Identification of Cracks
QUE.1 AIM -
What is the mode of failure or damage of the beams in the figure above? Are the damages repairable? Elaborate
ANS - THERE ARE THREE IMAGES SHOWING IN THE QUETION A,B,C
a)
OBSERVATION (A) -
1. CONCRETE CRUSHED AND REINFORCEMENT IS EXPOSED.
2. CONCRETE SPALLED BEYOND THE REINFORCEMENT WHICH MAY BE A SIGN OF RUPTURE.
3. BEAM TOP PORTION LOOK SAFE BECAUSE OF THE FLANGE ADVANTAGE FROM SAFE.
4. THE CRACK DEVLOP FROM BOTTOM TO TOP MEANS REBAR YEILDING OCCURS IN SUPPORT BOTTOM ONLY.
OBSERVATION (A) ANS -
1. IT IS THE FORM OF FLEXURAL FAILLURE DUE TO REVERSEL OF STRESS DURING EARTHQUAKE.
2. DURING STRESS REVERSEL,SUPPORT TOP EXPERIANCES COMPRESSION AND BOTTOM EXPERIENCESS TENSION.
3. TOP COMPRESSION IS MANNEGED BY SLAB AVANTAGE. BOTTOM TENSION WAS NOT SATISFIED BY THE PROVIDED REINFORCEMENT.
4. SINCE THE REINFORCEMENT GOT YEILDED IT CAN NOT BE REPAIRED.
OBSERVATION (B) -
1. CRACKS ALONG BEAM COLUMN AGE.
2. CRACKS SEEM TO HAVE DEVLOPED THROUGH THE STRUCTURE AS IT LOOK MUCH WIDER.
3. BEAM LOOKS SEPREATED FROM THE COLUMN AT JOINTS.
4. CONCRETE IS NOT SEVERLY CRUSHED.
OBSERVATION(B) ANS -
1. ITS BEAM PULLOUT FAILLURE DUE TO INSUFFICIENT DEVLOPMENT LENGTH OF REINFORCEMENT IN JOINTS.
2. DURING EARTHQUKE THE HORIZONTAL MOVEMENT OF STRUCTURE MAKES THIS CONDITION WORSE AND DETACHED A BEAM MEMBER FROM COLUMN.
3. PROVIDING ANCHORAGE LENGTH BETWEEN TWO EXISTING CONCRETE IS VERY DIFFICULT. SO IT IS NOT REPAIRABLE
OBSERVATION (C) -
1. CRACKS ARE EXACTLY AT THE JOINT OF COLUMN BEAM.
2. CRACKS IN BEAM DEVLOPED THROUGH ITS ENTIRE WIDTH.
3. SLAB ALSO DEVLOPED MORE CRACKS ALONG THE BEAM WIDTH DIRECTION.
OBSERVATION(C) ANS -
1. ITS PLASTIC HINGE FAILLURE.
2. THE DAMAGE OCCURED ONLY N THE JOINT ZONE FIRST OF ALL.
3. CYCLIC LATTERAL LOADING AND STRESS REVERSEL AT THE JOINTS LEAD TO THE DAMAGE.
4. EVEN THE PARTICIPATED TO ITS BEST TO HANDLE THE TENSION BUT UNABLE TO CONTROLE THE DAMAGE.
5. THE JOINT CAN BE STRENGTHEN.
6. IT IS REPAIRABLE.
QUE. 2 AIM -
What is the mode of failure or damage of the beams in the figure above? Are the damages repairable? Elaborate
ANS - THERE ARE THREE IMAGES SHOWING IN THE QUETION A,B,C
a) 
OBSERVATION 2(A) -
1. CONCRETE DAMAGE AT TOP OF A COLUMN.
2. CONCRETE DAMAGE ALL AROUND THE COLUMN FACE.
3. BEAM ARE SAFE.
4. THE LOCATION OF COLUMN LOOKS AT EDGE OF THE BUILDING.
5. NO WALLS ARE BUILT ALONG THE COLUMN MEANS IT IS PROBABLY AT GROUND FOR PARKING CAR MOVEMENT ACCES.
ANS OBSERVATION 2(A) -
1. IT IS SOFT STOREY FAILLURE. TECHNICALLY PLASTIC HINGE FORMATION.
2. DUE TO ABSENSE OF INFILL WALLS AT THE GROUND, THE PLASTIC HINGE FORMS AT THE TOP OF THE GROUND STOREY COLUMN DURING LATTERAL MOVEMENT.
3. BASED ON THE DEVLOPMENT OF CRUSH OF CONCRETE. IT CAN EITHER BE REPAIRABLE OR NON REPAIRABLE.
(B)
OBSERVATION 2(B) -
1. CONCRETE DEVLOPED COMPLETE BREAKAGE DIGONALLY.
2. LONGITUDANAL REINFORCEMENT ARE INTAKE.
3. SHEAR REINFORCEMENT LOOK WIDER.
4. LESS SHEAR REBAR PROVIDED.
ANS OBSERVATION 2(B) -
1. IT'S A PURE SHEAR FAILLURE.
2. INDEQUATE SHEAR REINFORCEMENT COMPELS CONCRETE TAKES ALL TGHE SHEAR STRESSES.
3. IT IS NOT REPAIRABLE.
(C)
OBSERVATION (C) -
1. COLUMN FAILLED COMPLETELY.
2. BEAM LOSSE ITS SUPPORT.
3. FAILLURE AT TOP OF THE COLUMN.
4. THERE ARE TWO SLABS CONNECTED TO THE COLUMN PROBABLY, ONE AT MID HEIGHT OF THE COLUMN.
5. THE WOODEN PILE MIGHT BE A POST FAILLURE SUPPORT AFTER COLUMN FAILLED. PROVIDING TEMPORARY PROP TO AVOID COLLAPS OF THE ENTIRE STRUCTURE.
ANS OBSERVATION (C) -
1. IT'S A SHORT COLUMN FAILLURE.
2. AN ADDITIONAL SLAB OR BEAM CONNECTED TO A COLUMN IN MID-HEIGHT LEDS TO THIS EFFECT.
3. IT IS SUBJECTED TO HEAVY SHEAR FORCE.
4. THIS LEADS TO FAILLURE ESPECIALLY IF THE CONNECTION IS UNINTENSIONAL AND NOT ACCOUNTED IN DESIGN.
5. THE FAILURE GIVEN IN THE PICTURE IS NOT AT ALL REPAIRABLE.