Seismic Improvement Program Presented to: The Northern California Earthquake Hazards Workshop February 12, 2014
Water Treatment and Distribution 1,300,000 customers 331 square-mile area ~ 4,000 miles of pipe ~ 135 pumping plants ~ 180 reservoirs/tanks ~ 125 pressure zones Elevation: MSL-1450 ft
Seismic Hazards in Service Area
Pressure Zone Damage
Predicted Damage: Seismic Evaluation Program 63% of our customers would be out of water Increased fire risk with 1/3 of reservoirs and 2/3 of pumping plants out of service Claremont Tunnel would be out of service 5,500 pipeline breaks 4 of 6 treatment plants would be out of service
Capital Improvement Program l Package #1 ($3 million) ―Improve service after smaller earthquakes l Package #2 ($84 million) – Limited service improvements after Hayward M-7 l Package #3 ($189 million) – Improved service after Hayward M-7 l Package #4 ($288-$360 million) – Low priority, low benefits
Water Treatment Plants
Column Weld Column Flange Beam Flange Backing Bar Fracture During Earthquake Beam-Column Connection Structural system is a welded steel moment frame Designed to the 1982 Uniform Building Code Seismic Improvement Program implemented in 1994 to provide life safety for all occupied structures Lessons learned from the 1994 Northridge Earthquake Welded joints do not perform as designed Beam Main Administration Building
Viscous Damper in Diagonal Brace State Office Building Project, San Francisco Piston Damper Detail
Pumping Plants
Implementation -Tank Seismic Upgrade Shotcrete over New Anchors Prestressed Strands Shotcrete Cover
Emergency Bypass System Manual isolation valves and by-pass manifolds –Isolate ruptured pipe and restore flow with temporary hoses
Pipeline Fault Crossings and Backbone Pipe at Landslides
Supplying the West of Hills
Southern Loop Pipeline 11-miles 30 inch to 42 inch diameter 1,800 ft. of 9 ft. dia. tunnel Connects Southern Part of Service AreaConnects Southern Part of Service Area
Claremont Tunnel Crosses the Hayward Fault
Claremont Tunnel Before Upgrade
Plan Configuration after design earthquake Section 8.5ft8.5ft carrier pipe i.d: 6ft; length: 85ft
Mokelumne Aqueduct No. 3 Elastomeric seismic isolation bearing install on 351 pipe supports
San Pablo Dam Seismic Upgrade
Chabot Dam Seismic Upgrade
Dam Remediation Design Alternatives Cement Deep Soil Mixing (CDSM)Conventional Earth Replacement
Questions Timothy McGowan Associate Civil Engineer P.O. Box Oakland, CA (510)