Bridge climbers, Rope access, structural inspection

I'm part of a structural inspection group. One of our tasks is inspecting overhead signs spanning the highway. There is some discussion within our group about best practice for climbing these signs.

Looking for opinions from others in the industry. Hopefully connect with people that also have experience with sign inspection. How would we safely and efficiently climb the truss (over live traffic) in the image below?

sign climbing

In order to draw unbiased opinions I'll withhold my thoughts for the time being.

Take a lane, use a bucket truck.

We use a bucket truck to access the truss from the shoulder. Not practical to close lanes for cost, time, schedule for routine inspections. The beauty of climbing is not impeding traffic.

We're trying to define best practices for for using lanyards/fall arrest systems.

If you're going to insist on climbing it, I'd go with something along the lines of a via ferrata rig. They're essentially designed for this, though you'd probably need to source larger than normal biners.

If I were to make my own....really large steel biner, dynamic rope, tube webbing over the rope for cut resistance, screamer, then tied to harness. I'd do some math to figure out how much force you'll generate based on your tether length and choose your screamer(s) accordingly.

Also, I'd look around for rope with a lot of stretch.

And a second tether for redundancy.

Oh wow Jason you'll be inspecting the entire structure by traversing across the box truss! That sounds like a OSHA nightmare. Very bridge, sign or cobra head we've inspected has been from a bucket truck or a lift.

I would speak to your PPE guy. Anytime I've had a job I thought the guys might actually fall I bought a high dollar harness and lanyards. I felt the nice padded harness and quality lanyard would catch a guy comfortablely and not just save his life. I use Grainger.

We had a BASE jumping event waaaaaaay down in Durango Mexico. The Baluarte Bridge, 2nd highest in the World. Before the jumping started we could to stick our nose around almost everything. They were still putting the final touches on everything. To the US eye, it looked so sketch. But the Mexican crew recorded not one loss of life for the entire construction. They were very proud of that.

Baluarte Bridge
Some of these columns were 400'-500' tall.
Construction

Safety

Siberia wrote:If you're going to insist on climbing it, I'd go with something along the lines of a via ferrata rig. They're essentially designed for this, though you'd probably need to source larger than normal biners. If I were to make my own....really large steel biner, dynamic rope, tube webbing over the rope for cut resistance, screamer, then tied to harness. I'd do some math to figure out how much force you'll generate based on your tether length and choose your screamer(s) accordingly. Also, I'd look around for rope with a lot of stretch. And a second tether for redundancy.

We do climb these signs. A lot of them. We have contacts in the state of Florida to inspect most of state via climbing methods. Currently we can knock out about 40/week. It's come under scrutiny recently for some of the methods our team uses.

It's actually similar to what Siberia suggests. They don't make biners/ladder hook larger enough for some of the huge trusses over 6+ lanes of traffic. So we typically just wrap a lanyard around the members and clip it back to itself, leap-frogging along the way. No scremers in the systems because unzippering one over live traffic would make you a pinata for truck traffic below.

The problem is most of the truss members are steel angles (with moderate sharp edges). In the event of a fall your lanyard is likely to slide down the angle member and you take a near factor 2 fall over live traffic. We're trying to limit forces (and keep you out of reach of truck traffic) in the event of a fall, eliminate connections to the angle members or at least connect to them safely, all while providing a quick/efficient inspection.

Without having specific tests conducted with our exact scenarios it's hard to justify to our safety committee exactly how it all works out. "I think he'll be fine in the event of a fall" isn't good enough.

Bill Kirby wrote:Oh wow Jason you'll be inspecting the entire structure by traversing across the box truss! That sounds like a OSHA nightmare. Very bridge, sign or cobra head we've inspected has been from a bucket truck or a lift. I would speak to your PPE guy. Anytime I've had a job I thought the guys might actually fall I bought a high dollar harness and lanyards. I felt the nice padded harness and quality lanyard would catch a guy comfortablely and not just save his life. I use Grainger.

Bill, it's not much of an OSHA nightmare. Climbing/rope access structures is becoming quite the norm. That's basically my 9-5 job, more like 7-7. We have training and equipment.

I don't see a rope line in your picture. It also looks like if the dude falls, his lanyard would slide the sixish feet to the lower support, possibly causing enough friction to burn through it. Is there a reason you cannot bring extra slings to leave at each support, using a running belay as in climbing? Is there a way to firmly anchor your lanyards above head height in such a way as to prevent them from sliding down the support in a fall?

I'm not a rope access guy, but I did stay at a motel 6 this year. I'm just posting what would appear to be common-sense questions. I know rope access work is pretty common, but what you have in the picture looks sketchy to me. Incidentally, what's the rescue plan if someone does fall?

sprat.org/

This is a tough one. 16 feet is the minimum clearance between interstate roadway and overhead objects. Truck height is 13.5 before an oversize permit is required leaving you with 2.5 feet of distance you could drop below the bottom edge of the truss before you're pinata meat (assuming you're on a structure at the minimum roadway to overhead object clearance).

Assuming the bucket truck is simply not an option, the only thing that comes to mind is incorporating a belayer and climbing it in lead fashion but this doesn't bode well for the climber if the belayer allows you to drop > 2.5' and trucks are wizzing by underneath. By leading, I mean instead of leap-frogging, bring several lanyards and, instead of using them on diagonals and members, using them only on the chords. The obvious drawback to this is, of course, that a 6 lane truss is going to have upward of 8 or 9 feet between upper and lower chords requiring longer lanyards and bigger swings. Chords are rounded (correct me if I'm wrong here) so this eliminates any lanyard cutting scenarios right? The other obvious drawback is that falling essentially drags the line over the last thing you stepped over which could be rusty and/or angled...

Seems to me like larger trusses (say greater than 4 lanes?) should have some sort of catwalk integrated into them. Yeah, so clearly I don't have any "good" ideas.. just thinking out loud is all I can provide really. Interested to see what you all come up with though so please to chime back in with how this pans out in the end.

johnnyrig wrote:I don't see a rope line in your picture. It also looks like if the dude falls, his lanyard would slide the sixish feet to the lower support, possibly causing enough friction to burn through it. Is there a reason you cannot bring extra slings to leave at each support, using a running belay as in climbing? Is there a way to firmly anchor your lanyards above head height in such a way as to prevent them from sliding down the support in a fall? I'm not a rope access guy, but I did stay at a motel 6 this year. I'm just posting what would appear to be common-sense questions. I know rope access work is pretty common, but what you have in the picture looks sketchy to me. Incidentally, what's the rescue plan if someone does fall?

What you describe is the exact problem we have. Lanyard sliding down causing abrasion to potentially sever the lanyard. Does the little rope protector we use provide enough protection for this? How about the heavy duty ones? Don't really know.

A running belay would just add time (and therefor cost). Another option would be leap frogging lanyards over the top chord of the truss which are round members. That's the method we use for small trusses, but these big trusses we need long lanyards to achieve that. I worry about carrying long lanyards and the cluster F it causes. Also, don't drop a 15ft lanyard with a biner on the end in traffic below... Best case you smash a window, worst case a truck takes you for a ride.

In the event of a fall (we haven't had one in nearly 10 years) we rely on self rescue. Prusiks on your lanyard, he-man yourself back onto the truss. We do have the bucket truck and to pick someone off if need be but may require a lane closure with the assistance of local authorities.

Bryan Ferguson wrote:http://sprat.org/

We have 2 SPRAT trained climbers on our team. SPRAT doesn't cover every scenario you may encounter on the job. This is definitely a topic that isn't covered.

Daryl Allan wrote:This is a tough one. 16 feet is the minimum clearance between interstate roadway and overhead objects. Truck height is 13.5 before an oversize permit is required leaving you with 2.5 feet of distance you could drop below the bottom edge of the truss before you're pinata meat (assuming you're on a structure at the minimum roadway to overhead object clearance). Assuming the bucket truck is simply not an option, the only thing that comes to mind is incorporating a belayer and climbing it in lead fashion but this doesn't bode well for the climber if the belayer allows you to drop > 2.5' and trucks are wizzing by underneath. By leading, I mean instead of leap-frogging, bring several lanyards and, instead of using them on diagonals and members, using them only on the chords. The obvious drawback to this is, of course, that a 6 lane truss is going to have upward of 8 or 9 feet between upper and lower chords requiring longer lanyards and bigger swings. Chords are rounded (correct me if I'm wrong here) so this eliminates any lanyard cutting scenarios right? The other obvious drawback is that falling essentially drags the line over the last thing you stepped over which could be rusty and/or angled... Seems to me like larger trusses (say greater than 4 lanes?) should have some sort of catwalk integrated into them. Yeah, so clearly I don't have any "good" ideas.. just thinking out loud is all I can provide really. Interested to see what you all come up with though so please to chime back in with how this pans out in the end.

I appreciate the thoughts. This scenario doesn't have a "good" idea it has safe and costly or unsafe and efficient. I'm trying to get our safety committee to think it through.

The biggest trusses are 12 feet deep from top to bottom chord. All three chords (including the middle) are round members.

Luckily most of the clearance measurements, the 16ft minimum you mention is to the bottom of the signs, which give an extra 2ish feet to the bottom chord. A fall using our current lanyards attached to the bottom chord you would be safe from trucks 99% of the time (my estimate) due to the clearance, crown of the roadway, etc. If your still coherent you might lift your feet as a precaution.

Hey if OSHA isn't giving you guys s hard time about safety then kudos.. I thought they would have a field day.

How bout installing a steel cable the length of the truss. You could clip onto the cable and be wherever you need to be. Tighten the cable with turn buckles and a possible fall shouldnt be far. There's plenty of nice lanyards and harnesses out there that would work. I own lanyards that stretch to provide dynamic properties.

Pretty sure Jason and crew are solely inspectors stuck with the current state of affairs. That being: no catwalks, via ferratas, or otherwise provisions for a running anchor point along the inside of these trusses. To retrofit these existing structures would be a monumental task that would take months or years of state and federal budgeting, planning, and execution - not to mention billions of taxpayer dollars.

Funny thing is that people (non-climbers) call climbers nuts for climbing but what these guys are doing here makes PG/R/X routes look boring in comparison. If we fall and things fail, we smack the ground or rock face, etc. If these guys fall, they smack the ground and THEN have to dodge traffic while tethered to that which they just fell from or immediately start batmanning the line back up to get out of the way of 75mph+ traffic! Yeah.. no thanks.

..and just wow. 12 feet between chords??? That's a massive truss.

What about some sort of temporary band that you could wrap around diagonals? I'm picturing a heavy duty steel band (big thick hose clamp) with a clasp that functions like a chain load tensioner? One of these:

Leave these along the way at prudent intervals in lead climbing fashion?

edit: Obviously, not something that large. I was suggesting the bands to have a mechanism that functions with characteristics similar to a chain clamp [above]. Some sort of locking feature could be incorporated to ensure the clamp didn't come undone.

The more I think about this method though (leading), the more it seems that the additional gear is going to increase the risk of a fall. :/

i'd imagine scooting your ass along the top beam with 2 slings around it, disconnecting one at a time moving them past a vertical beam would be the safest. that would give you the most distance between you and traffic if you fell, so a screamer could be used. and the 3 outer beams look round, which would be ideal for slinging.

This is what I'm picturing but with a secondary lock and provision for hanger or clip point for quick draw or other rope attachment point.

Different size band ranges to accommodate various chord and diagonal thickness.

Regarding Benlucky's suggestion, is there a requirement for you to inspect the truss from the inside or can it be done from outside the truss?

Am I getting this correct?
One guy walks the truss from the bucket truck, across, then back.
Double lanyards, alternately connecting to each strut as the only anchor point, which if he falls he faces the possible sawing effect and maybe or maybe not dangling low enough for a possible truck strike?

If the lanyard whips down the strut along with you, and you hit the bottom after an additional six foot fall, I would think that falls under the same scenario as falling on a daisy or sling from above an anchor. Bad juju.

If you're crossing from one side to the other in a single direction and exiting the other side, I can see how adding a roped belay would inconvenience you from a time perspective, even if conducted in multi-pitch style.

If you're crossing then returning, other than the inconvenience of carrying a number of slings, I don't follow how that would reduce efficiency substantially vs the gain in safety factor...

And finally, since you're obviously not going to retrofit these trusses with catwalks or safety cables, would a kleimheist or similar friction hitch hold slings in position on the struts (even though they appear to be square/rectangular)? If so, that could eliminate the sliding/sawing effect and/or make a roped belay feasible.

You said yourself, it's a matter of safety vs efficiency. Yes, there hasn't been a fall in 10 years, but how many accidents would it take to negate the gain in efficiency you get by sacrificing safety?