As part of the overall improvements associated with the Miami Beach Stormwater Master Plan, new pump stations and outfalls were proposed at the 14th Street end to facilitate the discharge of water collected through the upland stormwater system. Cummins Cederberg was retained by the Contractor to assist during construction with the engineering design of the position and support of the 60” outfall through the existing seawall. Due to the accelerated schedule to meet fast approaching king tides, Cummins Cederberg also provided construction engineering support during implementation of the design to ensure varying conditions encountered in the field could be addressed quickly.
The existing seawall consisted of a lightly reinforced concrete retaining wall supported by timber piles. A large cut in the seawall was made below the invert of the outfall pipe to accommodate the eschewed alignment. The large outfall pipe was then supported by several pin pile sand concrete foundation. Ultimately a new reinforced concrete collar was placed around the pipe to secure the location and retain backfill.
As a result of the seawall age, limited cap elevation, number and size of existing outfalls, as well as an additional large outfall, a new seawall was proposed for the shoreline. Cummins Cederberg designed the new concrete seawall to meet the recent specified higher cap elevations associated with the increasing sea level rise. In addition, the seawall was designed with appropriate specifications to accommodate the new stormwater outfalls, and provide a similar level service life as the new stormwater system.