Award of Merit: Parking Structures Category
Garage Repairs Building N4 - Albany Street Garage
Submitted by Contracting Specialists Incorporated
Massachusetts Institute of Technology
Simpson Gumpertz & Heger
Contracting Specialists Incorporated
J-Mac Building Specialties
The Albany Street Garage is 135,000 ft2 (12,541.9 m2), with nine half-levels of precast double tees supported by cast-in-place columns and beams. The roof level and easternmost portion of the garage is cast-in-place with an unbonded post-tensioning reinforcement system. The primary route when exiting the structure is through the four semicircular ramps at the east end of the garage. The semicircular ramps are cantilevered off the east end and primarily supported by a bonded post-tensioning system.
The typical concrete deterioration was caused by water exposure to the unprotected vertical, underside, and horizontal concrete surfaces. During Phase 1 work on the semicircular ramp, as the cleanup crew made their way down a large demolished area on the third level, they noticed that the bonded post-tensioned (PT) cables were deteriorated to the point of failure. These PT cables ran perpendicular to the direction of the ramp and amounted to approximately two-thirds of all the PT cables on this level. The work was immediately stopped, the owner and engineer were called, and it was determined that 18 emergency shoring towers were immediately required to shore the third-level ramp down to grade level.
The majority of the project funding and labor was redistributed from the main garage to the replacement of the PT system on the third level of the semicircular ramp. The most challenging aspect was completing the PT replacement work, grouting the PT ducts, pouring the concrete to embed the PT ducts, curing the concrete, and applying the urethane coating to the semicircular ramps. The ramp PT replacement, ramp coating, and 75% of the original garage repairs were completed by the original project completion date.