City of Austin Permitting and Development Center

The City of Austin Permitting and Development Center (PDC) is a striking campus designed to attract, retain, and inspire top talent, as well as serve the citizens of Austin more effectively and conveniently. Centrally located on the former Highland Mall site, the campus is energetic, walkable, and transit-friendly. Walter P Moore provided structural engineering and sustainability consulting for the building.

Sustainability was a key driver of the project. Our team conducted a Whole Building Lifecycle Assessment (WBLCA) to evaluate and minimize the environmental impacts of the project’s structural system. Early-stage LCA studies showed that more than 75% of the embodied carbon of the structure and enclosure was due to the concrete framing. These studies, and the design team’s understanding that portland cement—the binder used in concrete—is responsible for the majority of concrete’s embodied carbon, led to an aggressive approach to cement minimization. In addition to optimizing the use of cement and supplementary cementing materials, we found that we could thin the floors slabs by 3/8" without compromising the structural design or fire rating.

The city and designers wanted to create a slender, 500-foot-long building to best promote sharing and increase interaction between departments within the confines of the site. Such a long structure would generally require expansion joints, but the team wanted to avoid them due to concerns about aesthetics, construction cost, and long-term maintenance requirements.

Our solution was to design the two wings to be built independently of cast-in-place concrete, and then tie them together using the central lobby structure. Once the wings were complete, the two-story, 60-foot-wide steel lobby structure was erected between them and “hard tied” to each of the wings. By allowing the concrete wings to cure independently prior to tying them together with the lobby structures, we reduced the strain on the floor slabs by approximately 40%.

A key feature of the facility is a 12,000 square foot jewel box conference space enclosed by glass curtain walls on all four sides and capped by a pop-up central roof. The facility is designed to feel open and connected to the surrounding landscape, while providing much needed meeting space with substantial configuration flexibility. Typically, a space of this size would be supported by a series of braced frames and internal walls, but these elements would have detracted from the open feeling of the space and limited potential configurations. In response, our team designed the braced truss within the pop-up roof to not only support the roof over the long-span space below, but also serve as the top member of large un-braced frames below. Doing so allowed us to eliminate the need for braced frames within the space while still having sufficient strength to resist lateral loads like wind that the building would be subjected to. As a result, we maximized the openness and configuration options offering greater value to the city.

The consolidated PDC serves the residential and commercial citizens of the City of Austin by housing all the staff involved with any aspect of the development review process under one roof. The facility offers a modern and environmentally responsible workplace to the young talent the City of Austin desires to attract.