Moore’s Crossing Historical Bridge
Project Overview
The GBA team performed a comprehensive condition assessment of the Moore’s Crossing Historical Bridge in Austin, Texas. Located just south of the Austin Bergstrom Airport, this single-lane, four-span structure has a storied past, having been originally constructed in 1884 as the Congress Avenue bridge over the Colorado River. After being dismantled and stored in 1910, three spans were reassembled at the current location in 1915, only to be destroyed by a flood the same year. The bridge was finally reassembled in 1922, where it still resides today. Although closed to vehicular traffic since 1980, the bridge remains accessible to pedestrians and is recognized as a Recorded Texas Historical Landmark (RTHL). This project employed advanced rope access techniques under the expert supervision of an external SPRAT III technician, ensuring a thorough and meticulous evaluation.
Initial Problem and Innovative Solutions
The bridge has a history of overtopping from Onion Creek. Overtopping occurs when the water level surpasses the deck level of the bridge, leading to dangerous conditions for the traveling public, potential structural damage, or the bridge being washed off its supports. GBA was retained to determine the feasibility of raising this bridge in its current condition approximately five feet out of the floodplain.
GBA’s Involvement
GBA played a pivotal role in the project, conducting a condition assessment of the current condition of the bridge. This involved a thorough visual inspection of truss members (top chord, verticals, diagonals, pins and lower chords) and floor beams as well as non-destructive ultrasonic testing of the primary pins connecting each of the members.
Challenges and Unique Aspects
Due to the structure’s height, accessing the full length of truss members presented a significant challenge. Standing 26 feet tall and already 20-40 feet above ground, GBA successfully implemented rope access with anchor points along the top chord, marking a notable milestone as GBA’s first rope access bridge inspection.
Project Timeline
- December 2023: Notice to Proceed and commencement of rope access inspection.
- January-February 2024: Obtain approval from the Historical Commission, preparing pin ends and conducting ultrasonic testing.
- April 2024: Finalizing feasibility recommendation, comprehensive report and load rating assessment.
Community Impact
The project’s significance transcends structural enhancements, contributing to the preservation of this nearly 140-year-old historical gem. By safeguarding the Moore’s Crossing Historical Bridge, GBA is actively contributing to the preservation of Austin’s rich cultural heritage.