TxDOT US 290 Bridges Design
Improving Deficient Bridge Structures Along US 290 in Gillespie and Blanco Counties
Three aging bridge structures were identified in the counties to be deficient based on a variety of reasons which included geometry, condition, or hydraulic. The bridges were studied to determine the extent of the deficiencies and developed recommendations for necessary corrections.
KFA served as overall project manager and the prime engineering consultant for the design of two bridges in Gillespie County and one bridge in Blanco County along US 290. Working for the Burnet Area Office of TxDOT, KFA prepared the PS&E construction plans for the improvements which included new bridges and revised roadway profiles designed to meet current TxDOT design criteria. KFA prepared a preliminary hydraulic analysis and cost-benefit analysis to determine if the structures should be widened or replaced. The three structures were each evaluated to determine if they met TxDOT hydraulic standards to pass the 10-yr event without roadway inundation then evaluated again with the proposed replacement structure to determine relative impact and ensure compliance with local floodplain regulations. A scour analysis was performed for each structure following FHWA HEC-18 procedures and guidelines. This project required special attention to construction sequencing and traffic control, which required the phased construction of the proposed bridges.
The recommendation for all three structures was a replacement which KFA prepared the PS&E for replacement of the bridges and roadways. Once the project was complete, the three stream crossings of US 290 were improved to safer conditions with better hydraulic performance.