298 CONCRETE DESIGN 



.02199, d=lS, and d' = 2. Assuming that 

 12X18 



n = 15 and substituting these values in the formula, 



k = -\,'2X15 L01736 + . 02199 Xj + 152(.01736 + .02199) 2 



- 15(.01736 + .02199) = .380. 



6M 

 Now, F c = - ' 



Substituting the values in this equation, 

 _ 6X945,000 



" 



,2X 18.3X m-^X*- A) (1 - 



= 651 Ib. per sq. in., 



which, according to the stresses used in these examples, 

 is about safe. 



The stress in the steel in tension is found by the formula, 



Substituting the correct values, 



1 380 



' F J = 15X651X = 15,930 Ib. per sq. in.. 

 .380 



which is also safe. 



The stress in the steel in. compression is found by the 

 formula j' 



Substituting the correct values, 



380 - -A 



F/ = 15X651 X = 6,913 Ib. per sq. m. 

 .380 



This value is low, but it cannot be helped. It is this fact 

 that makes the double reinforced beam uneconomical. 



T Beams. The Joint Committee makes the following 

 suggestions in regard to T beams: 



"In beam and slab construction, an effective bond should 

 be provided at the junction of the beam and slab. When 



