Identification of Cracks

1)a)

 OBSERVATION:

• crack developed along the width of the beam and concrete get crushed in compression jone. 
• reinforcement get exposed to atmospher, reinforcement rusted in spalled concrete place.
• crack expand in column and slab. 
• beam located at the corner. 
• column has only beam to trasfer the load.
• cracks are develope from bottom to top of the beam, rebar yield occur at the bottom.

CONCLUSION:

• it is flexural failure due to stress reversal during earthquake.
• top of the beam express compression and bottom tension.

SOLUTION:

• it can not be repairable.

1)b)

 OBSERVATION:

• crack developed along the edge of the beam and column and it is spalled concrete.
• looks like beam saperate from column.
• concrete is not severely crushed.

CONCLUSION:

• this failure developes insufficient development length.
• during the earthquake the hiruzontal displacements will occur then it under goes the worest condition.

SOLUTION:

• providing of anchorage length between the existing column and beam is difficult so it can not be repairable.

1)c)

 OBSERVATION:

• crack developed at the beam and column joint.
• beam cracked along the width. 
• slab is also cracked.
• concrete is not severely crushed.

CONCLUSION:

• it is a plastic hinge failure.
• stress reversal and cyclic loads leads to damage structure at joints.
• slab is also takes more tension if it undergoes more cracks it will get damaged. 

SOLUTION:

• it can be a repairable.

2)a)

 OBSERVATION:

• concrete damaged all around the column.
• damage occur at bottom of beam and top of column. 
• there is no wall under the beam since it look like ground floor which is used for parking.
• reinforcement is exposed at some place.
• beams donot have any damage.
• concrete is not severely crushed. 

CONCLUSION:

• it is a plastic hinge failure.
• it is a soft storey failure as we consider that it is a parking area plastic hinge forms at top of ground floor building.

SOLUTION:

• it can be a repairable.

2)b)

 OBSERVATION:

• concrete is severely crushed.
• column breakage diagonally.
• rainforcement get exposed to atmospher.
• spacing of stirrups is more.
• cracks occur at bottom to top of column. 

CONCLUSION:

• it is a shear failure.
• there is a indufficient spacing between the stirrups

SOLUTION:

• it can be a repairable.

2)c)

 OBSERVATION:

• concrete is severely crushed.
• column failed completely.
• failure at the top of column.
• there is two slabs connected to column.
• slab to slab there is less distance it leads to short column failure. 
• woden piles are placed for support after the column failure, avoid the entair failure of structure

CONCLUSION:

• it is a brittle failure.
• mazzanine floor slab or beam connected at mid height of column leads to this effect

SOLUTION:

• it can be a repairable.