Challenge

Identification of Cracks

1.ANS:-

Concrete crushed and the reinforcement is exposed.
Concrete spalled beyond the reinforcement which may be sign of rupture.
Beam top portion looks safe becaude of the flange advantage from slab.
The crack develops from bottom to top means rebar yielding occurs in support bottom only.
Its form of flexural failure due to reversal of stress during earthquake.
During stress reversal, support top experience compression and bottom experience tension.
Top compression is managed by slab advanyages. Bottom tension was not satiesfied by the provided reinforcement.
Since the reinforcement got yielded, it can be repaired.

Cracks along Beam-Column edge.
Cracks seem to have developed through the structure as it looks much wider.
Beam looks separated from the column at joints.
Concrete is not severely crushed.
Its beam pull out failure due to sufficient development length of reinforcement in joints.
During earthquake, the horizontal movement of structure make this condition worse and detached the beam member from column.
Provoiding anchorage length between two existing concree is ver difficult. So not repairable.

Cracks are exactly at the joint of column and beam.
Cracks in beams developed throught its entire width.
Slab also developed more cracks aong the beam width direction.
Its a palstic hinge failure.
The damaged occur only in the joint zone first of all.
Cyclic lateral loading and stress reversal at the joints led to the damage.
Even the slab participated to its best to handle the tension.( slab is severely cracked means it has undergone tension with its flange condition)
But unable to control the damage.
The joint can be stengthened.

2.ANS:-

Concrete damaged at top of a column.
Concrete damaged all around the column face.
Beam are safe.
The location of column looks at the edge of the building.
No wall are built along the column means it is probable at ground florr, for parking car movement access.
Its a soft storey failure, technically plastic hinge formation.
Due to absence of infill wall at the ground floor, the plastic hinge forms at the top of the ground storey columns during lateral movement.
Based on the development of crush of concrete,
it can either be repairable or non-repairable.

Concrete developed complete breakage diagonally.
Logitudinal reinforcement are intact.
Shear reinforcement spacing looks wider, which means probably lesser shear bar provoded.
Its a pure shear failure.
Inadequate shear reinforcement compels concrete takes all the shear stresses.

Column failed completely.
Failure at top of column.
There are two slabs connected to the column, probably one at 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.
Its a short column failure.
An additional slab or a beam connected to a column at mid height lead to this effect.
This leads to failure especially if the connection is unintentional and not accounted in design.
The failure given in the picture is not at all repairable.

Ship work like this
in your own course.