“Many factors went into moving forward with building the new Des Moines U.S. Courthouse,” says Matthew Meeks, Lead Project Manager for the General Services Administration (GSA). “The investment allows GSA to leverage the resources of our agency, and the federal government, to foster economic development in local communities across the country.”
Congress funded construction of the new 230,000-square-foot courthouse in 2016. It contains nine courtrooms and 13 chambers, and supporting spaces for the Clerk of Courts, the U.S. Attorney’s Office trial-prep suite, the U.S. Marshalls Service office and detention spaces. The six-story structure also has a full basement with secure parking and a large mechanical penthouse on the roof, Meeks reports. It is located on the Des Moines Riverwalk along the Des Moines River.
The Des Moines Courthouse is a part of GSA’s Operational Excellence Program, which evaluates the maintenance and serviceability of the building over the duration of the building’s expected lifespan. Examples include specifying light fixtures that require expensive and hard to find replacement bulbs or making sure equipment that needs regular servicing is easy and safe to access. The efforts are expected to yield environmentally and fiscally responsible results far into the future.
Mack Scogin Merrill Elam Architects of Atlanta serves as the design architect and Neumann Monson Architects in Des Moines the architect of record.
The GSA conducted a two-part formal selection process for the construction manager as contractor contract, considering several factors including local knowledge, reputation and experience on past GSA projects. The contractor works with GSA and the design team with constructability reviews and cost-estimating.
“With the GSA being one of the world’s largest property management groups, our expertise in maximizing building operational efficiencies was especially relevant for this project,” says Brad Thomason, Senior Project Executive with Ryan Companies, which had built the U.S. Courthouse in Cedar Rapids, Iowa. “Our work with the GSA not only highlights our deep expertise in construction, but also in working with partners in all industries and market sectors, both public and private, across the United States.”
Ryan Companies suggested a “phased procurement process which accelerated the start of construction based on different design deliverables developed collaboratively with the design team. This alternative delivery method allowed construction to begin roughly 11 months sooner than originally planned and inadvertently assisted in avoiding some of the material escalation and procurement issues created by the pandemic,” Thomason says.
The entire building was 3D modeled and drew on information from pre-pour drone scans of each concrete deck in the building.
“The phased delivery strategy allowed construction to start sooner than planned and helped avoid any catastrophic impacts from the pandemic,” Thomason says. “Ryan Companies’ safety protocols helped prevent any significant COVID outbreaks as the job remained active throughout the entire pandemic.”
The GSA monitored soils during excavation, as the site had contained previous buildings, including a Coliseum and later a YMCA. Some naturally occurring arsenic was found and eliminated.
“Underground foundations and footings from both buildings, and many others, were encountered and removed to provide a ‘clean’ site for new construction,” Thomason reports.
The project required 236 auger grout cast piles to bedrock support the building. They reach to a depth of 60 feet, depending on the subsoil characteristics.
Unknown at the time GSA purchased the property, a historic storm sewer bisects the site. That necessitated a structural system that would span the brick structure.
“Downtown Des Moines has a unique feature called Bird’s Run Storm Sewer,” adds Thomason. “It is a historic storm sewer, which captures a significant amount of drainage run-off from the downtown watershed and directs it to the Des Moines River. This 8-foot by 8-foot brick barrel vault required foundation transfer beams at the basement level of the building to retain it in its active state.”
Ryan Companies self-performed the cast-in-place concrete for the structure, using a reinforced pan system. Crews topped off the building in July 2021.
“Rebar, floor sleeves, and floor openings were verified multiple times for accuracy prior to placing concrete,” Thomason says. “This saved on labor for quality assurance and quality control checks as well as being much safer than trying to walk around the deck prior to concrete being in place.”
Architectural precast concrete panels and a glass curtain wall clad the new courthouse.
“This project achieves a major part of the administration’s sustainability goals,” Meeks says. “It will be an all-electric, energy-efficient federal courthouse that features a highly reflective cool roof, insulated windows, and LED lighting. All of those measures help reduce the building’s carbon footprint.”
The building features electric heat, resulting in lower costs, because of wind energy generated in the area. Other sustainable features include daylight harvesting and occupancy sensors. Site stormwater drainage is directed to bioswales or drains and then into on-site underground detention structures. The exterior insulation is closed cell spray foam, which also acts as a vapor barrier, Thomason says.
The building also has natural gas available on site for utility redundancy on extreme cold weather days, Meeks reports. It also features highly insulated exterior skin, including glazing, precast walls and roof.
Substantial completion is scheduled for summer 2023. It will save the country millions in rental payments for the currently leased court spaces.
Thomason praised the project team’s “collaborative relationship throughout the entire process of design and construction.”
Photos courtesy of Ryan Companies