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旧 2009-09-09, 09:05 AM   #1
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默认 expansion bolts edge distance reduction for shear

expansion bolts: edge distance reduction for shear
assume an expansion bolt connects something to a concrete foundation wall and is loaded in shear parallel to the wall, with plenty of concrete in either direction parallel to the wall. assume the expansion bolt is close to the edge of the wall in the perpendicular direction. should the recommended shear reduction factor be used, even though the load does not act perpendicular to the wall?
i have always conservatively used the reduction factor in this situation, because i believe expansion bolts resist shear through "shear friction", and a tension cone failure must be avoided, even under shear load. i welcome any comments.
daveatkins
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you can find an explanation in any handbook such as hilti.
shear capacity reduction may be neglected only in case of 180 degrees angle between the edge and the load.
in your case the angle is 90 degrees and shear capacity reduction factor is to be consiedred.
hilti catelog gives you the procedure to get the safe load on these anchors after allowing reduction factors for edge distance and spacing of anchors. if you are using some different anchor bolts then you have to contact the supplier for furnishing these details.
there is an absolute minimum edge distance for each diameter bolt that gives about half of its full capacity.
gosh introduced an interesting idea about 180 degrees. i thought the shear capacity should not take a reduction if the shear is not towards or away from the edge. wouldnt the force 180 degree from the edge cause the bottom of the anchor to "push" toward the edge and thereby reduce the capacity?
just some gut feelings i have...
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