Identification of Cracks

Solution.1)

Aim: To observe the given situations and comment on the mode of failures or damage and decide whether it is repairable or not.

Procedure:

IMAGES	OBSERVATIONS	COMMENTS
	We can see the reiforcement is exposed as concrete cover has been crushed. Concrete Spalled beyond the reinforcement may be caused due to Rupture. Beam Top portion looks safe and uncracked because of Flange support from the Slab. Since, the cracks starts from bottom, this means the rebar yielding occurs in support bottom only.	Its form of flexural failure due to reversal of stress during earthquake. Top compression is managed by slab but the bottom tension was not satisfied by the provided reinforcement. Since the reinforcement got yielded, it can not be repaired.
	Cracks are developed along beam-column edge. Cracks developed are wider. Beam looks seperated from the column at joints. Concrete is not severely crushed.	Its Pull out failure due to insufficient development length. During Earthquake, the horizontal movement of structure makes the situation more worse and the may detach the member from column. Since providing Anchorage length between two existing concrete is very difficult, so not repairable.
	Cracks are exactly at the joint of column-beam. Cracks in beam is developed through its entire width . Slab also developed more cracks along the beam width direction.	Its a Plastic Hinge failure. The damage occured only in the joint zone first of all. Cyclic lateral loading and stress reversal at the joints led to the damage. Even the slab participated to its best to handle the Tension (Slab is severely cracked means it has undergone tension with its flange condition), but unable to control the damage. The joint can be strengthened, hence the damage is repairable.

Result:

The observation has been made and whether the damage is repairable or not, has been justification has been made.

Solution.2)

Aim: To observe the given situations and comment on the mode of failures or damage and decide whether it is repairable or not.

Procedure:

IMAGES	OBSERVATIONS	COMMENTS
	Concrete damaged at top of a column. Concrete damaged all around the column face. Beams are safe. The location of colun looks at edge of the building. No walls are built along the column means it is probably at groung floor, for parking car movement access.	It's a soft storey failure, Technically Plastic Hinge formation. Due to absence o infill walls at the ground floor, the plastic hinge forms at the top of ground storey columns during lateral movement. Based on the development of crush of conrete, it can either be repairable or Non-repairable.
	Concrete developed complete breakage diagonally. Longitudinal reinforcements are intact. Shear Reinforcement spacing looks wider (which means probably lesser shear rebar are provided)	We can see a diagonal cracks, this means its a Pure Shear Failure. Inadequate shear reinforcement compels concrete takes all the shear stresses.
	Column failed completely. Failure at top of column There are two slabs connected to the column, probably one at the mid height of the column. The wooden piles might be a Post failure support after the column failed, providing temporary prop to avoid collapse of the entire structure.	It's a Short Column Failure. An additional slab or a Beam Connected to a column in mid-height leads to this effect. This lead to failure especially if the connection is unintentional and not accounted in design. The failure given in the picture is not at all repairable.

Result:

The observation has been made and whether the damage is repairable or not, has been justification has been made.