Las herramientas computacionales como factor de error en los procesos de diseño de infraestructura civil

El uso inadecuado de programas de computadora y de procedimientos que se relacionan directamente con la utilización de herramientas computacionales pueden causar errores en proyectos de diseño de infraestructura civil. Algunas veces estos errores son directamente atribuibles a los usuarios: mala planificación de los recursos computacionales, datos entrados inadecuadamente a los programas de computadora o mala interpretación de los resultados. En otros casos los errores tienen que ver con las herramientas computacionales mismas: errores de programación del software, implantaciones de algoritmos sobre la tecnología incorrecta o pueden surgir de la combinación de los factores anteriores. En algunos casos la aparente simplicidad de un proceso hace que no se le preste atención al control de calidad y en otros casos la complejidad del proceso imposibilita medir correctamente la magnitud del mismo y la relevancia dentro de todo el diseño. (AU)

Las ventajas de una aplicación informática para evaluaciones de riesgos, estudios y planes de seguridad

El autor aporta la creación de este programa informático como contribución personal y ayuda para reducir la alta siniestralidad laboral de nuestro país, adecuando dicha aplicación al cumplimiento de las necesidades de los técnicos de prevención de riesgos laborales al presentar una mejora de los procedimientos de evaluación habituales y porque, ademásincluye un análisis pormenorizado del proceso contructivo en sus distintas fases, así como una información amplia y rigurosa para los trabajadores (AU)

Development of a GIS-based framework for ground motion analysis

This paper describes the framework for the development of a ground motion analysis software based on MapInfo, a geographical information system (GIS). The GIS-based system maintains and manipulates the soil stratum information of Singapore, interfaces with WAVES, a site response analysis software, to compute the peak ground accelerations (PGAs) at selected sites, and integrates with MATLAB a numeric processor for the 2-D spatial interpolation of PGAs. The interpolated PGA values are shown as a fringe plot overlaid on the Singapore map

Development of a database of projects related to pollution hazards on the natural environment

The increase in population and urbanization has necessitated the monitoring of hazards to the environment. The Ministry of Environment and Parliamentary Affairs of Sri Lanka had identified the need to execute a survey of environment pollution related projects to create a database. The present work comprises of the collection of pollution related data from projects in Sri Lanka and the construction of a database for the effective storage, retrieval and presentation of such information. A survey was carried out by development of a questionnaire identifying the key areas relevant and adequate to achieve the ministry needs. Data sources were identified and data collectors were assigned after training. The developed database is founded on information from actual projects exceeding two hundred and collected from over fifty contacted resource personnel and/or organizations. The developed database provides information pertaining to the current projects and interests, the available information and their sources, and the contact of current practitioners related to the pollution hazard management of the natural environment. The database would certainly help a developing country like Sri Lanka to avoid executing expensive project activities. Therefore the present database would initiate steps to create an environment to disseminate the information not only to managers but also to a much wider audience. The database technology provides such facilities to enhance the much needed optimum utilization of available resources efficiently and effectively for the benefit of a developing country like Sri Lanka

The implementation of GIS technology in urban flood dynamic simulation model

This paper presents the implementation of geographic information system (GIS) technology in Urban Flood Dynamic Simulation Model (UFDSM). The method of melting UFDSM models into one integrated system model base is discussed too. It shows in detail the steps of acquiring, storing, updating, analyzing, and displaying these data in conjunction with UFDSM. The viability of the GIS/UFDSM linkage in a microcomputing environment is demonstrated on a case study area in the Liuhuahu subdivision in Guangzhou City, China

Use of NOAA/AVHRR data for flood disaster monitoring in Mekong River Delta

The Mekong River Delta is one of the most important agricultural lands in Vietnam. Every year, it faces flood and water logging causing a lot of hardships and damages. The NOAA/AVHRR data have been used to monitor flood in this area. The method of Sheng Yongwei (1996) has been modified, using information from different channels of NOAA/AVHRR data, including visible and infrared split window channels to remove cloud influences, including cloud's shadows, when cloud contamination is not very serious. The quantitative split window channel threshold value has been given for an identification of waterbody and land surface under semi-transparent clouds. By this way, much wider ground areas for any condition of the weather, for any kind of the cloud systems can be analyzed and detected. The techniques for objectively defining the threshold values and automatically running the program for flood monitoring have been developed. A technique for identifying the image's pixels with different rate of mixing between water and land has been developed too. The case study for flood monitoring in Mekong River Delta in the late 1997 year was done and the results of flood monitoring on 15 November 1997 is shown in the paper as a demonstration

Topographic measurement of volcanic mountains using SAR interferometry

SAR Interferometry technique is the most effective technique, among the Remote Sensing based methodologies for the measurement of ground elevation as well as change of surface elevation. In this paper, the methodology for generating digital terrain model (DTM) using SAR Introferometry from Japanese earth observation satellite 1 (JERS1) is presented. DTM of Mt. Fuji is generated using the derived methodology. The estimated DTM is found to have a maximum error of 217 m and a R.M.S.E. of 27.7 m respectively. The main factors contributing to this less than theoretical accuracy are the position and orientation of the satellite, precision of geometric correction and the accuracy of phase unwrapping algorithm. The DTM accuracy obtained in the present study reflects the total errors from the above

Developing decision support systems for mitigating natural hazards risks through relocation

This paper explains the need for integrating decisions for mitigating natural hazards risk with other socio-economic factors based on the fact that some mitigation measures can reduce the risk of natural hazards, but they might introduce new risks for communities. Relocation is among these mitigation alternatives, which has a high potential for creating new risks especially impoverishment and social destruction risks. While planners and decision-makers would like to consider all possible impacts, they are constrained by financial and time issues. In such conditions decision support systems can help planners make better decisions. The process of developing a decision support system using multi-criteria valuation technique and GIS and non-GIS based development tools for relocation and regrouping of rural settlements exposed and affected by natural disasters has been illustrated. The experience shows that such systems can improve the quality and speed of decision making process significantly

Database centered simulation using WWW

A model for WWW based simulation environment is presented. The simulation environment is coordinated through a RDBMS that contain both spatial and time series data for use with forecast and simulation programs. Any client WWW browser can communicate with the Database either through the Web Server or directly through Java applets. The data preparation and execution as well as storage of the output in the database is automated through database scripts that are stored within the database. Communication with operating system resident simulation programs is carried out through server side Java programs initialized by the database trigger scripts. This approach provides a generic mechanism for integrating spatial and time series data with simulation programs to carry out scenario modeling and impact assessment studies. The methodology is scalable and can evolve into a decision support system incorporating database and simulation functionality

Response history analysis of structures with seismic isolation and energy dissipation systems : Verification examples for Program SAP2000

SAP2000 is a recently released commercial structural analysis program with capabilities for dynamic analysis of structures with seismic isolation and energy dissipation systems. This report presents five verification examples in which results obtained by SAP2000 are compared to experimental results and to results obtained by programs 3D-BASIS and ANSYS. Three of the examples involve seismically isolated structures, of which one was tested on the shake table under conditions resulting in bearing uplift. The other two examples involve structures with linear and nonlinear fluid viscous energy dissipation devices, which were also tested on the shake table. In general, SAP2000 produced results in excellent agreement with other analysis programs and in good agreement with experimental results, except for the case of the structure tested with nonlinear viscous damping devices. In this case, SAP2000 underpredicted the displacement response of the structure

Seismic evaluation of a masonry infilled reinforced concrete frame by pseudodynamic testing

Seismic evaluation of a masonry infilled frame was performed by pseudodynamic testing. The half-scale experimental specimen consisted of a two-story, two-bay, lightly reinforced concrete frame infilled with unreinforced concrete masonry block. The second story infill included window openings. Following stiffness and damping characterization by static and free vibration tests, the specimen was subjected to four pseudodynamic tests of increasing magnitude, based on the Taft (1952) ground motion. Explicit numerical integration with a small time step and an iterative actuator control algorithm limited the displacement control errors normally associated with pseudodynamic testing of stiff structures. The displacement control matrix necessary for the iterative actuator control was directly measured. The final sequence of pseudodynamic tests produced extensive cracking in both upper and lower story masonry infill, as well as distress in frame columns. Relations between energy dissipation and the types of observed masonry cracking are investigated. A detailed history of crack development is presented, keyed to both story hysteresis and input excitation. Evidence of compressive strut mechanisms are drawn from frame moments and axial forces, and measured local strains and infill panel diagonal changes of length. Simple strut models are used to estimate infill stiffnesses and strut forces, and the results are compared with measured values. The effects of infill bed-joint shear failures on overall behavior are investigated with a simple analytical model. Estimated infill shear strength is shown to be highly dependent upon the assumed coefficient of friction

Using cyberspace to enhance disaster mitigation, planning and response : Opportunities and limitations

The new information technologies will, no doubt, be more effectively used in the future. The current generation of web sites, only hint at their potential. Web sites could list such individuals, along with their email addresses and telephone numbers at which they could be paged 24-hours-a-day. In addition, information could be provided in cyberspace which provides an all-hazards check list of what the emerging EOC should consider during pre-impact, impact, post-impact periods. The purpose of the current paper is to offer a few suggestions in answer questions like How might the educational processs, be more effectively facilitated to potentially involve all of us? How might we develop a process, which might also enable practitioners to interact with one another and with researchers during emergency time periods to employ the knowledge and experience of others at a critically useful time? and to raise a few important issues, which may be useful to keep in mind pursuant to implementing answers to these questions

IDARC - BRIDGE : A computational platform for seismic damage assessment of bridge structures

This report presents the theoretical background of a computer platform for three-dimensional inelastic analysis of bridge structures. IDARC-BRIDGE utilizes recent developments by the authors and other researchers involved in the current and related NCEER projects. The program adapts and extends some of the component and damage models of the existing platform for two-dimensional analysis of buildings IDARC-2D (Kunnath et.al, 1987, Valles et. al, 1996). A number of unique features, however, expand its range of applicability to include bridge structures, which often present unusual and uncommon modeling problems. Two distinct goals define the scope of IDARC-BRIDGES: 1) to serve as an efficient and user-friendly analytical tool for investigating the behavior of bridge structures by engineers and researchers, and 2) to provide a framework for future software development by allowing the user to incorporate new modules, element types and component models or replace the existing ones.(AU)

Inelastic response prediction of structures subjected to seismic loads

A brief overview of analytical techniques to carry out an inelastic time-history analysis of structures under seismic loads is presented. The primary objective of the discussions presented in this paper is to explore the adequacy and limits of approximate methods and the enhanced reliability of more refined computational methods. In particular, the use of flexibility-based member models, the choice of multi-parameter hysteretic models, and the effects of energy-dissipation on global structural response will be examined. A sample application of inelastic seismic evaluation of an existing concrete building damaged in the recent Northridge earthquake concludes the paper.(AU)