53 



Since 



=A, ./, (4-f-r+y) 

 . , M 



*** / I fi * 



and from / s =n . f c . 



dex 



~ Js 'n (dex) 



Derivation of formulae for use of T beams is obtained 

 thus: 





x -~- = a , 



E c 



.-.xr=a.n 



_a.n 



x r 



and since 7 = C. 



2 " 



f c .x.bj>.x 

 M 



From formula (4) = b , n . (d _ e} 



2r(r+n 



n(d-e)' 



