Identification of Cracks
1.What is the mode of failure or damage of the beams in the figure above? Would you characterize the case as damage or as a failure? Are the damages repairable? Elaborate
Answer:
a.
The above image shows a Damage at the Beam-column joint.
It is clearly observed that the Damage is more for the part of Beam.
The Damage is mainly caused due to not providing sufficient cover to the Beam from the reinforcement.
It may also be caused due to insufficient vibration of concrete as there will be hinderence of the reinforcement while vibration.
The repair can be done by providing proper cover at the joint.
b.
In this image it is clearly a Damage.
This Damage is caused due to improper shotcrete plaster material.
This Damage can be repaired by removing pieces of plaster surrounding the damaged material and shotcreting once again by applying suitable adhesive.
This damage is exactly at the Beam column joint.
This occur due to joints subjected to high shear forces.
The damage can be temporarily repaired but during the long run this damage may cause Harm and also can turn into a Failure.
2.
What is the mode of failure or damage of the beams in the figure above? Would you characterize the case as damage or as a failure? Are the damages repairable? Elaborate
a.
This image shows a Failure of column due to buckling.
The column should be long column,even though the beams are provided at intermediate levels the column couldn't resist the Bucking load so the failure occured.
Generally buckling occur at the midpoint of the column where the Bending moment is maximum and the shear force force is zero.
To avoid this type of failures the reinforcement should be provided in such a way that the lapping of the all reinforecement bars in a single column not meeting at the same point.
It is better if alternate bars are provided for lapping of joints.
b.
It is a Failure due to Shear.
Generally shorter columns attract high shear forces.
This undesirable mode of deformation caused called as SHORT COLUMN EFFECT.
This is one of the mainly observed failure during Earthquakes which generally occur at the open ground floor levels.
c.
It is Failure at Beam column joint.
It is looking like the column got misplaced after concreting and during which the concrete was unable to set for the required dimension.
So it resulted in uneven placemnt of concrete which caused the exposure of reinforcement.
or
During the earthquake due to Strong column and weak beam phenomenon the beam got some movement in horizontal direction which resulted in failure of the joint and rebars got exposed.