Identification of Cracks
1.Objectives of Challenge:-
1.Awareness on Structural Failures
2.Distinguishing Structural & Non- Structural Failures
3.To Know how to Observe A Structural issue
4. Understanding Seismic Failures
Questions :- A set of photos From Concrete Structures
Answar:-
1. To Find out the Mode of Failure /Damage
2. Is it Repairable?
(A):-
Observation:-
1.Concrete Crushed and The Rainforcement is exposed.
2.Concrete spalled beyond the Rainforcement Wich may be a sign of rupture.
3.Beam top point looks safe because of the Flange advantage from slab.
4. The Creck Develops From bottom to top means rebar yielding occursin support bottom only.
Answar:-
Result:-
1. Ita Form of Flexural Failure due to reversal of Stress during earthquake.
2.During Stress reversal, Support top experiences Compression and bottom expriences tension
3. Top Compression is manged by slab advantage bottom Tension was not satisfied by the provided reinforcement.
4.Scince the reinforcement got yielded, it can not be repaired.
(B):-
Observation:-
1.Cracks along Beam - column edge
2.Crecks seem to have developedthrough the Structure as it looks much wider.
3.Beam looks sepatated from the column at joints.
4. Concrete is not severely crushed.
Answar:-
Result:-
1.Its Beam pull out failure due to insufficient development length of reinforcement in joints.
2.During earthquake. the horizontal Movement of structure makes this condition worse and detached the Beam member From Column.
3.Providing anchorage length between two existing concrete is very difficult . So not repairable.
(C):-
Observation:-
Answar:-
1.Crecks are exactly at the joint of column-Beam
2.Cracks in Beam developed through its entire width.
3.Slab also developed more cracks along the beam width direction
Answar:-
Result:-
1.It's a Plastic hinge failure.
2.The damage occurred only in the joints Zone First of all.
3.Cyclic lateral loding & Stress reversal at the joints led to the damage.
4.Even the slab participated to its best to handle the tension ( Slab is severely crecked means it has undergone tension with its flange condition), But unable to control the damage.
5. The joint con be strengthened.
2.What is the mode of failure or damage of the beams in the figure above? Are the damages repairable? Elaborate
Question 2:
Observation:-
(A):-
1.Concrete damaged at top of a column
2.Concrete damaged all around the column face.
3. Beam are safe.
4.The location of column looks at edge of the building
5.No walls are built along The column means it is probably at ground floor,for Parking car movement access.
Answar:-
Result:-
Image Credit:- Some concepts in earthquake behavior of building by C.V.R.Murty
1.It's a soft storey failure, Technically Plastic hinge formation.
2. Due to absence of Infill walls at the Ground Floor, The plastic hinge froms at the Top of ground storey column during lateral movement.
3.Based on the development of curse of concrete it can either be repairableor Non-repairable
Observation:-
(B):-
1. Concrete developed complete breakage diagonally
2.Longitudinal Reinforcement Are intact.
3.Shear reinforcement spacing looks wider (which means probably lesser shear rebar provided )
Answar:-
1.It's a pure shear failure.
2.Inadequate shearReinforcement compels concrete takes all the shear stresses.
Observation:-
(C):-
1.Column failed completely.
2.Failure at top of column.
3.There are two slab connected to the column,Probably one at mind heigth of the column .
4.The wooden piles might be a postfailure support after column failed, providing Temporary prop to avoid collapse of the entre structure.
Answar:-
Result:-
Image credit :- Some Concepts in Earthquake
behavior of building by C.V.R.Murty
1.It's a Short Column failure
2.An additional slab or a Beam connected to a Column in mid -height leads to this effect.
3.This leads to failure especially if the connection is unitentional and not accounted in design.
4.The Failure given in the picture is not at all repairable.