Decartes
Structural
- Oct 23, 2001
- 8
thread507-253979
EST = Equivalent Solid Thickness and is calculated based on the "Absoulte Volume" of the CMU Block divided by the Face Shell Area (usually equal to 7.625"x15.625"/144 = 0.83 ft^3). This "absolute volume" (founded by testing:see includes the ENTIRE horizontal cross-sectional area of the block/wall (which also includes the "toe areas" at the web and face shell intersections). The "An" (Net Area) values from NCMA Tek Notes (TEK 14-1B,2007) is based on the "Mortar Bedding" on the block's horizontal cross-sectional area, i.e. Full or Face Shell(note: face shell thickness may be 1.25" or 1.375" or 2", varies!-Pay attention when using these tables). This "An" is the correct values to use when considering the stress on the "motar bedded area" due to Axial and bending loads, especially for unreinforced CMU. RMEH's 'fa = P/(EST)x(b =12")' is considering "full bedding". Engineer judgement must be used here.
EST = Equivalent Solid Thickness and is calculated based on the "Absoulte Volume" of the CMU Block divided by the Face Shell Area (usually equal to 7.625"x15.625"/144 = 0.83 ft^3). This "absolute volume" (founded by testing:see includes the ENTIRE horizontal cross-sectional area of the block/wall (which also includes the "toe areas" at the web and face shell intersections). The "An" (Net Area) values from NCMA Tek Notes (TEK 14-1B,2007) is based on the "Mortar Bedding" on the block's horizontal cross-sectional area, i.e. Full or Face Shell(note: face shell thickness may be 1.25" or 1.375" or 2", varies!-Pay attention when using these tables). This "An" is the correct values to use when considering the stress on the "motar bedded area" due to Axial and bending loads, especially for unreinforced CMU. RMEH's 'fa = P/(EST)x(b =12")' is considering "full bedding". Engineer judgement must be used here.