Independence Excavating Teams with Clark Construction in downtown Washington, D.C.

Independence Excavating is subcontracted to Clark Construction to perform the demolition of the existing building and excavation to the foundations of the new office building to be constructed at 400 6th Street in downtown Washington, DC.

The first phase of the project consists of installing erosion control measures and demolishing the 7-story concrete frame building. Skid steers will be crane lifted onto each floor of the building to assist with the removal of all internal nonstructural elements of the building. After the internal elements are removed, a high reach excavator will demolish the building structure. This work will be completed during the night-shift to decrease the impact on the public in this business district. Special precautions such as protective netting and plate barriers need to be installed prior to demolition as the adjacent buildings are within 15' of the building Independence Excavating is demolishing. During the day-shift, demolished material will be processed and loaded into disposal containers to be taken to a recycling facility in accordance with the project's LEED requirements.

The second phase of construction starts with the installation of a bench for the beam and lagging shoring operation. When demolition is complete there will be a 15' deep hole where the bottom two parking levels that were below street level used to be. In order to provide a bench at existing street level for the shoring contractors drilling machine to sit, Independence Excavating will build a bench using the processed concrete from the demolished building. After the bench is built, the shoring contractor will install the beams for the beam and lagging retaining wall.

Independence Excavating will then coordinate the 30,000 CY of excavation with the installation of the lagging to provide for a safe excavation to a depth 20'lower than the current buildings foundation, or approximately 35' below street level. Portions of the excavation contain petroleum-contaminated soil. Geotechnical inspectors will be on-site full time during excavation to measure levels of contamination and direct Independence Excavating if the soil needs to be transported to a normal waste facility or a specialized facility for disposing of contaminated soils.

During the excavation, Independence Excavating will also be responsible for connecting the water, sewer, and storm utilities to the existing city lines. Independence Excavating will obtain all permits and set up the traffic control to connect the utility lines in the street.

Construction of the new building at 400 6th Street is scheduled for completion in the summer of 2015. Independence Excavating looks forward to contributing to Clark Construction's successful completion of this project along with future opportunities to work with Clark Construction and other new partners in our expanding Mid Atlantic division.