Identification of Cracks

Question:1
a) The mode of failure observed in this image is Beam Column Joint Failure were the Beam Seems Looses its capacity and tends to breakout
Causes:
The Beam Column Joint is considerd as the critical point in which it carries larger Force and moment of the structure. During the seismic behaviour in the structure the beam column joint mainly experience the bond and shear failure mechanism in which it would tends to brittle. In this case the Beam tends to loose its load capacity. The Corner Portion of the beam is the Boundary element for the prevention of bucking. When this fail the Concrete begins to crack in a diagonal manner and then the corner of the beam leads to brittle.
Damage Repair:
This can be repaird at the begining stage using steel jacking or steel configuration using steel plates. But if the beam ungergoes brittle it is not safe to repair

b)The mode of failure observes in this image is torsional failure were seems twisting of beam is happend
Causes:
Tortional Beam Failure is caused due to the sudden action of seismic behaviour of the structures in which tortional moments are acted on the structures. Due to this sudden action of rotation sudden expansion of steel reinforcement in the structure is performed. This begins with the Crack on member tends to the brittle behaviour due to tortional moment.
Damage Repair:
This Failure cannot be repaired since this failure occurs in sudden action.

c)The mode of failure observed in this image is Pull-out Failure of Beam

Causes:
This is the Force on the Structure which tends to produce sliding failure along the member.The Beam Column Joint absorbs the larger shear force and so the anchorge of beam column joint should be strong enough to prevent the crack. If the anchorage of Beam column joint is not done in a proper manner the pull out of the beam column is done in which leads to crack on the junction. Also if the Bonding is not perfored correctly in the junction or if the are more air voids in the structure then also it leads to crack in the junction.
Damage Repair:
This can be repaird using steel jacking or steel configuration using steel plates. Therefore Connecting the Beam Column using the Steel plates and Steel Rods at the Junction of Beam Column would Minimise the Expansion of Crack.

Question-2
a)The mode of failure observed in this image is compression failure or short column failure. The Reinforement in the column seems bulged.
Causes:
When the axial force of the column is increaed the Compression failure gets happen. Also if there is short column developed to withstand more compression force then the column automattically gets to bulge in which the conctrete gets crused with the reinforcement in the area tends to bulge. The loads are tranferd generally in the longitudnal direction. So the column performs the major role in both tension and compression. The column should be designed respectivelly to its height to tranfer the load. In absence of its required heigth or width the column losses to transfer the load and tend to bulge.
Damage Repair:
In this Compression failure its not possible to repair since tranfer of longitudnal force to be done repair is not possible.

b)The mode of failure observed in this image is Buckling Failure of the column were its noticed the reinforcement of the column is buckled laterally.
Causes:
The Buckling Failure of the column occurs when the Length of the column increses also with more axial force the length of the column tends to buckle. Normally for the load on the structures the column should be designed in a well stability manner. So if there are large amount of load performed in the structure the the column slould not be designed in the larger length if designed then bracing have to be made for the proper load transfer.This failure occures due to axial compression of force performed in the column with the length greater than its cross section.
Damage repair:
In Bucking failure of column its not possible to repair to retain the column since longitudnal force is to carry.

c)The mode of failure observed in the image is Plastic Hinge failure due to soft story structure where the failure occurs in its connection
Causes:

The Stiffness on the failure member would be considerably lower than the adjacent storey. This is caused due to the sudden presence of lateral load that is the seismic load to the structure would perform reduction in the lateral stiffness considering in the deformation of the member. This would be due to the less rigidity or the absence of the shear wall or the intermediate structures between the column.Also the cause would also due to the less stiffness or resistance of the structure above the failure structure.
Damage Repair
In Plastic hinge failure of soft story structure failre its not possible to repair or retain the structure since this is the major issue of failure.