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blow out of side face due to shear loads on bolts
how do people satisfy themselves that the bolt will not blow out the side of the concrete and confirm the edge distance required. im uk based so aci guide reference will not helo im afraid. theory based stuff needed!
thanks all.
are you talking about a cast-in anchor, a through-bolt or a drop in/post-casting installed anchor?
if you're talking about a through bolt or a cast-in anchor i use a u-shaped loop of reinforcing bar and develop it back into the main mass of concrete... i specify that the u-bar be tied tight to the cast-in element (anchor or duct) and cast the section solid. no great deal of theory required; just bar development and good detailing.
regarding post-install, i just follow the hilti guidelines. they are my favorite fastener manufacturer, if only because of how detailed and in depth their design procedures are.
typically i only ever have this situation with individual or single line of fasteners in tilt-up panels. i'd probably try to stay away from the edge if dealing with a narrow section like a strip footing. groups of bolts typically behave well thanks to the connecting plate and u-bars into the main slab.
hopefully there will be other people with opinions; i'll be quite interested to see what they have to say...
cheers,
ys
b.eng (carleton)
working in new zealand, thinking of my snow covered home...
i was typically looking at a baseplate with 4 cast in bolts. for ease of construction we generally dont loop around bars. just provide flat slab with rc both ways so i am relying on the concrete only. although we will have side bars.
try to get this
fastenings to concrete and masonry structures: state of the art report (hardcover)
by comit e euro-international du b eton
aci basically follows this anyway. there should be eurocodes available.
if you are using proprietary fixings (hilti, rawl, liebig, spit etc) the you can consult the etag guidance. this is a standard for assessment and testing of fixings on which the capacities of manufacturers fixings are determined.
it has a lot on the effect of edge distance, reductions depending on distance, grouping etc. annex c is the design guide. as you are using cast in fixings this may not be directly applicable but is worth noting for the future. |
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