Identification of Cracks

1 ANS :-

1a) . In the fig 1a seen clearly then identified here is- the rupture occoured as the concrete spalled beyound the reinforcement , reinforcemnt is seen / visible and the concrete is crushed , top portion of beam looks safe because of flange advantage of the slab , crack develped from bottom to top.

* form of failure - flexural failure occured to reversal stress during earth quakes .

during stress involvement top support experiences compression and the bottom experience tension.

botom was not enough with provided reinforcement.

* it cannot be repaired since reinforcement is yielded.

1b). In the fig 1b identified here is - beam looks separated from the column at the joints , cracks seem to have developed throgh the structures, cracks formed along the beam column edge . concrete is not fully crushed.

* form of failure- beam pull out failure occured due to insufficient length of reinforcement in joints during earth quake

detached the beam member from the column

* providing the anchoage length between the two concrete which are present is very difficult .

hence not repairable .

1c). In the fig 1c identified that the cracks are at joints of column and beam , also the cracks developed along the beam width direction .

* form of failure- its a plastic hinge failure damage occured only in the joint , the lateral loading and stress reversal at

at joints led to damage, slab did to handle the tension but was not able to control .

* as its not a huge failure the joints can be strengthened .

2ANS :-

2a). observed in fig 2a is that concrete damage at the top of column , concrete damage all aound column face . beams are safe here . walls are not built along the coumns it must be the ground floor for parking .

* its a soft storey failure , means the plastic hinge formation actually. the plastic hinge forms at top of ground storey columns due to lateral movement .

* it can either be reparilable or not beacause it depends on development of crush of concrete.

2b). observed in fig 2b is that the concrete is breaken completely over diagnol , shear reinforcement spacing is wider

reinforcement are intact that means it is not damaged, brokn , or divided.

* form of failure - its a pure shear failure

* shear reinforcement compels concrete takes all the shear stresses.

2c). as obseved in fig 2c is that the column is failed completely . failure at top of column the 2 slabs are connected to the columns , and the temorary props provide to avoid collapse of entire structures.

* its a short column failure

due the additional slab or a beam connected to the column in mid height leads to this effect .

its not built according to design by the way .

* the failure is not repairable at all .