Maricopa County officials say that after years of studying options for the facility, it became clear that renovating it for use as a correction facility would have been more expensive than building new jails. Complete demolition of the facility was estimated at approximately $10 million. Combined with a need to unify the county attorney’s offices—currently scattered across downtown Phoenix—the county ultimately decided to strip the facility to its structural bones and pursue the office reinvention.

“This would have been a wasted asset,” says Joy Rich, Maricopa County manager. “It would have cost $10 million to tear this building down, we would have disrupted downtown to do that and we would have had the additional cost of building office space at this location.”

Demolition began in November 2017 and is expected to be completed in stages through the summer as build-back begins incrementally. Project completion is expected in late 2019 or early 2020. DLR Group is providing engineering and architectural design for the project, which is being led by general contractor Layton Construction.

When complete, 225 W. Madison will be an open space with sunlight filtering through each floor thanks, in large part, to expanded windows, translucent transom and side windows and a 2-ft-high subfloor that will contain power, information technology and climate control systems, among other elements.

But before the energy efficient office space could be constructed, the interior components of the jail had to be demolished and removed. The building housed more than 1,100 prisoners from 1985 to 2005 in one- or two-person cells featuring interior cast-in-place walls 8 in. thick. The construction team initially considered demolition drop zones on the building’s exterior but eventually found a way to keep demolition within the structure.

The solution was turning the central stairwell into a central drop zone for construction debris. Outer stairwells were repurposed into pick points. Crews covered drop areas on each floor with half-inch steel plate to protect the in-place concrete. On the ground floor, contractors also positioned steel plate over plywood for further protection. Structural supports in the underground parking lot were enhanced with additional tube and coupler shoring to handle the extreme weight of debris and machinery.

“That ended up being a great plan because it helped with noise and dust handling,” says Bob Hendrickson, senior superintendent, Layton Construction.

Remote-Controlled Demolition

Crews are using Brokk remote-controlled demolition machines to perform much of the work. Hendrickson says the team is using four sizes of Brokk excavators, with weights ranging from 2,000 lb to 11,000 lb.

As the excavation/demolition robots started demolishing the jail’s interior, managing debris proved paramount.

“The real bottleneck for the project was debris handling,” says Darcy Gray, Layton construction manager.

Fortunately for the construction team, creating and using a debris chute in the central stairwell was an efficient process and managing the trucks was executed primarily by using the sally port formerly used to transport inmates. On average, contractors fill seven trucks with debris each day.

“Even the interior walls are largely cast-in-place or fully grouted concrete masonry units,” Hendrickson says. “So there is just a lot of volume and a lot of debris.”

Demolition is not as straightforward as setting up the robots and hauling it out, however. The presence of non-friable asbestos and lead paint mandated remediation. Further, the design of the jail made it difficult for remediation crews to access certain areas.  Crews return to identical locations after initial demolition is completed to remediate areas inaccessible in the original jail configuration. Consequently, demolition subcontractor Dickens Quality Demolition and remediation subcontractor Spray Systems work together in a staggered fashion.

“One of the advantages of how Layton is phasing demolition from floor to floor, is that by June or July, they should be able to mobilize for build-back,” says Tom Roth, architect, DLR Group.

Cleaner, Brighter, Cooler

Once internal demolition is complete on a floor, workers begin cutting out the 6-in. windows that were the hallmark of the jail to make way for the new ribbon windows that will bring sunlight into the facility. Hendrickson says the new openings were cut to make about a 32-in. opening. The old windows and wall sections are retrieved after cutting and sent to waste handling via the central debris chute.

Roth says since most of the building’s load is supported by the cast-in-place concrete exterior walls, weighing design needs with structural forces was a balancing act. He adds that although preconstruction and in-process investigations revealed that the ribbon windows could be of varied heights, each variation forced another concession due to shear and load concerns, diluting design.

“We could have cut even deeper because the spandrel was lower. But from an architectural standpoint, we would be better served by keeping them consistent,” Roth says. “From a design perspective, we had to be very protective of what we cut out to maintain building shear.”

Future cooling needs of the facility will be served by traditional chillers via NRG’s underground cooling loop in downtown Phoenix, which serves about 40 buildings. That portion of the project was completed in late 2017. Roth says the new facility has approximately 1,250 tons of cooling capacity.

The remodeled facility will be served by two NRG plate-and-frame heat exchangers along with four high-efficiency condensing, natural gas-fired boilers.

“Plate-and-frame heat exchangers are going to be awesome for this building,” Roth says, adding it is a massive upgrade over the evaporative cooling system used in the jail.

Once build-back begins this summer, the facility will get all new plumbing and electrical elements. One of the most notable construction challenges during build-back will be the creation of a secured bridge from the building to the adjacent courts facility.