ABC is a paradigm shift in the project planning and procurement approach where the need to minimize mobility impacts which occur due to onsite construction activities are elevated to a higher priority.
Intrinsic benefits of the ABC approach include improvements in:
From the Owner Agency perspective ABC may require a change in how a project is approached and how it is justified.
As such, Project Planning tools with innovative solutions are provided to help streamline the development process and ensure successful implementation of ABC.
Accelerated Bridge Construction (ABC):
ABC is bridge construction that uses innovative planning, design, materials, and construction methods in a safe and cost-effective manner to reduce the onsite construction time that occurs when building new bridges or replacing and rehabilitating existing bridges.
A common reason to use ABC is to reduce traffic impacts (or "mobility impacts" as defined below) because the safety of the traveling public and the flow of the transportation network are directly impacted by onsite construction related activities.
However, other common and equally viable reasons to use ABC deal with site constructability issues. Oftentimes long detours, costly use of a temporary structure, remote site locations, and limited construction periods present opportunities where the use of ABC methods can provide more practical and economical solutions to those offered if conventional construction methods were used.
Approximately one-fourth of the Nation's 600,000 bridges require rehabilitation, repair, or total replacement. However, the work that occurs from on-site construction activates can have significant social impacts to mobility and safety. In many cases, the direct and indirect costs of traffic detours that result from the loss of a bridge during construction can exceed the actual cost of the structure itself. For example, full-lane closures in large urban centers, or on highways with heavy traffic volumes, can have a significant economic impact on commercial and industrial activities in the region. Partial lane closures and other bridge activities that occur alongside adjacent traffic can also lead to safety issues. Because of the potential economic and safety impacts, minimizing traffic disruptions is a goal that should be elevated to a higher priority when planning bridge related construction projects.
Time Metrics for ABC:
To gauge the effectiveness of ABC, two time metric are used:
Onsite construction time: The period of time from when a contractor alters the project site location until all construction-related activity is removed. This includes, but is not limited to, the removal of Maintenance of Traffic, materials, equipment, and personnel.
Mobility impact time: Any period of time the traffic flow of the transportation network is reduced due to onsite construction activities.