Upgrading essential Bay Area maritime infrastructure
At a glance
GHD was contracted as the Design Engineer of Record by Manson Construction for the Alameda Main Street Ferry Terminal refurbishment project, as part of Water Emergency Transportation Authority’s ongoing effort to address aging structures, projected sea level rise and modernize the infrastructure to support their future electric fleet.
The challenge
The Water Emergency Transportation Authority (WETA) maintains and operates several ferry terminals throughout the San Francisco Bay Area, including the Alameda Main Street Ferry Terminal. While these terminals support commuter vessel operations daily, they are “essential facilities” that need to be operational after earthquakes and/or flooding to assist with evacuation efforts in regional emergencies. Therefore, the facility modernization design was challenged to comply with the current seismic codes and performance requirement to remain operational without damages, as well as address future sea level rise and tide changes.
GHD oversaw the structural, civil, electrical, plumbing and fire protection components of the project, which comprises replacing the existing steel float landing, guide piles, bridge, gangway, bridge support pier and donut fenders. The main challenges faced by the GHD team were addressing softer soils, deeper bedrock and seismic performance requirements while minimizing changes to the facility's footprint.
Our response
The new steel float used for berthing of the passenger ferries is designed to handle tide variation throughout the day (5 to 6 feet twice daily), as well as accommodate tide elevation for the next 50 years (12+ feet). The internal compartments of the float are specifically designed to avoid flooding and accommodate storage of batteries for the electric fleet in the future. The ramps on the steel float are modified to suit the range of new vessels with higher freeboard.
The two aluminum structures, a fixed 100-foot-long bridge and a hinged 80-foot-long gangway that lands on the steel float, meet the American Disabilities Act requirements at operational tides, providing a better gradient of walking surfaces at all tide levels to access the ferries. The access structures are supported on concrete platforms that are designed to respond to the design earthquake event, with minimal damage and no loss of serviceability.
The electrical utilities were also upgraded with consideration to integrate with WETA’s future electrification project, with LED lighting and solar-powered navigation beacons. A new firewater line, dry standpipe and fire department connection were provided as part of the refurbishment.
The impact
The WETA Alameda Main Street Ferry Terminal remodel project has increased the capacity and efficiency of the ferry service, improved the access and connectivity of the waterfront and continues to promote the economic and social development of the region.