Challenge

Identification of Cracks

Aim&Introduction :To know What is the mode of failure or damage of the beams in the figure above? Are the damages repairable? Elaborate

A :Observation :

From the above picture it is known that the Concrete has been crushed and the bottom reinforcement is visible
Spalling of Concrete has been taken place below the reinfocement that results in rupture
The top portion of the beam seems to be safe because of the flange advantage on slab
Crack has been developed from bottom to top means rebar yielding in Support bottom only.

Answers:

It forms a flexural Failure due to reversal of stress during earthquake
During Stress Reversal,At Supports Top of Slab Experiences Compression and the bottom Experiences the tension,so that Compression takes place on concrete and Tension acts on steel
Top Compression is Managed by slab Advantage .Bottom Tension was not satisfied by the provided Reinforcement.

Result :

B : Obsevation :

Cracks are Visible along the Beam column Junction
Cracks Are visible on the entire structure the crack width seems to be wide along the structure
The concrete has not been Crushed
it seems to be the beam and column has no bonding (i.e) it seems to be seperated
Answer :
Its beam pull out failure due to insufficient Development length of reinforcement in joints
During Eathquake,the horizontal movement of the structure make this condition worse and detached the beam member from the column
providing Anchorage length between two existing concreten is very difficult

Result :

C : Observation:

Cracks are Developed at the joints of beam Column exactly
Crack in beam has developed to its entire width
Moreover the randomly the crack has also been developed in the slab in along the directions of the beam

Answers :

It is a plastic Hinge failure develops at the beam column joints
The damage has occured only at the joints initially
cyclic lateral loading and stress reversal at the joints leadto the damage
even the slab has participated to its Best to handle the tension.But unable to control the damage

Result:

2) Aim & Introduction :To know What is the mode of failure or damage of the beams in the figure above? Are the damages repairable? Elaborate

A : Observation :

Spalling of concrete has taken place at the top of column\
All sides of column has been Spalled
Beams tends to be safe
Location of column looks at edge of buliding
No walls are built around the columns that means ground floor alloted for car parking

Answers :

It is a Soft Storey failure,Technically Plastic Hinge has been Formed
Due to absence of infill walls at the ground floor the plastic hinge forms at the top og ground storey column suring latgeral movement.
Due to bucikling of longitudinal reinforcement it has been taken place.

Result :

Based on the development of crush of concrete it can be either be Repairable or Non- repairable.

B : Observation :

Answer :

It is a Pure Shear Failure
All the shear failure acts on Concrete and damages the concrete Completely
Due to inadequate Shear reinfocements Compels the concrete to take over all the shear stresses.

Result :

It is not repairable.

C : Observation :

Column has been Failed Completely
No bonding Between upper and lower column
Two Slabs Connected to column one at the midway
Wooden piles might be the post failure support after the column fails to provide temporary support to avoid the collapse

Answer:

Its a Short Column failure heavy shear force acts at this kind.
Additional slab or beam connected to column leads to this effect
this Leads to failure if the connection is unintentional or not accounted in design

Result :

The Failure is not at all repairable

Ship work like this
in your own course.