Sunday River Lift Falls Over

[rogman]

The precipitation for the last 30 days for Rumford (about 30 minutes away) doesn't indicate any unusual weather events, so this had to be an existing problem that perhaps should have been detected. It does point out how lucky Killington was in that no lifts were affected by Irene. It is possible, with the ground frozen, that this sort of accident is less likely in the winter.

I continue to have a problem with REITs owning ski areas. It creates an impossible situation for maintenance personnel. Boyne operates Sunday River, but the equipment and infrastructure is owned by CNL. Capital costs (e.g. lifts) are paid for by CNL. Maintenance costs are paid by Boyne. I assume a failure like this could have been picked up by testing. But wherein lies the responsibility? This sort of checking is beyond routine maintenance. Who pays? Can CNL order Boyne to run appropriate (and presumably expensive) tests to protect their investment? I suspect there is a blurry area in the middle that isn't properly handled.

One failure can be attributed to bad luck and statistics. Two you start to pay attention. I'm sorry, but three failures in a short period of time, you have to sit up and take notice. How embarrassing for Boyne. Are any other organizations seeing similar failure rates? Nobody misses South Ridge more than me, but perhaps Nyberg was correct in removing it.

I suspect there are a lot of nervous ski resort execs this morning, telling their peeps to double and triple check their footings and foundations.

[skiadikt]

looks like sunday river's facing "impending infrastructure collapse" ...

[Big Bob]

Not a very clear picture, but the rebar or rock bolts are straight, not bent into a curve as it pivoted out of the ground. I would assume these were grouted into holes drilled into the bedrock below. As someone noted they look clean with no cementus material stuck to them. The steel may of been rusting which can cause expansive forces. The grout may of failed due to the expansion from the rust. I will be in Norway south of there this weekend, but it sounds like the area is closed off for safety reasons.

[Big Bob]

The precipitation for the last 30 days for Rumford (about 30 minutes away) doesn't indicate any unusual weather events, so this had to be an existing problem that perhaps should have been detected. It does point out how lucky Killington was in that no lifts were affected by Irene. It is possible, with the ground frozen, that this sort of accident is less likely in the winter.

I continue to have a problem with REITs owning ski areas. It creates an impossible situation for maintenance personnel. Boyne operates Sunday River, but the equipment and infrastructure is owned by CNL. Capital costs (e.g. lifts) are paid for by CNL. Maintenance costs are paid by Boyne. I assume a failure like this could have been picked up by testing. But wherein lies the responsibility? This sort of checking is beyond routine maintenance. Who pays? Can CNL order Boyne to run appropriate (and presumably expensive) tests to protect their investment? I suspect there is a blurry area in the middle that isn't properly handled.

One failure can be attributed to bad luck and statistics. Two you start to pay attention. I'm sorry, but three failures in a short period of time, you have to sit up and take notice. How embarrassing for Boyne. Are any other organizations seeing similar failure rates? Nobody misses South Ridge more than me, but perhaps Nyberg was correct in removing it.

I suspect there are a lot of nervous ski resort execs this morning, telling their peeps to double and triple check their footings and foundations.

Other than a load test and visual inspection of the foundation, how would you suggest this failure point be tested? When the carpet loading was installed recently was the lift load tested then?

North east of there a week ago there was a foot of r*in in a day, only a heavy downpour about 10 PM Sat night.

[skixc2]

Well, sh*t

[rogman]

The precipitation for the last 30 days for Rumford (about 30 minutes away) doesn't indicate any unusual weather events, so this had to be an existing problem that perhaps should have been detected. It does point out how lucky Killington was in that no lifts were affected by Irene. It is possible, with the ground frozen, that this sort of accident is less likely in the winter.

I continue to have a problem with REITs owning ski areas. It creates an impossible situation for maintenance personnel. Boyne operates Sunday River, but the equipment and infrastructure is owned by CNL. Capital costs (e.g. lifts) are paid for by CNL. Maintenance costs are paid by Boyne. I assume a failure like this could have been picked up by testing. But wherein lies the responsibility? This sort of checking is beyond routine maintenance. Who pays? Can CNL order Boyne to run appropriate (and presumably expensive) tests to protect their investment? I suspect there is a blurry area in the middle that isn't properly handled.

One failure can be attributed to bad luck and statistics. Two you start to pay attention. I'm sorry, but three failures in a short period of time, you have to sit up and take notice. How embarrassing for Boyne. Are any other organizations seeing similar failure rates? Nobody misses South Ridge more than me, but perhaps Nyberg was correct in removing it.

I suspect there are a lot of nervous ski resort execs this morning, telling their peeps to double and triple check their footings and foundations.

Other than a load test and visual inspection of the foundation, how would you suggest this failure point be tested? When the carpet loading was installed recently was the lift load tested then?

North east of there a week ago there was a foot of r*in in a day, only a heavy downpour about 10 PM Sat night.

About 30 seconds googling "How do you test a concrete foundation" returned this http://www.foundationperformance.org/pr ... c-02-0.pdf (as well as many other answers). I'm not sure why you think testing is not possible. And why are you so quick to give Boyne/CNL a pass on everything? A lot of people could have been killed. Their record speaks for itself.

[rogman]

Go home lift, you're drunk.

[E O Eleven]

[Mister Moose]

Just found this way better photo via Sunday River's forum

In a statement, Sunday River noted, “Decisions on repairing or replacing the lift have not been made at this point and will depend on several factors, including the results of the investigation. The resort is committed to moving forward as quickly as possible.” The mountain is working with its insurance company, Willis MountainGuard, and state investigators. Presumably there is still time to get a brand new lift built in time for the coming 2016-2017 winter season if the order is placed soon.

https://liftblog.com/2016/07/13/sunday- ... more-24693" onclick="window.open(this.href);return false;

Looks like the haul rope completely departed the neighborhood.

[Big Bob]

The precipitation for the last 30 days for Rumford (about 30 minutes away) doesn't indicate any unusual weather events, so this had to be an existing problem that perhaps should have been detected. It does point out how lucky Killington was in that no lifts were affected by Irene. It is possible, with the ground frozen, that this sort of accident is less likely in the winter.

I continue to have a problem with REITs owning ski areas. It creates an impossible situation for maintenance personnel. Boyne operates Sunday River, but the equipment and infrastructure is owned by CNL. Capital costs (e.g. lifts) are paid for by CNL. Maintenance costs are paid by Boyne. I assume a failure like this could have been picked up by testing. But wherein lies the responsibility? This sort of checking is beyond routine maintenance. Who pays? Can CNL order Boyne to run appropriate (and presumably expensive) tests to protect their investment? I suspect there is a blurry area in the middle that isn't properly handled.

One failure can be attributed to bad luck and statistics. Two you start to pay attention. I'm sorry, but three failures in a short period of time, you have to sit up and take notice. How embarrassing for Boyne. Are any other organizations seeing similar failure rates? Nobody misses South Ridge more than me, but perhaps Nyberg was correct in removing it.

I suspect there are a lot of nervous ski resort execs this morning, telling their peeps to double and triple check their footings and foundations.

Other than a load test and visual inspection of the foundation, how would you suggest this failure point be tested? When the carpet loading was installed recently was the lift load tested then?

North east of there a week ago there was a foot of r*in in a day, only a heavy downpour about 10 PM Sat night.

About 30 seconds googling "How do you test a concrete foundation" returned this http://www.foundationperformance.org/pr ... c-02-0.pdf (as well as many other answers). I'm not sure why you think testing is not possible. And why are you so quick to give Boyne/CNL a pass on everything? A lot of people could have been killed. Their record speaks for itself.

I am not giving them a pass on their lift failures. This one is pretty bazaar. Neither Boyne or CNL had this lift built and it may predate Ls Otten. It was load tested last fall. Why did it fail under just a dead load without and live load? Was it struck by lighting? Looking at the larger pictures the rebar does not appear rusted. It was imbedded in the footing foundation with a cold joint at the juncture of the piece of concrete holding the bull wheel and the rebar pulled out by the tension in it. Was the concrete below at design strength or degraded? I am sure the investigation will reveal what caused the failure. And ANSI should defiantly add the screw driver test to the lift inspection foundation criteria you suggested.

[Southside_Bobby]

Chills down the spine..

[Captain Hafski]

FWIW: tension in a cable is constant. For most lifts, the tension in maintained by a counterweight [bottom of most chairs at K, e.g. snowdon triple].

Interestingly, this does not change loaded or unloaded. It's taken up, so to speak, by additional sagging between towers when loaded. Sparing folks some diff eq here.

The vertical downward component does change [increase] when loaded. However, I suspect in this case, it was a horizontal force [the constant cable tension [x2 as Moose pointed out]] and the associated torsional moment that overstressed whatever it was that gave out.

[freeski]

If you have a rope hanging from a tree and you add a 100lb weight there is more downward force on the rope. Are you saying the force on the cable doesn't change if the lift has a counter weight when the lift is at capacity? Is that because it's already under tension?

[Big Bob]

I am sure the cable tension increases with additional load. The counter weight puts a minimum amount of tension on the cable for the lift to spin, think friction between the bull wheel and the cable to drive the cable. The cable has a safety factor of five, so it can takes 5x the design load before breaking.

[Mister Moose]

If you have a rope hanging from a tree and you add a 100lb weight there is more downward force on the rope. Are you saying the force on the cable doesn't change if the lift has a counter weight when the lift is at capacity? Is that because it's already under tension?

You're missing two things:

1) The downward force is (nearly) perpendicular to the cable. 2) The cable tensioning device (in this case a counterweight) moves to regulate tension to be a constant. This is easy to visualize as a counterweight applies a constant weight - lets say 55,000 lbs. (A concrete block 6x6x10) As the load on the cable changes, the counterweight moves, (attached to the lower terminal) and the terminal slides forward and backward as needed. As the load increases, the terminal slides forward, there is less distance between upper and lower terminals, and the cable sags. (Think about where the bamboo poles always are just above the GN crossover under the NRT. When fully loaded, the chairs are low enough to warrant the pole theres to keep skiers from hitting the lowered chairs.)

To make a better comparison, stretch a cable between TWO trees. Now add your 100 lb weight on a rope in the center of the cable. With no counterweight on the cable, the tension will increase on the cable. You would be correct here. However the chairlift does not fix the cable between the two trees. The chairlift takes the cable on one tree over a pulley, and hangs a large weight from it. With the cable freed from the tree and tensioned with a weight, the tension remains constant regardless of the weight you place on your rope.