The following excerpt was featured in the June 2019 edition of the American Public Works Association’s (APWA) Reporter.
Everyone knows the saying: if it ain’t broke, don’t fix it. But when it comes to a community’s infrastructure, you should consider a plan to preserve it before it’s too late.
As the United States’ infrastructure ages and funding measures are often unable to keep up, the search for a solution has led many to consider preservation instead of building new. Because of this, many public agencies are shifting their focus – and funding – to preserving their infrastructure.
“At the beginning of my career, we had more expansion and modernization projects because the funding was still in place for that work,” said Jon Karst, GBA Bridge Special Projects Leader. “Due to changes in funding, we’ve seen a trend towards preservation and maintenance at both the municipal and state level.”
Karst and his team at GBA were seeing a regular pattern emerge with bridge owners: chain drag bridge decks to find delaminated (poor condition) concrete, create deck maps showing these areas based on the field evaluation, then send the plans out to bid. This tried-and-true method of deck evaluation works for many bridges but gets increasingly difficult and costly under high traffic volumes. The purpose of chain dragging is to hear the different sound made by the chain passing over delaminated concrete. With high-traffic volumes going by, this process becomes less reliable due to the road noise. This causes errors in estimating the quantities of repairs, which often translates to change orders and cost overruns. Additionally, this method inherently disrupts traffic as lanes are required to be closed to perform the chain drag.
Faced with the challenge of meeting client’s needs, GBA set out to find a better way. Their task: providing a final deliverable that could be created in an efficient and cost-effective manner. Instead of using traditional methods of data collection, GBA’s Bridge and Advanced Robotics and Remote Sensing (ARRS) groups teamed up to create a solution that would help their clients preserve their infrastructure by using emerging technology.