The Transit Center resolves the complex challenges of interrelated University of Iowa entities. Located in Iowa City, the University of Iowa is the state’s flagship public research university. Its urban, 1,700 acre campus on the banks of the Iowa River, is best known for programs in health care, law, and the fine arts, with programs ranking among the top 25 nationally.
The University of Iowa Hospitals and Clinics (UIHC) is a 761-bed public teaching hospital and level 1 trauma center. It is a critical component of University of Iowa Health Care, a partnership that includes the University of Iowa Roy J. and Lucille A. Carver College of Medicine and the University of Iowa Physicians group practice. UIHC and its adjacent Stead Family Children’s Hospital are ranked nationally by U.S. News and World Report in eleven specialties.
The University’s Parking and Transportation Department provides access, mobility, and transportation services to faculty, staff, students, patients, and visitors both on campus and among a network of satellite facilities. The department consists of five operating units; Cambus, Commuter Programs, Fleet Services, Facility Operations, and Parking Services. These units collaborate to provide a broad range of parking and transportation options and services.
In the near future, an adaptation to the transit center’s upper level will also provide direct, elevated access to Kinnick Stadium, where a North End Zone Expansion by Neumann Monson is currently under construction.
The project’s impetus was a large expansion of the University Hospital that required relocation of the existing transit hub and Parking and Transportation Department. The program size, combined with the lack of available buildable land, seemed to require a separation of hub and offices, despite the major inefficiencies that such a de-coupling would have entailed.
The building would be an integral cog in the University’s free mass-transit system, with roughly 4,000 people passing through each day. Many employees and students would either arrive on the bus directly from their neighborhoods or carpool to outlying commuter lots before riding a bus to the central hospital. As constructed, the transit hub serves ten transit routes, 458 bus departures, and over 4,000 riders every day. The skywalk allows both transit users and thousands of parkers to bypass a dangerous intersection. Of the transit system’s 4.5 million rides it provides each year, over 1 million of those stop at this transit hub.
Iowa City, Iowa
2,640 SF (renovated)
2014 AIA Iowa Sustainable Design Award
2013 AIA Iowa Design Award
2013 AIA Central States Design Award
Where We Started
Two guiding parameters informed the transit building’s composition. The first was the stacking of program elements initially planned to be sited separately. The second was the navigation of a densely knotted underground utilities web.
First, the team confirmed the viability of collocated facilities if the office component was cantilevered, and the resulting overhang was used to shelter bus loading and unloading. That direct, simple solution engendered a compelling form and allowed the project to tread lightly: the building’s footprint takes up less than one-third of the two-story structure’s gross area.
The unexpected space to spare allowed for a holistic review of the site. Away from the underground utilities, surface parking to the north of the building could incorporate an underground storm water retention system sized to accommodate a 100-year rain event. Native plantings should replace any hardscape not dedicated to pedestrian or vehicle traffic. Finally, amidst the utilities, roadways, and walkways, we saw the raised walkway’s requisite long spans as an opportunity to invest our efforts in developing an elegant tectonic assembly.
What We Did
The building’s first floor accommodates bus interchange functions. Paired escalators and a grand stair lead to offices and the skywalk above. The glazed skywalk, transit hub, and connecting elevator maximize views and visibility. Rain screen cladding and a glazed curtain wall with operable exterior sunshades clad the remainder of the building. At grade level, durable stained ipe wood responds to the surrounding buildings’ brown brick. Above, fiber cement panels extend beyond the offices to cradle the skywalk’s angled connection. The fiber cement system was selected for its durability, the economy of its fabrication and installation, and its ability to variegate color tones to visually mitigate the overhang’s dramatic scale.
Due to the nearly ubiquitous underground utilities, only six 3’-0” diameter caissons support the skywalk’s length. Large roof beams span between forked piers anchored in each caisson. The thin floor assembly is suspended from stainless steel rods at 5’-0” on center. Completing the shell are insulated, structural glass sidewalls supported with clamp plates located at the bottom of the roof beams and, at handrail height, by plates cantilevered from the floor.
How it Works
The two distinct components – terminal building and skywalk – are designed with environmental control systems appropriate to their use. In the second level offices, chilled beams and radiant slabs harness water from the nearby university chiller plant for heating and cooling. The skywalk’s traffic intensity inhibits humidity control, so fan coil units provide cooling. Radiant ceiling panels provide heat and a slight cooling factor, gaining efficiency from the project’s proximity to the nearby chiller facility.
The building’s east-west orientation and full-height glazed curtainwall maximize daylight. Low-e coated, argon-filled glazing provides insulation. A ceramic frit pattern reflects solar radiation. High-performance glazing minimizes the cooling requirements in the skywalk as well. The offices’ south facade utilizes operable exterior screens to control sunlight year-round. A sun-tracking device linked to the screens automatically deploys or retracts them based on sky conditions. The screens significantly reduce cooling loads. The lower mechanical system costs offset the screens’ initial expense. Occupancy and daylight sensors allow light fixtures to remain off when daylighting light levels are sufficient.
Minimizing the need for applied finishes reduces material use and heightens indoor air quality. Concrete serves as the typical floor finish except where acoustic concerns exist, in which case carpet was selected for its recyclability and high recycled content. Low-VOC paints meet LEED standards for indoor environmental quality. Though this project did not pursue LEED certification, the contractor followed a rigorous construction waste management plan.