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Liability for harness tie off
3

Liability for harness tie off

Liability for harness tie off

(OP)
A glazier has asked me to provide structural calculations for a concrete anchor bolt use to tie off his harnesses which he will use in multiple locations on a skyscraper during glass replacement. They do the replacement from the inside of the building, and the anchor bolt will hopefully never see load.

Is this a high liability assignment? Would I be named in the lawsuit if there was an accident unrelated to the anchor failing ? Or is this more like designing a catwalk for an industrial plant?

RE: Liability for harness tie off

Yes.
Yes.
No.

RE: Liability for harness tie off

I don't think Ron's reply was brief enough.

RE: Liability for harness tie off

(OP)
I had vague sense that this would be high liability, but does anyone have any war stories about an engineer getting sucked into a situation like this?

I have a PE, btw.[/sup]

RE: Liability for harness tie off

No war stories, but this must be nothing compared to being the Struct EOR for any condo.

RE: Liability for harness tie off

(OP)
AELLC - interesting comparison to condos.

RE: Liability for harness tie off

I did incredibly scary stuff when I did struct engrg for offshore oil platforms, but condos and the lawyers that swirl around them is much scarier...

RE: Liability for harness tie off

(OP)
Since we are all numbers people, assign a dollar value to taking the responsibility for designing one safety harness related anchor bolt. Assume a 40 story office building built in the 80's in NYC. The glazier probably comes back once per year for the next 20 years to replace a couple of panels at a time.

My rule of thumb is that if anything happens, innocent parties have to spend $50k to extract themselves in legal fees and settlements. If its got a 1% chance of occurring, my risk premium is $500, which doesn't seem too bad.

If this were a condo, the chance of the lawsuit would be probably more like 20%.

RE: Liability for harness tie off

I also ask myself, am I running short on billable this month, should I take on a very risky job?

But never a condo.

RE: Liability for harness tie off

(OP)
You can and should do condos if they pay you for the risk you are taking, which does occur on occasion. Some of the NYC structural firms in the 2006 condo boom were making big money from condos. Partners were taking home 7 figure bonuses. Along side that, they laid off most of their staff in 2008, are probably paying 10% of their receivables in E+O insurance, and have in house counsel for the constant stream of legal action.

RE: Liability for harness tie off

Probably also a huge difference in concrete/steel vs wood construction.

The wood construction, including deterioration of any ltwt. conc. floor topping, is a ticking time bomb.

RE: Liability for harness tie off

(OP)
Are they building timber joists with concrete decks now? God forbid developers should do things properly.

RE: Liability for harness tie off

glass99...that's the world I live in. Most of what I do is construction and structural forensics so I see problems. I see engineers get sued for a variety of things, mostly because they have an insurance policy to chase.

What you asked is a very high liability issue because its failure would result in a personal injury. When you're dealing with property damage, it's only money. When you're dealing with a person's life, it takes on a whole new meaning.

As for liability....your fee level has no relationship to the liability to which you'll be exposed. It doesn't make any difference if your fee is $1000 or $100,000....your exposure can be in the millions on either.

Exposure does not necessarily equate to liability. We are always exposed, but our true liability often depends on our diligence or lack thereof. When we write proposals and reports, the intent is to limit our exposure.....try not to get invited to the party....the one the lawyers are attending. If you have true liability, they'll find you anyway.

RE: Liability for harness tie off

(OP)
Ron: good point about it being personal injury as opposed to property damage.

There must be some level of fee that would cover the weighted risks involved. The risk is not infinite.

RE: Liability for harness tie off

@ glass:

Wood is very common here for condos, the low rise kind at least. Plywood alone may result in bouncy floors, and soft spots, even with 1-1/8". So the common practice is to top w/ 1.5" gypcrete or ltwt conc, then that is nightmare if it wasn't done right, years later.

RE: Liability for harness tie off

Any structure could kill anyone, especially during construction, so this OP didn't worry me extremely.

One example was the hotel under construction, spindly barely-adequate pipe column, steel beam, builder stupidly started placing Dycore only on one side of the beam, column wasn't braced, then a construction worker below was crushed to death.

RE: Liability for harness tie off

(OP)
AELLC - does the concrete not crack? Timber creeps unevenly based on load variations etc. For residential renovation work here in NYC you see 100 year old timber joists that have sagged by 3 inches over 20ft.

RE: Liability for harness tie off

It cracks, therin lies the problem. Oy Vey.

RE: Liability for harness tie off

In Santa Fe, I did tons of renov work. Opposite there. The timber becomes hader than concrete. Like the

RE: Liability for harness tie off

(OP)
Oy Vey is right. I would rather have a plywood floor. I have used cement board on top of light gage metal studs for floors, and its rock solid and cheap. Although maybe not cheap enough.

RE: Liability for harness tie off

The best most practical method for customs is 1-1/8" T&G, glued and screwed. The builders here have a cute slang for that which is unprintable.

RE: Liability for harness tie off

(OP)
Developers are so frigin' sketchy it makes me want to puke. No corner left un-cut! Why use metal when plastic is cheaper? The condo owners are too f*cking dumb to know the difference! That is until they wise up and hire someone smart like Ron to do a forensic investigation, and they turn into a lynch mob hell bent on retribution.

RE: Liability for harness tie off

Tract home builders are the worst, but the few that I deal with are relatively polite.

Tract is only about 10% of my biz anyway.

Back when I did wood condo and multi-family (I was an employee), it took 6 months for the daily revisions to stop. That left me burned out to the point I couldn't do that stuff anymore. The construction methods were not as shabby as tract, but it took 6 months to finish every project, and I like to get things done with less revisions and confusion.

RE: Liability for harness tie off

(OP)
Speaking of liability:

I have a client who wants to build a structural glass slippery slide on the outside of a skyscraper right on top of a seismic fault, from the 70th floor down to the 69th floor . Basically a big glass tube. Cost is no object. What could possibly go wrong?

RE: Liability for harness tie off

I am glad I am not in your biz.

I did work on the Stratosphere Tower in LV that made me very nervous, but am glad I survived that.

RE: Liability for harness tie off

(OP)
The difference between the glass slippery slide and the harness anchor bolt is that we are going to engineer the pants off the slippery slide. The whole enchilada, including fancy materials, prototypes, testing, fancy FEA, quality control to aerospace standards, peer review, and they are going to pay for it. Everyone expects the anchor bolt to be nothing and easy, so they pay for like 5 minutes of your time, but you are just as liable.

The roller coaster thing on the top of the Stratosphere tower is a similar concept.

RE: Liability for harness tie off

I had nothing to do with that roller coaster, but the stuff I did for the MGM Grand Amusement Park was a royal PITA.

I do have a slightly funny story about the "Stupak Tower" and a few not so funny.

RE: Liability for harness tie off

I imagine this customer is a repeat client, needs a stamp for his roof anchor, and because glass99 is his guy, he needs to do it. if not for this job, then to keep the next ones coming in.

What do they want to hang? a swing stage or just a bosun chair? I would over engineer the hell out of it, with backup supports should one fail for whatever reason. Tell them your going to need a big chunk of change to pay to up your insurance- this scope of work carries high liability. Inspect the installation, and stipulate that once the work is complete, the anchors must be removed.

Believe it or not, construction workers have been taking care of themselves for years, hanging swing stages and bosun chairs off the sides of buildings safely. They aren't just hopping on any shady line 300ft up. My guess is this request originated with the general contractor. Large contractors are so concerned with liability that the safety requirements on building construction sites have gotten ridiculous in recent years. I wouldn't be surprised if you give your client a bill, they'll pass it on to the general as an extra, and suddenly the glaziers won't need engineered supports anymore.

RE: Liability for harness tie off

(OP)
NorthCivil: You have described the situation pretty much bang on. Its a repeat client and a bit of an over-cautious request from the building owner to be "safer". The only difference is that these anchors will probably never see load because they are just a harness tie off on an as needed basis. If they have a broken facade panel on the 25th floor, 11th bay from the east, they want to pop an anchor in only at that location. No one should ever hang from the anchor because they do the work from the inside. They asked for some sort of powder actuated fastener so that the anchor can be installed quickly, though that's probably going to be hard for me to sign off on. Its going to be hard to inspect.

RE: Liability for harness tie off

Well without wanting to get sucked into discussions on timber vs concrete , the rule of thumb I use for such anchors is they have to withstand 5000 lbs. Now in good rock conditions I can get this quite easily but the hardware I use, and installation techniques are a bit more substanstanial than the average dummy GC might be expecting, and I certainlly wouldnt trust any kind of explosive actuated tool. And the main practical issue is the quality of installation ...... I can and do a design for 40,0000lb loads , but if the guy doing the install is not the same guy whose life is on the line when a load is put on the anchor , my enginneering calcs arent worth a pinch of s**t

RE: Liability for harness tie off

glass99,

Now i see a little more clearly what you've got going on. I had thought you needed an anchor to the roof, to hang over the side. You really just need an anchor for the guys working on the inside, in case they fall out the open hole.

I'm really not a fan of the idea of powder actuated fasteners into concrete. you never really know what the shape of the concrete is that you are nailing to. into steel would let me fall asleep a little easier. Still surprised this is the way they want to go about it... why not let the tradesmen figure out where to tie their harness ropes around the nearest sound spot? Classic case of a bunch of suits over complicating things. And they say us engineers have our heads in the sky...

RE: Liability for harness tie off

I would have a quick word with your client about the absurdity of the situation, and give him a big fat quote for the job, quickly detailing why its so expensive. have your client pass it along to the owner, who can get all upset about it. Either he'll decide he doesn't need the anchors stamped, or he'll pay the bill. Win-win either way. If he pays it, then the next time you have a slow afternoon you can take your client out to a round of golf.

RE: Liability for harness tie off

(OP)
@NorthCivil. Yes, the situation is madness. Not only is the work being done from the inside of the building, but there is 3 ft tall solid wall above the floor before the glass starts, so you have this barricade preventing you from falling out. It is a matter of people in suits trying to transfer risk from their ledger to mine.

@miningman. Thanks, good to hear what other folks are using. 5000lb is a lot, but I guess you don't want to mess with safety.

RE: Liability for harness tie off

OSHA require a "PE-designed"/"engineered" certification for any anchor used to tie off a worker.

5,000 lbs load per person for each anchor requirement. That is, one anchor per person, that anchor needs to be rated to 5000 lbs for aperson to tie off their harness to. So, find an interior wall for each room, drill through to the other side and bolt a backing plate on each side. The anchor bolt goes through the wall with a loop on each end for the tie off hook.

to prevent future liability (er, use) require the anchor bolts and plates be removed when done.

RE: Liability for harness tie off

(OP)
rocookpe1978 - thanks, i didn't know that the 5000lb thing was actually an OSHA requirement. Good to know!

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