Holdfast Training Services Trial Blog

I have another problem, the bottom brackets of my walers clashes with my basement level 5 slab-exactly what we wanted to avoid.   So I need to cut the brackets off before I can lay the slab.  My sub contractor who designed the waler is not so happy with this idea.

My email below:

There are currently 12 bolts either side of the anchor.  If we removed the four bottom bolts this would leave 8 bolts remaining. 

These bolts are AS1252 M30 8.8/s with a shear capacity of 214 KN.  Which would leave the bolts with a total shear capacity of 1712 KN not including the friction of steel on concrete.  If I look at the anchor summary Q2454-0007 and apply the vertical shear at 45 degrees from the safe working load I get the following:

Even if we factored the SWL by 1.5 this would still be within the capacity of the 8 bolts.  Please slap me down if I am being an upstart…

I have since read a paper that indicated the coefficient of steel on dry shotcrete as 0.57, which could potentially reduce my shearing force by 467 KN.  Now part of the problem I believe is that the ground anchor does not act through the ‘middle third’ of the waler and so there is a moment induced and the bolts therefore act in tension and shear reducing their capacity.  How do I get around this and still cut off the brackets?

I have had a look at the UK’s Steel Bluebook and I think that with the bolts in tension the shear capacity is reduced to 80% – I am having issues looking at Australian Standards at the moment though to confirm what they use here.  Any help gratefully received.

The offensive article:

For you Richard: