Identification of Cracks

Ans 1.

(a)

• Observations :

1. The given image showing the Breakage of concrete from below.
2. Concrete leaves out from reinforcement due to tensioning in beam which results in rupture of beam.
3. The top part of beam is safe because of slab connection.
4. The yeilding of rebar is going to be done at bottom of the beam because breakage occurs from bottom to top and the top is safe.

• Results :

• From given image it is shown to be a Flexural Failure in beam because the magnitude of shear force and bending moment are higher at that point during earthquake.
• It is clearly shown that top part of beam experience compression and tension at the bottom part.
• Beacuse of slab it gives support to top part of beam therefore it is safe and due to uneven reinforcement provided at bottom it results in tensiion failure.
• Therefore the reinforcemnet reached yeilding hence it can't be repaired.

(b)

• Observations :

1. The given image showing the Crack occured at corner were beam and column get join.
2. It is found that the crack covers the entire structure.
3. Beam and column get seperated from each other as shown in image.
4. Concrete does not comes out fully.

• Results :

1. Due to insufficient development length of reinforcement the beam gets pulled out.
2. It occurs due to the horizontal movement of structure during earthquake and the beam gets seperated from column.
3. It is not repairable because it is difficult to provide anchorage length between two concrete structure.

(c)

• Observations :

1. The given image showing the Crack occured exactly at joining of beam and column.
2. The beam gets cracked fully from its width horizontally.
3. Beacause of this results in crack damage at slab also.

• Results :

1. It is plastic hinge failure.
2. In this firstly the damage occurs at joint of beam and column.
3. The damage occurs due to cyclic lateral loading And reversal of stresses.
4. Due to this the slab also gets damaged because it is failed in supporting against the action.
5. But after all the joint can get to be strengthened.

Ans 2.

(a)

• Observations :

1. The given image showing the damage occured at the top of column.
2. Concrete Damaged from all side but the beam seems to be safe.
3. The column seems to be the outer one.
4. No wall construction is to be done at the building right now thats why it seems a basement area or parking etc.

• Results :

1. The failure is called th esoft storey failure and formation of plastic hinge.
2. As there is no walls are constructed at this floor so due to the lateral movement at the top of the storey columns ,plastic hinge is formed.
3. it is observed that concrete is crushed at that portion so the condition of columns is either repiarable or jnon repairable.

(b)

• Observations :

1. The given image showing the concrete damage occured diagonally at the column.
2. The vertical reinforcement remains same in there position.
3. The spacing between the shear bars seems wider that means less rebar are provided.

• Results :

1. This Failure is called as pure shear failure.
2. Uneven spacing in reinforcement may results in this failure in concrete.

(c)

• Observations :

1. The given image showing the Column get damaged fully.
2. The failure occurs at the column top.
3. It seems that there are 2 slabs connected to the column one is at the top and other is at 2/3rd of the height of column.
4. Ater the structure gets failed it is suppoted by wooden pillers to avoid collapsing of structure by temporary support.

• Results :

1. This failure is called short column failure.
2. May be this failure occurs due to providing additional slab or beam provided at mid part of column.
3. This failure is also occurs due to unwanted connection of structure component which is not mentioned in the design.
4. The repairing of this failure cant be possible.

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