CR 661/Blackhall Road Bridge over Rum Creek
Blackhall Road crosses Rum Creek just downstream from, and generally parallel to, the dam impounding 600-acre Lake Spivey. The existing two-lane bridge, constructed in 1961, was designed for an H15 truck. The Georgia Department of Transportation (GDOT) decided to replace the bridge and approach roadway because of substandard geometrics and posted weight restrictions.
The proposed new bridge was 195 feet long with a three-span configuration (60-93-42 feet). The bridge and roadway section consisted of two 11-foot-wide lanes with 8-foot-wide shoulders and concrete barriers on each side of the bridge. The bridge substructure consisted of concrete hammerhead piers on pile-supported foundations and pile-supported abutments. The roadway profile grade was raised 7 feet to improve stopping-sight distance in the vertical sag curve, and a 93-foot-long main span over the creek channel was required to satisfy GDOT hydraulic requirements.
The bridge was removed and replaced with an innovative design and construction strategy involving accelerated bridge construction (ABC). As an outcome of the public meetings, the preferred alternative required ABC techniques to limit the road closure to two months. CHA identified, refined and optimized the ABC strategies throughout the concept to letting the process for the replacement of this bridge, just below the Lake Spivey dam and spillway.
CHA prepared the NEPA CE document that included a robust community engagement campaign to present and receive feedback on multiple alternatives for the new alignment and bridge configuration. Critical elements of the ABC strategies included using pre-cast deck beam units, pre-cast concrete substructures, and rapid set substructure concrete and Ultra High-Performance Concrete (UHPC) for deck elements. CHA’s ABC design development was done in collaboration with the bridge office and following GDOT’s PDP. PFPR was held in November 2016. FFPR was held in late 2017, and final plans were delivered to GDOT in early 2018. The project was let in August 2018, and construction was completed and opened to traffic in early October 2019 after closing the road for only 60 days.
This award-winning bridge project was also featured in an article in the February 2021 issue of ASPIRE detailing the traffic maintenance challenges and ABC solutions.