Guidelines for the seismic design of fire protection systems

The engineering knowledge gained from earthquake experience data surveys of fire protection system components is combined with analytical evaluation results to develop guidelines for the design of seismically rugged fire protection distribution piping. The seismic design guidelines of the National Fire Protection Association Standard NFPA-13 are reviewed, augmented, and summarized to define an efficient method for the seismic design of fire protection piping systems. 8 refs

Low-rise shear wall failure modes

A summary of the data that are available concerning the structural response of low-rise shear walls is presented. This data will be used to address two failure modes associated with the shear wall structures. First, data concerning the seismic capacity of the shear walls with emphasis on excessive deformations that can cause equipment failure are examined. Second, data concerning the dynamic properties of shear walls (stiffness and damping) that are necessary to compute the seismic inputs to attached equipment are summarized. This case addresses the failure of equipment when the structure remains functional. 23 refs

Fragility Curve Development for the Seismic Vulnerability Assessment of Retrofitted RC Bridges under Mainshock-Aftershock Seismic Sequences

Bridges are one of the most important lifeline structures such that loss of functionality of the network system is directly related to the social and economic losses experienced following an earthquake. Due to the potential of strong aftershocks to cause further damage to mainshock damaged bridges, accurate evaluation of the structural performance during a real seismic sequence is essential. This paper investigates the seismic damage of a reinforced concrete (RC) skewed bridge subject to a sequence of earthquake ground motions. Fragility curves are developed for both with and without consideration of the effects of aftershocks on the seismic vulnerability of the bridges for two cases: original bridge and retrofitted bridge by FRP. Results of this study have revealed that the effect of aftershocks on damage states appears to increase the seismic vulnerability of RC bridges. In addition, the strategy of retrofit will significantly affect the seismic response and therefore fragility of bridges

Screening criteria for the verification of seismic adequacy of piping systems

This paper describes practical screening criteria to be used by engineering walkdown teams, for the evaluation of seismic adequacy of piping systems. The application of the screening criteria to a nuclear facility are described and compared to the results achieved using conventional analytical techniques. 13 refs

Seismic evaluation of safety systems at the Savannah River reactors

A thorough review of all safety related systems in commercial nuclear power plants was prompted by the accident at the Three Mile Island Nuclear Power Plant. As a consequence of this review, the Nuclear Regulatory Commission (NRC) focused its attention on the environmental and seismic qualification of the industry's electrical and mechanical equipment. In 1980, the NRC issued Unresolved Safety Issue (USI) A-46 to verify the seismic adequacy of the equipment required to safely shut down a plant and maintain a stable condition for 72 hours. After extensive research by the NRC, it became apparent that traditional analysis and testing methods would not be a feasible mechanism to address this USI A-46 issue. The costs associated with utilizing the standard analytical and testing qualification approaches were exorbitant and could not be justified. In addition, the only equipment available to be shake table testing which is similar to the item being qualified is typically the nuclear plant component itself. After 8 years of studies and data collection, the NRC issued its Generic Safety Evaluation Report'' approving an alternate seismic qualification approach based on the use of seismic experience data. This experience-based seismic assessment approach will be the basis for evaluating each of the 70 pre-1972 commercial nuclear power units in the United States and for an undetermined number of nuclear plants located in foreign countries. This same cost-effective developed for the commercial nuclear power industry is currently being applied to the Savannah River Production Reactors to address similar seismic adequacy issues. This paper documents the results of the Savannah River Plant seismic evaluating program. This effort marks the first complete (non-trial) application of this state-of-the-art USI A-46 resolution methodology

Seismically induced relay chatter risk analysis for the Advanced Test Reactor

A seismic probabilistic risk assessment (PRA) was performed as part of the Level I PRA for the Department of Energy (DOE) Advanced Test Reactor (ATR) located at the Idaho National Engineering Laboratory (INEL). This seismic PRA included a comprehensive and efficient seismically-induced relay chatter risk analysis. The key elements to this comprehensive and efficient seismically-induced relay chatter analysis included (1) screening procedures to identify the critical relays to be evaluated, (2) streamlined seismic fragility evaluation, and (3) comprehensive seismic risk evaluation using detailed event trees and fault trees. These key elements were performed to provide a core fuel damage frequency evaluation due to seismically induced relay chatter. A sensitivity analysis was performed to evaluate the impact of including seismically-induced relay chatter events in the seismic PRA. The systems analysis was performed by EG G Idaho, Inc. and the fragilities for the relays were developed by EQE Engineering Consultants