Using Angles for a Coped W-Beam Seat

[dlclarkii]

I'm designing a crane bridge beam with a coped beam seat for the bridge. I've always used a flat plate as an intermediate flange for the bearing plate. The contractor is asking if they can use two angles as the intermediate flange for the bearing plate with the web of the bridge beam sandwiched instead of using one flat plate as the bearing plate. Is there any concern with this approach? Never done it this way.

Thanks,

 

[MotorCity]

I think I have an idea what you are trying to do, but can you post a sketch for clarification? If my understanding of your situation is correct, I don't see a problem with it as long as the outstanding legs of the angle and the welds are designed accordingly. The only area you may run into trouble is checking fatigue. The detail you are proposing may be a more penalizing stress category. (so, you are designing the BRIDGE beam? my experience has been that this is designed by the crane manufacturer and that structural engineers only design the runway beam)

 

[dhengr]

Actually, the double angle detail might lead to a better stress and fatigue condition and detail. In the first instance a 8x10" x .75" bearing plate (or some such) is welded to the beam web, with the two welds terminating short of the edge of the pl. and short of the cope radius. In both cases the cope radius should be ground and cleaning up of any cutting notches, etc. for a nice smooth transition radius. In the second case, the double angles can extend a foot beyond the cope, out into the beam, for improved shear cap’y. and stresses in that region, and they are set so the horiz. web cut is .25-.375" above the horiz. angle legs/flgs. so as to leave a weld groove to be filled btwn. the beam web and the angle heels. Again, the welds should stop and start short of the cope radius. Otherwise, the angles can be welded all around, and in the groove length/area they could have a small bevel ground or nibbled on the heels to open up the groove a bit.

 

[hokie66]

But, dhengr, the plate can be slotted to fit around the web. I don't see a lot of difference in the two solutions, except that the angles require more welding.

 

[dhengr]

Hokie:
I guess I’ve seen that detail too, and more than likely used it too, in one form or another. The one advantage of the angles, is that they add considerable extra web material/thickness in an area of the beam where the shear is high and the shear stresses may be quite high because of a deep cope. If the vert. legs on the angles are to long, you may not be able to get into them to weld them to the beam web, the beam flg. will be in the way for welding access.