STEEL REINFORCEMENT 



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tensile nor compressive stress at the neutral axis. Therefore, 

 the point in the beam marked a, which is on the neutral axis, 

 is subjected to zero stress. 



Imagine that the concrete is cut away below the neutral 

 plane, leaving the steel reinforcing rods, or bars, exposed as 

 at b. It is evident that the strength of the beam is not much 

 affected by the cutting away of the concrete in this manner, 

 as the necessary tension below the neutral axis is supplied by 

 the reinforcing rods of steel, while the necessary compression 



ft e 



above it is furnished by the concrete, as at c, c. The amount 

 of compression in each square inch of concrete above the 

 neutral axis varies from zero at the axis to maximum at 

 the extreme upper surface of the beam. The concrete 

 below the neutral axis y y is usually so filled with very fine 

 cracks that all the tension must be carried by the steel alone. 

 In ordinary reinforced-concrete column construction, 

 merely vertical rods are employed. They are tied, however, 

 at intervals with wire or other ties. 



