2x Failed Rock Anchors in Western Cape

Let everyone know about any suspect/dodgy/misplaced bolts to be renewed or avoided.
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AndyDavies

2x Failed Rock Anchors in Western Cape

Post by AndyDavies » Fri Apr 29, 2005 9:46 pm

This forum has been initiated to deal with TECHNICAL queries regarding the MCSA's \"press release\" about the 2 failed anchors. Please don't post rubbish, else the clutter will confuse this sensitive and technical issue. (andy.davies@eskom.co.za)

Derek Marshall

Post by Derek Marshall » Fri Apr 29, 2005 9:47 pm

On bolts placed at Morgan Bay in 2000. Upat bolts on sea cliff. The bolts attaching hangers(SS Vector)show outward signs of rust. On the same route: bolts attaching(directly) galvanized chain show no signs of rust. (marshall@reworkafrica.co.za)

Paddy

Post by Paddy » Fri Apr 29, 2005 9:48 pm

I have recently found out about torque spanners/wrenches (unsure of terminology) and intend to use them when bolting (if of a feasible size). Question though is what reading should one be setting on the wrench. Any help?

Paddy

Post by Paddy » Fri Apr 29, 2005 9:48 pm

Andy. Not sure if last posting was clutter - but thought the issue was pertinant as I understand overtorquing can contribute to SCC and thus may have been a probable contributor to the failures.

Paddy

Post by Paddy » Fri Apr 29, 2005 9:49 pm

This has got to be a pertinant question. I understand the one failure was at a Montague crag. The report, as I understand it, also attributes that failure to SCC. I thought that SCC would not have been an issue at such an inland crag. Is there a possible explanation for this? It did not seem to come out in the report or I have I missed something.

Derek Marshall

Post by Derek Marshall » Fri Apr 29, 2005 9:49 pm

The box that Hilti 68 & 90mm bolts come in indictes 30Nm of torque. (marshall@reworkafrica.co.za)

Colin Sillman

Post by Colin Sillman » Fri Apr 29, 2005 9:50 pm

The UPAT M10 EXA (double clip) anchor should be set to 45Nm, and the newer fischer FBN 10x90 A4 (single clip) anchors should be set to 30Nm. The FBN 10x90 anchors are now available in A4 (316) stainless steel and are in stock in our Cape Town branch (021) 552-4973. Colin Sillman PrTechEng, UPAT SA (Pty) Ltd 082 824-7377 (colin@fischerfixings.co.za)

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