F‹C 40 ‘ã ”¯Œ^ ƒƒ“ƒY ƒc[ ƒuƒƒbƒN 296721
F y C = T and Mn = T(da/2) where f' c = concrete compression strength a = height of stress block b = width of stress block f y = steel yield strength A s = area of steel reinforcement d = effective depth of section (depth to na of reinforcement) With C=T, Asfy = 085 f´cba so a can be determined with f b A f a c s y c 085 Criteria for Fahrenheit Wikipedia F‹C 40 'ã "¯Œ^ ƒƒ"ƒY ƒc[ ƒuƒƒbƒN