GSA FEDERAL OFFICE BUILDING 3
Total Site Remediation
Federal Office Building (FOB) 3, owned by GSA, was formerly occupied by U.S. Census Bureau workers. Skanska, GSA’s general contractor, constructed new buildings on the site to replace the outdated, former headquarters structures. Removal of all asbestos containing material consisting of VAT/Mastic, drywall, duct installation, windows and caulk, roof flashing, transite, pipe insulation. Complete interior demolition, complete structural demolition, processing and crushing of 90k tons of concrete, soil and erosion control, asphalt removal. NorthStar (formerly NCM) created a waste diversion/recycling plan, segregated waste materials, tracked weights for LEED calculations and obtained over 97% recycling total. NorthStar self-performed asbestos abatement, interior and structural demolition, sorted wastes for recycling, backfilled, graded, compacted and seeded entire site of about 10 acres. Project crews installed and maintained all stormwater protection such as super silt fence, drain inlet protection and vegetation of stockpiled materials. Potential dust from demolition was a sensitive issue. A reinforced poly barrier was installed around the side of a multi-story parking lot which kept dust from GSA vehicles in new building and the owner was very satisfied.
Sequencing was critical to abate ACM from several wings, generate a buffer zone, follow behind with interior demolition, then follow behind with structural demolition and backfill operations. This “piggy-back” sequencing greatly assisted with overall schedule. During sitework, several sinkholes were identified from unknown moisture in the ground, soil was excavated, crushed material/clean soil backfilled and compacted properly with immediate response to allow site improvements to continue.
Masonry and concrete material from the superstructure was segregated and crushed on site to a 3″ minus and used for backfill instead of bringing in new backfill or experiencing the costs of disposal of the concrete materials. Waivers were obtained through the state asbestos regulatory agency to containerize select ACM in sealed dumpsters, dispose of that ACM burrito wrapped and expedite the removal process as much as possible. Multiple dumpsters, sea containers and trucks were utilized to expedite transportation and disposal. Dust samples were collected and analyzed to monitor proper dust exposure. A third party geoservices firm was utilized to collect proctor samples of soil/crushed material stockpiles used for backfill. Field density measurements and reporting was conducted throughout backfill and compaction operations.
The Schedule began slowly due to a subcontractor who was eventually removed. A recovery schedule was implemented, met and the customer was satisfied. The Project Manager was stationed on site the entire project along with multiple supervisors and foremen for abatement and demolition tasks. The PM was readily available for prompt communication and could troubleshoot site activities making field decisions immediately. Project schedules were reviewed weekly and discussed with site construction management to forecast as quickly as possible.