Identification of Cracks

1. (A) OBSERVATION

• concrete crused and the the reinforcement is exposed.
• concrete spalled beyond the reinforcement which may be a sign of rupture.
• beam top portion looks safe beacause of the flange advantage fronm slab.
• the crack develops from bottom to top means rebar yeilding occurs in suppports bottom only.

ANSWER -

• it form of flexural failure due to reversal of stress during earthquake.
• during strees reversal support top experince compression and bottom experinces tension.
• top compression is managed by slab advantages bottom tension was not satisfied by the provided reinforcement.
• since the reinforceemnt got yeilded , it can not repaired.

1 (B) OBSEVATION-

• CRACK ALONG BEAM - COLOUUMN EDGE.
• CRACKS SEEM TO HAVE DEVELOPED THROUGH THE STUCTURE AS IT LOOKS MUCH WIDER.
• BEAM LOOKS SEPERATED FROM COLOUMN AT JOINTS.
• CONCRETE IS NOT SEVERLY CRUSED.

ANSWER-

• its beam pull out failure due to insufficient development of reinforcement developement length of reinforcement in joints.
• during earthquakethe horizontal movement of stucture makes this condition worse and detached the beam menmber fronm column.
• provinding anchorage length between two existing concrte is very difficults so not reiplarable.

1 (C) OBSERVATION-

• CREACKS ARE EXCTLY AT THE JOINT OF COLOUMN BEAM.
• CRACKS IN BEAM DEVELPOED THROUGH ITS ENTIRE WIDTH.
• SLAB ALSO DEVELPOED MORE CRACKS ALONG BEAM WIDTH DIRECTION.

ANSWER-

• it is plastic hinge failure.
• the damage occured only in the joint zone first of all.
• cylinc lateral loading and stress reversal at the joint led to the damage.

2.(A) OBSERVATION-

• concrete damaged at top of the column.
• concrete damaged all around the column face.
• beams are safe.
• the location of column looks at edge of the building.
• no wall are built along the coloumn means probebly at ground floor. for parking car movement acess.

ANSWER-

• it is a soft story failure.technically plastic hinge formation.
• due to absesse of infill wall at the ground floor, the plastic hingeforms at the top of ground story during lateral movement.
• based on the development of crush of concrete it can eighter be repairble or non- repairble.

2. (B) OBSERVATION-

• CONcrete developed completly breakage diagonally.
• longitudanal reinforcement are intact.
• shear rainforcementspacing looks wider.

ANSWER-

it is pure shear failure.

inadequate shear reinforcement compels concrete takes all the shear stress.

2. (C) OBSERVATION-

• COLUMN FAILED COMPLETLY.
• failure at the top of column.
• there are two slbs connected to the column.
• the wooden piels might be postfailure supports after column failed.

ANSWER-

• it is short column failure.
• an additional slab or a beam connecterd to a coloumn in mid height leads to this feilds.
• this lead to failureespecially if the connection is unitenisonal and not accounted in design.