364 COST DATA 



WL 



simple beam, the bending moment shall be taken as . 



16 



"When the shearing stresses developed in any part of a 

 reinforced -concrete building exceed the shearing strength as 

 fixed in this section, a sufficient amount of steel shall be 

 introduced in such a position that the deficiency in the 

 resistance to shear is overcome. 



"When the safe limit of adhesion between the concrete and 

 steel is exceeded, provision must be made for transmitting 

 the strength of the steel to the concrete. 



"Reinforced concrete may be used with the unit stresses, 

 previously given, for columns in which the ratio of the length 

 to least side or diameter does not exceed fifteen. If more 

 tfyan fifteen diameters, the allowable stress shall be decreased 

 proportionally. Reinforcing rods that are introduced for 

 lateral stresses must be tied together at intervals of not more 

 than the least side or diameter of the columns. 



"Longitudinal reinforcing rods will not be considered as 

 taking ,ny direct compression. 



"The contractor must be prepared to make load tests in any 

 portion of a reinforced-concrete building within a reasonable 

 time after erection, and as often as may be required by the 

 Chief of the Bureau of Building Inspection. The tests must 

 show that the construction will sustain a load equal to twice 

 the calculated live load without signs of cracks." 



COST DATA 



The cost of reinforced-concrete construction depends on 

 the local cost of labor and materials. In making an approxi- 

 mate estimate of the cost of a building, unit prices per cubic 

 yard or per square foot of floor surface may be used. These 

 prices are obtained from the cost of similar buildings already 

 erected in the same locality. In making an exact estimate of 

 the cost of a building, the materials can usually be accurately 

 determined and their cost found from the current market 

 prices. The cost of labor, including the placing and mixing 

 of concrete, and the cost of form construction are usually 

 more difficult to determine. The latter cost is greatly 



