Performance of global optimization models for dynamic site layout planning of construction projects

Dynamic construction site layout planning is a complex optimization problem that is characterized by nonlinear objectives and constraints, which impose great challenges in obtaining global and feasible solutions. This paper presents and compares between two global optimization models of dynamic site layout planning that were developed to overcome the limitation of previous models in the literature. The first model utilizes Genetic Algorithms (GA) while the second model utilizes Approximate Dynamic Programming (ADP). The performance of these two optimization models is analyzed in terms of the effectiveness of reaching optimum solutions and the efficiency of reducing the computational time. This analysis is performed using a designed set of problems of dynamic site layout planning with changing size and complexity. It was found that ADP outperformed GAs in terms of effectiveness and efficiency. However, GAs still prove to be a viable optimization tool because of its simplicity and multi-objective optimization capabilities.     

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.     

施工现场平面布置方法及要点

根据以往工程的施工经验,介绍了施工现场平面布置的依据、原则和主要内容,及施工现场平面布置中塔吊、施工电梯布置等方面的注意要点,以期指导实践。     

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.     

网页制作与网站建设

描述了网页制作的基本工具、常用软件和技术及其发展趋势,包括ＨＴＭＬ,ＣＧＩ,ＡＳＰ,网络数据库和图形处理技术;结合暖通空调制冷领域网站对大量数据和网形的需要,指出了行业网站建设中这些技术的应用和专业资料查询中的使用方法。介绍商业网站和个人网站的建立步骤和方法 。     

基于SLP的建筑施工现场平面布置

为了解决建筑施工现场不合理布局造成的成本和工期问题,采用系统布置设计的方法,对郑州国龙商务中心在建项目的施工现场平面布置进行分析,达到了降低材料二次搬运费等建筑成本的效果。     

Dynamic construction site layout planning using max-min ant system

Construction site layout planning (CSLP) is a dynamic multi-objective optimization (MOO) problem as there are different facilities employed in the different construction phases of a construction project. In this study, a new method using continuous dynamic searching scheme to guide the max-min ant system (MMAS) algorithm, which is one of the ant colony optimization (ACO) algorithms, to solve the dynamic CSLP problem under the two congruent objective functions of minimizing safety concerns and reducing construction cost is proposed. Using weighted sum method the MOO problem can be solved by the proposed MMAS method. An office building case was used to verify the capability of the proposed method to solve dynamic CSLP problem and the results are promising. The approach could be benchmarked by researchers using other advanced optimization algorithms to solve the same problem or expand the applications to other fields.     

浅析施工总平面图的设计步骤与方法

施工总平面图是施工项目管理规划及施工组织设计中的一项重要设计内容,它与施工方案、施工进度及资源计划等相互影响,是施工项目现场管理、实现文明施工的依据。本文针对施工总平面图设计的设计步骤与方法进行了一些分析及阐述。     

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.     

Application of 4D for dynamic site layout and management of construction projects

Construction schedules and site space arrangement are essential to project management, as they directly influence security, machine running, material deployment, power distribution as well as construction progress and cost. There has been a strong need for more effective planning and management of site space and facilities. This paper introduces a 4D Integrated Site Planning System (4D-ISPS) which integrates schedules, 3D models, resources and site spaces together with 4D CAD technology to provide 4D graphical visualization capability for construction site planning. The features of 4D-ISPS are described in detail. The implementation techniques of this system are also discussed and a real life case is presented.     

A hybrid CAD-based construction site layout planning system using genetic algorithms

The efficient layout planning of a construction site is a fundamental task to any project undertaking. In an attempt to enhance the general practice of layout planning of construction sites, the paper introduces a novel approach for producing the sought layouts. This approach integrates the highly sophisticated graphical capabilities of computer-aided design (CAD) platforms with the robust search and optimization capabilities of genetic algorithms (GAs). In this context, GAs are utilized from within the CAD environment to optimize the location of temporary facilities on site. The functional interaction between GAs and CAD and the details of the GA-based layout optimization procedure are presented. A fully automated computer system is further developed to demonstrate the practicality of the chosen approach. In order to evaluate the system's performance, a local construction project with a 24,000m² site is used. The automated system produced highly satisfactory results and showed notable flexibility through its CAD-based input/output media.     

Optimisation of site layout planning for multiple construction stages with safety considerations and requirements

This paper develops a mathematical formulation to model and optimise site facility locations inside a construction site for a construction project's different stages. The existence and dimensions of a construction project's available locations and site facilities can be varied across the construction stages. Without proper planning, unnecessary facility relocations may be required in each construction stage, resulting in a higher construction cost and longer construction time due to the need to dismantle and set up site facilities. Site layout plans should be optimised using a multiple-stage model to avoid unnecessary changes to facility settings across construction stages, improving efficiency. The proposed site layout problem with multiple construction stages is formulated as a binary-mixed-integer-linear programme, which can be solved by a standard branch-and-bound algorithm using the commercial software package LINGO. The mathematical objective function established in the solution process aims to minimise the total cost, which consists of the material transportation cost between the relevant site facilities and the dismantling, setup and relocation costs for all of the involved site facilities in each construction stage. Numerical examples using the proposed mathematical model to optimise different site layout settings for a construction site are given, including (1) a reference site layout plan using the conventional static single-stage approach, (2) a multiple-stage construction site layout plan and (3) a multiple-stage site layout plan with additional safety design considerations.     

谈施工现场管理中存在的问题及解决对策

简述了加强建筑工程施工现场管理的意义,针对建筑施工现场管理中存在的问题,从安全教育、施工技术、质量控制、材料管理等方面,阐述了加强施工现场管理的措施,为企业创造出优质工程奠定了基础。     

施工现场存在的安全问题及对策

通过长期的现场施工实践，针对当前施工现场存在的安全问题进行了分析，从健全专业教育培训机制、提高施工企业整体素质等方面，提出了施工现场安全管理的有效控制措施。     

The application of JIT philosophy to construction: a case study in site layout

The just-in-time (JIT) philosophy has been used in the manufacturing industry for some forty to fifty years. This system increased not only the productivity of the industry but also the quality of its products. Explorative studies have been completed in recent years to see how JIT can be applied into the construction industry to reap the benefits of the system. Most of these studies have concluded that it is possible to apply the techniques of JIT in the construction industry with some modifications. Taking into consideration that one of the key components of site management is concerned with waste management (i.e. bringing wastage down to the minimum), this study focuses on applying JIT for site layout to improve productivity and quality. By eliminating waste on site, controlling the movement of inventory coming into the site and within the site, and controlling the usage of mechanized plant and equipment, smooth work flow can be achieved.     

市政道路工程施工现场管理问题剖析

从现场布置管理、环境保护管理、劳务管理三方面分析了市政道路工程施工现场管理的主要内容,并探讨了现场各区域的管理措施,对市政道路工程的顺利进行具有重要作用。     

建筑施工现场临时用电中存在的问题及相应对策分析

因临时用电不当,建筑施工现场频繁发生触电、漏电事故,安全隐患严重。本文通过分析施工现场当前常见的临时用电问题,提出相应对策,以期提高用电安全性。     

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.     

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.     

施工现场安全管理中存在的问题及应对措施

对施工现场安全管理中存在的项目部安全管理人员配备不足,人员素质较低,监督部门管理力度不够,企业管理人员重经济效益、轻安全生产等问题进行了分析,并提出了一些针对性的改进措施,以保证安全生产。