Effect of tension and compression reinforcements on the serviceability of HSC beams with relatively small shear span to depth ratio

Abstract EN

To investigate the serviceability performance of High-Strength Concrete (HSC) beams, 12 beams (L = 2 m, b = 0.

2 m, h = 0.

3 m and shear span to depth ratio of 1.

8) with different ratios of ρ and ρ' (percentage of tensile and compressive steel) were cast and tested under bending.

During the test, concrete and steel strains, deflections, and crack widths were measured at different locations along each beam.

Based on the experimental readings and observations, the cracked moment of inertia (Icr) of HSC beams was determined and the results were compared with some selective theoretical methods.

Also, the flexural crack width of the beams was measured and the applicability of ACI, BS, and CSA code for normal strength concrete (NSC) was verified for HSC beams tested.

The experimental (Icr)exp values of HSC beams were lower than the theoretical (Icr)th values from different codes.

It was concluded that, the serviceability and post serviceability performance of reinforced concrete structures can be improved using high strength concrete.

In general, for almost all HSC tested beams at three crack width (0.

1, 0.

2, 0.

3 mm) ; the use of ACI equation led to predict 50% of the crack width conservatively (the ratio of ((ωcr)th/(ωcr)exp) is greater than unity) but the results of the BS equation are conservative while compare to the ACI equation.

The use of the CSA equation for the beams of higher and lower reinforcement ratio, caused a more conservative, and a closer value respectively, to limiting values of CSA.The deflection at initial steel horizontal yield plateau, is less than 9 mm, which is a sign of excellent deflection performance of HSC beams.