Improving earthquake loss estimation : Review, assessment and extension of loss estimation methodologies

The overall goals of the research are to link engineering system vulnerability analysis with the best-available techniques of economic analysis, to produce integrated models of physical and economic loss, and to improve the efficiency and effectiveness of loss estimation methods through the application of advanced and emerging technologies. This program of research focuses both on general methodological refinements and model improvement and on applications that will support MCEER's power and water lifeline and hospital demonstration projects

Development of bridge fragility curves

This paper presents preliminary results of an on-going research on bridge fragility curve development focusing on (1) development of emprirical fragility curves utilizing bridge damage data obtained from the past earthquakes, particularly the 1994 Northridge earthquake, (2) development of analytical fragility curves, on the basis of dynamic analysis, (3) the issues of hypothesis testing and confidence intervals of these fragility curves, and (4) demonstration, on the basis of dynamic analysis, of effective use of a protective system for fragility enhancement using a representative bridge in the Memphis area.(AU)

Effect of spatial variation of earthquake ground motion on seismic response of bridges

A methodology is presented to generate spatially varying seismic ground motion time histories at a number of prescribed location on the ground surface, complatible with prescribed response spectra and duration of strong ground motion, and reflecting the wave propagation and loss of coherence effects. The prescribed locations can correspond to differencial local soil conditions and therefore different response spectra can be assigned to each location. In such a case, the generated ground motion time histories will have different frequency contents. This methodology is the used in two case studies involving the SR 14/I-5 Interchange that has partially collapsed during the 1994 Northridge earthquake, and a typical three-span concrete bridge designed BERGER/ABAM Engineers for the Federal Highway Administration. Each case study considers a set of different scenario earthquakes with different apparent velocities of wave propagation and/or different angles of incidence of seismic waves with respect to the axis of the bridge and/or combinations of vertical and horizontal components of ground motion. It is concluded that the maximum stress at critical locations of the bridge can show increases up to 18

for the SR14/I-5 Interchange and upto 7

for the typical three-span concrete bridge, compared to the case of identical support ground motion. (AU)

Systems analysis for Memphis light, gas and water

In this study, a coordinates systems approach was used to examine the overall seismic perfomance of MLGW's lifeline systems. The study examined: seismic hazard and ground motion characteristics of the area; geotechnical features, with a special emphasis on liquefaction and resulting lateral spread; the effect of ground motion and geotechnical features on the seismic perfomance of mechanical and structural components including pipelines, storage tanks, pumping stations, treatment facilities, etc., measured in terms of fragility quantities; reliability and interactive nature of system functionality under severe seismic conditions with the aid of Monte Carlo techniques utilizing component fragility information; and the socioeconomic impact arising from system failure.(AU)

Development of passive and semi - active sliding bearings

This study demonstrates that friction isolation systems, especially those equipped with a friction controllable device, offer more desirable base isolation characteristics. This demonstration was done through experimental, analytical and numerical effort, by developing sliding base isolation systems with and without friction controllable devices and by developing sliding base isolation systems with and without friction controllable devices and by verifying their base isolation capabilities for bridges and buildings through shake table tests and a numerical simulation study.(AU)

Part II : Lifelines. Chapter 10 : Gas and liquid fuel systems

Past earthquakes have shown that gas and liquid fuel lifelines are vulnerable to earthquake ground shaking and ground failure. Although there are gaps in the knowledge base for seismic design of new systems, information is more complete for mitigation of seismic damage to new systems than for existing systems. The critical issues primatily center on the vulnerability of existing systems and include: the expected level of damage, direct and indirect impacts of seismic damage, damage mitigation procedures, and appropriate performance criteria. The state-of-the-art in dealing with these issues is reviewed as a basis for recommendations to improve implementation of existing knowledge and to advance the development of new technologies.(AU)

Restoration planning for Memphis water delivery network based on simulated seismic damage

The post - earthquake restoration of a seismically damaged water delivery system is one of the critical issues for cities that face significant seismic hazards. In this paper, we present an approach for optimum temporary restoration of a seismically damaged water delivery system. First, a short route network is established by determining the shortest route from each demand node to the nearest supply node. The links not include in the short - route network and included from temporary repairing. (AU)

Experimental and analytical study of a hybrid isolation system using friction controllable sliding bearings

This study deals with a hybrid isolation system using friction controllable sliding bearings [1,2]. During earthquakes, this isolation system controls the friction force on the sliding interface between the supported structure and the ground, by adjusting the pressure in a bearing chamber,to confine the sliding displacement within an acceptable range, while keeping the transfer of seismic force to a minimum to obtain the best isolation performance. This is the advantage of the hybrid sliding isolation system that cannot be achieved by the passive sliding system. Instantaneous optimal control and bang-bang control algorithms are developed for controlling the friction force, since standard control theory is difficult to apply in a straightforward fashion in this case where the control force has a nonlinear feature. The effectiveness of the algorithms in controlling seismic response of a structural model is demonstrated by shaking table experiments and computer simulation. A hybrid sliding isolation system using friction controllable bearings is physically developed, and shaking table experiments are performed using a rigid structural model equipped with such a hybrid system. The dynamic characteristics of the control system for bearing pressure and sliding friction is identified, and the advantage of the hybrid sliding isolation system over the passive system is demonstrated by experiments. Computer codes for simulation of structural response under passive or hybrid control are developed. The numerically simulated results show good agreement with the experimental results, verifying that the analytical model developed represents the actual system very well. Both experimental and analytical studies demonstrate the effectiveness of the hybrid sliding isolation system and suggest its advantageous use in civil structures (AU)

A hybrid sliding isolation system for bridges

This study deals with a hybrid isolation system using friction controllable sliding bearings. During earthquakes, this isolation system controls the friction force on the sliding interface between the structure and the ground to confine the aliding displacement within an acceptable range, while keeping the transfer of seismic force to a minimum. This is the advantage of the hybrid sliding isolation system that can not be duplicated by the passive sliding system. Instantaneous optimal control and bang-bang control algorithms are developed for controlling the friction force. Shaking table tests are perfomed using a bridge model equipped with such a hybrid isolation system. Computer simulations show good agreement with the experimental results, demonstrating the effectiveness of the hybrid sliding control system and the feasibility of its applications for bridges.(AU)