Identification of Cracks

Ans 1a:

• Its is a form of Flexural Failure due to reversal of stress during earthquake.
• During Stress reversal, support top experiences Compression and Bottom experiences tension.
• Top compression is managed by Slab advantage. Bottom tension was not satisfied by the provided reinforcement.
• Since the reinforcement got yielded, it cannot be repaired.

Ans 1b:

• Its Beam pull out failure due to insufficient developement length of reinforcement in Joints.
• During Earthquake, the horizontal movement of structure makes this condition worse and detached the beam member from column.
• Providing anchorage length between two exixting concrete is very difficult. So not repairable.

Ans 1c:

• It's a Plastic hinge failure.
• The damage occured only in the joint zone firstof all.
• Cyclic lateral loading & stress reversal at the joints led to the damage.
• Even the slab participated to its best to handle the tension ( Slab is severely cracked means it has undergone tension with its flange condiction). But unable to control the damage.
• The joints can be strengthened.

Ans 2a:

• It's a Soft storey failure, Technically Plastic hinge formation.
• Due to absence of infill walls at ground floor, the plastic hinge forms at the top of ground storey columns during Lateral movement.
• Based on the development of crush of concrete it can either be repairable or non-reoairable.

Ans 2b:

• Its a pure shear failure.
• Inadequate shear reinforcement compels concrete takes all the shear stress.

Ans 2c:

• It's a short column failure
• An additional slab or a beam connceted to a column in mid-height leads to this effect.
• This leds to failure especially if the connection is unintentional and not accounted in design.
• The failure given is not at all repairable.