Looking At The Structures That Define Us
The goal of every bridge replacement project is to minimize traffic disruption. Although this can be achieved using temporary structures, it results in high construction costs. More recently, modular construction has been used to cut down the on-site construction time. However this method still significantly impacts traffic flow.
A new technique, known as Accelerated Bridge Construction (ABC), has been developed to mitigate traffic disruption. This process begins with the construction of the new bridge superstructure alongside the existing bridge. Once this is completed, the existing bridge is quickly demolished and the new bridge is slid into place. The final few pieces are installed, and the bridge can quickly reopen to traffic with minimal disruption. This procedure is outlined in detail by the Iowa Department of Transportation:
There are a number of projects throughout the United States that are using this new technique.
Michigan’s Department of Transportation (MDOT) is finalizing plans to replace three bridges this year using this process (M Live). MDOT spokesperson John Richard stated, “You’ll definitely see a lot more bridge slides taking place just because of the less impact on traffic. It’s really changing the industry. All the engineers at MDOT are very excited” (M Live).
New York’s Department of Transportation has already constructed a number of bridges using this process. The construction of the I-84 bridges, which began in June, was completed in October of last year. Despite the length of the project, the actual replacement time totaled 18 hours for each bridge, occurring over two weekends. This resulted in savings of $4 million dollars (Roads Bridges). You can view the time lapse construction video of the bridge here: Accelerated Bridge Replacement
It is evident that the use of ABC as a bridge replacement technique will increase in the coming years. However, it is important that researchers around the world continue to develop more efficient ways to replace the worlds ageing infrastructure. This includes reducing construction time, reducing costs, mitigating the effects on traffic and recycling materials from the demolished bridges.
For more information regarding ABC see the brochures recently published by Aspire Bridge:
Part 1 – Winter 2013
Part 2 – Spring 2013
Part 3 – Summer 2013