An Evaluation System for Steel Structures of Hydroelectric Power Stations based on Fault Tree Analysis and Performance Maps

This paper presents an evaluation system for steel structures of hydroelectric power stations, including hydraulic gates and penstocks, based on Fault Tree Analyasis (FTA) and performance maps. This system consists of fault tree diagrams of FTA, performance maps, design and analysis systems, and engineerin databases. These four modules are integrated by appropriate hyperlinks so that the user of this system can use it easily and seamlessly. A well developed system was applied to some illustrative example cases, and they showed that the developed methodology and system worked well and the users found the system useful and effective for their maintenance tasks at powerstations

Concentration of Bid Prices Just Above the Standard Minimum Price in Public Construction Works

In Japan, contract offices are mandated to set threshold prices for public works. A threshold price is the upper limit of the bid price, and a contractor who exceeds this threshold is disqualified. Furthermore, based on the threshold price, a minimum price is set as a price requiring investigation before acceptance. In recent years, bids and contracts for public works have generally had bid prices concentrated slightly above the standard minimum for investigation. It has been pointed out that this tendency is detrimental in terms of the motivation of engineers and social costs. In this study, we confirm that this tendency was alleviated and that the level of the winning bidder's technical evaluation score was feasible at the same time. In addition, we obtained quantitative findings on variables that affect both above. Furthermore, although it is impossible to achieve a perfect balance between alleviating the tendency of prices to concentrate slightly above the standard minimum for investigation and sufficient technical evaluation scores, elements necessary to improve the overall situation were quantitatively identified

A Steel Bridge Design System Architecture using VR-CAD and Web Service-based Multi-Agents

This paper presents a new design environment based on Multi-Agents and Virtual Reality (VR). In this research, a design system with a virtual reality function was developed. The virtual world was realized by using GL4Java, liquid crystal shutter glasses, sensor systems, etc. And the Multi-Agent CAD system with product models, which had been developed before, was integrated with the VR design system. A prototype system was developed for highway steel plate girder bridges, and was applied to a design problem. The application verified the effectiveness of the developed system

A Building Information Modeling (BIM)-Integrated System for Evaluating the Impact of Change Orders

Change orders are inevitable in most construction projects. The conventional change order practice is usually associated with 2D drawings and various paper-based documents, which cannot illustrate the existing and altered building conditions efficiently. This often leads to misinterpretation and miscommunication among project participants. In addition, cost and schedule information, which is basic inputs for analyzing the impact of change orders, is usually scattered and poorly organized resulting in difficulties in retrieving it. The evaluation of cost and schedule impacts is often subjective and unsystematic contributing to construction disputes. Building information modeling (BIM) is widely used in modern construction projects. BIM is a promising construction information management tool, which can address the aforementioned challenges. In this paper, we develop the BIM-Integrated System for Evaluating the Impacts of Construction Change Orders (BIM-ISICO), which can systematically analyze three main impacts of a change order: physical conditions, schedule, and cost. The BIM-ISICO assists users in observing and visualizing the effect of a change order on building conditions systematically via 3D BIM models. The system can also evaluate the impacts of such change order on project cost and schedule. It establishes a new paradigm of delay and cost analysis by minimizing subjectivity and providing the auditing trails of change orders. To demonstrate its efficacy and practicality, the system is applied to an actual 18-story building project for analyzing the impact of a construction change order. The system can successfully assess and report all three aspects of change order impacts. These results can mitigate the conflicts between the project owner and the contractor about the construction claims resulting from change orders

A BIM-Integrated Relational Database Management System for Evaluating Building Life-Cycle Costs

Sustainable procurement is an important policy for mitigating environmental impacts attributing to construction projects. Life-cycle cost analysis (LCCA), which is an essential requirement in sustainable procurement, is a principal tool for evaluating the economic efficiency for the total life-cycle budget of a building project. LCCA is a complex and time-consuming process due to repetitive complicated calculations, which are based on various legal and regulatory requirements. It also requires a large amount of data from different sources throughout the project life cycle. For conventional data management systems, data are usually stored in the form of papers and are input into the systems manually. This results in data loss and inconsistent data, which subsequently contribute to inaccurate life-cycle costs (LCCs). Building information modeling (BIM) is a modern technology, which can potentially overcome the asperities of the conventional building LCCA. However, existing BIM tools cannot carry out building LCCA due to their limited capabilities. The relational database management system (RDBMS) can be integrated with BIM for organizing, storing, and exchanging LCCA data in a logical and systematic manner. In this paper, a BIM-integrated RDBMS is developed for compiling and organizing the required data and information from BIM models to compute building LCCs. The system integrates the BIM authoring program, the database management system, the spreadsheet system, and the visual programming interface. It is part of the BIM-database-integrated system for building LCCA using a multi-parametric model. It represents a new automated methodology for performing building LCCA, which can facilitate the implementation of sustainable procurement in building projects

Laser measurements on experiments on plate girders with a very slender web under pure bending

This paper is about the laser measurements as part of the research on the distribution of a certain amount of steel over the flanges and the web of an I-shaped plate girder to achieve the maximum bending moment resistance [1]. In many steel structures standard hot-rolled sections are used. These sections are divided into specific types in Europe and similar profiles in the USA. The range of hot-rolled sections is limited and therefore fabricated plate girders are used. Double symmetric I-shaped plate girders are built up with steel plates for the top and bottom flange and the web, welded together to a cross-section. Using this type of plate girders, a high degree of optimisation of material use is possible by using different plate thicknesses and widths for the flanges and thickness and height for the web. In the thesis the main topic for optimisation is the bending moment resistance of a plate girder. The maximum bending moment resistance appears for plate girders with a lot of material in the flanges and with a large web height. The web thickness has to be as small as possible and so the web slenderness has to be as large as possible. The limitation of the web slenderness is according to the Eurocode and the American standard based on flange induced buckling. The web of cross-section class 4 buckles and this buckling is during experiments measured by lasers. This paper gives an overview of the results of the laser measurements. Based on these measurements, it is concluded that flange induce buckling is not a limitation for the web slenderness. High web slenderness can be applied and the bending moment resistance increases enormously and the stiffness increases even more. Because of this, the use of HSS becomes of high interest

Improvement of registration accuracy of a handheld augmented reality system for urban landscape simulation

The need for visual landscape assessment in large-scale projects for the evaluation of the effects of a particular project on the surrounding landscape has grown in recent years. Augmented reality (AR) has been considered for use as a landscape simulation system in which a landscape assessment object created by 3D models is included in the present surroundings. With the use of this system, the time and the cost needed to perform a 3DCG modeling of present surroundings, which is a major issue in virtual reality, are drastically reduced. This research presents the development of a 3D map-oriented handheld AR system that achieves geometric consistency using a 3D map to obtain position data instead of GPS, which has low position information accuracy, particularly in urban areas. The new system also features a gyroscope sensor to obtain posture data and a video camera to capture live video of the present surroundings. All these components are mounted in a smartphone and can be used for urban landscape assessment. Registration accuracy is evaluated to simulate an urban landscape from a short- to a long-range scale. The latter involves a distance of approximately 2000 m. The developed AR system enables users to simulate a landscape from multiple and long-distance viewpoints simultaneously and to walk around the viewpoint fields using only a smartphone. This result is the tolerance level of landscape assessment. In conclusion, the proposed method is evaluated as feasible and effective