Better Roads Staff
“About 15 years ago, we started [climbing] bridges and created our own program,” Sahs points out. A Caltrans engineer, who was also a mountaineer, adapted climbing to bridges. “We put together our own code of practices,” Sahs explains. Meanwhile, the Society of Professional Rope Access Technicians (SPRAT) was formed, along with its now industry-standard certification process, to create industry-wide standards with enforceable rules. “If you’re certified by [SPRAT], you’re pretty much good to go anywhere,” he says. “It means you’ve passed the tests and can perform at a certain level of rope confidence.”
In 2000, the Occupational Safety and Health Administration (OSHA) adopted the Title 8: General Industry Safety Orders Chapter 4, Subchapter 7, Article 1, Section 3207, And Article 4, Section 3270.1 along with Cal-OSHA. The code has spelled out what constitutes a viable Rope Access program. SPRAT was instrumental in the development of these codes.
However, adds Sahs, although OSHA does not require an engineer using rope access for a bridge inspection to be SPRAT-certified, the organization helps regulate that safety practices are adhered to. (Safe Practices for Rope Access Work, go to http://www.betterroads.com/sprat-safe-practices-for-rope-access-work/.)
Regardless of the means of access to a bridge member, every bridge inspector must undergo the two-week course from the National Highway Institutes, Safety Inspection of In-Service Bridges, as a mandate through the National Bridge Inventory and National Bridge Inspection Standards.
“Because of increasing costs and difficulties associated with using traditional inspection equipment, Caltrans bridge maintenance engineers, materials testing engineers and technicians felt it was reasonable to explore alternative means to gain access to bridges,” Sahs says.
A View from the Top
As I step out of the bridge inspection truck, bright yellow lights flashing, cars and semis blazing by at 70 mph, my first thought is for the safety of my crews and how this day will end up. Questions run through my mind: “What will we find on this structure? Is the rope access team ready for another grueling day of physical activity? Is the client happy with our work? Is the weather going to hold out?”
About this time — it never fails — a passenger car will pull up into our shoulder safety zone and ask us for directions to the nearest gas station or inquire what we are doing on the bridge. After explaining to them that they need to exit our safety zone and get on their way — very carefully, I add — the team gets back to the task at hand.
Next, the daily site safety review and coordination meeting is conducted. I inform the teams who will pair with whom, which person is the overall team leader for the pair, and what the team should expect during the course of the day. After answering numerous questions, reviewing the bridge drawings, handing out our field computers and notebooks and reviewing the emergency rescue operation plan, we get to work.
Setting our primary and backup anchors is the first order of business. Extreme care and concentration must be taken to ensure that no issues whatsoever will cause a failure of our rope anchor systems. These systems are literally holding us to the bridge, and to life. Without a solid redundant system that can hold the weight of a pickup truck, our work cannot and will not begin. After checking our anchors and connecting double-locking carabineers to the ends, we begin to deploy the double rope systems. We always use two ropes at a minimum, and in some situations we use four independent ropes, depending on the site’s work positioning needs. One rope acts as the primary means of support and the other is a safety backup. Anchors and ropes are now set, harnesses have been fitted and tightened; the gear we need is checked to make sure it is tied off to our harnesses. Everything must be tied off. None of the cameras, scrapers, rulers, carabineers, slings, markers, headlamps, radios, cell phones, field computers, or notebooks can be allowed to drop into traffic or the river below.
One more double check on my Petzl Rig, which is my main rappelling mechanism, and one good pull on the backup device to ensure it’s working correctly and I’m ready. It is now time to climb over the edge of the bridge rail. I take a deep breath, triple-check my systems with a quick glance, and look down hundreds of feet into the large gorge this structure spans. The wind is really whipping today, I realize, but not enough to call off the inspection for safety.
Our job today is to visually inspect, observe, and document the condition of the main supporting members of this bridge. After rappelling past the lower portion of the bridge rail, the exterior steel stringer comes into view. These beams support the loads from the concrete deck above. The deck sits on stringers, the stringers frame into floorbeams, and the floorbeams frame into verticals of the truss. Other crucial components to evaluate during today’s rope access mission are the members of the top and bottom truss chords, diagonals, bolted or welded connections, and gusset plates. The highly trained and experienced team is here to find areas of corrosion, missing bolts, misalignment, distortion, fatigue damage and anything that looks out of the ordinary. Every square inch of each face of every steel beam is inspected at an arm’s-length distance to get the best viewing angle in which to determine its condition.
MORE FROM Better Bridges
- Sydney uses water curtains to alert drivers to stop (VIDEO)815 Views
- Obama signs memorandum to expedite infrastructure projects652 Views
- Florida’s Red Light Camera Game: G R E E N orange R E D399 Views
- Seattle tests bikes as disaster relief (VIDEO)326 Views
- FHWA deploys bridge-inspecting robots297 Views