Rehabilitation of the Austin Avenue bridges and approaches in Georgetown is 90% designed. These twin bridges over the North and South Forks of the San Gabriel River are the gateway to Georgetown’s downtown area. The Aguirre & Fields team has been designing the structures and roadway with public, historic, and environmental needs in mind.
“Over the last 80 years, the bridges’ joints have deteriorated, resulting in consistent, prolonged drainage on the steel elements likely causing corrosion and spalling.” says Structural Engineer Victoria Shekarchi, P.E. “The rehabilitation gives us the opportunity to extend the bridges’ lifespans.”
Built in 1940, the bridges have been deemed eligible for the National Register of Historic Places and must meet National Historic Preservation Act requirements to preserve their cantilevered, suspended-span configuration. In the 1930s, suspended-span designs allowed TxDOT to cover larger distances than was typically possible at the time. The bridge rails and bents also represent an art deco style from the 1930s and, although not historic, provide aesthetically pleasing features for pedestrians in Blue Hole Park to pass by on the trails underneath.
During alternatives analysis, Aguirre & Fields evaluated five options to rehabilitate the bridges, without affecting the integrity of the critical elements, and presented it to the State Historic Preservation Officer and the City of Georgetown.
“Presenting multiple options for the rehabilitation of these historic beam bridges demonstrates our commitment to the City and all who use Austin Avenue,” says Project Manager Dave Lubitz, P.E. “By providing various alternatives, we address different needs, consider budgetary constraints, and accommodate specific requests while ensuring the preservation of the bridges’ historic value.”
The Aguirre & Fields team tested materials and inspected the structure using a boom lift and drone and determined that the bridges could be rehabilitated while preserving their historic elements. The selected alternative will replace bridge decks and bearings, widen bridge roadways, improve approach drainage, repair concrete caps and riprap, and clean and repaint steel beams and diaphragms. Based on a city vote, the bridge rails are also being preserved while adding a crash-tested rail.
Public involvement has been a crucial component of this project. Throughout the planning process, the City of Georgetown and Aguirre & Fields have held five public meetings, gathering valuable input from local businesses and residents.
“Many voiced the importance of keeping the bridges open during construction,” says Shekarchi, “so we have designed the rehabilitation to be phased in such a way that two of the four bridge lanes will remain open, allowing traffic to flow in both directions.”
“Austin Avenue carries over 6,000 vehicles per day and serves as a critical corridor for the City” adds Design Project Manager Paul Hahn, P.E. “Long-term closures on Austin Avenue would severely impact mobility within Georgetown.”
Another project consideration was one of environmental impact, as the bridges reside over the habitat of a protected salamander species. To protect this species, as well as seven natural water springs, we proposed overcoating the existing lead paint, as removing it would be costly and time-consuming, due to environmental constraints.
“One of the things that makes me most proud to work for Aguirre & Fields is our dedication to finding transportation solutions which protect local ecosystems, as well as the unique character of the communities we work with,” says Hahn.
Aguirre & Fields is proud to work with the City of Georgetown to rehabilitate the Austin Avenue bridges and approaches, and we look forward to enhancing the safety and quality of life for those who live, work, and travel throughout the area.