Challenge

Identification of Cracks

AIM:

To understand the concept of failures in a RCC structure.

This is a crack, resulted due to flexural failure of a beam.
Felxural strenght is the the modulus of rupture, bend strength or the racture strength ie the stress in a material just before it yields a flexural test.
It represents the highest stress experienced within the material at its moment of rupture.
It is measured in terms of stress.
To overcome this type of failure, main steel is provided at the bottom or top of the beam.
The damages are repairable.
To do it, first locate a local welder or metal shop and request angel iron, cut and drilled to the length of the beams.
Be sure to turn off the water, power, etc before doing so
Pry the joist Hanger away from the beam. MOunt the angle iron on the jack and temprory post.
Get the angle iron in place and slowly raise the jack until the anfgle iron is wedged against the damaged beam.
Screw the angle iron into the beam and remove thr temperory post.
Slide any pipes or wiresnpreviously removed back through the beam and turn the water back on.

This crack is formed due to the mistakes done in construvction and honeycombing in concrete.
To avoid cracks in concrete, avoid using high slump concrete.
Concrete of moderate controlled by concrete admixture or designed such that seggregation and bleeding of concrete is controlled.
Concrete admixture such as water reducers or super plasticicsers can beused to increase the slump while reducing the addition of water content.
Air entertained concrete can also be produced to increase slump especially when concrete s to be subjected to freeze and thaw cycled.
The honeycombing occurs when the fine mortar fails to thotoughly fall and fill the gaps created by the coarse aggregate.
As mentioned previously, poor concree consolidation is usually the top cause of honeycombing, along wht poor vibration, improper ration to fine and coarse aggregate, dty concrete and construction conditions that are not upto the standard.

This crack is formed due to the beam-column joint failure.
In the strong column-weak beam beam design, beams are expected, to form plastic hinges at their ends and develop flexural overstrength beyond strength.
The high internal forces developed at plastics hinges, cause critical bond conditions in the longitudinal reinforceing bars passing through the joint and also impose high sjear demand in the joint core.
The bond perfomance of the bars anchored in a joint affects the shear resisiting mechanism to a significant extent.

____________________________________________________________________________________________________________________

This crack will be formed due to the flexural failure of column.
Columns have the most impportant role in all structure members of a building.
According to the base civil concepts, columns failure wents to be occuring after beams and other components damages.
Performance of exixting buildings in earthquakes indiates that the beams are less vulnerable to damage during earthquakes and their damage appears to tbe less critical to performance as compared with that of colums and column-beam joints.

This is formed due to the shear failure of a column.
Lateral load in a structure are carrying by vertical elements such as columns and shear walls.
When there are no shear walls, columns carry the lateral loads which are generate by the winds, earthquakes, etc.
Shear links are provided to columns basd on the shear force wxcreted on them.
Further the size of the column is increased in the direction of shear to increase the shear capacity.

This is formed due to the short column failure.
In short column, failures take place due to the yielding and we define this as Crushing.
Short Column are classified based on slenderness ratio which is the ratio of the effective length and least lateral dimensionof the column.
Failure f the column usually occurs due to anyone of the folllowing stresss developed in the column.
Short column will fail only because of the direct compressive stress developed in the column or we can also say that short column will ususally fail due to direct compression or crushing.

Ship work like this
in your own course.