Identification of Cracks
Q.01] a]
OBSERVATION:
- Reinforcement bars are clearly visible.
- Concrete in tension zone is cracket and reinforcement is in yielding.
- Beam-Column joint is safe.
- Spalling of concrete is visible.
- Surface concrete is removed at bottom where as Concrete in compression zone is looks safe and fine.
ANSWER:
- Due Reversal loading of Earthquake there is yieling of main reinforcement bars of beam is appened.
- confinement of concrete looks great.
- Cracks are seems like shear cracks.
- Repair is not possible.
Q.01] b]
OBSERVATION:
- Spaaling of concrete surface is happened.
- Cracks reached to the sufficient depth by looking to the width of surface cracks.
- Beam -column joint is weak due to the reversal of loadings.
ANSWER:
- It seems column and beam get displaced from their joint position.
- We can say there is slipage joint failure occurs.
- Due to imporper provision of development length of main reinforcement joint became displaced.
- Column concrete is not losse by looking so the column is fine.
- We cannot provide the extra reinforcement after the damage in this case, so This case is not repairable.
Q.01] c]
OBSERVATION:
- column and beam position looks fine and good in position from figure.
- Big crack is found at the face of column which define concrete in compression zone is cracked.
- Formation of crack at the face ensures formation of plastic hinge at the end of beam.
- cracks in the slabs are also happened.
ANSWER:
- In earthquake loading there is large horizontal movement is obserced and stress reversal causes the formation of Plastic hinge.
- There is cracks in slab shows slab provide the support to the beam to resist lateral force.
- Joint is not displaced and also concrete is not spooiled so the Joint can be strengthen.
Q.02] a]
OBSERVATION:
- Beam-column joint is fine but column fails at the Top.
- Beams is not damaged.
- Beam width looks very thin so it can be the enge column having beam to support balcony.
ANSWER:
- Column is failed where as beam is safe so it shows weak column and strong beam design.
- Weak column and strong beam design leads to the soft story failure.
- Hinge is form at the top face of column.
- Due to plastic hinge joint is not repairable.
Q.02] b]
OBSERVATION:
- Surface concrete is in loose state and inner concrete also loses its bonding.
- There is diagonal cracks are develpoed in the column.
- At the mid of column height spolling is occured.
- Proper shear reinfocement is not provided.
ANSWER:
- Due to insufficient shear reinforcement the shear failure is happened.
- Spacing between the transverse reinforcement is too large which does not give enough strength in shear.
- Due to loosen inner concrete we cannot repair the damage.
Q.02] c]
OBSERVATION:
- Here Beam-Column joint is failed.
- Not enough vertical (main) reinforcement is provided.
- Joint is diplaced from it's position due to Earthquake forces.
- Improper monolithical construction seems.
- There are two slabs are provided with improper floor height.
ANSWER:
- Column vertical reinforcement is not enough and continuos.
- less numbers of bars are provided.
- Beam column slab joint is not continuous.
- At the joint spacing between shear (transverse) reinforcement should be less but in the figure it is not closely spacing provided.
- there is wooden rod is provided for the vertical support to slab whoch not the true solution for the problem.