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CONCRETE DESIGN 



The Joint Committee recommends that the bonding stress 

 between plain reinforcing bars and concrete be assumed to 

 be 80 Ib. and in the case of drawn wire, to be 40 Ib. for the 

 same grade of concrete as specified in discussing beams. 

 The difference in stress in the tensile steel at two sections 

 must be taken up by the bond to the concrete between these 

 two sections and should be investigated. 

 COLUMNS 



Concentrically Loaded Columns. There are two general 

 methods of reinforcing concrete columns with steel. One 



FIG. 3 



method is known as straight reinforcement and the other as 

 hooped reinforcement. These two styles of reinforcement are 

 illustrated in Fig. 3. In (a) is shown straight reinforcement. 

 This consists of steel rods that stand vertically in the con- 

 crete. Sometimes, the rods are placed directly in the middle 

 of the column, but as a rule they are arranged around the 

 outside of the column about 2 in. from the surface. These 

 steel rods are tied together by wire ties, as shown at a. The 



