Imaging a safer future - No 22 - April 2020
Those involved in work on or near roadways have a sobering story to tell about work zone fatalities. These tragedies blindside us brutally, unforgivingly, and persistently. Fatalities in the U.S. average 700 to 800 lives per year, and ss a result, best practices for roadside work continue to improve. Unfortunately, even with current best practices in place, no amount of safety training can prevent the unpredictability of driving patterns and the increased risk associated with setting up a work zone in the first place. Studies published by FHWA and numerous State DOTs show that work zones inherently introduce risk due to a disruption of traffic patterns, leading to variable reactions of drivers.
Luckily, these safety risks can be greatly reduced on all fronts. On the contractor/agency front, rapid scanning practices will reduce the overall time a work zone is set up because the locations of deficiencies will be known beforehand. Rapid scanning systems now can detect and locate all known places of concern on a map, which can be accessed on-site. On the highway user front, vehicles with enhanced safety features, such as proximity sensors, lane divergence detection, and auditory alert systems can contribute to safer driving.
Everyone has the right to safe work, and we want highway workers across the globe to know that they have this right. With informative data in-hand, roadside work on both inspection and construction projects could decrease to a very small fraction of what they currently are. We have already seen this take place in several bridge inspection projects along the east coast, and have brought roadway workers in the field back to the safety of their offices to analyze the very same road or deck using high-definition visualizations.
Not far from the catastrophic 2018 bridge collapse in Genoa, Italy, a second major Italian bridge failed on the 8th of April in the town of Aulla (between Genoa and Florence). Fortunately, only two people were injured as a result of the collapse, as much of the country is on lock-down from the COVID-19 outbreak. Should this have happened at any other time, the number of people impacted would have been much higher.
Taking a look at the probable causes of the collapse, engineers are a bit baffled as to why each and every span buckled. The structure was an arch bridge with multiple reinforced-concrete arch spans. It seems likely that one of the spans experienced a compression failure and, like dominoes, brought each neighboring span down in a chain reaction. Though a very rare occurrence, this failure demonstrates how the health of one member can significantly affect its surroundings and in this case, the entire structure. Commentary thus far points to inadequate maintenance, which could certainly be a byproduct of inadequate inspections.
In the face of grim news such as this, we stress the importance of digital records in investigating structural health at all points during a bridge life cycle. Repeated failures such as these can be prevented with the knowledge of what damages are present in the structure and of how fast they are propagating. Digital imagery shows this undeniably, making it a non-negotiable need for bridge engineers as they continuously observe crack and spalling patterns.