- Tennessee’s Department of Transportation will use accelerated bridge construction (ABC) when it replaces a set of Interstate 24 bridges in downtown Nashville, according to Equipment World.
- The construction method requires the road being worked on to be closed down completely, allowing the $28.5 million project to finish sooner than if conventional roadway construction methods were used.
- TDOT previously used ABC for bridge replacement projects in 2012 and 2015. The latest project will start this fall and is expected to wrap up in June 2018; the road being repaired is traveled by more than 148,000 vehicles each day.
The Federal Highway Administration offers two metrics for determining ABC’s effectiveness: onsite construction time and transportation mobility impact, such as through delays and detours. Other reasons cited for its use include reducing the risk of weather-related delays and improving safety for those around the job site.
With ABC, roadways close completely for short periods of time to allow work to progress unabated, rather than completing the work alongside a fully or partially open road or off-hours. ABC requires large components to be fabricated offsite and then transported to the job for installation; a design-build contract can also help maintain the accelerated schedule.
The Georgia Department of Transportation and contractor C.W. Matthews recently used the method to repair a portion of Interstate 85 in Atlanta that was damaged by fire earlier this year, Equipment World reported. The use of ABC — in addition to the inclusion of accelerated curing concrete and the fact that the new bridge was using an existing footprint — helped facilitate the compressed schedule required to get the vital stretch of roadway back up and running.
The Massachusetts Department of Transportation also used ABC for its Morton Street Bridge replacement project, which lasted from December 2013 to August 2014, during which the bridge was closed to traffic for just nine days.
The volume of work required on America's roadways encourages creative approaches, like ABC, for completing projects as efficiently as possible when funding shows up — or, in Atlanta's case, when disaster strikes.
In its latest infrastructure report card, the American Society of Civil Engineers gave the country's infrastructure a score of D+ and said that $4.6 trillion in investment is needed by 2025 to make the required upgrades and repairs. Of the 16 categories graded, roads earned a D, with the ASCE citing an $836 billion highway and bridge funding backlog. Of that figure, $123 billion concerns bridge repair.
The ASCE recommends the use of 3-D models, pavement preservation strategies and streamlined permitting processes as ways to improve and expedite roadwork in the future.