Special Section on Performance of Bridges under Critical Natural Hazards

Abstract

In recent years, extreme monsoon events and devastating earthquakes have caused serious damage to infrastructure, including bridges. Failures of bridges not only result in threats to vehicles and people traveling on them at the time of the failure but also interrupt emergency evacuation and rescue traffic, increasing the severity of the disaster and adding to casualties and economic loss. Often, awareness of the need for design or retrofit code revisions is raised immediately following extreme hazard events. Bridges that fail during extreme natural hazards usually have complicated failure causes, including environmental system collapses and massive structural malfunctions. Forensic investigations and performance analyses for bridges suffering such natural hazard events can be more challenging than those for bridges that fail in general service condition. General investigation guidelines or specific observational methods for such forensic investigations are not an easy task. Thus, actual performance of bridges under critical natural hazards is of great interest to practicing engineers and researchers. This special section of the Journal of Performance ofConstructed Facilities (JPCF) was proposed in an effort to introduce the current state-of-the-art for forensic investigations of bridge failures in recent extreme natural hazard events and to provide insights of performance analysis for the behavior of bridges under such extreme natural hazards. Fortunately, we were able to invite professional experts who had personally been involved in forensic investigation, failure analysis, and performancemonitoring during recent extreme natural hazards including the 2011 Turkey Van Earthquake, the 2010–2011 New Zealand Christchurch Earthquakes, the 2011 Japan Tohoku Earthquake, the 2005 Hurricane Katrina in the United States, and the 2009 Typhoon Morakot that overran Taiwan. Case histories and performance data presented in these invited papers are invaluable to practicing engineers and researchers. This special section includes case histories of bridge performance involving more than 20 bridges suffering from a variety of natural hazards such as strong ground motions, soil liquefaction, tsunami, storm surge, extreme winds, scour, and debris impact. Whether the bridge was damaged, failed, or luckily survived, such performance information and analysis results are instrumental to bridge design and retrofit against critical natural hazards, including great earthquakes and massive storms. Results of the forensic investigations and analyses have deterministic influences on upgrading guidelines of risk assessment, hazard mitigation, structural design, and retrofit. Invited papers within this special section are generally divided into two major categories: bridge performance under seismic hazards and under storm hazards. The reported seismic hazards include strong ground motion in a recent Turkish earthquake and the Japan Tohoku Earthquake that caused severe damage to both highway and railroad bridges. These bridges were in locations that had undergone in-depth evaluations and design code revolutions in recent years. Very rare, yet devastating, failures caused by the tsunami accompanying the 2011 Japan Tohoku Earthquake are instructive not only to bridge engineers, but also to the general public. Studying these failures leads to a better understanding of the power of Mother Nature. A research team from the University of Canterbury at Christchurch, New Zealand, introduces valuable performance data from bridges suffering from soil liquefaction and describes useful investigation practices. Such soil liquefaction causing bridge damage was broadly observed in previous large earthquakes, yet less detailed forensic investigation works were previously reported. Both the 2005 Hurricane Katrina and the 2009 TyphoonMorakot are recognized as critical storm events. Both resulted in substantial damage to bridges and a large number of bridge failures. Invited papers contributed by the Bridge Technology Office of the U.S. Federal Highway Administration (FHWA) and by Taiwanese research groups provide valuable forensic investigation and failure analysis techniques. Study efforts described in these papers are applicable internationally including advanced field investigation technologies and innovative Fig. 1. Wei F. Lee, Ph.D., A.M.ASCE, Guest Editor