Bridges are one of the oldest transportation systems around. That means that most bridges are also in need of repairs or need to be replaced. Approximately one-fourth of the nation's 600,000 bridges require rehabilitation, repair, or total replacement. The work that occurs from on-site construction activities can have significant social impacts to mobility and safety.
Usually 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. 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.
Accelerating Progress
With that goal in mind, a lot of Department of Transportation (DOT) offices are implementing 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.
ABC cuts down on overall construction time, which is beneficial to the DOT and mostly to the people using the bridge. Some intrinsic benefits of the ABC approach include improvements in:
- Safety
- Quality
- Durability
- Social costs
- Environmental impacts
Other 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.
The most common ABC method is replacing the bridge by building the new structure alongside the old one or underneath it. New technology in equipment helps these methods. Heavy lifting equipment that can handle more weight and is more compact is used to take the pieces of the bridge and put them into place. Mike Beres, sales leader, Enerpac Heavy Lifting Technology, says when constructing the bridge they will use cranes and jacks and specialty lifting equipment to pull the pieces up to the level where the bridge is and where it is being replaced. “The difference between the older equipment and the newer lift systems is size. A 500-ton crane is as big as a garage. A 500-ton jack is 6-feet by 6-feet,” Beres states.
Using the ABC method solves a lot of current problems with bridge and road construction. Alex DiDomenico, general manager special projects group, AGF Access Group Inc, points out some of the issues being faced. “Current challenges include building a bridge safer, aesthetically better, as quickly as possible, and of course within allowed budgets,” DiDomenico says.
The ABC method provides more safety on the jobsite for the contractors and opens the door to new technology. Beres says some of the systems and equipment have computer systems in them that allow one operator to use them. That makes the work go smoother and it is quicker. The technology being introduced is helping with ABC construction and the industry as a whole.
“Bridge launching in Europe is gaining traction and will come over to the U.S. As this newer equipment that is more advanced than older equipment is used by contractors and they complete these bridge projects successfully, they will have a more competitive advantage when getting another bridge job. Contractors need to embrace the new methods to stay competitive,” Beres states.
Improving Project Transparency
DOTs are in a catch-22 when it comes to public sentiment. Motorists want safer bridges and better roads, but major construction projects seems to evoke as much public discontent as the conditions they seek to correct. The DOTs and construction companies are finding that making the construction site visible with construction cameras improves public relations. With the use of construction cameras on site, transparency is heightened.
Sue Silva, marketing for OxBlue says, “Construction companies want to market themselves and DOTs want to communicate with those affected by their projects and the way the world communicates today is via social media and video.” A lot of DOTs use construction cameras to keep the cities, commuters, and businesses informed about what is going on with the construction project, she explains.
Construction cameras have been around for a while, and with most technology, early adopters were the first to have them on their jobsites. This technology is being seen as beneficial to all parties on a project and a lot of DOTs are requiring them on bridge projects. “This technology has worked its way into the construction world as a common piece of equipment that’s necessary to make a job run more smoothly and, in the case of bridges, help DOTs and construction companies communicate with those affected by the builds,” Silva says.
Besides the transparency of the overall job that cameras provide, companies that have their equipment used on site can reap some benefits. “Construction cameras on the jobsite help a company that has its equipment on the jobsite because we can use it to showcase that equipment to customers and contractors,” Beres says.
A recent example of the ABC method and cameras at the site coming together was the Atlanta I-85 bridge rebuild project. A portion of the bridge collapsed after a massive fire ignited below the bridge, damaging it to the point of needing replacement. This bridge collapse affected millions of commuters, those who lived near the bridge locally and commercial traffic, and it was important to the Georgia Department of Transportation that everyone knew it, along with C. W. Matthews, the contractor, working 24/7 to get that bridge rebuilt as soon as possible. The contractors completed the project a month ahead of schedule and all those involved were able to follow the progress on the cameras.
These technologies will evolve and become the standard in bridge construction. Advancements in bridge construction will lead to stronger structures that will need fewer repairs, which will mean less traffic disruptions and safer construction jobsites for all.
