Gwinnett County Police Annex

Use of CarbonCast® High Performance Insulated Wall Panels was instrumental on a new, 45,000 sq. ft. police headquarters constructed for “hardened first responders” according to Federal Emergency Management Agency (FEMA) 361 guidelines.

This single-story annex in Gwinnett County, Ga. houses a fully equipped, state of the art E-911 communications center, emergency operations and data backup centers as part of a $16 million dollar project completed in the fall 2009. Challenges included its location in a designated Wind Zone III, a tight construction schedule and aesthetics.

Meeting the demands of FEMA 361

FEMA’s 361 guidelines mandate the building must maintain effective, uninterrupted communication, control and assistance in the wake of natural disasters or other regional crises.

The great strength of the Gwinnett’s new steel-framed facility is derived from its 150 CarbonCast High Performance Wall Panels with C-GRID® carbon fiber shear trusses for a fully structurally composite panel with relatively low thermal conductivity. CarbonCast High Performance Wall Panels consist of interior and exterior concrete wythes with continuous insulation (c.i.) between the C-GRID. Truss grids cut on a 45-degree angle, structurally join inside and outside wythes so the facility’s walls and roof withstand corresponding design loads for a total exposed area of 12,335 sq. ft.

Four times stronger than steel by weight, non-corrosive carbon fiber is not subject to thermal bridging. Three-inch thick extruded polystyrene was placed as continuous insulation throughout the panels except at connections where thickness is an inch and a half. Overall insulating value for the panels is R-10, which exceeds the code requirement listed at R-5.7.

Thinking outside the bunker

In the past, structural strength demands of buildings like this limited their visual appeal. In this case, the architectural potential of CarbonCast High Performance Wall Panels granted exceptional results.

Two different exterior faces were created for the panels. A sandstone-color concrete with stacked-stone ashlar block formliner and medium sandblast was applied to the lower part of the precast wall. Higher up, the panels display buff-colored sandblasted concrete with 1” reveals at foot intervals. Precast coping was also applied to the tops of the CMU walls, pillars for an ornamental fence and the entrance sign/monument.

The inherent design flexibility of CarbonCast High Performance Wall Panels complemented the adjacent existing police headquarters in color, form, scale and sense of entry.

Getting the job done

Construction, which began on July 7, was quick relative to other conventional on-site methods and was completed by October 31, 2009.

The panels were manufactured by neighboring Metromont Corporation, a premier precast concrete company headquartered in Greenville, S.C., at its plant in Hiram, Ga.

“The construction time for the precast was approximately three weeks, which really helped expedite the entire schedule,” said Angela San Martin, regional sales representative for Metromont.

Overall, the new building incorporates many technological advances beyond superior building materials. The annex, which occupies an 8.9-acre site, employs design elements that emphasize natural light, stress mitigation, openness, expandability and public interaction. Functionally, the center represents the pinnacle of current development in emergency and law-enforcement communications.