Identification of Cracks

• Answer to the question one

Mode of failure is excessive shear due to lateral forces from earthquakes. In the image A, it shows the perfect plastic hinge formation and the deformation seen is well within the elastic limit; hence repairable, latest modes of strengthening include nano concrete filler with high compressive strength used to repair the edges. More recent developments in the mode of strengthening are wrapping the beam surface with a material increasing cohesion and load taking capability of the beam.

Image b shows slight deformation along the column which is a result of the whole structure contributing to the deformation due to plastic hinge formation at all the joints of the structural. This was probably due to good design at the critical joints with sufficient reinforcement

• Answer to the question two

images a, b & c show excessive damage, most likely beyond repair. Mode of failure being for a is the excessive shear at edges.

for image c it is the insufficient shear reinforcement along the column, this might be one of those short columns which attracts more force hence leading to failure

Image c shows a soft story collapse most likely occurring at bottom story levels in the upper region of the columns. Soft story is mostly due to more