Identification of Cracks
Question 1:
a)
Observation:
- Concrete crushed and the reinforcement is exposed.
- Concrete spalled beyond the reinforcement which may be a sign of rupture.
- Beam top potion looks safe because of the flange advantage from the slab.
- The crack develops from the bottom to bottom Means rebars yielding occurs in support bottom only.
Answer:
- Its form of structural failure due to reversal of stress during earthquake.
- During stress rehearsal supports top experience compression and bottom experience tension.
- Top comparison in managed by slab advantage bottom tension was not satisfied by the provider reinforcement.
- Censor reinforcement got yielded, it can not be repaired.
b) 
Observation:
- Cracks along beam column edges.
- Cracks seem to have developed through the structural as it looks much wider.
- Beam looks separated from the column at joints.
- Concrete is not severely crushed.
Answer:
- It’s been pull out failure due to the insufficient development length or reinforcement end joins.
- During earthquake, the horizontal movement of structure makes the condition worse and detached the beam member from column.
- Providing encourage a length between two existing concrete is very difficult. So not repairable.
c) 
Observation:
- Cracks are exactly at the joints of the column beam.
- Cracks is being developed through its entire width.
- Slab also developed more cracks along the beam with directions.
Answer:
- It’s a plastic hinge failure.
- The damage occurs only in the joint zone First of all.
- Cycle lateral loading and stress reversal at the joints led to the damage.
- Even the slab participated to its best to handle the tension (labels several leak crack means it has undergone tension with the flange condition) but unable to control the damage.
- The joints can be strengthened.
What is the mode of failure or damage of the beams in the figure above? Are the damages repairable? Elaborate
Question 2:
a) 
Observation:
- Concrete damaged at top of column.
- Concrete damaged all around the column face.
- Beams are safe.
- The location of column looks at edge of the building.
- No walls are built along the column means it is probably at ground floor, for parking cars moment access.
Answer:
- It’s a soft storey failure, technical plastic hinge formation.
- Due to absence of infill walls at the ground floor the plastic hinge forms at the top of ground story columns during the lateral moments.
- Based on the development of crush of concrete it can either be repairable or non-repairable.
b) 
Observation:
- Concrete tabs complicate breakage technology diagonally.
- Longitudinal reinforcements are intact.
- Shear reinforcement spacing looks wider which means probably lesser rebar provides.
Answer:
- It’s a your sheer failure.
- Inadequate shear reinforcement campus concrete takes all the sheer stresses.
c) 
Observation:
- Column failed completely.
- Failure at top of column.
- There are two slabs connected to the column probably one at the mid height of the column.
- The wooden piles might be a post failure support after column failed, providing temporary prop to avoid collapse of the entire structure.
Answer:
- It’s a short column failure.
- And additional slab or a beam connected to the column in mid height leads to the effect.
- This leads to failure especially if the connection is unintentionally and not accounted in design.
- The failure given in the picture is not at all repairable.