October 27th, 2011
INNOVATIVE INTEGRATIONUncategorized, by Catherine Higgins.
Combining two safety countermeasures is preventing cross-over crashes and keeping cable barrier up to do its important job.
Cable barrier and guard rail are ubiquitous on interstates and highways across the nation. But, UDOT’s innovative integration of those two safety countermeasures is only being used in Utah.
Cable barrier is tensioned steel cable held up by break-away posts. When installed properly between opposing traffic lanes, cable barrier prevents crossover collisions and saves lives, so keeping cable barrier up and functional is critical. If a vehicle hits the break-away posts or the anchor point where cable is tensioned, the posts can fall and lower the cable or the cable can lose tension. After such a hit, fully repairing the cable barrier can be an extensive and expensive effort.
UDOT Safety Specialist Glenn Schulte has conducted cable barrier and guard rail installation and repair training for contractors and maintenance workers for seventeen years. The “one-bad-hit” issue has been effectively addressed by Schulte, an engineer FHWA and cable barrier vendor from Washington state.
Schulte and his two associates came up with an idea – why not integrate guardrail with the cable barrier system at the point where a vehicle hit can make the cable lose tension? Schulte and friends discussed the idea and did some initial problems solving. A quick sketch on paper, and the idea took flight.
Schulte took on the responsibility for developing standard drawings at UDOT and getting FHWA approval. The Cable W-Beam Anchor System uses guardrail, crash cushion or end treatments and a secondary anchor. The system protects the area where cable is tensioned and anchored from being damaged by a crash. UDOT contractors can choose from proprietary and non-proprietary components commonly available and crash tested for safety to assemble a system that’s appropriate for a specific location.
The system was first used on Bangerter Highway. Since inception and first use, many changes and improvements have been made. Now the innovative system that was first a rough pencil sketch is a common and significant safety feature all over Utah. Schulte has sent standard drawings to other states for use, and he expects the system to be more widely used as transportation officials see the value of the system.
These slides show how the Cable W-Beam System protected cable barrier during a crash.