USEFUL DATA 



Steel ratio, for balanced reinforcement. 



1 



(b) T-Beams. 





(5) 



f fe — -^ : 



A^n- 



FiG. 2. 



Case I. When the neutral axis lies in the flange, use the formulas for rectan- 

 gular beams. 



Case II. When the neutral axis lies in the stem. 



The following formulas neglect the compression in the stem. 

 Position of neutral axis. 



kd= 



.2ndAs+bi'' 



Position of resultant compression, 



z 

 Arm of resisting couple. 



Fiber stresses. 



2nA,-\-2bt 



^3Jc d-2t J_ 

 ^ 2kd-t ' 3 



jd = d—z. 



M 



Ajd 



/c = 



MM 



bt(kd--t)jd 



n 1-k 



(6) 

 (7) 

 (8) 



(9) 



(10) 



(For approximate results the formulas for rectangular beams may be used.) 

 The following formulas take into account the compression in the stem; they are 

 recommended where the flange is small compared with the stem: 

 Position of neutral axis. 



l.^^ J 2ndAs+{b-b')t' ^ / nAs+{b-b')t y 

 Position of resultant compression. 



nA,-\-(b-b% 



(kdi^-^fi)b+[(kd-t)Hii-l(kd-t))]b' 

 t{2M-t)b+{kd-ty V 

 7 



(11) 



(12) 



