US-231 Bridge Design – Montgomery, AL
Highway, HSIP, Structures
HMB replaced the US-231 railroad bridge over the CSX Railroad in Montgomery’s Northern Bypass. With 34,300 vehicles daily (anticipated to grow to 74,338 by 2022), the existing four-lane highway had narrow 28′ bridges and a substandard 20′ vertical clearance. Our challenge was raising the grade to ensure 23′ clearance, while maintaining two lanes of traffic. We built new bridges on the outer lanes at a 2.5′ higher elevation, using concrete barriers as both protection and retaining walls. Drainage inlets prevented water accumulation, and after completion, the final product was a six-lane bridge, boosting capacity and providing safe clearance over the CSX Railroad on US-231.