Question

Describe the mechanism of failure of Reinforced Concrete beam in bending        

Answer 1

The mechanism of failure of Reinforced Concrete beam in bending :

The analysis of failure and crack development in beams made of concrete is presented. The analysis was carried out on the basis of the performed experimental investigation and numerical simulations. A fictitious crack model based on nonlinear fracture mechanics was applied to investigate the development of strain softening of tensile concrete in plain concrete and slightly reinforced concrete beams.

The load capacity of concrete structures is affected by the cracking behavior of concrete.

Concrete is considered to be a quasi-brittle material, and therefore, when analyzing the cracking behavior of concrete, not only tensile strength but also tensile toughness is of paramount importance .

A brittle failure due to the formation of a flexural crack takes place in plain and slightly reinforced concrete beams. The strain softening of tensile concrete is of paramount importance when analyzing crack propagation and failure process in these beams. The cracking moment decides about the load carrying capacity of the beams.

The progressive microcracking appears in the tip of the inclined crack, but strain softening of tensile concrete is not the only mechanism of carrying shear stresses.

Failure modes in reinforced concrete beams are classified into two major types:

flexural failure and

shear failure.

Flexural failure modes:

1)Flexural Tension failure

2)Fluxural compression Failure

3)Balanced failure
.Shear Failure Modes

1)Diagonal Tension Failure.

2)Shear Compression Failure.

3)Splitting Shear (True Shear) Failure. 4)Anchorage failure.