4D CAD技术在施工管理中的应用研究

4D CAD技术属于计算机技术在工程施工领域应用的一项新技术,本文作者通过论述4D CAD技术的发展,分析了4D CAD技术在施工管理中的优势。通过对比分析常见4D CAD软件的基本功能,结合一座大型桥梁工程的施工实践,具体说明4D CAD技术的优点和应用障碍。最后,提出4DCAD技术发展的趋势和方向。     

An evaluation of the applicability of 4D CAD on construction projects

4D CAD models that integrate physical 3D elements with time, have been used to visualize construction processes in several projects worldwide. 4D models have been used and have been shown to have benefits over processes that span the entire lifecycle of a project such as collaboration with stakeholders, making design decisions, assessing project constructability, identifying spatial conflicts in construction and so on. Despite these benefits, several organizational and project-specific barriers have hindered the widespread adoption of 4D CAD. In order to reconcile the theoretical benefits of 4D models with the practical difficulties faced in implementation, there is an urgent need to explore the implementation of 4D models on construction sites as well as the perceptions of intended users/beneficiaries towards this implementation. This paper aims to address this need and contribute to our understanding of how 4D models must be introduced, positioned and implemented on construction sites, so as to maximize both their acceptability and their usefulness. We describe two 4D models of infrastructure projects and two 4D models of commercial projects that have been built and implemented. Through a process of structured and unstructured interviewing the paper gauges the response of project participants across various organizational levels on each of these projects as to the usefulness of 4D in project planning and control. Through qualitative and statistical analysis of the data we establish that 4D CAD is likely to be most beneficial in the project shaping or planning stage and in the construction stage. In the project shaping stage, 4D CAD is likely to be particularly useful in communicating construction plans and processes to clients, while during the construction phase, 4D CAD is likely to be particularly useful in comparing the constructability of work methods visually in order to detect conflicts or clashes, and as a visual tool for contractors, clients, subcontractors and vendors to review and plan project progress. Further, upper management and site workers are more likely to use and derive benefits from the visualization of processes using 4D given their lack of site related knowledge or skills, while construction professionals who are more construction-savvy are more likely to appreciate and benefit from the analytical and planning aids that 4D simulations provide during the construction phase. However, it is likely that despite these benefits 4D CAD models might not diffuse through the construction industry unless 4D modelling and analysis is integrated into existing project planning approaches. The paper concludes with a brief discussion on future 4D software development that seeks to bring about such integration and leverages the benefits of 4D CAD to bring about improved operational efficiencies on construction sites.     

Trends of 4D CAD applications for construction planning

Since the early 1990s, there has been a growing interest in four‐dimensional computer aided design (4D CAD) for construction project planning. Commercial 4D CAD applications are becoming more accessible and the use of this technology allows the construction planner to produce more rigorous schedules. A review of the technical competencies of these packages highlights that most of the commercially available packages concentrate on the use of 4D CAD simulations for aesthetic visualization purposes. Very few packages offer the ability to carry out analytical tasks on the developed simulation and this is often left to the interpretation of the user. A thorough appraisal of emerging research developments in 4D planning highlights that this technology is employed for various applications; however, the amount of detail required in a 4D simulation is still ambiguous. A model is proposed to determine the attributes required for use with each of the various applications of 4D CAD simulations. Finally, various lines of future research are highlighted, including the need for improved use of data exchange standards and the automation of linking the construction tasks to the 3D CAD model.     

高速公路建设对保护生态环境可持续发展的思考

通过介绍山西高速公路建设对沿线空气、水环境、声环境、水土保持等环境的影响,阐述了高速公路建设对保护生态环境可持续发展的对策,觖决了公路建设者和管理者所面临的难题,进而推动公路建设的科学发展。     

4D CAD model updating using image processing-based construction progress monitoring

For a four-dimensional (4D) computer-aided design (CAD) model to be useful for users throughout a construction project, the model must be updated in a timely and accurate manner during the construction. Only when it has been properly updated can the 4D CAD model reflect the real progress of a construction site to inform managerial decision making. However, updating a 4D CAD model is time-consuming and labor-intensive because the full updating process, from site data acquisition to 4D model regeneration, is typically conducted manually. This difficulty in updating a 4D model discourages industry practitioners from actively adopting 4D models. This paper presents an image processing-based methodology for the automatic updating of a 4D CAD model. Characterized by 3D CAD-based image mask filters, color-based noise removal, and area-based progress calculation, the image processing approach provides as-built schedule information. The schedule information is then automatically integrated with an existing 3D CAD model in batch-processing modes to produce the updated 4D CAD model. The proposed methodology was applied and verified in a cable-stayed bridge construction project and is expected to facilitate the wider use of 4D CAD models in the construction industry.     

Visualizing high-rise building construction strategies using linear scheduling and 4D CAD

Project teams face ever increasing pressure to deliver projects as quickly as possible. To meet these demands, contractors are faced with the need to explore various construction strategies in order to meet delivery dates, and to assure themselves as to the achievability and quality of a schedule. Various visual representations of a project's schedule and associated information combined with visual representations of the project in progress, i.e. 4D CAD, can assist with these tasks of identifying effective construction strategies for shortening project duration, assessing their workability, and judging schedule quality. Such visual representations aid communication amongst project staff and facilitate brain-storming, and, implemented well they can provide clear, fast, and multi-dimensional feedback to the project team. In this paper, we describe aspects of our work which is directed at formulating a dynamic visualization environment that links 3D CAD, a generalization of traditional CPM which embraces linear scheduling, dual product representations (scheduling and CAD system) and their mapping onto each other, and schedule and CAD graphics in a manner which facilitates the relatively rapid exploration of alternative construction method and scheduling strategies for large scale linear projects (e.g. high-rise buildings, bridges, etc.). Requirements of such an environment include quickness, treating scale, working at multiple levels of detail, dealing with design variability, and realistic representation of the work. Use is made of a realistic example to highlight aspects of our approach and identify important issues that must be addressed if a visualization environment useful for construction professionals is to be developed.     

公路施工期环境监理引入公众参与的探讨

根据银古(银川—古窑子)高速公路施工期开展环境监理的实践,论述了公路施工期实施环境监理的重要性,分析了公路项目环境监理引入公众参与的必要性,探讨了公路施工期公众参与环境保护的内容和方法。     

公路CAD发展综述

首先介绍了国外及公路CAD的发展概况,然后介绍了目前国内以及国外常用公路CAD软件的情况,并且指出了目前公路CAD软件存在的问题,最后对未来公路CAD软件的发展趋势进行了概括。     

我国公路建设与筑养路机械的发展

我国公路的发展，特别是高等级公路的建设促进了筑养路机械工业的发展，并对其提出更高，更多的要求和需求。     

高速公路既有路堤受桥梁施工影响的分析

借助有限元分析软件,以某铁路桥梁跨越高速公路的施工过程为背景,建立三维有限元模型探讨其施工过程对临近高速公路路堤的影响及该桥梁的自身沉降。通过研究,取得了桥梁施工过程对高速公路路堤影响形式,以及桥梁在整个施工过程沉降与工后沉降的进一步认识,对于桥梁施工时保护临近建筑设施有一定的参考意义。     

公路CAD课程教学改革探讨

分析了目前公路CAD课程所面临的形势和问题,阐述了公路CAD课程教学改革的解决方案,并通过标准横断面图子项目教学示例进行了说明,论述了用项目教学法开展公路CAD课程教学的优势,从而提高公路CAD课程教学质量。     

公路建设项目环境影响后评价公众参与研究

公路项目建设的实践表明 ,对已经投入正常营运的公路建设项目开展环境影响后评价是非常必要的 .环境影响后评价公众参与可以提高环境影响评价的有效性 ,真实反映项目在施工期和营运期造成的实际环境影响 ,并就项目提出的环保措施进行合理性和可行性的分析 ,从而为加强项目营运期环境管理和今后拟建项目科学决策论证提供参考依据 .阐述了公路建设项目环境影响后评价公众参与的概念、目的和作用 ,以及公众参与与项目建设全过程的关系 ,并就公众参与的调查方法、调查对象、调查范围及调查内容等进行了研究 .     

Virtual construction of architecture using 3D CAD and simulation

3D modeling and computer simulations provide new ways for architecture students to study the relationship between the design and construction of buildings. Digital media help to integrate and expand the content of courses in drafting, construction and design. This paper describes computer-based exercises that intensify the student's experience of construction in several courses from sophomore to senior level. The courses integrate content from drafting and design communication, construction, CAD, and design.Several techniques are used to strengthen students' awareness and ability in construction. These include:

• •Virtual design–build projects in which students construct 3D CAD models that include all elements that are used in construction.
• •Virtual office in which several students must collaborate under the supervision of a student acting as project architect to create a 3D CAD model and design development documents.
• •Virtual sub-contracting in which each student builds a trade specific 3D CAD model of a building and all of the trade specific models must be combined into a single model.
• •Construction simulations (4D CAD) in which students build 3D CAD models showing all components and then animate them to illustrate the assembly process.
• •Cost estimating using spreadsheets.

These techniques are applied and reapplied at several points in the curriculum in both technical laboratory courses and design studios.This paper compares virtual construction methods to physical design–build projects and provides our pedagogical arguments for the use of digital media for understanding construction.     

关于公路景观建设的几点探讨

分析了目前我国公路景观建设中存在的主要问题,参考国外发达国家公路工程技术标准、设计和施工规范提出了解决我国公路景观建设问题的途径,具有一定的理论参考价值。     

农村公路建设的几点思考

结合农村公路实例,介绍了农村公路建设中应注意的问题,从严把公路质量观、公路养护观等方面进行了论述,指出只有科学规划、精心设计、施工,做到建养并重,才能达到促进农村经济发展的目的。     

高速公路施工测量工作浅谈

交通运输是国民经济的命脉,是经济建设不可缺少的基础设施,高速公路的发展满足了城市间的交通运输需求,对当地经济的发展有着重要的意义.高速公路的通行能力以过硬的质量为基础,高速公路在施工过程中要严格控制施工质量.而测量工作贯穿于高速公路施工的整个过程,直接影响工程进度与质量.伴随现在工程测量技术的不断更新,施工测量工艺也呈日新月异的变化,文章简要介绍了高速公路建设中路基桥涵工程施工各阶段测量工作、常见问题及其处理方法,从使用测量仪器规则、交接桩及护桩制度和工程竣工测量等方面进行论述,对提高工程测量水平,保证工程质量,加快施工进度,对提高经济效益,更好地为公路建设服务有一定的积极意义.     

利用CAD三维技术辅助解决异形屋顶施工

某工程屋顶结构由多坡屋面、4个角部各一个壳体塔楼及2个中部棱台塔楼组成.由于空间结构复杂,无法用二维设计图纸完整清晰地表达,给屋面结构施工带来很大困难.利用CAD三维辅助施工,完成了复杂建筑空间形体的三维模型分析,较好地解决了空间曲线、曲面的定位、形体的生成、空间构件的调整等技术难点,与二维平面图纸加实物模型相比较,达到了速度快、表达清晰准确,并可以多角度观察对象,预先发现构件不合理的情况,并及时修改调整.     

公路施工中路面垫层施工技术探讨

简单介绍了路面垫层的含义,提出了路面垫层施工技术现存的问题,从施工标准、施工方法、施工过程控制、注意事项等方面,分析了公路施工中路面垫层施工技术,有利于确保公路的稳定性与实用性。     

探讨公路施工技术管理及公路养护

通过分析公路施工中技术管理工作的必要性,介绍了公路施工技术管理所涵盖的内容,并从公路养护规范、管理系统、机械设备等方面,阐述了公路养护的技术措施,有利于延长公路的使用寿命。     

Using the MD CAD model to develop the time–cost integrated schedule for construction projects

Time and cost are two critical factors determining the success of a construction project. However, it is still a daunting task for project planners to develop a time–cost integrated schedule due to the tremendous amount of information that need to be processed. Various research efforts have been made to develop model-based systems to facilitate information processing and integrate time and cost throughout the project life cycle. However, the results of the previous studies are not comprehensive enough to fulfill the requirements of project management. This paper presents a scheduling system that applies Multi-Dimensional (MD) CAD model, Object Sequencing Matrix (OSM), and genetic algorithms (GAs) to generate the time–cost integrated schedule for the construction project. A computer implementation called MD CAD model-based Project Scheduling System (MD_PSS) is also developed to verify the feasibility of the proposed approach.