Minimum Bearing of Steel Beam at CMU Wall
Minimum Bearing of Steel Beam at CMU Wall
(OP)
I have a modification to an existing building in which we are removing some precast hollow core planks and replacing it with a composite deck floor system supported by steel beams. I wanted to try and utilize the existing foundation stem walls for support of the beams. I have a 12" thick CMU wall which supports the ends of two of the hollow core planks back to back. We will be removing one of the planks leaving approximately 5-13/16" allowable bearing on the CMU wall for the new steel beam. Is there any code stipulation that specify the minimum bearing of the steel beam in this case. I was going to utilize a bent plate anchored into the face of the CMU wall as a bearing plate and weld the ends of the beam to the bearing plate. Any help would be greatly appreciated.






RE: Minimum Bearing of Steel Beam at CMU Wall
It seems low but that's the code.
RE: Minimum Bearing of Steel Beam at CMU Wall
RE: Minimum Bearing of Steel Beam at CMU Wall
If the steel beam bears on hollow block, provide a poured concrete bearing pad under the beam. Anchor the base plate in the pad and weld the beam to the plate.
If the steel beam bears on top of the existing bond beam, the base plate should bear on the concrete fill, not on the masonry face wall. Anchors should be drilled vertically down into the concrete fill.
If the beam reaction is large, filling cores with concrete below the bearing area may be considered.
BA
RE: Minimum Bearing of Steel Beam at CMU Wall
I have used 8500 psi(net area)8x8x16 hollow CMUs used in a 2 block prism that tested at 4800 psi. - The mortar was 2200 psi and was not involved in the failure mechanism.
The value of the f'm is for masonry structural design were the design involves the design of the wall panels and not a myopic analysis of a small element of a structure. The strength of the concrete in a concrete block is at least 3000 psi and could be as high as 5000-8000 psi. The mortar is much weaker by design.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Minimum Bearing of Steel Beam at CMU Wall
Can you provide a design example of the method stipulated?
Thanks, Dik
RE: Minimum Bearing of Steel Beam at CMU Wall
RE: Minimum Bearing of Steel Beam at CMU Wall