Summer Street Parking Garage
In expanding the Park Square West residential development in Stamford, Connecticut, developers knew they would need additional parking space. Rather than create a second parking facility, they added onto the existing precast concrete structure by removing some end spandrels and extending the space. That resulted in an additional 110,000 square feet of space on five levels for 229 spaces.
The complex features residential units in the heart of the downtown area, near restaurants, theater, shopping, and a brewery as well as near the transportation center. With a new residential building being created, adding parking was a must. The construction team worked out a plan to expand the existing facility rather than build a new one requiring new approaches and entrances.
The addition has five stories, one more than the existing facility built in 2005, with no ramping inside except for a speed ramp between the fourth-level extension and the new fifth level. The building consists of a total precast concrete structure, comprising double tees, girders, columns, shear walls, lite walls, spandrels, stairs, slabs, and wall panels. The precast concrete components were fabricated by Blakeslee Prestress, who also provided the components and erected the original structure.
“Having the original drawings made the process move smoother,” says Peter Bertolini, field operations manager for Blakeslee. “We could have done it without them, as we’ve done both vertical and horizontal expansions of existing projects before. But it aided the shop drawings process, particularly where we modified and added onto the original stair/elevator tower.”
The addition had not been planned when the original structure was built, so the designers had to meet the challenge of modifying the existing structure to meet the additional needs. Spandrels and nonload-bearing wall panels were removed on the end to an additional 60-foot bay could be placed across the one end.
One challenge that proved more difficult was matching the original finish on the spandrels and walls, which has an exposed-aggregate finish. The aggregate used on the original structure was no longer being quarried, he explains. “We worked with our original supplier, who found a small amount of the material and remobilized the equipment to quarry some more for the project.” The effort paid off, as the finish matched the original almost exactly.
Another challenge came with extending the existing stair/elevator tower to the new fifth floor. The existing tower had to remain open while the stair tower was modified and new components were installed to extend it another level. “We had to coordinate all of the demolition, modifications to the existing tower, and installation of the new components while maintaining public access to the existing garage.” One additional stair/elevator tower was built at the new corners of the building.
The limited access within the site, which is surrounded by buildings and city streets as well as an existing roadway under the parking structure, added further challenges. The new structure, consisting of 347 precast concrete components, was erected in less than one month, with crews working overtime to accelerate the schedule so the road through the site could be reopened.
Timeline: Start Precast Erection - September 16, 2014
Complete Precast Erection - October 14, 2014
(229-space parking structure addition to existing building)
Structural Precast Elements:
• 154 Double Tees
• 53 Wall Panels
• 50 Spandrels
• 37 Shear Walls
• 17 Columns
• 14 Stairs
• 8 Girders & L-Beams
• 8 Slabs
• 6 Lite Walls