Identification of Cracks
What is the mode of failure or damage of the beams in the figure above? Are the damages repairable? Elaborate
Ans :
a)
Concrete cushed and reinforment is exposed and this sign to the flexural failure , no damages severe issues are found at the top of the beam because of the flange advantage from the slab and the correct in support bottom only the reinforcement is still active at the support.this failure occurs when th load on the beam exceed its flexural .to repair damaged beams locate a metel shop or request angle iron cut and drilled to the length of the beam repaired .
b) 
The cracks along the column line crack developed throught the structure cracks it could have developed throught the column ,concrete is not severely crushed .And it is formed due to the high slump concrete and heavy loads on the beam and column , the repair of a concrete column, the axial dead load, axial live load, horizontal load and its associated moments must be known. Repairs to concrete columns can be divided into two categories. Surface or cosmetic repair only covers local deterioration and structural repair restores or strengthens the affected columns. If the deterioration does not significantly reduce the cross section, the conventional concrete repair.
c)
Cracks are at the joint of the column beam , cracks in develop throught the entir width and slab also develop from cracks along the beam . its is a plastic hinge failure it occure , the damage occured only in the joint , cyclic lateral loading stress reversal at the joint led to the damage . The slab participated to its best to handle the tension ,But unable to control the damage . the joint can be strengthened .
Question 2:
a) 
The column damage at the top of column and it damage around the column ,beam are safe and column see at the edge of the buliding .
Bucking failure occurs in the column ,the load carrying capacity of the column decreses very much the column tends to become unstable and start bucklng to side ward even under small loads. That means the concrete and steel reached their yeild stress for even small loads and start failiing due to lateral buckling .
b) 
it is due to the shear failure .shear failure can occur not only in nonductile frames but also in ductile frames. Column shear failure is important because it can induce a decrease in the axial load resistance of the column .Lateral loads in a structure are carrying by vertical elements such as columns and shear walls.When there are no shear walls, columns carry these lateral loads. If no adequate shear links these types of column failure could occur.Lateral loads are generated by winds, earthquake loads, from retaining structures, etc.Shear links are provided to columns based on the shear forces excreted on them. Further, the size of the columns is increased in the direction of shear to increase the shear capacity.
c) 
Short Columns failure takes place due to yielding and we define this phenomenon as crushing.Short Columns are classified based upon Slenderness Ratio which is the ratio of the effective length Length between point of zero moments and least lateral dimension of the column.