Structure Evaluation Engineers, Inc. (SEE) was retained to evaluate the existing condition of the two-level post-tensioned parking garage with a total combined area of approximately 142,000 square feet, or with a capacity of approximately 420 car spaces. The parking garage was approximately 20 years old. The existing waterproofing had deteriorated severely, and it was no longer providing adequate protection for the post-tensioned concrete slab. Water was infiltrating into the lower level through failed expansion joints and construction joints. 

One post-tensioned tendon failed and spalled the concrete. However, upon exposing and reviewing tendons at four locations, we found out 25% of the tendons had failed due to corrosion at the construction (intermediate stressing) joints. SEE recommended a comprehensive repair program that included reviewing all post-tensioned tendons, removing the existing waterproofing membrane and installing a new membrane, removing and replacing all deteriorated expansion joints, and repairing concrete cracks and joints.

A total of 94 tendons were repaired or replaced. A new trenched drain was installed to improve surface drainage. Existing concrete approached aprons were removed and replaced. All expansion joints were removed and replaced with high-performance non-metallic expansion joints. Finally, a new heavy-duty vehicular waterproofing membrane was installed to protect the concrete slab from rainwater and de-icing salt. 

SEE provided structural evaluation and condition assessment, prepared the repaired bid documents for the parking garage, assisted the owner with bidding the project, and oversaw the construction.