The north parking garage at Laketown Wharf, located at 9902 South Thomas Drive in Panama City Beach, Florida, was built in 2008 and utilizes reinforced concrete construction. The walls utilized conventionally reinforced precast concrete panels, while the elevated slabs utilized precast concrete double-tee (DT) beams to provide a driving surface. There is a pool located on the top level of the garage. A leaking floor drain in the pool equipment room on the top level of the garage and leaking conduits exposed the lower levels to the chlorinated pool water.
In addition, there were visible indications that the leak extended from level 8 down to level 2 of the garage, resulting in a chloride exposure of reinforced beams, columns, precast DT beams, and walls comprised of precast panels on these floors. The exposed concrete elements consisted of. Emerald View Association Management reached out to VCS Engineering Inc. to assess the extent of corrosion in the affected areas of the garage and to provide recommendations for corrosion mitigation.
VCS performed the corrosion potential survey and calculated corrosion potential delta values on the stems of the DT beams, walls, and columns on levels L8 through L2. It was determined that most of the tested areas in these elements had active corrosion.
Chloride concentration testing indicated chlorides were above the corrosion initiation threshold at rebar depth in 10 out of 20 locations (50%). Carbonation was not contributing to reinforcement corrosion.
VCS recommended installing Type 2 drilled galvanic anodes in the areas of active corrosion or applying sprayed zinc in the areas affected by the leaks and on the first and last 10ft. of the DT beams.