CAD在土木工程设计应用中的优劣探讨中英.docx

CAD在土木工程设计应用中的优劣探讨一 引言 计算机辅助设计（Computer Aided Design，简称CAD），诞生于20世纪50年代，它是利用计算机强有力的计算功能和高效率的图形处理能力来进行工程的设计和分析的一种技术，它是综合计算机技术和土木工程设计方法的一门新兴学科，是与计算机软硬件及工程设计方法的发展而发展起来的。它集成了计算机、图形学、数据库技术、数值分析等技术，随着软硬件技术的不断发展及工程方法的更新换代，CAD技术也日趋完善，已经广泛应用于电子、轻工、纺织、服装、医疗、国防及工程设计等国民经济的各个领域，发挥了极大的经济技术效益。 二 CAD在土木工程中的应用 CAD技术最早应用于汽车工业，随后随着计算机软硬件的发展及普及，逐渐扩展到其它领域，包括土木工程领域。在土木工程领域，它包含工程设计中采用计算机技术辅助分析、计算和绘制图形的全过程。我国在土木工程中使用CAD技术开始于上世纪八十年代，在开始阶段，主要依靠外国引进的通用或专用图形软件包在屏幕上做交互式图形设计，与结构计算与分析没有结合，参与者主要是长期与计算机打交道的专门人员，到八十年代末期，由于较高性能的廉价计算机的普及，土木工程CAD才有了真正的发展和较广泛的应用，在很大程度上推动了CAD技术在我国土木工程上的应用和发展。 土木工程CAD的应用包含以下方面： 1）建筑与规划设计：用于绘制建筑、规划类图纸，如建筑施工图、效果图，规划效果图，桥梁的造型设计等，其软件有天正建筑软件、中国建筑研究院的APM（PKPM的建筑模块）、QXCAD（一种桥型设计软件）、3 D M A X、M A Y A、计，构造设计指根据结构计算的结果，完成构件和截面的选配筋的构造设计，绘制施工图是用CAD取代传统的手绘来完成施工图纸的绘制；（3）给排水设计：用于给水、排水方面的计算与绘图；（4）暖通设计：用于取暖与通风方面的设计；（5）电气设计：强弱电方面的辅助设计；（6）施工组织与设计：用于施工项目的项目管理、施工工艺的流程设计与优化、施工现场布置等；（7）工程项目的预决算：从广义上说，这也算C A D在土木工程上的一个应用；（8）其它方面的：比如家庭装修等。 以上所列只是CAD技术在土木工程上应用的主要方面，在实际工程中，还有很多的边缘的、交叉的的新兴的应用技术在开花结果，日新月异。 三 CAD在土木设计图中表现出的优势 1、绘图劳动强度降低，图纸保持清洁、美观 传统的手工绘图法需要设计人员经常性更换十几种绘图工具。一旦画错，就要在图面上修修补补，破坏图面的整洁性。而CAD制图，只要配齐了电脑，安装好绘图软件、打印机或绘图仪，鼠标轻轻移动就可以完成心中设计的图形。同时，软件本身还可以提供UNDO限制防错功能，让工程设计师们制图事倍功半。更有甚者，软件还可以为每个设计人员的独特的表达方式、思维模式和绘图习惯，提供广阔的空间，只要充分使用参数化绘图工具就可达成。 2、提高设计工作效率 土木设计过程一般经过提条件、方案设计、初步设计、施工图设计。各工种之间的配合默契与否，条件与方案改变大小都直接影响着制图的速度。传统的手工制图方式下，各阶段各工种之间的不同设计成果要分时制作；在CAD制图中，实现了各工种间的图纸资料互换，即使方案有所调整，设计人员只需在原有的设计图纸上加以调整，从而减少大量重复劳动，提高了工作效率。 3、增强计算功能，提高精确度 土木工程设计不同于其他领域的设计，它需要正确无误地计算出裂缝宽度、挠度、承载力、配筋面积。而且在实际工程中，要先符合设计规范地对各个结构构件如梁、板所承受的各种外部荷载，再根据混凝土结构设计规范规定进行计算和调整，如果计算数值稍有偏差或参数取值不符合规范要求，便会造成设计出的产品不合设计规范、不经济，严重的还会造成人民生命、财产的巨大的损失。 4、提供动态的检验效果 结构的板、梁、柱、墙的设计要考虑其他专业的相容性、相配性。如管道、设备不能和梁、柱相碰等。从实践中可知道任何工程都可以从形态上拆分为圆柱体、斜圆柱体、圆锥、圆台、斜圆台、球体、球冠体、圆形断面环体、矩形断面环体以及多面体等基本形体。为此，CAD制图中，可以在真色彩、真三维、光照的情况下，按物体的运动轨迹构造出一个虚拟的实体，在房屋中实时漫游，检查虚拟的实体与管道、设备、墙、梁、柱、门、窗等物体不发生碰撞，预先感受结构的空间效果，以便在发现问题的地方仔细端详、修改，直至满意为止。这给了工程设计师在设计工程提供非常有益的帮助。 5、资料管理方便 CAD软件制作的图形、图像文件可直接存储在软盘、硬盘或刻成光盘存储，从而避免资料因受潮、虫蛀以及破坏性查阅造成的不必要损失，电子数据的保存年限可以延长至50年。一个设计院的整柜整柜的资料被几张光盘所替代，查找和管理都比较方便。 6、数据传输的信息化 随着信息技术、网络技术的普及和CAD智能化的应用、跨地区合作设计、异地招投标、“在家工作”等都成为可能。如1992年日本执行的CALS（综合信息系统）研究，其就是指企业和机关不受部门企业间特定机器和系统的制约利用网络进行开发设计运筹及运用全过程的公用系统工程。 四 CAD技术出现的劣势 CAD技术在给土木设计业带来巨大效益的同时，其劣势也随之发挥作用，也不可避免地滞缓了其发展，具体表现如下： CAD技术需要相关的软件，运转速度较快的电脑以及熟练掌握电脑的设计师、网络维修人员等。购买任何正版的工程建筑软件都要花费12万元。设计师们还要开展专门培训工作，总之，备齐所需的人力和财力则价值不菲。同时，在使用过程，设计师们只能看到面前的一处图纸，而土木工程设计是一个系统工程，只看到一处图纸是远远不够的，它需要一整套图纸打印后才能看清楚。电脑图纸需要经过输出后才能实现审核、修改、再审核、再修改直至正式出图，增加了单位成本和社会成本。 2、工种配合默契与否及信息传递的速度影响工作效率 众所周知，土木工程设计是一个系统工程，它涉及到许多专业和步骤。每个设计师在设计任何图纸时不仅要考虑自身设计的合理性，还要考虑与本专业和其他专业设计人员设计上的协调性。完整的土木工程设计流程从合同签定起点经过测量数据、地质调查数据、设计说明、打印图纸、施工管理计划等步骤，其所需的数据量是非常大。任何数据变动，就会造成设计方案的变化。所以在动手设计前，要根据现况、地质、道路、建筑物、生产设施的关系进行规划、设计、施工、使用和管理。而地质、地物、道路的考察由建设单位来进行，生产设施之间的配合关系论证由勘察设计院来进行，大量数据的整理、交换、组合都需要时间。任何环节的阻塞和停滞都会影响完成工作效率。 3、缺乏统一的智能化结构设计软件 目前的专业软件，如PKPM软件，大多数只停留在二维基础上，充其量只是个绘图工具，缺乏智能化。智能化结构软件不仅体现三维立体图镜像，而且能自动执行相应的规范，设计所需参数取值不但要在经济范围内，还要便于施工。如中国建筑科学研究院PKPM CAD工程部和新加坡建屋发展局开发的BEAM CAGE软件，是按英国规范完成的钢筋混凝土梁的配筋、选筋、挠度的计算、施工图生成等一系列功能，虽然该软件自动化程度高，出图质量好，但毕竟是基于英国规范的基础上。而在国内流行的工程智能化设计软件如PKPM设计软件，它还需要设计师们调整梁、板、柱的配筋，尤其是柱的配筋，PKPM软件自动生成的顶层柱配筋常常因为屋面梁传递来的弯矩比较大，配筋也较大，而下层由于梁传递来的弯矩较小，配筋也较小，形成大柱种在小柱上。这需要设计工程师进行人工调整。还有按照规范规定，同一构件中钢筋的型号差别不宜大于两个级别，也就是说在一个构件中如果使用了直径为16的钢筋，那就不能使用直径为22以上的钢筋。但是在软件自动出图中常常会出现直径为14的钢筋和直径为22的钢筋一起使用的现象，这也要进行人工调整。以上说明我们还缺乏统一的智能化结构设计软件。 4、扼杀土木设计师的创作灵感 俗话说：“建筑是凝固的音乐”这句话点明了建筑也是一种艺术，它是一门融科技、文化、艺术、哲学于一体的学科。任何土建设计师都需要艺术家的灵感和天份，这种灵感和天份在处理建筑物的造型方面应有不少的“模糊感”。但CAD制图所要求的尺寸精确消磨和扼杀了这种灵感和天份，让设计师的设计图样屈从于电脑的机械和准确。还有，不少设计单位为了能够中标，将自己的设计投标文件，尤其是总平面效果图，做得非常精致美观，不惜投入大量的人力物力在CAD的制图上，而忽略了总平面布置图的建筑效果和建筑师的艺术创造。 综上所述，CAD的使用提高了土木设计中的高效率、高质量和高水平，同时也显示了不完善的方面。因此，设计师们在使用过程中总结经验，注意克服CAD带来的负面影响，努力提高自身的计算机知识和对土建规范的使用，促进CAD的健康发展。 CAD design applications in civil engineering in the pros and cons of一 IntroductionComputer Aided Design (Computer Aided Design, referred to as CAD), was born in the 20th century, 50 years, it is the use of powerful computers and efficient computing power of graphics processing power to carry out engineering design and analysis of a technology, it is an integrated computer technology and civil engineering design methods of an emerging discipline, with computer hardware and software and engineering design, the development of methods to develop. It integrates the computer, graphics, database technology, numerical analysis techniques, hardware and software technology, along with the continuing development and upgrading of engineering methods, CAD technology has gradually improved, has been widely used in electronics, light industry, textiles, clothing, medical, defense and engineering design in all areas of the national economy played a tremendous economic and technical benefits.二 the application of CAD in civil engineeringCAD technology was first used in the automotive industry, and then with the development and popularization of computer hardware and software, and gradually extended to other fields, including civil engineering field. In the civil engineering field, which contains engineering design using computer technology-assisted analysis, computation and graphics rendering the whole process. Chinas use of CAD technology in civil engineering began in the eighties of the last century, at the initial stage, mainly relying on foreign introduction of generic or dedicated graphics package on the screen to do an interactive graphic design, and structure calculation and analysis is not binding, the participants mainly long-term deal with the computer specialists, to the late eighties, due to the higher performance, the popularity of low-cost computer, the Civil Engineering CAD have a real development and wider application, to a large extent driven CAD Technology in China civil engineering applications and development.Civil Engineering CAD application includes the following areas:1) Architecture and Planning: for drawing architectural, planning class drawings, such as building construction plans, renderings, plan renderings, bridges, shape and design of its software Tengen building software, the China Construction Research Institute APM (PKPM of building blocks), QXCAD (a kind of bridge-design software), 3 DMAX, MAYA, terms, structure design means the structure calculation results, the completion of the election section reinforcement components and structural design and draw construction plans is to replace the traditional CAD The hand-painted to complete the construction drawings drawn; (3) water supply and drainage design: for the water supply, drainage calculations and drawing; (4) HVAC design: for heating and ventilation design; (5) Electrical Design : strong and weak aspects of electric-aided design; (6) Construction Organization and Design: project management for construction projects, construction techniques, process design and optimization, construction site layout, etc.; (7), the project budget and final accounts: From the broad sense that it can be considered on a CAD application in civil engineering; (8) other aspects: for example, home decoration and so on.Listed above is only the application of CAD technology in the key aspects of civil engineering in the actual project, there are a lot of edge, cross-application of emerging technologies bear fruit, with each passing day.三 CAD in civil engineering design demonstrated the advantages of1, the drawing to reduce labor intensity, drawings kept clean and beautifulThe traditional manual mapping method requires the designer to replace a dozen regular drawing tools. Once the picture wrong, it is necessary tinkering in cartographic, destruction of surface cleanliness. The CAD drawing, as long as the fully serviced the computer, install a good graphics software, a printer or plotter, mouse, gently move the hearts of the design can be completed graphics. At the same time, the software itself can also provide limited anti-UNDO error function, so that the project designers drawing less effective. Moreover, the software can also each designers unique expression, thinking and drawing habits, provide a broad space, as long as the full use of the parametric drawing tools can be reached.2 and improve the efficiency of the design workCivil engineering design process, after mentioning the general conditions, program design, preliminary design, construction design. The tacit understanding between the various types of work or not, the conditions and changes in the size of the program have a direct impact on the speed of graphics. The traditional manual mapping methods, the various stages of the differences between the various types of design results to time-making; in CAD drawing, the realization of the various types of information exchange between the drawings, even if the program has been adjusted, the designer simply in the original The design drawings to be adjusted, thus reducing the large number of duplication of effort, improve work efficiency.3, increased computing power, improved accuracyCivil Engineering Design different from other areas of the design, it needs to correctly calculate the crack width, deflection, bearing capacity, reinforcement area. But also in practical engineering, the first design specifications to meet the individual structural elements such as beams, plates are exposed to various external loads, and then under the design of concrete structures, the provisions of the calculation and adjustments, if any mistakes in calculation of values or parameters values do not meet regulatory requirements, it will result in substandard design of the product design specifications, not the economy, will result in a serious peoples lives and property of huge losses.4, provide dynamic test resultsStructural panels, beams, columns, walls and other professionals to consider the design of the compatibility, match sex. Such as pipes, equipment can not, and beams, columns and so touching. From practice can be aware of any project can be split from the form on the cylinder, oblique cylinder, cone, frustum of a cone, oblique frustum of a cone, sphere, spherical body, circular cross-section ring body, rectangular cross-section ring body, as well as the basic shape polyhedron . To this end, CAD drawing, it can be in the true color, true three-dimensional, light of the situation, the trajectories of objects to construct a virtual entity, real-time roaming in the house, check the virtual entities and pipelines, equipment, walls, beams , columns, doors, windows and other objects, collision does not occur, pre-experience effects of the structure of space in order to identify problems where a closer look, modify, until satisfaction. This gives the engineering designer in the design project provides a very useful help.5, data management to facilitateCAD software, create graphics, image files can be directly stored on a floppy disk, hard drive or optical disc carved so as to avoid the information due to damp, moth-eaten, as well as destructive access to the unnecessary loss of life the preservation of electronic data can be extended to 50 years. An institute of the entire cabinet entire cabinets full of information have been replaced by a few CD-ROM, locate and management are more convenient.6, data transfer of information technologyAs information technology, network technology, intelligent CAD popularization and application of inter-regional cooperation in the design, off-site bidding, home work and so possible. Such as the implementation of the 1992 Japan CALS (Integrated Information Systems) research, which refers to enterprises and organizations not subject to inter-enterprise sector-specific constraints of the use of machines and systems development and design logistics networks and the use of the whole process of the common systems engineering.四 CAD technology, the disadvantages appearCivil CAD Technology in the design industry has brought enormous benefits, while its disadvantages also will play a role, but also inevitably slack in its development, as exemplified by the following:1, CAD technology, designed to promote the field of civil human, financial, and material waste of intensifiedCAD technology needs related software, running faster computers and proficiency in computer design, network maintenance personnel. The purchase of any genuine engineering and construction cost of the software should be a 20 thousand yuan. Designers are also specialized training to carry out the work, in short, Prepare all the necessary human and financial resources are required for the value of a lot of money. Meanwhile, in the use of the process, designers can only see in front of a drawing, while the civil engineering design is a systematic project, only to see a drawing is not enough, it needs to look at a set of drawings before printing . Computer drawing need to go through the output can be achieved after the review, modify, re-examined, and then modify the pending formal plot, an increase of unit costs and social costs.2, type of work or otherwise act in harmony, and the speed of information transmission efficiency of the impactAs we all know, the Civil Engineering design is a systematic project, which involves many professional and steps. Every designer in the design of any drawings, when the design must consider not only their own rationality, but also consider the professional and other professional designers to design coordination. A complete civil engineering design process from contract signing through the measured data point, geological survey data, design specifications, print drawings, construction management plan and other steps, the required data volume is very large. Any data changes, it will result in design changes. Therefore, hands-on design before, based on the current situation, geology, roads, buildings, production facilities, the relationship between the planning, design, construction, use and management. The geology, surface features, roads, construction units of the study carried out by the production facilities, with the relationship between the argument carried out by the Survey and Design Institute, a large number of data collation, exchange, combination will take time. Any part of the obstruction and stagnation will affect the completion of work efficiency.3, the lack of a unified intelligent structural design softwareThe current professional software, such as PKPM software, most of them just to stay in two-dimensional basis, at best, only a drawing tool, the lack of intelligence. Intelligent three-dimensional structure of the software not only map the mirror, but also can automatically implement the corresponding specification, design values of the parameters needed not only to the economic context, but also to facilitate the construction. For example, China Academy of Building Research PKPM CAD Engineering and Singapore Housing Development Board developed by BEAM CAGE software is based on British specifications are completed, the reinforcement of reinforced concrete beams, the election tendons, deflection calculations, construction drawings and a series of generating functions, although the The software is a high degree of automation, a map of good quality, but that is based on the British normative basis. Popular in the domestic engineering design software, such as PKPM intelligent design software, designers also need to adjust the beam, plate, column reinforcement, especially the column reinforcement, PKPM software automatically generates the top column reinforcement is often because the roof beam to pass to the moment relatively large reinforcement is also large, whereas the lower beam to pass to the moment due to less reinforcement would be smaller, forming large column types in the small column. This requires the design engineer manual adjustments. There are according to specification, the same component in the steel bars not more than two levels of difference between models, meaning that