Engineering for the Geotechnical, Geostructural, and Environmental Elements of the Boston City Hall Plaza
With thanks to the City of Boston and Mayor Marty Walsh for such a rewarding opportunity, Weston & Sampson - as a partner to Sasaki, Shawmut Design and Construction, the City of Boston, and MBTA - recently completed the engineering for the geotechnical, geostructural, and environmental elements of the Boston City Hall Plaza renovation that is currently under construction.
Weston & Sampson designed a structural bridging system over the top of three Green Line tunnels that run beneath the plaza, which included demolition of the plenum over the tunnels and installation of deck beams that are supported by the tunnel walls. To ensure the tunnels can support the new plaza loads, the tunnels beneath the plaza were load rated, and repairs to several columns were also designed. Upcoming work will include installation of transfer girders supported on piles that span critical portions of the tunnels.
Weston & Sampson’s structural engineering approach saved the city $6 million, compared with other design alternatives, and builds upon Mayor Walsh’s vision of increased environmental sustainability and critical infrastructure improvements to ensure the Plaza is safe and accessible for all for generations to come.