The work includes the construction of an approximately 720 foot earth channel between the end of an existing concrete box culvert and Kennedy Avenue, including demolition of miscellaneous features, clearing and grubbing, constructing new steel channel walls and anchorages adjacent to the existing box culvert, earthwork for the channel, deep soil mixing, and stone channel base material. An existing 90-inch diameter sanitary effluent outfall main is to be relocated, while remaining active; including the use of pile supported temporary and permanent piping. The work also includes construction vibration monitoring and control, site drainage, pavements, fencing, pile tests and incidental related work. The project work occurs in three general phases. The objective of Phase 1, Exploratory Excavation and Preparation, is to locate and document the existing outfall main so that a new relocated main can be accurately constructed. Work in this phase includes: clearing and grubbing along with degrading portions of the site; cutting off flows of surface water into the site by plugging the existing box culvert near one end of the work area and building an earthen berm near the other end; determining precise location and elevations of the existing outfall main; and installing a cofferdam and bracing system along with protective measures adjacent to the outfall main. In Phase 2, Sanitary Outfall Main Relocation, the objective is to construct a new main along an alignment below the new channel while keeping effluent flows continuous. Work in this phase includes: providing a temporary bypass main including taps, line stopping and diverting flows to the bypass main; demolishing portions of the existing main and constructing a permanent main following the new profile below the channel; deep soil mixing and backfilling of areas adjacent to the permanent main; diverting flows to the permanent main; and removal of the bypass main. Phase 3, Slope Stabilization and Finishing, involves performing the remaining work activities for a complete and functional project. Work in this phase includes: additional deep soil mixing for stabilization of the new channel; providing the wing walls and anchorage system at the end of the existing box culvert; constructing the new earthen channel with stone channel base material; removing portions of the cofferdam; constructing local drainage features, pavements, and fencing; removing the temporary earth berm and box culvert plug; and miscellaneous construction and closeout activities.
Developed complete bid estimate (AACE Class 1 Estimate) for general contractor.