Identification of Cracks

Ans1. Aim-To find out the mode of failure / damage and it's repairable or not.

a). Figure 1.

.It's form of flexural failure due to reversal of stress during earthquake

. during stress reversal, support top experiences compression and bottom experiences tension

. top compression is managed by slab because the slab has concrete so the T section of the beam has trying to manage the exis compression but the bottom tension was not satisfied by the provided reinforcement thats why the bottom reinforcement has yielded.

. Since the reinforcement got yielded, it can be not repaired.

b). Figure 2.

.it's Beam pull out failure due to insufficent development length of reinforcement in the joints.

. During earthquake, the horizontal moment of structure makes this condition worse and it detached the beam member from column.

because the sufficent Anchorage length that means development length puls the beam develop suficent bond which the supporting member if the anchorage of reinforcement is not sufficient that is in adiquate reinforcement at the beam column joint the letral member can not be stisfiyed so the beam ultimatly gating detached from the virtical member

.Providing anchorage length between two existingconcrete is very difficult

at least one is old concrete and other one is new section we can use any double kind of thing and we can acchive the anchorage length but near the both element are existing concrete and devolopment acchiving the anchorage length is very deficult so it can not be repairable.

c). Figure 3.

.it's a plastic hinge failure usually plastic hinge failure happning at the joints only

.The damage occurred only in the joint zone first of all

.cyclic lateral loading & stress reversal at the joints led to the damage.

. Even the slab participated to it's best to handle the tension because slab is severely cracked means it was undergone tension with it's flange condituion but unable to control the damage.

even the flange advantegs of the slab the slab with T advantages unable to controle the damage

. The joint can be strengthened.

Ans2.

a). Figure 1.

it's a soft story failure, Techinically Plastic hinge formation.

.Due to absence of lnfill wall at the ground floor, the plastic hinge form at the top of ground storey column during leteral moment.

.Based on the development of crush of concrete, it can either be repairable or non- repairable.

b). Figure 2.

it's a pure shear failure because the crack has is in digonal direction and the complete concrete head crashed they have detached and specly shearing reinforcement are not suficeant so intair shairforce is transfaring through the concrete only

c). Figure 3.

.It's a pure shear failure.

. Inadequate shear reinforcement compels concrete takes all the shear stresses.

. It's a short Column failure.

. An additional slab or a Beam connected to a Column in mid-height leads 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.