Hal Brown Bridge And Pathway Replacement Project, Greenbrae, CA

The project is located in Creekside Marsh, a restored wetland between Bon Air Road and the Corte Madera Creek multi-use pathway. The scope of the project generally includes removing 2,300 square feet of existing asphalt pathway and an existing wood-framed bridge and foundations; and the installation of a new prefabricated bridge, an elevated wooden boardwalk, and new sections of asphalt pathways. The new bridge, boardwalk and pathway will be 10-feet wide and shall be compliant with all ADA accessibility requirements. The existing asphalt pathway will be removed, backfilled with native soils, and regraded to match existing adjacent grades. Construction of the new raised pathway includes the use of asphalt pavement, aggregate base, and lightweight backfill material. The purpose of the lightweight backfill is to reduce settlement in the underlying bay mud. The new prefabricated bridge will span 120 feet between new concrete abutments. The new wooden boardwalk will be approximately 47 feet in length and span between new concrete abutments. Helical piers will be utilized to support the concrete abutments and wooden boardwalk. The new sections of asphalt pathways will be installed at both ends of the project, adjacent to the new prefabricated bridge and adjacent to the new wooden boardwalk. Construction of bridge abutments, boardwalk, and raised pathway will be outside the limits of wetlands.