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IMPACTS OF EARTHQUAKES ON WATER RESERVOIRS, PIPELINES, AQUEDUCTS, AND DISTRIBUTION SYSTEMS. Walter Hays, Global Alliance for Disaster Reduction, University of North Carolina, USA. OVERVIEW OF EARTHQUAKE RISK.
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IMPACTS OF EARTHQUAKES ONWATER RESERVOIRS, PIPELINES, AQUEDUCTS, AND DISTRIBUTION SYSTEMS Walter Hays, Global Alliance for Disaster Reduction, University of North Carolina, USA
OVERVIEW OF EARTHQUAKE RISK WATER RESERVOIRS, PIPELINES, AQUEDUCTS, AND DISTRIBUTION SYSTEMS FACE DIFFERENT RISKS FROM THE POTENTIAL DISASTER AGENTS OF EARTHQUAKES
WATER RESERVOIRS, PIPELINES, AQUEDUCTS, AND DISTRIBUTION SYSTEMS • Have POINT-SENSITIVE and AREA-SENSITIVE components, … • which have varying vulnerabilities when exposed to the TIME – and SPACE- DEPENDENT potential disaster agents of EARTHQUAKES.
EARTHQUAKES • INVENTORY • VULNERABILITY • LOCATION • PREPAREDNESS • PROTECTION • EMERGENCY RESPONSE • RECOVERY PPLICIES:FOR RESILIENT SYSTEMS RISK ASSESSMENT ACCEPTABLE RISK RISK UNACCEPTABLE RISK GOAL: DISASTER RESILIENCE WATER,RESERV.,AQUEDUCTS, PIPELINES,, AND DISTRIBUTION SYSTEMS DATA BASES AND INFORMATION HAZARDS: GROUND SHAKING GROUND FAILURE SURFACE FAULTING TECTONIC DEFORMATION TSUNAMI RUN UP AFTERSHOCKS
DAMAGE; INJURIES FAILURE; DEATHS LOSS OF FUNCTION ECONOMIC LOSS ELEMENTS OF UNACCEPTABLE RISK RISK
SEISMICITY TECTONIC SETTING & FAULTS EARTHQUAKE HAZARD MODEL
THE BASIC FAULT MODELS Strike-Slip Reverse Normal
LOCATION OFWATER SYSTEMS IMPORTANCE AND VALUE OF SYSTEM AND CONTENTS EXPOSURE MODEL
QUALITY OF DESIGN AND CONSTRUCTION ADEQUACY OF LATERAL-FORCE RESISTING SYSTEM VULNERABILITY MODEL
WATER RESERVOIRS, PIPELINES, AQUEDUCTS, AND DISTRIBUTION SYSTEMS • Vulnerability is a function of materials, age, maintenance, and the system’s exposure as a site-specific, or a spatially- distributed above-or-below-ground system.
35 30 25 UNREINFORCED MASONRY, BRICK OR STONE 20 REINFORCED CONCRETE WITH UNREINFORCED WALLS 15 10 REINFORCED CONCRETE WITH REINFORCEDWALLS STEEL FRAME ALL METAL & WOOD FRAME 5 0 V VI VII VIII IX CONSTRUCTION MATERIALS HAVE DIFFERENT VULNERABILITIES TO GROUND SHAKING MEAN DAMAGE RATIO, % OF REPLACEMENT VALUE INTENSITY
COMMENTS ON DAMAGE • MMI VI DENOTES TO ONSET OF DAMAGE DUE TO LIQUEFACTION • MMI VII DENOTES DAMAGE FROM CRACKING; APPROXIMATELY 12% g • MMI VIII DENOTES SEVERE DAMAGE, TYPICALLY AT JOINTS OF PIPES; APPROXIMATELY 25 % g • MMI IX DENOTES VERY HEAVY DAMAGE, MANY BREAKS/KM; 50 %^ g.
TSUNAMI FAULT RUPTURE DAMAGE/ LOSS TECTONIC DEFORMATION DAMAGE/ LOSS DAMAGE/LOSS FOUNDATION FAILURE EARTHQUAKE DAMAGE/ LOSS SITE AMPLIFICATION DAMAGE/ LOSS LIQUEFACTION DAMAGE/ LOSS LANDSLIDES DAMAGE/ LOSS DAMAGE/LOSS AFTERSHOCKS DAMAGE/ LOSS FIRE DAMAGE/ LOSS GROUND SHAKING
CAUSES OF DAMAGE INADEQUATE RESISTANCE TO HORIZONTAL GROUND SHAKING SOIL AMPLIFICATION PERMANENT DISPLACEMENT (SURFACE FAULTING, LIQUE-FACTION & LANDSLIDES) IRREGULARITIES IN ELEVATION AND PLAN, AND [OOR ROUTE EARTHQUAKES TSUNAMI IMPACTS “DISASTER LABORATORIES” POOR DETAILING AND WEAK CONSTRUCTION MATERIALS FRAGILITY OF NON-STRUCTURAL ELEMENTS
EXAMPLES OF FAILURES (AND ALMOST FAILURES) IN PAST EARTHQUAKES
INADEQUATE SEISMIC DESIGN PROVISIONS (I.E., BUILDING CODES ) MEAN 1) INADEQUATE RESISTANCE TO HORIZONTAL GROUND SHAKING 2) COLLAPSE AND FAILURE OF ABOVE-GROUND SYSTEMS
UNDERGROUND PIPELINES AND DISTRIB-UTION SYSTEMS NEED PROTECTION • A UTILITY CORRIDOR IS VULNERABLE TO LOSS OF FUNCTION WHEN IT IS ROUTED THROUGH SOILS THAT ARE SUSCEPTIBLE TO LIQUEFACTION. (USA 1995)
INADEQUATE SEISMIC DESIGN PROVISIONS (I.E., WATER SYSTEM STANDARDS) AND THE ROUTING) MEAN 1) SUSCEPTIBILITY TO PERMANENT GROUND FAILURE (LIQUEFACTION, LANDSLIDES), 2) FAILURE OF BELOW-GROUND SYSTEMS
ABOVE-GROUND SYSTEMS NEED PROTECTION FROM LANDSLIDES • RESEVOIRS ARE SUSCEPTIBLE TO LANDSLIDES INDUCED BY EARTHQUAKES. (CHINA 2008)
AQUEDUCTS: ABOVE-GROUND SYSTEMS THAT CARRY WATER FROM “A” TO “B” • AQUEDUCTS ARE SUSCEPTIBLE TO LANDSLIDES INDUCED BY EARTHQUAKES. (ARIZONA);
AQUEDUCTS: ABOVE-GROUND SYSTEMS THAT CARRY WATER FROM “A” TO “B” • ELEVATED AQUEDUCTS ARE VERY SUSCEPTIBLE TO GROUND SHAKING.
JAPAN 2011: ABOVE GROUND SYSTEMS NEED PROTECTION IN AN EARTHQUAKE
KEY CONSIDERATIONS FOR PROTECTIVE DESIGN AND SMART ROUTING WATER RESERVOIRS, PIPELINES, AQUEDUCTS, AND DISTRIBUTION SYSTEMS
WATER RESERVOIRS, PIPELINES, AQUEDUCTS, AND DISTRIBUTION SYSTEMS • Above-ground siting makes water- reservoirs and aqueducts more vulnerable to earthquake ground shaking than the buried pipelines and distribution systems are.
EARTHQUAKE SCENARIOS A DISASTER RISK ASSESSMENT TECHNIQUE FOR USE IN AN EARTHQUAKE-PRONE AREA
DESIGN SCENARIOS • Distributed Systems: The risks need to be assessed in terms of regional ground shaking and ground failure maps; --- • Non-distributed systems: Assess risks in terms of site-specific criteria.
EXAMPLE: PROBABILISTIC GROUND SHAKING HAZARD MAPSPGA: 10 % P(EXCEEDANCE) IN 50 YEARS SOURCE GLOBAL SEISMIC HAZARD ASSESSMENT PROGRAM US GEOLOGICAL SURVEY
MAPS = INTEGRATED KNOWLEDGE A probabilistic ground shaking hazard map integrates physical properties determined from geology, geophysics, and seismology in a consistent way to define: Seismic source zones Regional seismic wave attenuation rates
SEISMIC SOURCE ZONES AND ATTENUATION RATES Seismic Source Zones: Each zone has its own unique spatial and temporal distribution of faults, magnitudes and recurrence intervals. Regional Seismic Attenuation Rates: seismic waves decay more rapidly near a plate boundary than far from the boundary.
SESMIC SOURCES RECURRENCE ATTENUATION PROBABILITY GROUND SHAKING HAZARD ASSESSMENT
WHAT DOES THE MAP SHOW? Each map shows relative levels of the ground shaking hazard on a small scale in terms of the mapping parameter: peak ground acceleration (and sometimes MMI).
PEAK GROUND ACCELERATION Peak ground acceleration correlates best with the short-period asymptote of the response spectrum, and is related to how a short waste water facility would respond to ground shaking.
BEST APPLICATION The maps are most useful for small-scale applications such as comparison of the relative ground shaking hazard between the end-points of a long, distributed water pipeline system.
LIMITATIONS OF MAPS The mapping parameter, peak ground acceleration, is not as good a descriptor of how the ground actually shakes as is a time history The response spectrum of a time history is an approximation of how a water system element might respond to ground shaking of a certain period.
LIMITATIONS OF THE MAPS The regional-scale peak ground acceleration maps are not appropriate for site-specific design.
LIMITATIONS OF THE MAPS Regional maps do not incorporate information on soil properties (e.g., shear wave velocity; data related to liquefaction; slope stability). Soils data require sampling and mapping on a larger scale.
PGA SCALE FOR MAPS Afghanistan http://www.seismo.ethz.ch/gshap/eastasia/
