Identification of Cracks

Q1 a

Observations

• From the picture we can see that there is spalling of concrete at the bottom of the beam
• The reinforcement are visible, but there is no damage at the top side of the beam.
• The cracks are developed at the bottom means rebar yeilding occurs at the bottom only.

Answer

• This is a form of flexure failure due to stress reversal during earthquake.
• During earthquake support top experiences compression and bottom experiences tension.
• Since there is a slab above which manages the top compression but at bottom it wasnt managed because tension was not satisfied by the r/f provided.
• Now this is a failure where R/f got yeilded hence it cannot be repaired.

Q1 b

Observations

• Visible from image above we can see that there are cracks develop at the junction of beam and column
• Now this is a crack and conc is not crushed.

Answer

• Its beam pull out failure due to insufficient development length of r/f in joints
• Now when the lateral forces were applied due to Earthquake the condition became worse.
• Now to provide Anchorage in this structure is very difficult task, hence it cannot be repaired.

Q1 c

Observations

• We can see cracks are devloped at the junction of beam column.
• Large visible crack are to be seen across the width of beam.
• We can also see the crack being developed on the slab.

Answer

• This is a classic example of plastic hinge failure.
• The damage are seen to be occurred at the joints.
• Cyclic lateral loading and stress reversal leads to this cracking or damage to the structural elements.
• Even slab tried to handle the stress but couldn't help, leading to cracks been developed on slab.
• It can be strengthened.

Q2 a

Observations

• Spalling of concrete is visible on the column.
• We can also observe that its a exterior column.
• This column is either or parking space or entry point because there is no partician wall.
• We can also observe that the damage is limited to the column and beam is intact.

Answer

• This is a soft storey failure, there is a formation of plastic hinge.
• Due to the absence of wall in the GF, the plastic hinge is formed at the top of GF column.
• Based on the development of crush of concrete it can be either repairable or not repairable

Q2 b

Observations

• this the most severe damage can be seen on the column.
• The spalling of cconcrete resulting the R/F is been exposed.

Answer

• Spalling of concrete is visible, this is a shear failure.
• We can see that main r/f are intact and placed properly which the shear r/f are not spaced properly.
• This cannot be repaired

Q2 c

Observations

• We can see the column is disconnected from the joint, also we can see the mid span a slab is provided.
• The props used of wooden planks and bamboo are used to support the structure.

Answer

• This is short column failure.
• The connection of beam and slab at the midheight leads to this effects.
• The connection here is unintentional and wasnt accounted in design.
• This is not repairable.