The West Refrigeration Plant (WRP) is a four-level reinforced concrete structure located on the grounds of the US Capitol Power Plant, constructed in the late 1970s. Many buildings located in the historic Capitol Hill area of Washington D.C. receive chilled water service from the WRP.
In 2012, WDP performed a concrete condition assessment survey due to observed exposed reinforcing steel and concrete spalling. The survey identified and quantified delaminating and spalling concrete, corrosion of reinforcing steel and abandoned precast anchors, cracking on vertical and horizontal surfaces, including select columns. A series of nondestructive and destructive testing was performed to obtain material properties and assist in identifying the damage mechanisms. Based on the condition assessment, the engineer developed a concrete repair and maintenance program intended to extend the WRP’s service life by 50 years.
The repair program included concrete delamination and spall repair (with galvanic corrosion protection), removal of abandoned precast anchor points and repairs to remaining precast anchors, sealing of cracks, select column reconstruction, preventive galvanic protection for select members, and application of water repellant and waterproof coatings. Most of the required concrete repair could not be performed while the plant was in operation. Demand resulted in a very limited window of opportunity when operations could be suspended, allowing the repair work to proceed. Preparation, cooperation, and communication between all parties involved was vital for this project’s success.
Time restraints, due to limited shut down period available to the plant, required careful planning and efficient performance of the concrete repairs. With the extensive cooperation and oversight by the Owner, construction management team, design engineers and repair contractors, a timely restoration was completed in a manner that not only helped increase the service life of the WRP, but also enhanced the buildings appearance. In a span of only 12 weeks, a total of nearly 2,000 square feet of concrete repair, over 5,000 bar ends/form ties, over 2,000 linear feet of crack rout and seal, over 1,000 linear feet of crack injection, over 45,000 square feet of coatings and various other repairs were completed by the team. There were significant challenges to this project due to access difficulties, time constraints, and differing conditions, but collaboration between the Owner, project management team, contractor, suppliers, and engineers all resulted in a successful project. To date, all repairs are performing well.
ServicesForensic Structural Engineering
John M. Grill, P.E., Associate, Manassas Headquarters Division Manager
Affiliated Engineers, Inc. on behalf of Architect of the Capitol