Stream Sockets versus Web Services for High-Performance and Secure Structural Analysis in Internet Environments

The increased growth of internet use in the last several years has opened up new possibilities for structural engineering analysis, moving from personal computer oriented software to client–server distributed software. In this paper two client–server applications for structural engineering based on stream sockets and on web services are presented. These two technologies have been chosen to compare, in terms of performance and complexity, new internet protocols with traditional ways of implementing client–server applications. Moreover, special care has been taken in the security aspects as the internet has become much more susceptible to breaches of security. Therefore, two new applications based on the same technologies have been created that guarantee a secure use of structural software. Also, two different client applications are presented to emphasize the versatility and power of internet distributed technology—one as a stand-alone application and the other as an integrated commercial computer-aided design program.     

Structural Design of Lunar Radio Telescope Using Interactive CAD

Some astronomers are considering the moon as an attractive location within the inner solar system for a variety of astronomical observatories, some of which could be operational early in the 21st century. This paper describes the computer‐aided structural design of a 122‐m diameter, fully steerable, parabolic radio telescope to be located on the moon. The loads acting on such a reflector differ substantially from those acting on a reflector that must operate in earth's environment. The moon has excellent advantages as a location for such an instrument. The absence of atmosphere completely eliminates the wind, snow, and ice loads. The gravity field is only one‐sixth that of earth's. The thermal changes from night to day are severe, but structural problems can be avoided by using a thermally stable composite material. Structural elements for the reflector dish have been analyzed and designed for static loads with a specially written interactive graphical computer program. The resulting structure has a mass nearly 40 times less than its earth's counterpart made of steel. The evaluation of the results of the design studies supports the possibility of building a large‐aperture parabolic radio telescope on the moon.     

Computer-Aided Model Generation for Nonlinear Structural Analysis Using a Structural Component Model Database

This paper presents an approach for efficiently building analytical models for nonlinear analysis. The objective has been achieved by establishing structural component model database by collecting various structural component models addressing various structural details. A common data structure and a relational database schema for storing structural component models were proposed in this study. The proposed structural component model database can serve as a decision supporting system for building nonlinear analytical models manually. In addition, the modeling information stored in this database can be presented in XML document format to be parsed and manipulated by computer system for generating nonlinear analytical model in file automatically. A school building database is used as a case study to show the feasibility of automatic modeling for nonlinear analysis using the proposed structural component database. A semiautomatic model generation system was developed to provide an efficient modeling process, which is in the manner of form filling and option selecting on web-based user interfaces, so that the model builder can focus on making engineering decisions. The modeling details are handled automatically by the proposed system based on user selection and setting.     

Application of a Virtual Environment System in Building Sciences Education

This paper includes a brief review of the application of virtual environments in building sciences and presents details of the application of virtual structural analysis program (VSAP), a virtual reality based structural analysis system developed at Virginia Polytechnic Institute and State Univ. (Virginia Tech), in education and practice. Different elements and modeling options in addition to the implementation of two major earthquakes within VSAP for the demonstration of the behavior of building structures during seismic activities are presented. Modifications to the VSAP in order to simulate progressive collapse of building structures are discussed. Different versions of this system were used in architectural structures courses at Virginia Tech. Results of feedbacks from students in these classes are presented. From these results it is concluded that the VSAP can be used effectively as an experiential teaching∕learning tool in classroom settings. Possible applications of VSAP as a design and research tool in construction industry are discussed.     

Automation of Quantity Surveying in Construction Projects

The preparation of a complete and concise project document is a critical issue facing professionals, developers, and contractors working in the building industry. The lack of an accurate, fast, and effective method for estimating the bill of quantities creates problems during the design, tender, and construction supervision of construction projects for designers and contractors practicing in Saudi Arabia. The capability of a computer-aided drafting (CAD) based system to interface with local data, either from the designers and contractors, or from manufacturers and commercial libraries, that allows for the estimation of the building bill of quantities in a more rigorous way is also lacking. The availability of an accurate and automated method to produce the bill of quantities from such libraries creates a benchmark in professional construction practice. This paper presents a computer program developed by the writer. This program is a third-party achievement that automates the aforementioned task and complements the standard AutoCAD system, which is not capable of extracting the project data pertinent to performing an automated bill of quantities. The program is written in C-language and has the capability to interface with other databases possessed by the designer or contractor. The AutoCAD has been taken as the base software because this is a cost-effective CAD software. Though Archicad, Design + available softwares can perform the automated quantity survey, it should be remembered that these packages are very expensive and used by fewer people compared with AutoCAD, which is used very widely.     

Framework for Building Intelligent Simulation Models of Construction Operations

Modeling and analyzing construction operations using simulation techniques allows researchers to capture the uncertainty and randomness usually associated with these operations and can thus be an effective tool for analysis and improvement. However, the effort and knowledge required to build simulation models and experiment with them tend to limit the use of simulation in construction. A common recommendation for removing this obstacle found in the literature leans towards developing simulation tools that reduce model development and experimentation time on the construction engineer’s side by packaging most of the knowledge required into the tool itself. Such “intelligent” simulation modeling tools may significantly impact the way construction engineers use simulation techniques in day-to-day decision?making. This paper presents a framework that extends and formalizes this recommendation by providing the foundation for building intelligence into simulation objects. The proposed framework provides the structure necessary for building intelligence and autonomy into simulation objects and permits a further reduction in the knowledge required to experiment with simulation models. This approach also automates model modification, not only through changes in numeric parameters, but through topological model changes as well, which may assist the model user in making many decisions throughout the different phases of simulation experimentation.     

Application of Peer-to-Peer Network for Real-Time Online Collaborative Computer-Aided Design

The Internet has revolutionized the way software systems work. Many applications, such as online games and instant messengers, have utilized Web-related technologies to cooperate over the Internet. Recently, some researchers have utilized Web-related technologies in computer-aided design to allow real-time collaboration between users over the Web. All these systems are based on the client-server model. In this kind of collaborative design environment, the system grouping, operation, and communication all have to rely on the central server. In order to improve accessibility and flexibility in collaborative design and to provide a more load-balanced and extensible environment, this paper presents a prototype implementation of collaborative design tools based on a peer-to-peer (P2P) model. The users can conveniently form design groups by connecting directly to each other, anytime and anywhere, without the presence of a central server. All peers are equal in functionalities and computing loads. In addition, application level multicast (ALM) technology is adopted in the proposed system to improve efficiency in Internet communication. Based on the P2P network model and ALM communication scheme, several mechanisms are proposed in this paper to form a working model of this system. Then, the object model design and implementation of this P2P system is presented.     

Automated Code Compliance Checking for Building Envelope Design

Automating the checking of building envelope design according to design regulations is a complex process because these regulations consist of complicated logic sentences covering multiple functions. Existing mechanisms of building code computer-aided checking have some limitations dealing with design regulations. This paper presents a new integrated approach to automated code compliance checking for building envelope design based on simulation results and building codes. In this approach, building codes and simulation results are seamlessly linked with the compliance checking software. A hierarchical object-based representation of simulation results is proposed as an extended building information model (EBIM) to describe the attributes of a building and its subsystems. A representation of building codes based on decision tables and compatible with the EBIM is also proposed so that users can check the building envelope design against building codes based on the standardized simulation results. A prototype system is developed and a case study gives an example of evaluating the hygrothermal performance of an exterior wall.     

Vibration Serviceability of a Building Floor Structure. II: Vibration Evaluation and Assessment

People are generally very sensitive to unexpected vibrations. Very small levels of building floor movements due to activities such as walking can become annoying to occupants. Accurate prediction, evaluation, and assessment of vibrations can greatly assist engineers and architects to design cost-effective building structures without such problems. In an attempt to clarify some of the issues related to this common serviceability problem, this paper presents a study of the various parameters used for the evaluation and assessment of building vibrations. Provisions of several current standards and design guides commonly used in North America and U.K. to evaluate and assess building vibrations as related to human perception and comfort are reviewed. These provisions are then applied using the vibrations measured during a number of walking tests conducted on a large cantilevered office building floor. Based on the results of this study, it is concluded that the vibration dose value (VDV) recommended by some standards and design guides provides a consistent and reasonable method of evaluation of building floor vibrations. In addition, new relationships between VDV, peak frequency-weighted acceleration, and crest factor are established to estimate the VDV.     

Computer-Aided Healthcare Facility Management

The decision-making process in the field of health-care facility management is multifaceted and encompasses many different areas, including maintenance, performance, risk, operations, and development. Information and communications technologies are perceived as the interface that integrates these topics. The main objective of this research is to develop a decision-support system based on core parameters affecting the performance of health-care facilities. This paper presents the preliminary development of a quantitative integrated health-care facility management model, subdivided into the following three interfaces: input, reasoning evaluator and predictor, and output. The model proposes the following five modules: maintenance, performance and risk, energy and operations, business management, and development. It offers projection of maintenance costs, performance, and risk of built facilities in the health-care sector. The model hypotheses are that age, occupancy, and environment affect the maintenance of the facility. These factors are quantitatively developed and analyzed for performance-based maintenance planning, employing an occupancy coefficient and a projection of performance indicator. Simulations of the facility coefficient for different combinations of occupancy and environment reveal that the occupancy level is a major factor that causes an augmentation of more than 18% in the allocation of resources for maintenance compared with standard occupancy. Prediction of the performance score of a building is carried out using a nonlinear pattern for the structural components and linear patterns for the rest of the components.     

High-Performance Green Building Design Process Modeling and Integrated Use of Visualization Tools

High-performance green buildings require close integration of building systems with a special focus on energy, daylighting, and material analysis during their design processes. Design process modeling and use of visualization tools can facilitate better communication and collaboration between team members; hence better integration in the design process. This paper presents a case study of the integrated design process of an Early Childhood Learning Center as performed by a team of university students and faculty. A process modeling approach of key decisions, required consultants, and virtual prototypes of the building was used during the design development stages of the case study. This case illustrates the use of process modeling and visualization tools to provide an accurate building information system for integrated teams. Through this experience, process modeling and visualization tools were found to be useful mechanisms to achieve high performance design goals and minimize design process waste.     

Automated Generation of Construction Plans from Primitive Geometries

Current construction simulation systems need detailed architectural models and schedules in order to estimate costs and visualize the construction process. However, the process of developing a building model, formulating a schedule, and eventually synchronizing them is a time-consuming and laborious process. When changes occur, the model and schedule must be modified or rebuilt using the same time-consuming and laborious process. Therefore, systems of this kind are used only for some demonstrations. This paper describes a new way to automate construction simulations using simple architectural information and predefined “construction method templates.” A number of construction method templates are computer readable and are stored as a knowledge base. The writer proves the concept by implementing a computer system to process building models and construction methods. The concept allows designers and construction engineers to build a model and simulate construction processes in a short period of time in the early stage of construction projects.     

Computer-Integrated System for Estimating the Costs of Building Projects

The cost estimate is considered one of the most important and critical phases of a construction project. Preparing reliable and accurate estimates to help decision makers is the most challenging assignment that cost engineers and estimators face. For decades, practitioners in the construction industry focused only on estimating the initial cost of a facility, neglecting costs associated with operating and maintaining it. Today, more interest lies in investigating the economics of facility management, which include the cost of owning and operating a building over its useful life. This paper presents a methodology that can be used for an integrated conceptual cost estimating and life-cycle cost analysis for construction projects during their initial phase. The methodology describes the development and implementation of a system that automates the preparation of parametric cost estimates and forecasts future running costs of building projects. The system integrates relational databases, a parametric cost estimate module, an AutoCAD module, a global module, a cost estimate forecasting and decision support system module, and a life cycle costing and sensitivity analysis module. The system will automatically generate a new parametric estimate upon any modification in building design. Once the capital costs are identified, the system forecasts the cost of running and maintaining the new building throughout its expected service life. After assigning the range of deviation, a sensitivity analysis is conducted, which identifies the most sensitive parameters for further consideration and analysis. Designing the system in a user-friendly environment allows owners and decision makers to envision the feasibility of new building projects within their anticipated life cycles. Moreover, it assists architects and cost engineers in generating parametric cost estimates in a dynamic environment. A numerical case example is presented to illustrate the usefulness and capabilities of the developed system.     

Application of Small Computers in Construction

The deliberations of the ASCE Task Committee on the Application of Small Computers in Construction are presented. The paper first identifies needs that are stimulating the application of small computers in construction, and then examines their present and potential utilization in several representative application areas. Applications include accounting and payroll, estimating, field office administration, contract language retrieval, electronic communications, scheduling, process simulation, graphical reporting, computer‐aided design, and process control. The role that ASCE might take in supporting the effective application of small computers in construction practice is considered. Possibilities include participation in the development of standards, education of practitioners, stimulation of innovative techniques, liaison with other organizations, input to computer manufacturers and software developers about specific needs and requirements in construction, studying the organizational and behavioral aspects of computers in construction, and input to ASCE awards committees about meritorious work in this area. It is concluded that an ongoing ASCE Construction Division committee is needed to monitor and influence the effective application of this rapidly evolving small computer technology in construction.     

Application of Web Services for Structural Engineering Systems

The Internet has revolutionized the way computing is done and the way software systems work. Many systems, such as search engines and PC games, have utilized Web-related technologies for Web-based systems. However, the application of Web-based engineering software is still in its infancy, especially regarding engineering computing. This paper presents a prototype development of Web-based structural engineering systems by utilizing modern computer graphics and information technology to provide Web-based analytical services. The system design emphasizes platform-independence, graphical interface, system performance, and a multiple-user environment. The user needs only an Internet-connected machine to access high-performance services provided at remote sites over the Web. This framework will provide users a powerful tool to efficiently perform analysis with minimal computer resource requirements. The user will always have access to the most up-to-date and functional system with no client-side updates or maintenance required. Two Web-based system implementations are given as examples in this paper.     

CAD and Management of Construction Projects

The increasing interest in computer‐aided design (CAD) has prompted research that is aimed at identifying the opportunities for construction managers and building contractors. It has been found that the use of CAD systems in the U.K. is mainly confined to the production of detailed drawings. Indeed, most of the systems used are 2‐D drafting tools and incapable of supporting the integration of even modest amounts of nongraphical (construction) data. On the other hand, many 3‐D modeling systems have the potential to integrate construction data, although they appear to be almost ignored. The use of 3‐D modeling systems is considered to be the most suitable vehicle for successfully integrating these data. However, this is likely to necessitate the introduction of separate databases, preferably of the relational type. The use of 3‐D modeling systems in assessing the construction implications of outline designs also presents interesting possibilities and is discussed.     

Implementing a B2B e-Work System to the Approval Process of Rebar Design and Estimation

In reinforced concrete construction, it is still common for rebar suppliers to accept computer-aided design (CAD) drawings and then generate new drawings for the shop floor, which ultimately are presented to the contractor as blueprints. In other cases, rebar suppliers accept hard copies of blueprints and return CAD files featuring different design layers and elements. Under this arrangement, communication between project participants is fragmented and depends solely on the direct input of the participants in a specific task. This paper proposes a business-to-business (B2B) e-Work system to improve the approval process for rebar estimation data. This system is composed of extensible markup language-based databases that support essential tasks of the approval process such as design and revision of structural drawings, bidding, shop drawing preparation, revision, and correction, and rebar delivery. The performance of the proposed system is compared with existing industry practices based on data obtained from structural designers, contractors, and rebar suppliers.     

基于商用CFD软件的双层皮幕墙热工性能模拟程序的开发

Double-skin facade （DSF） is widely used in commercial buildings for its excellent performance in saving energy. But it＇s very difficult for the ordinary designers to predict the thermal performance of DSF due to the complexity of the energy transmitting through the DSF and the difficulty of manipulating the complicated commercial CFD （computational fluid dynamic） simulation software. This paper take an effort in the foundation of the DSF analysis code with VC ＋ ＋ 6. 0 based on the commercial CFD software. This code is complied to analyze and predict the thermal behaviorof the ‘standard＇geometry natural ventilation DSF. The analyzer can gain the thermal behavior and the air flow characteristics of DSF after entered the relevant parameters of the model. This code gives the designer a tool to make quick design decisions in analyzing and optimizing DSF.     

Computer Simulation Model: Construction Analysis for Pavement Rehabilitation Strategies

Most state highways in the United States were built during the 1960s and 1970s with an infrastructure investment of more than $1 trillion. They now exceed their 20?year design lives and are seriously deteriorated. The consequences are high maintenance and road user costs because of degraded road surfaces and construction work zone delays. Efficient planning of highway rehabilitation closures is critical. This paper presents a simulation model, Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS), which estimates the maximum amount of highway rehabilitation/reconstruction during various closure timeframes. The model balances project constraints such as scheduling interfaces, pavement materials and design, contractor logistics and resources, and traffic operations. It has been successfully used on several urban freeway rehabilitation projects with high traffic volume, including projects on I-10 and I-710. The CA4PRS helps agencies and contractors plan highway rehabilitation strategies by taking into account long-life pavement performance, construction productivity, traffic delay, and total cost.