Water System Seismic Fragility Webinar
The Seismic activity is a significant threat to buried infrastructure, particularly water systems. East Bay Municipal Utility District (EBMUD), serving more than a million customers in the San Francisco Bay area, developed water system damage prediction models to estimate the level of fragility of embankment dam reservoirs, tank reservoirs, and large diameter pipelines using multiple scenario earthquake events. The goal of the analysis was to understand the estimated level of water system damage for pre-event response planning purposes. This webinar will present the damage prediction results and an approach for other agencies to produce similar damage predictions models.
When: Tuesday, September 16
Time: 1:00 PM CDT
Who: Roberts McMullin, P.E., Associate Civil Engineer, East Bay Municipal Utility District – Pipeline Infrastructure
Yogesh Prashar, P.E., G.E. , Associate Civil Engineer, East Bay Municipal Utility District – Materials Engineering
The following water system components were evaluated in the damage prediction model:
1. 29 embankment dam reservoirs.
2. 147 water distribution reservoirs consisting of 86 steel tanks, 58 concrete tanks, and 4 wood tanks.
3. Approximately 360 miles of large diameter pipelines consisting of welded steel pipe, reinforced concrete cylinder pipe, cast-iron pipe, and pre-tensioned concrete cylinder pipe.
EBMUD successfully modeled and documented the water system fragility results using six separate input scenario earthquake events. USGS provided the following scenario earthquakes:
1. Aagaard Mw 7.05 combined Hayward South and North,
2. Aagaard Mw 6.76 Hayward South,
3. ShakeMap Mw 7.05 Hayward,
4. ShakeMap Mw 7.05 Hayward Directivity Northwest (dirnw),
5. ShakeMap Mw 7.05 Hayward Directivity Southeast (dirse), and
6. ShakeMap Mw 7.9 San Andreas.
EBMUD obtained USGS grid XML and ShakeMap GIS shapefiles, which provided the necessary spatial ground shaking intensity metrics required for the damage prediction model. Along with ground shaking, EBMUD also acquired current hazard maps from the Bay Area to model damage due to liquefaction, landslide, and fault offset on the large diameter pipelines.