Waller Creek Tunnel Inlet Facility at Waterloo Park
Owner: City of Austin
Lead Design Firm: KBR
General Contractor: Oscar Renda Contracting Inc.
Civil Engineer: CAS Engineering
Structural Engineer: JQ Engineering
MEP Engineer: BGE | Brown & Gay Engineers Inc.
The Waller Creek Tunnel Inlet Facility was designed to protect downtown Austin from flash flooding. But that same risk posed severe safety concerns for crew members working on the $39.7-million project. The project entailed open excavations of more than 80 ft underground. The team redesigned the tunnel to allow for continuous visual supervision of workers during excavation and concrete placement.
Flash-flooding risks also created safety concerns at the connection between the inlet facility and an adjacent tunnel that links the inlet to Lady Bird Lake. The project team designed a reinforced-concrete plug to ensure the safety of workers downstream. But because it would take more than 72 hours to remove such a large mass of concrete, the city of Austin requested an alternate-plug design. The team provided the alternate design and had the original plug removed in under 48 hours.
Texas laws protecting views of the state Capitol created additional challenges. Construction was halted because the height of the facility impeded a state-protected view corridor. The team agreed to redesign the facility to accommodate the views. Designers proposed a two-way pitched roof that allows clearance of the protected corridor. The overall building footprint remained the same while allowing room for all the original process equipment.