Identification of Cracks

1 Answer

Aim: To identify the type of failure from the above figures.

a) Failure due to the improper nominal cover to the beam, Buckling of reinforcement provided in the bottom of the beam and crushing of concrete at the beam- column junction. This type of failure happens if the nominal cover for the beam is inappropriate and the large deformation of the beam due to cyclic loading in which strain is develops cracks.

b)Failure due to insufficient bond strength and improper curing. This type of failure happens when the development length of the reinforcement is insufficient which indirectly decreases the bond strength of the reinforcement and also due to improper curing the cracks develops along the wall.

c)Tension failure at the beam and failure of beam-Column junction due to the earthquake. Junctions are most common type of failure in the earthquake prone areas. To avoid this type of failure the rigidity is avoided at the junctions and proper anchorage and bond strength is provided.

2 Answer

Aim: To identify the type of failure from the above figures.

a) Failure due to Flexural compression in column. This type of failure occurs due to very high axial load in multi storey buildings and also due to bending moments. This type of failure can be avoided by providing high compressive strength concrete and by providing proper longitudinal and lateral ties throughout the column.

b) Shear Failure of the column. This type of failure occurs due to large horizontal loads like wind load and seismic loads like earthquake loads . This type of failure can be avoided by providing the proper shear links and shear connectors and also increasing the size of the column in the direction of the shear which increases the shear capacity.

c) Failure due to crushing. This type of failure occurs due in short column. the column is classified as short column if its slenderness ratio is less than 3. Slenderness ration is the ratio of effective length to least lateral dimension. this type of failure is avoided by providing intermediate column instead of short column that is having slenderness ratio 3 to 12 and also by providing high characteristic compressive strength concrete and high yield steel reinforcement.