Creating a Resilient New Waterfront Neighborhood in San Francisco, Mission Rock Phase 1 Development-Paper

Paper

Pdf Summary

Mission Rock Phase 1 is a 16.6-acre waterfront development in San Francisco comprising four buildings, public streets and utilities, and a park. Built on reclaimed bayland, the site has loose, potentially liquefiable fill over thick, compressible Bay Mud. It is also exposed to strong earthquake shaking and projected sea-level rise of up to about 5.5 feet by 2100. Raising streets with conventional fill could have caused as much as two feet of consolidation settlement.<br /><br />To reduce earthquake-related liquefaction and lateral-spreading risks, the team installed stone columns in a triangular grid, with wick drains between them to dissipate excess pore pressure and support densification. Test sections and post-installation cone penetration testing guided the design. Analyses indicated that column spacing of up to eight feet substantially reduced liquefaction potential and limited predicted settlement to less than an inch. Piezometer monitoring also indicated that installation did not remold the underlying Bay Mud.<br /><br />For sea-level-rise adaptation, streets were raised using lightweight cellular concrete (LCC) rather than conventional fill. Existing soil was overexcavated so its removal compensated for the weight of the new street section, avoiding added loading on the Bay Mud. The design also checked future groundwater uplift, vehicle loading, and potential settlement or heave.<br /><br />Because LCC had not previously been approved for San Francisco public streets, the project team built a full-scale mock-up. Flooding tests showed no buoyancy, and a heavy fire truck test found no observed damage or settlement; the LCC could also be excavated for utility work. The City approved its use following the successful tests. Construction quality controls included density and strength testing, surveys, and long-term monitoring. At the time of the paper, monitoring showed no unexpected deflection. The project demonstrates methods for creating resilient waterfront infrastructure on settlement-prone sites vulnerable to earthquakes and sea-level rise.

Keywords

Mission Rock

San Francisco

waterfront development

earthquake liquefaction

stone columns

wick drains

Bay Mud

sea-level rise

lightweight cellular concrete

resilient infrastructure