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.

a):

• At the column and beam junction the concrete portion is damage but there is no effect on the reinforcement bars so it can be a repairable one
• Such type damages are cause due to heigh compressive stress and tensile stress acting on the beam
• The damage occurs due to lateral force as we can see the beam is damage the junction point the plastic hinge forms at the bottom end of the beam.
• No, the damage cannot be repaired as the reinforcement has yeilded.

b):

• This cracks are formed due to the mistakes done in concreting and honeycombing in concreting.
• The concrete portion is effect due formwork or curing.
• The cracks are developed due heat energy effect.
• To avoid cracks in concrete, avoid using high slump concrete.
• So this failure is not repairable.

c):

• As it is clears that the structure is effected at the beam & column junction is causes due to lateral forces
• The beam column junction is not design properly which effect form of the plastic hinge at the junction point
• The bond performances of the bars anchored in a joint effect the shear resisting mechanism to a significant extent
• The joint can be strengthed therefore repairable.

2):

a):

• This column is partially crushed and reinforcement bars are slightly bent. This type of effect occurs due heavy load on the column
• This type of failures are subjected to shear failures. Or there is a possibility external forces or lateral forces.
• Beams are looking safe.
• Its a soft story failure, Technically plastic hinge formation.
• Based on the development of crush of concrete it can be either repairable or non repairable.

b):

• As it is clear that the concrete is crushed completely. But the reinforcement bars are not bent
• This kind of failure are also subjected to shear failure in the column.
• Lateral loads are generated by winds, earthquake loads, from reataining structures, etc.
• There is no possibility of repairing of the column without the function of the structure

c):

• It is clear that the failure is occurred at the time of construction only even the formwork is not removed
• The concrete is completely collapsed and reinforcement bars are bent slightly. This is mainly occur due to improper design
• This kind of failure are also subject to the shear failure as we can that the bars are bent so the external lateral force is act on the column.
• This leads to failure especially if the connection is unintentional and not accounted in designs.
• The failure shown in the picture is not at all repairable.