Capítulo II : Proyecto cívico "Nicaragua Nuestra" Colegio Bautista El Calvario

Esta ponencia fue preparada por un grupo de estudiantes de nivel secundario del Colegio Bautista El Calvario, la cual fue finalista del Concurso Cívico Nacional; celebrado en 1999. Es un proyecto que pretende generar la idea de trabajar en una solución estratégica para afrontar los sufrimientos presentes y futuros ante nuevas catástrofes. El proyecto presenta soluciones previas e inmediatas con la formación necesaria del trabajo de prevención primaria y secundaria de salud mental, necesario ahora y para nuevas catástrofes

INCEDE : At the end of a decade : Summarizing its 8-year activities

United States (UN) declared 1990-2000 as the International Decade for Natural Disaster Reduction (IDNDR). The International Center for Disaster-mitigation Engineering (INCEDE) was established in April 1991, within a year after the UN declaration, as a national contribution of Japan towards UN initiative of natural disaster reduction. The center was established in a university environment at Institute of Industrial Science (IIS) of the University of Tokyo with the objectives of doing fundamental research on various aspects of disaster reduction and tackling problems in disaster mitigation through synthesizing information and methodologies from different fields, mainly from earthquake, water induced disasters, remote sensing and GIS fields.(AU)

Monitoring and analysis of the dynamic and static characteristics of Yuan-Shan Bridge System

The Yuan-Shan Bridge System is one of the major projects currently under construction in this country. This system, when completed, is expected to alleviate drastically the traffic congestion around the Yuan-Shan area. Because of the great variation in the geometry of the system, a five-year research project has been issued by the freeway authority, Taiwan Area National Freeway Bureau, Ministry of Transportation and Communications, to the National Center for Research on Earthquake Engineering (NCREE) for the investigation of the static and dynamic behaviors of the bridge system. In this short article, a brief presentation will be made of the research topics that are currently undertaken or to be undertaken by the researchers in the monitoring and analysis of the static and dynamic behaviors of the Yuan-Shan Bridge System.(AU)

Applications of high-performance concrete to prestressed concrete bridge girders

The development of high-perfomance concrte has led to advances in the building and bridge industry in terms of more economical and durablestructural systems. This paper focusses on recent research conducted at the University of Minnesota in the area of high-strength concrete applications to the prestressed bridge girder industry. The research comprisesan investigation of the mechanical properties, long term creep effects and durability of high-strenght concrtete. In addition, two long span prestressed bridge girders have been constructed to investigate transfer lengths, prestress losses, fatigue perfomance, shear and ultimate strength of girders cast with high-strength concrete.(AU)

Shear strength and ductility of high - perfomance concrete deep beams

The experimental study was conducted on the shear strength and ductility of simply supported high-perfomance concrete (HPC) deep beams. Twenty speciments having cross sections of 140mm x 600mm were tested with the following primary variables: shear span-effective depth ratio a/d, compressive strength of concrete F'c ratio of vertical web reinforcement Pv, and ratio of horizontal web reinforcement. Pvh. Test results indicated that the ultimate shear strength of specimens without web reinforcement increased almost linerly with the increasing compressive strength of concrete. The contribution of horizontal web reinforcement to the shear strength is not pronounced even at a/d=0.5. For specimens with a/d=1.0, the contribution of vertical web reinforcement to the shear strength did not increase proportionally to its quantities. The ultimate shear strength predicted by the design provisions of ACI 318-89 is still conservative.(AU)

Shaking table tests on base-isolated bridge with sliding system

A shaking table test was perfomed for a model bridge isolated by a sliding system at PWRI (Public Works Research Institute), Ministry of Construction, Japan, under the joint research proyect between NCEER (national Center for Earthquake Engineering Research) and PWRI. This paper describes the results of experimental testing and related numerical studies both for the tested model bridges and an actual bride. The model bridge used for the shaking table test has flexible piers and was previously used for testing the base isolation perfomance of lead rubber bearing (LRB) and high damping rubber bearings (HDR). A numerical model that can be efficiently used for the analysis and numerical simulation of the seismic response of the bridge isolated by a sliding system is proposed and utilized. The shaking table testing and numerical simulation study demonstrade the effectiveness of the sliding isolation system for protecting bridges with flexible piers from earthquakes, especially large earthquakes.(AU)

Field testing of bridges before and after retrofitting with seismic isolation bearings

This paper reports on full-scale large-amplitude field experimental studies being conducted in conjunction with bearing component tests, results to date and their comparison with theoretical modeling predictions, for a pair of 3-span continuous slab-on-girder bridges whose existing steel bearings are being retrofitted with laminated elastomeric bearings and lead-rubber bearings. The results of this study will assist a bridge engineer to make more informed decisions among the fundamental options for analytical modeling and for seismic retrofitting of such bridges.(AU)

CANLEX (Canadian Liquefaction Experiment) : A one year update

The Canadian Geotechnical engineering community has embarked on a major study regarding the liquefaction of sand entitled The Canadian Liquefaction Experiment (CANLEX) through a collaborative effort of industry, engineering consultants and university participants, with the support of the Natural Sciences and Engineering Research Council of Canada (NSERC). The study is examining the characterization of sand for dynamic and static liquefaction. The project was started in 1993 and is expected to last at least 3 years with equal funding by both industry and NSERC for a total of about C$1.8M. This paper provides a brief progress report on the Project. Three test sites have been selected and characterized using in-situ testing, conventional sampling as well as in-situ freeezing to obtain undisturbed samples. Laboratory testing is underway on both reconstituted samples and undisturbed samples. A full scale liquefaction event is planned for year three of the Project and a feasibility study regarding the event has been completed. As part of the planning for the liquefaction event some preliminary centrifuge testing has been carried out. A static liquefaction flow failure has been successfully produced in the centrifuge. As part of the Project, a set of definitions for liquefaction have been defined and a flow chart developed to aid in the liquefaction analyses.(AU)

VELACS project : A summary of achievements

In a collaborative and unprecedentent effort, seven major universities from United States and England studied the liquefaction phenomena and its consequences by conducting extensive centrifuge tests on nine carefully selected centrifuge models. In addition, more than 20 groups of researchers from all over the world participated in a Class-A prediction exercise to predict the response of centrifuge models before they were conducted. This paper summarizes the lessons learned from the VELACS project in relation to repeatability of centrifuge models and perfomance of the existing numerical procedures in analyzing soil liquefaction and its consequences.(AU)

An assessment of VELACS "Class A" predictions

A method to compare numerical predictions with experimental recordings is presented. Two comparison indices are proposed:(1) the root mean square error of the predictions with respect to the mean of the experimental results; and (2) the size of a confidence interval centered at the predicted value which contains the estimated true value of the experimental results with a 75

probability. The reliability of experimental results is accounted for by the second index. The method is used to compare numerical "Class A" predictions perfomed within the framework of the VELACS Project with experimental results recorded in centrifuge experiments. The comparison is made in terms of excess pore pressures.(AU)