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Re: Need "Flitch-plate" design example

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Bruce

Agreed.  I generally find a greater number of connectors near the end.  I also usually specify a double (or staggered) row of connectors, not just on the neutral axis.  The adding of a side plate may, as I noted before, add torsional complexities due to relative stiffnesses taking the centre of shear out from the section centroid and therefore needs greater care in applying simplistic analysis.  Also as you pointed out the stability of the plate itself may be compromised by being on the outside but again good bolt detailing can minimize the problem.  I still think that the flitch plate can be used in most simple cases by considering the collection as a simple transformed section without too much worry.

Thor
Subject: Re: Need +ACI-Flitch-plate+ACI- design example


+AD4-Thor
+AD4-
+AD4-Sorry,  but I always use the critical bolting for either plate buckling or 
+AD4-for horizontal shear.  True composite action can only be acheived for proper 
+AD4-horizontal shear transfer.   Otherwise the combined action depends on the 
+AD4-end bearing situation and the relative stiffness of the respective elements.  
+AD4-This clearly will be satisfactory in many cases.
+AD4-
+AD4-In the case under consideration I assume the an existing timber beam has to 
+AD4-be supplemented.  (I have deleted the original message so stand to be 
+AD4-corrected.)  In this case the end bearing is likely to be through the 
+AD4-timber.  Then a load transfer operation is required for the steel plate to 
+AD4-be effective. E.G. jack up the timber beam, fix the flitch plate and release 
+AD4-the beam for the load transfer onto the composite section.   And for the 
+AD4-steel plate to be properly utilised the horizontal shear transfer needs to 
+AD4-take place.  At the beam ends I often find that the shear transfer  governs 
+AD4-bolt spacing,  and then in the timber/bolt bearing stress.
+AD4-
+AD4---------------------------------------------------
+AD4-Bruce Shephard, Principal Consultant Seismic Risk
+AD4-Opus International Consultants, New Zealand
+AD4-DD Telephone  4 4717597,  Fax  4 4711397
+AD4-Email bruce.shephard+AEA-opus.co.nz
+AD4---------------------------------------------------