Installing a 2 post lift (not my first one). 8 out of 10 anchors worked just fine. 2 spin out. I used the proper tools, etc. (I know someone will be foaming at the mouth to ask even though it is irrelevant at this point). Can't pull them, can't relocate the lift, concrete too thick to pound anchors through. I welded a large washer on the anchor bolt and then a large eye bolt. I stuck a rod of steel through the eye bolt to hold the anchor in place while I tightened the nut. I have tightened the nut to 110 foot pounds (spec for this anchor) with a 1/2" torque wrench with crowfoot wrench (can't get a socket on with eye bolt welded on top). I tried welding nuts, vice grips, etc. before the eye bolt and it failed, so there was a lot of continued spinning before using the eye bolt method. I think the wedge spread, but spinning because a groove was made in the hole by the wings being spread. Am I off my rocker here? Any other suggestions? Or should I just go with it? I still have the other one to tackle, just haven't got to it yet. Thanks for the comments and help!
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ANOTHER WEDGE ANCHOR SPINNING QUESTION
- Thread starter rock7174
- Start date
wssix99
Well-known member
If you have the torque on the nut, then you are good. It sounds like you are on a good path! Torque on the nut is a funciton of the tension required within the bolt needed to confirm you have a safe hold on the concrete. If you have the torque and the bolt isn't coming out, then the wings have spread. (If they weren't spread, the bolt would pull out.)
The only little concern is that when these spin and we lift up for a bite, the penetration of the bolt isn't all the way down in the hole. This reduces the holding power of the connection, but the lift manufacturers build in factors of safety for this. (They usually make the bolts a little longer than they need to be and over design the connection so bolting every single hole perfectly isn't critical.) Sometimes the lift instructions will give specifications of maximum threads visible on the bolts above the nut in order to confirm the right level of penetration. If you had significant uplift in the holes and/or have any concerns once you are all bolted in, the lift manufacturers will typcially work with you to give you the green light based on how far you were able to sink the bolts.
The only little concern is that when these spin and we lift up for a bite, the penetration of the bolt isn't all the way down in the hole. This reduces the holding power of the connection, but the lift manufacturers build in factors of safety for this. (They usually make the bolts a little longer than they need to be and over design the connection so bolting every single hole perfectly isn't critical.) Sometimes the lift instructions will give specifications of maximum threads visible on the bolts above the nut in order to confirm the right level of penetration. If you had significant uplift in the holes and/or have any concerns once you are all bolted in, the lift manufacturers will typcially work with you to give you the green light based on how far you were able to sink the bolts.
I appreciate the reply. I've done a ton of mechanical work in my day, but just needed a little reassurance. You would think with all the bright minds in this world, there would be a fool proof anchor. Maybe start selling these lifts with epoxied anchors? Anyways, thanks again!
nadogail
Well-known member
I don't mean to minimize your concerns about the Spinning Anchor.
Whenever an Idiot Proof design hits this world, some village breeds a better idiot.
Whenever an Idiot Proof design hits this world, some village breeds a better idiot.
wssix99
Well-known member
I appreciate the reply. I've done a ton of mechanical work in my day, but just needed a little reassurance. You would think with all the bright minds in this world, there would be a fool proof anchor. Maybe start selling these lifts with epoxied anchors? Anyways, thanks again!
I had this probablem frequently with my first lift and then started using a new bit for every install and then also used a $80 diamond coated, rebar cutting bit in the area where I have steel. Those switches (while more expensive) removed a lot of the headaches.
With a perfect hole, the wedge anchors are fool-proof. Epoxy is problematic and much harder to get a "fool-proof" installation. (Their max strength requires getting a perfect bond all the way through the hole. If there are any issues towards the bottom of an epoxied hole, their holding power decreaces dramatically.)
strutaeng
Well-known member
There's pros and cons to each anchor system; nothin is foolproof.
In the past I sometimes had push back from contractors saying the wedge anchors took too long to install; I've since been specifying more concrete screw anchors, provided the loads are light to modest. Contractors like to drill and drive them. It's faster.
I still specify wedge anchors if loads are higher; they do generally have higher capacity. Sometimes that's the only thing that works.
Epoxy anchors are also good. I like epoxy, but it does have more things to follow on instructions, then there's temperature, set time, etc. Benefit is you can get deeper embedments.
OP, I would contact the manufacturer of the anchor. Hilti, Simpson, Dewalt (Powers) are the ones we use, and they have technicians that can help you out. Not sure of the other manufacturers out there, but you can always call them.
In the past I sometimes had push back from contractors saying the wedge anchors took too long to install; I've since been specifying more concrete screw anchors, provided the loads are light to modest. Contractors like to drill and drive them. It's faster.
I still specify wedge anchors if loads are higher; they do generally have higher capacity. Sometimes that's the only thing that works.
Epoxy anchors are also good. I like epoxy, but it does have more things to follow on instructions, then there's temperature, set time, etc. Benefit is you can get deeper embedments.
OP, I would contact the manufacturer of the anchor. Hilti, Simpson, Dewalt (Powers) are the ones we use, and they have technicians that can help you out. Not sure of the other manufacturers out there, but you can always call them.
I contacted the lift manufacturer, I’m good to go. They said my assumptions were correct. BTW, I will say AGAIN that I used the correct equipment. New bit, etc. Not my first spinning anchor, just the first stubborn one that would still spin after welding something to the bolt and using other methods. The is finished the other spun one last night. No longer spins and is torqued to spec.