I am building a 16 ft tall masonry wall with a bond beam at the top and it supports hollow core slabs. The superintendent says that the code requires an intermediate horz. bond beam at 8 ft. Is that correct? No, that is incorrect. There is no code, state or national, that requires a bond beam at 8 ft in non-seismic zones. The FBC 6th Ed. specifically exempts Florida from ANY seismic considerations so the seismic issue cannot apply. Florida's seismic category would not require intermediate bond beams in any case.
A designer might choose to include bond beams at an intermediate location but that would be a design choice NOT a codes issue.
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What is a typical Florida bond beam and how is it built?Florida masonry bond beams are usually 1 or two courses of bond beam block grouted solid. Bond beam block differs from regular block in that the center webs are cut down to receive horizontal steel. One course bond beams must be tied down at a closer spacing than 2 course bond beams because they don't have as much strength. The masonry industry recommends the two course bond beam for several reasons: Larger allowable spacing between vertical tie downs and a longer embedment length for vertical tie down bars are the main structural reasons.
Cost wise there is not much difference between the one and two course bond beams, especially when bars are only called for in the top course. The mason can lay his block all the way to the top of the wall without stopping. He simply puts in his grout stop under the second course then finishes laying his wall up and places his steel in the top. The second course can be built out of regular block so the only additional cost is about a cubic yard for grout for a typical 2000 sf home. The steel is more effective in the top of the bond beam because of the uplift forces on the roof from wind. To summarize, the most common bond beam used in Florida and the bond beam recommended by the masonry industry is a 2 course solid grouted bond beam with a single bar in the top course. The top course would be bond beam block and the second course would by regular block. Vertical wall steel should hook into the top of the bond beam. The spacing of vertical wall steel will vary depending on your height of wall, span of roof and wind speed. ICC 600 gives specific instruction all of these issues and is accepted by the current 6th Ed, 2017 Florida Building Code, Residential. Engineer from Texas writes "If the specs and code noted are not followed, then Florida Building Code section 2109.5.2 governs, which states that bond beams would then be required spaced not more than 48 inches apart. Is this true? Although I don't have access to the plans and specs I can assure you of two things. The first is that there is no section 2109.5.1 in either the 2014 or the 2017 editions of the Florida Building Code. The second thing is that there is no requirement for bond beams at 48" on center in any code pertaining to the State of Florida.
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