Ingenuity
Structural
- May 17, 2001
- 2,374
I have not designed or checked masonry for more than 20+ years - my past masonry design experience was to AU and CAN standards - so I have no experience with the provisions of TMS.
I am involved (on the periphery only) with a project with existing 8" unreinforced CMU wall panels - about 24' high x 15' wide, that 'spans' between bond beam on the top, floor slab/foundation to the base, and reinforced CMU pilaster on both vertical sides.
A re-use of the 1970's building is going to require new 16'H x 3'4" window openings to cut up the wall panels, as per the following graphic:
I am in the middle of verbal disagreement between the contractor and the EoR on what needs to be done to strengthen the resulting wall panels. EoR said no strengthening is required. The contractor is nervous, and rightly so, as I expressed my opinion that it wont work as a 'do-nothing'.
I am uncertain what the window manufacturer is assuming with mullions, but I expect they will assume that the CMU will be SUPPORTING the mullions for in-plane and out-if-plane loadings.
Sorry for the long-back story - my question is, for out-of-plane loads (up to hurricane level wind loads) with flexural failure across the bed joints (wall spanning vertically), what is the allowable flexural tensile stress for UNreincroced concrete masonry, assuming type M or S mortar?
I am involved (on the periphery only) with a project with existing 8" unreinforced CMU wall panels - about 24' high x 15' wide, that 'spans' between bond beam on the top, floor slab/foundation to the base, and reinforced CMU pilaster on both vertical sides.
A re-use of the 1970's building is going to require new 16'H x 3'4" window openings to cut up the wall panels, as per the following graphic:
I am in the middle of verbal disagreement between the contractor and the EoR on what needs to be done to strengthen the resulting wall panels. EoR said no strengthening is required. The contractor is nervous, and rightly so, as I expressed my opinion that it wont work as a 'do-nothing'.
I am uncertain what the window manufacturer is assuming with mullions, but I expect they will assume that the CMU will be SUPPORTING the mullions for in-plane and out-if-plane loadings.
Sorry for the long-back story - my question is, for out-of-plane loads (up to hurricane level wind loads) with flexural failure across the bed joints (wall spanning vertically), what is the allowable flexural tensile stress for UNreincroced concrete masonry, assuming type M or S mortar?
