Identification of Cracks
1 a
Observations
Concrete crushed and the reinforcement is exposed
Concrete spalled beyond the reinforcement which may be a sign of rupture
Beam top portion looks safe because of thr flange advantage from the slab
The crack develops from the bottom to top means rebar yielding occurs in the support bottom only
Its form of flextural failure due to reversal of stress during the earthquake
During the stress reversal support top experiences compression and bottom experiences tension
Top compression is managed by the slab advantage.bottom tension was not satisfied by the provided reinforcement
Since the reinforcement got yielded it cannaot be repaired
1 b
Observations
Cracks along the Beam-Coloumn edge
Cracks seem to have developed through the structure as it looks much wider
Beam looks separated from the coloumn at joints
Concrete is not severely crushed
Its beam pull out failure due to insufficient development length of the reinforcement in joints
During the earthquake the horizontal movement of the structure makes this condition worse and detached the beam member from coloumn
Providing anchorage length between two existing concrete is very difficult so not repairable
1 c
Observations
Cracks are exactly at the joints of the Coloumn-Beam
Cracks in Beam developed througth 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 & stress reversal at the joints led to thr damage
Even the slab participated to its best to handle the tension slab is severly cracked means it as undergone tension with its flange condition but unable to control the damage
The joint can be strengthened
2 a
Observations
Concrete is damaged at the top of the coloumn
Concrete damaged all around the coloumn face
Beams are safe
The location of the coloumn looks at the edge of the building
No walls are build along the coloumn means it is probably at the ground floor for parking car movement access
Its a soft storey failure technically plastic hinge formation
Due to absence of infill walls at the ground floor the plastic hinge forms at the top of the ground storey coloumns during lateral movement
Based on the development of crush of concrete it can either be repairable or Non repairable
2 b
Observations
Concrete developed complete breakage diagonally
Longitudinal reinforcement are intact
Shear renforcement spacing looks wider (which means probably lesser the shear rebar provided )
Its a pure shear failure
Inadequate shear renforcement compels concrete takes all the shear stresses
2 c
Observations
Coloumn failed completely
Failure at the top of coloumn
There are two slabs connected to the coloumn,probably one at the mid height of the coloumn
The wooden piles might be a post failure support after the coloumn failed, providing temporary prop to avoid collapse of the entire structure
Its a Short Coloumn failure
An additional slab/beam connected to a coloumn in mid-height lead to this effect
This leads to the failure especially if the connection is unintentional and not accounted in design
The failure given in the picture is not at all repairable