I’ve been pretty heavily focused on investigating a new phenomenon being observed in some of the bolts installed at 82 and the Quarry. These bolts have completely non-functional expansion mechanisms that allows them to be removed from their hole simply by tightening the nut down. The expansion sleeves are never catching and engaging with the tapered cone. In the next couple weeks I’ll have more info on this as I compile some field observations and touch base with additional more knowledgable sources.
So, just to update on the work carried out, I’ve removed the following counts of bolts (by hand) and replaced with glue-ins on the following routes. Note: One of the bolts on Year of the Dog is technically the bolt that protects the traverse to Arms Reduction, and Truffle Hog has already had 2 bolts previously replaced last year that were pulled by hand.
- Politics of Dancing – 2 bolts
- Crimp Chimp – 4 bolts
- Year of the Dog – 4 bolts
- Arms Reduction – 4 bolts
- Quills – 1 bolt
- Truffle Hog – 1 bolt
- Pussy Galore – 1 bolt
2 thoughts on “82/Quarry work”
Likely holes were wet (just damp rock will do it) and not thoroughly cleaned when expansion bolts were installed. Friction is critical in making the expansion portions of expansion bolts expand. Rock dust makes the expansion portion of a bolt not grab as it will spin as if on ball bearings if the hole is not cleaned. Other mistakes witnessed over the years are people not including the plastic portions in the bolt assemblies – either because they fell apart in the box, maybe not included on some bolts (manufacturing defect), or installer didn’t understand the purpose of the pieces. Some of the older Rawl assemblies had spacer washers that allowed the tension to gradually build along the bolt shaft to properly wedge as the bolt was tightened. Rawl also had plastic end caps that were designed to help keep dust from getting onto the bolt threads. Dust on the threads would mess up torquing the bolt (threads jam on the dust) and it would not be properly seated after reaching the appropriate torque on a wrench. Cleanliness is essential for proper installations of any bolting hardware. Other errors are not using a consistent torque during tightening. The process is to gradually increase the torque until (say 28 ft lbs on some makes) the correct limit is reached. Quite often I used to witness installers simply cranking away on their wrench until they said there…that’s tight enough. Unless all components function, the anchor is not secure. Responsible bolting includes verifying the installation on more than one occasion as the bolt weathers in place. Anyone ever hear of applying torques/loads to finished bolts to physically test an installation at lower loads (especially on any questionable installation)? I believe a crowbar helps in this part of the installation skill-set and can be done without damaging anything. It’s simply used to provide enough leverage to verify installations are complete and installed correctly. Hope this helps if you didn’t already know this stuff. BTW – nice work out there – very appreciated.
I actually did a lot of leg work to talk to Raumer, Greg Barnes at the ASCA, & Jim Titt from Bolt Products. Jim has previously spoken with the people who engineered the bolt for its original use in the construction industry for a specific type of concrete with large aggregate. The consensus and Raumer’s final opinion was that the bolt design is just not compatible with softer rock. The idea being that the expansion clip is too strong and never engages in softer rock. This is backed up by Raumer having redesigned this bolt with changes to the expansion clip. That’s also consistent with how all the bolts pulled show an expansion clip that really never deployed.
Pull testing torque-controlled bolts in-situ should be avoided as you can damage the installation unless you have a specific protocol from the manufacturer that has been signed off on by an engineer. Maintenance should be limited to verifying the bolt meets the installer specified torque and tightening to that torque if needed. All of the above bolts failed the torque inspection test and were identified in this manner.
The corollary to that is that a torque wrench is a mandatory tool for properly installing and maintaining any torque-controlled bolt to the manufacturer’s specifications.