Award of Merit: Strengthening Category
Strengthening of 1230 Washington Street Parking Garage
Submitted by Simpson Gumpertz & Heger Inc.
Newton Investors Ltd., Partnership
Simpson Gumpertz &
North Hampton, New Hampshire
DeNeef Construction Chemicals, Inc.
In the last several years, fiber-reinforced polymer (FRP) composite systems emerged as a powerful tool in concrete strengthening applications. Large-scale use of these systems, particularly near-surface-mounted (NSM) carbon FRP (CFRP) bars, however, remains relatively uncommon. The strengthening work at the 1230 Washington Street Garage in Newton, MA, is a clear-cut example of the innovative thinking, technological savvy, and expertise in materials and engineering techniques that using NSM CFRP systems demand. The garage exhibited numerous signs of distress, such as excessive deflections of the decks at bay midspans and extensive concrete deterioration, cracking, and spalling.
The project began with a condition survey of the garage, structural analysis of the decks, load tests of decks with and without prototype strengthening repairs, and design of the strengthening system with NSM CFRP bars.
To review the performance of CFRP systems, the evaluation of the structure included a load-testing program of garage decks with and without the NSM system in place. The goal of the testing program was to define a satisfactory safety factor against collapse in case CFRP is lost due to exposure to fire and to demonstrate superior performance of a strengthened structure—all the while ensuring that any solution would meet the client’s budget and maintenance expectations. This project featured comprehensive concrete repairs and introduced a high-performance CFRP strengthening system, featuring 14,000 linear feet (4267 m) of CFRP bars that resulted in a durable structural solution and an extended life expectancy of the garage.