tunneling project site.     

Optimal utilization of interior building spaces for material procurement and storage in congested construction sites

Congested construction sites, such as urban building projects, often have insufficient exterior space to accommodate all needed temporary facilities and material storage areas. Accordingly, interior building spaces need to be used for material storage while exterior space is left for temporary site facilities. Existing models of site layout and material logistics, however, do not support the utilization of interior spaces due to the complexity of interior space modeling. This paper presents the development of a new congested construction logistics planning (C2LP) model that is capable of modeling and utilizing interior spaces of buildings under construction to generate optimal logistics plans. The proposed C2LP model includes novel computational algorithms to model interior space allocation, complex space constraints, and impact of interior space utilization on activity scheduling. C2LP considers four types of decision variables, material procurement, material storage, facility layout, and scheduling of noncritical activities. The model is implemented by using multi-objective genetic algorithms to generate optimal logistics plans that provide optimal tradeoffs between minimizing total logistics costs and minimizing schedule criticality. The model is evaluated by using an application example to illustrate its capabilities in utilizing interior building space in the logistics plan of congested construction projects.     

A BIM-based approach for automated tower crane layout planning

Tower crane layout design and planning within construction site is a common construction technical issue, and is regarded as a complex combinatorial problem. Previous research focused on utilising either mathematical methods or visualisation tools to find an optimal tower crane layout plan. Both these two approaches require large amounts of manual data input by the layout planners, which is time-consuming and not very practical in industry. The purpose of this paper is to develop an integrated approach which combines Building Information Modelling (BIM) and Firefly Algorithm (FA) to automatically generate an optimal tower crane layout plan. Firstly, BIM is utilised to provide inputs for the mathematical model. Then the FA is used to determine the optimal locations of tower cranes and supply points. Finally, the optimal tower crane layout scheme will be visualised and evaluated through BIM-based simulation. A practical case is selected to demonstrate the proposed approach. The final result is promising and demonstrates the practical value of this approach.     

Schedule-dependent evolution of site layout planning

The appropriate layout of temporary facilities on a construction site has a large impact on construction safety and productivity. For the duration of a project the site layout may need to be efficiently re-organized at various intervals to satisfy the schedule requirements and to maintain site efficiency. This paper presents a practical model for schedule-dependent site layout planning in construction. The proposed model uses a combination of artificial intelligence tools (knowledge-based systems, fuzzy logic, and genetic algorithms) to generate, optimize, and re-organize the site layout plan at frequent intervals during the project. The model incorporates flexible representation of irregular site shapes and several options for placing facilities. Based on the proposed model, an automated system is developed, fully integrated with widely used scheduling software. At each schedule interval, the system recalculates the space requirements and, for the convenience of congested sites, can utilize parts of the constructed space to accommodate temporary facilities. Details of the schedule-dependent model are described, and its application in an actual case study project is presented to demonstrate its capabilities.     

城市电力设施布局规划-变电站选址定容

随着城市发展日益加速,电力需求相应增长,对电力设施建设提出了新的需求,即由供电企业和规划部门联合开展城市电力设施布局规划.为解决电力设施布局规划中的变电站选址定容问题,通过建立变电站经济容量、经济供电半径和经济个数等相关数学指标模型,提出了一种基于变电站建设和运行费用最小为目标函数的变电站定容优化方法,提出了一种基于“覆盖圆”的变电站选址优化方法,并通过工程算例说明了选址定容优化方法的使用方法和和实用性.     

Automated multi-objective optimization system for airport site layouts

Airport construction planners often face the problem of identifying optimal locations for temporary construction facilities on site, as the planned locations of these facilities usually influence important and conflicting planning objectives such as improving the efficiency of construction operations and maintaining safety on site. Careful evaluation of all feasible locations for temporary facilities and the selection of an optimal layout are needed in order to achieve these multiple important objectives. This paper presents the development of a practical automated system to optimize multiple conflicting planning objectives and provide all possible optimal tradeoff solutions among these objectives. The system is implemented and integrated in four main modules: (1) a comprehensive multi-objective optimization engine that integrates and optimizes construction work zone safety, construction-related aviation safety, construction-related airport security, and all relevant site layout costs; (2) a relational database that integrates planning data and stores all the generated optimal solutions; (3) an Input/Output module to facilitate specifying planning and optimization parameters and retrieving the generated optimal site layout solutions; and (4) a visualization module that communicates with external CAD software in order to support the visualization of the generated optimal site layout plans.     

A tri-objective ant colony optimization based model for planning safe construction site layout

Realizing safety improvements in construction site layout planning (CSLP) is vitally important to construction project safety management. Unlike previous studies in which the safety objective is built without detailed risk factors analysis, this study transforms CSLP into a multi-objective optimization (MOO) problem with designing two safety objective functions due to facility safety relationships (potential risks arising from interaction flows) and geographic safety relationship (potential risks arising from hazardous sources) from the holistic interpretation of interaction relationship connecting temporary facilities. Besides, a supplementary cost reduction objective function was also derived as cost is a critical barrier against safety improvement. Subsequently, a tri-objective ant colony optimization based model was developed to solve MOO problem. Finally, a case study is used to verify the proposed model. The study enriches safety implications by considering onsite safety issues from interaction relationship and enhances site safety of CSLP in the pre-construction stage.     

Layout optimization of construction site facilities with dynamic freeform geometric representations

Traditional approaches to the construction site layout problem have been focused mainly on rectilinear and simple interpolated static geometrical shapes for modeling site facilities. Moreover, they have used proximity measures based on Cartesian distances between the centroids of the facilities. This is a fair abstraction of the problem; however it ignores the fact that many facilities on the construction sites assume non-rectilinear shapes that allow for better compaction within congested sites. The main focus of this research is to develop a new approach of modeling site facilities to overcome limitations and inefficiencies of previous models and to ensure a more realistic approach to construction site layout problems. A site layout optimization model was developed through a series of new algorithms for modeling regular and irregular freeform shapes of site facilities. The model mimics the “dynamic” behavior of the geometries of site facilities; where the geometrical shapes automatically modify their forms to fit in congested areas. Moreover, new proximity measures and distance measurement techniques were introduced. Furthermore, the research introduced the concept of selective zoning that significantly enhances optimization efficiency by minimizing the number of solutions through selection of pre-determined movement zones on site. At the end, a real site layout planning problem was solved using the developed model and the results were compared to two past models from the literature. The model has shown to be superior to the past models in optimizing congested and geometrically-complex site layouts.     

A decision-making system for construction site layout planning

A decision-making system, which consists of input, design, evaluation and selection, and output stages, is proposed to solve dynamic, multi-objective and unequal-area construction site layout planning (CSLP) problem. In the input stage, the multiple objectives, schedule planning and site condition are determined. In the design stage, two mathematical optimization models max-min ant system (MMAS) and modified Pareto-based ant colony optimization (ACO) algorithm are employed to solve single objective optimization (SOO) and multi-objective optimization (MOO) problem respectively. In the evaluation and selection stage, the intuitionistic fuzzy TOPSIS method is used to evaluate and select the best layout plan among the generated layout alternatives from the design stage. The performance of the proposed decision-making system, which was verified by a residential building project, shall assist the practitioners in the construction industry to deliver construction projects in a more efficient and effective manner, and thus construction costs could be reduced significantly.     

基于突发公共卫生事件应急医疗设施的 城郊森林公园研究

面对新型冠状肺炎的突然暴发,国家快速启动应急医疗设施的建设。选址科学性和建设时效性是建设过程中面临的两大问题。利用城市绿地的防灾功能,通过平灾结合可在一定程度上缓解以上问题。通过比较发现,城郊森林公园在选址、规模、环境、基础设施、覆盖率等诸方面与应急医疗设施需求具有高度的契合性。将城郊森林公园纳入突发公共卫生事件应急预案,可以通过早期的合理选址、布局,预先勘探、铺设管网,加强污水、垃圾处理系统,合理规划康养功能等手段,大大提升灾时应急医疗设施建设的速度,并在一定程度上降低传染性疾病对人口和环境造成的危害。     

基于GIS-AHP的建筑废弃物消纳场选址优化研究——以广州市番禺区为例

随着我国城市化进程的加快,新建建筑和拆迁改造项目产生了巨量废弃物。如果建筑废弃物消纳场场址选择不当,就会对环境、社会和经济造成重大的影响。为此,结合AHP-Entropy方法,利用GIS技术,使用整数规划建立建筑废弃物物流回收网络,以广州市番禺区为例,构建选址优化模型,确定了番禺区内最适宜建设消纳场的位置。综合考虑了与消纳场建设和运营有关的各项成本,确定了消纳场的理想数量和建议容量。建筑废弃物消纳场属于邻避型设施,因此建设时要考虑当地居民对建设消纳场影响,研究结果可以为政府管理部门规划建筑废弃物物流管理链,以及为消纳场选址等方面提供参考。     

昆明新机场A2标段施工总平面图设计要点

从机械设备选型、场区位置布局、场区道路设计、水电管线设置和生活区设置五方面总结了昆明新机场A2标段施工总平面图设计要点,指出施工总平面图应以材料、设备、临时周转材料为设计核心,并兼顾配套设施和施工过程变化的设计理念。     

建筑工程施工现场的平面布置

建筑工程施工平面布置是工程施工单位项目设计中的重要组成部分,是对建筑物或构筑物施工现场的平面规划和空间布置。合理的施工平面布置对于顺利执行施工进度计划非常重要,对现场的文明施工、工程成本、工程质量和安全生产都会产生直接影响。     

A multi-attribute model for construction site layout using intuitionistic fuzzy logic

Most researchers have concentrated on studying optimization models to produce optimal construction site layout plans using different algorithms, while the overall method for evaluating and selecting the best site layout generated from optimization models has received less attention. In an optimization model, construction cost is generally considered in the objective function. However, several objectives, such as security and tie-in with external transportation, are difficult to quantify in the objective function and were not considered in previous studies. This paper focuses on evaluating and selecting the construction site layout considering qualitative objectives. An intuitionistic fuzzy multi-attribute decision-making model is developed that combines intuitionistic fuzzy set theory and the technique for order preference by similarity to the ideal solution (TOPSIS). This model overcomes the shortcomings of a traditional fuzzy set when describing ambiguous and unclear circumstances by using membership functions. The application of this model for site layout selection is shown to be reasonable and effective based on data from a real construction project.     

An innovative approach for generation of a time location plan in road construction projects

Existing linear scheduling methods for earthwork activities lack accurate scheduling locations in road construction projects. Project planners and construction managers largely depend on subjective decisions for the allocation of resources at correct locations. This has caused uncertainties in planning and scheduling, and consequently delays and cost overruns of projects. Accurate information of working locations is vital for efficient resource planning, scheduling and equipment mobilisation. A theoretical framework for a virtual construction prototype model is developed using the theory of location‐based planning and this is used as the basis of sensitivity analysis to identify critical factors affecting road construction. An arithmetic algorithm is developed by incorporating road design data, sectional quantities, variable productivity data, unit cost, site access points and haulage distance. The model generates a time location plan automatically with the aim to provide location‐based scheduling information of earthwork activities. Weekly progress profiles, terrain surfaces, cost profiles and S‐curve are the other outputs of the model. Data and information collected from the case studies are used to demonstrate functionalities of the model. Critical factors controlling the productivity of earthwork activities such as different types of equipment, soil characteristics and site access points were used to display the sensitivity effect by means of ‘what‐if scenarios’. The model is a valuable tool in analysing impacts of different factors associated with productivity data and resource planning from location aspects in the earthwork construction projects.     

健康的韧性城市规划模型构建与策略

2020年春节前后爆发的新型冠状病毒肺炎疫情对我国城市应急能力和治理水平提出了巨大的挑战。文章反思了当前公共卫生防疫在设施布局、区域联防、预警机制和治理水平等方面的痛点,指出营造健康的韧性城市迫在眉睫;随后引入韧性理论,分析了韧性城市的内涵以及国内外研究和实践进展,进而构建了健康韧性城市规划的EERR("双评估"和"双响应")模型,并提出了韧性城市构建策略:首先,通过建设有机的健康城市结构、谨慎布局卫生风险类设施,营造韧性的空间格局;其次,以平灾结合、刚弹相济的理念分区分级分类规划公共卫生设施,并对应急设施进行战略性预留;再次,对疫情期间的交通系统和应急物流实施分区分块的弹性管理方案;最后,利用互联网和大数据技术提高治理水平,并通过数据共享,跨区域联合建立风险管理体系。     

基于BIM的高铁连续梁桥施工过程可视化管理技术研究

为研究信息化技术在高铁连续梁桥施工管理中的应用,以跨新沂河连续梁桥为工程背景,基于BIM技术开展了高铁连续梁桥施工过程可视化管理技术研究。基于BIM技术参数化设计特点,完善了桥梁结构及施工临时设施的参数化族库,建立了施工场地和桥梁结构模型; 开展了钢筋的碰撞检查和施工过程的碰撞分析,优化桥梁的设计方案; 基于BIM模型,模拟了施工现场布置方案,形成了3D施工文档用于可视化交底,并将BIM与施工监测结合,实现桥梁施工监测布置方案的可视化; 针对传统施工进度管理模式存在的问题,开展了高铁连续梁桥的4D(3D+时间)施工进度模拟与施工进度管理研究。结果表明:采用参数化建模策略提高了高铁连续梁桥的建模效率; 基于BIM的施工全过程可视化模拟不仅有利于施工方案的完善,同时降低了施工人员的理解难度; 4D进度管理可实现材料、设备、场地布置和施工进度的动态及可视化管理,有效提高了现场管理的精细化程度,研究成果为高铁桥梁施工过程可视化管理提供了可靠的技术支撑。     

基于罚函数的设施定位布置问题模型与算法

针对系统内部设施布置决策,以定位布置问题为研究对象,提出了一种求解该问题的改进分布估计算法（IEDA）。通过分析定位布置问题的基本特征,建立了带容量约束的基本非线性整数规划模型;引入了基于罚函数的约束处理方法建立了定位布置问题的改进数学模型,进而使用带惩罚项的目标函数引导IEDA 的搜索方向;在IEDA 中融入了一种概率矩阵变异机制和基于互换型邻域结构的局部搜索策略,用于平衡算法的全局和局部搜索能力;并通过仿真实验比较和对某建筑工地实例求解验证了模型的合理性与算法的有效性。