James River Bridge Grid Deck and Roadway Review
Project at a Glance
Est Completion Date
Isle of Wight
July 24, 2013
The Virginia Department of Transportation (VDOT) has released its analysis of the Route 17 James River Bridge (JRB) grid deck and roadway. Several non-structural mitigation measures and one structural enhancement have been identified to improve the safety and functionality of the James River Bridge for motorists.
VDOT conducted a three-month evaluation of the bridge after observing an increase in crashes that began two months after the new grid deck’s installation. The JRB Grid Deck Replacement Project was completed in December, 2012.
“The purpose of this analysis was to evaluate the crashes that occurred on the James River Bridge grid deck in 2013 and the factors that were involved with each crash, as well as to identify if any further actions could be taken to heighten motorists safety on our infrastructure,” said Jim Utterback, VDOT Hampton Roads District Administrator.
VDOT initiated an internal evaluation in May 2013, of the bridge deck’s roadway surface and a safety audit of the structure. During the analysis, an advisory speed limit for the grid deck was posted at 45 mph during inclement weather, a 10 mph reduction from the regulatory speed limit of 55 mph. Additionally in June 2013, VDOT contracted with the Virginia State Police (VSP) to station troopers on the bridge at peak travel times on days with predicted poor weather conditions.
According to Dwayne Cook, VDOT Assistant District Administrator for Operations, there were 20 crashes on the James River Bridge from February through early July, 2013. The majority of the crashes occurred in the southbound direction during wet weather and involved a light truck or sport utility vehicle (SUV). Approximately 30,000 drivers travel the bridge safely every day.
VDOT examined such possible crash factors as driver behavior, mechanical failures and roadway deficiencies. While no traffic safety deficiencies were found, Cook noted that a variety of options were identified that could heighten standard safety measures and motorist awareness. Traffic safety options include:
• Continued use of overhead electronic message signs to post the 45 mph advisory speeds during inclement weather
• Continued presence of Virginia State Police during inclement weather
• Installation of “Slippery When Wet”/”Steel Deck” signs
• Installation of “Stay in Lane” signs, along with solid white double lane lines
• Continued monitoring of crashes to determine the effect of mitigation strategies and modification to the grid deck to increase friction and skid resistance
• Use of traffic calming devices to slow down traffic in the event that further safety options prove necessary
In addition to the roadway safety audit, a grid deck assessment was performed to include skid testing that evaluated surface traction in both dry and wet conditions. “At this time, our analysis of the skid testing on the newly installed bridge grid deck has found no structural deficiencies or abnormalities,” said John Jacobs, VDOT Assistant District Administrator for Maintenance. “However, we will continue to study the grid deck for contributing factors and evaluate ways to help increase the traction for vehicles on the deck’s surface, thereby increasing motorist safety.”
Jacobs noted the new bridge grid deck has a different design and an increased contact surface area as compared to the old bridge deck. With this, four potential courses of action were identified to enhance traction on the new grid deck surface during inclement weather conditions. Among the options reviewed were:
• Scarifying (roughening) of the grid deck surface
• Installing studs to the grid deck surface
• Adding two-foot wide concrete strips beneath the concrete wheel lines
• Metalizing (or applying a metal coating) to the surface of the grid deck.
After evaluating the five criteria (reliability, installation, surface friction, ridability and cost) for each course of action on the new deck, VDOT determined that installing studs to the deck surface was the best course of action to help provide enhanced vehicle traction.
“By installing the additional traction and implementing further traffic safety measures, we can help provide an added level of security for motorists utilizing the James River Bridge,” said Utterback.
Installation of the studs is expected to begin late summer/early fall and is anticipated to take approximately three months to complete at an estimated cost of $800,000. VDOT will provide ample notification to motorists before the work and any related lane closures are scheduled to begin.