Many communities are turning to precast concrete as a way to create a safer correctional facility in a timely manner.
By Mark Crawford
When Herkimer County in New York decided to replace its jail, which was built in 1978, county officials had a lot of steps to take. First the county acquired the property for the new correctional facility in February 2018. Then, the New York State Commission of Correction approved plans for the jail that summer.
It was during the planning and design stages that precast concrete was selected as the building material for the cells and several other structures. Precast concrete jail cells are chosen for many correctional housing facilities because precast provides a higher level of security and design flexibility. Bunks, toilets and other amenities are fixed to the cells with tamperproof bolts, and the quality and design flexibility. The quality of construction can be closely monitored because cells are manufactured in a quality-controlled environment. They are also easy to install, which saves time and money.
Gilbane Building Company of Syracuse, N.Y., was selected as the general contractor and PennStress of Roaring Springs, Pa., was chosen as the precast manufacturer.
“Precast was chosen because of its uniformity, ease and quickness of construction, and lower cost,” said Herkimer County Legislator Vincent J. Bono. “Precast was also recommended by the architect and other counties we contacted.”
The speed of installation was also important as the new jail should be fully operational by September 2020.
“Precast is a preferred building material for correctional facilities,” added Russell Dickson, vice president of engineering for PennStress. “One reason is that the consistent geometry between the pieces lends well to precast, but it also allows for more work to be completed outside of the secure prison area by the modular units arriving to the site, fully fitted out and ready to be hooked into the site utilities. Precast also decreases the time of construction and minimizes interruption at the facility.”
Ease of installation
Precast components for the jail included cell modules, balcony slabs and plenums. Cell modules are stacked forming a lower level and upper level, with balcony slabs in between. The ceilings of the lower cell modules serve as floor slabs for the upper cell modules.
“The plenums on top of the upper modules serve as attic spaces to provide mechanical, electrical and plumbing feeds to each individual cell,” said Mark AuClair, project manager for Gilbane Building Company.
A total of 128 70-square-foot precast structures will be installed. Each structure is a two-cell unit, called a double module. Modules consist of external walls on all sides and a roof slab cast monolithically. Openings for cell doors, embeds and amenities were set at the time of casting. Exterior walls exposed to the weather were insulated. Electrical ducts, plumbing and other mechanical ducts were embedded in the concrete and placed through the triangular chases shared with the adjacent cells. The chase allows the utilities to reach the cells easily. Access to the chase is provided with a full-height door.
Balcony slabs placed between the upper and lower cell modules serve as corridors and places for lighting fixtures for the lower level. Railings installed on the slabs prevent inmates from falling and are typically tapered to reduce the structural weight.
This job provided a first for Dickson, building concrete furniture in the form of cell beds. The beds consist of a 4-inch-thick reinforced concrete slab extending from the common wall to the exterior wall and tying into the rear wall.
“The day after the module was removed from the form, we installed a pre-made wood form to cast the bunk and used a wheelbarrow to transport concrete into the cell and up a small ramp to be able to pour the concrete into the form,” said Dickson. “Each bed took about six cubic feet of concrete. The forms were removed the next day and moved to the next module that just came out of the module form.
Transportation and erection
Construction at the site has already started, and several modules have been delivered. All lower-level modules, which have a 5-foot balcony extending out over the front wall, are more than 15 feet wide and required an escort. The second-level modules were spun 90 degrees so they did not require an escort.
At the job site, construction cranes move the cell modules directly from the trucks to designated locations. The mat foundation is also used as the ground floor slab for the prison housing facility. Dowels inserted into pre-bored holes in the mat foundation fix the cell modules in place.
A win for all parties
The project is proceeding on schedule and should be operational by fall of 2020. With the project well underway, all parties are pleased with the design.
“Precast concrete cells are gaining in popularity due to their security, structural durability, short construction period, quality and workmanship,” said AuClair. “The structural design is not complicated and can be mastered in a short period. Modular precast construction is a good way to control material and labor costs and shorten build time.”
Dickson agreed, noting the efficiencies of the manufacturing process.
“Precast modular construction is by far the best approach for correctional types of buildings, as long as symmetry and repetitive pieces are kept in check,” added Dickson.
Another huge benefit of this type construction, noted Dickson, is the beneficial effect of concrete’s thermal mass on the building’s heating/cooling system. Precast concrete has a higher thermal mass because a lot of heat energy is required to change its temperature, allowing the material to keep the building’s interior cool in the summer and warm in the winter. Thanks to its ability to store heat, precast flattens daily interior temperature differentials, reducing energy demands on a building’s HVAC system.
“Once the building is up to temperature, it remains at that temperature due to this large mass,” said Dickson. “This type of construction also allows for continuous insulation, which again helps with the efficiency of the overall building.”
For other counties that are considering new correctional facilities, Bono highly recommends using precast concrete, due to cost savings, quicker construction time, easier maintenance and uniformity in the finished product.
Mark Crawford is a Madison, Wis.-based freelance writer who specializes in science, technology and manufacturing.