REINFORCED CONCRETE. 49 



REINFORCED CONCRETE, Paper III. 



The Adhesion of Concrete to the Steel Reinforcement. The 

 Experimental Determination of the Strain Curves and the 

 position of the Neutral Axis in a Reinforced Concrete 

 Beam subjected to Flexure. The form of the Stress Curves 

 derived from the actual Strain Curves. The Design of 

 Reinforced Concrete Structures. 



By W. H. Warren, wh. sc, m. inst. c.e., m. Am. soc. c.e., 

 Challis Professor of Engineering, Sydney University. 



[Read before the Royal Society of N. S. Wales, September 6, 1905.'] 



The following matters will be dealt with : — 



a. The adhesion of cement mortar and concrete to steel. 



b. The experimental determination of the neutral axis in a 



plain concrete and also in a reinforced concrete beam, 

 and the curves of strain for loads increasing from zero 

 to the load producing fracture, also the determination 

 of the true form of the stress curve from the actual 

 strain curve in a plain and in a reinforced concrete 

 beam. 



c. The safe working stresses and the fundamental equations 



recommended for the design of reinforced concrete 

 structures. 



a. The adhesion of cement mortar and concrete to steel. 



The adhesion of cement mortar and concrete to steel 

 was referred to in a former paper, 1 but the results obtained 

 are given in connection with direct tension tests in which 

 failure occurred by the steel bars pulling out of the heads 

 of the specimens. In the following experiments the adhesion 



1 Further Experiments on the Strength and Elasticity of Reinforced 

 Concrete— Proc. Roy. Soc. N.S. Wales, Sept. 7, 1904. 

 D— Sep.t 6, 1905. 



