Officials at the Market Basket Supermarket chain have found that using a precast concrete façade on some of their new stores provides a cost-effective and quickly constructed design in the right circumstances. A new 80,000-square-foot store in Rochester, New Hampshire, is the most recent addition to the line.
The store features 61 CarbonCast High Performance insulated precast concrete wall panels fabricated by Strescon Limited. The panels consist of two concrete wythes separated by continuous insulation and connected by C-Grid brand shear trusses. For primary flexural reinforcement, prestressing strand or steel rebar is used in each wythe and in pilasters internal to the panel.
With low thermal conductivity, the trusses create insulating values up to R-37 depending on the thickness and type of foam insulation. In this project, the panels featured 5 inches of insulation sandwiched between 3-inch interior and exterior wythes of concrete.
Market Basket has used precast concrete panels on other stores, although the final design of each is based on a variety of factors including situational needs and location, explains Essa Ahmed, project architect at the architectural firm Prellwitz Chilinski Associates.
“The precast concrete panels helped save time and construction cost on this project,” he says. “When all of the penetrations are known and adaptations are not required, it’s an almost perfect solution for this type of project.” An as-cast form finish was provided for the panels.
The precaster supplied an 8-inch Strescore plank for the mezzanine area of the store, consisting of 46 pieces of 10-inch-wide planks, and was asked to provide pricing to include the insulated panels. “Many other products could not meet the schedule that was needed, and Strescon was able to come to the plate and provide a high-quality panel for a competitive price on their schedule,” says Tim Macdonald, project manager at Strescon. This was the first time Strescon had provided the company with its insulated panels, he notes.
“The precast process—building the system off-site, transporting components to the site and erecting them—saves labor, time, and money,” says Ahmed. “It also provides continuous insulation, which is a key contributor to meeting code requirements.”
The panels were erected for the back wall of the project, with a curtain-wall type storefront used across the front. The erection progressed on schedule with no disruptions, reports Tom Koistinen, project manager for Seppala Construction, the general contractor. “It went very smoothly, with nothing noteworthy about it,” he says. “Noteworthy aspects usually mean something went wrong, and everything went well.” The panels were erected in six days.
Both Seppala and Prellwitz Chilinski have designed and built other stores for Market Basket, including two using precast concrete panels. “The materials we use typically depend on the client’s needs and the architectural context of the town,” Ahmed explains. “But when it’s possible to use precast concrete, we will definitely go for the savings.”