Identification of Cracks

1.)What is the mode of failure or damage of the beams in the figure above? Are the damages repairable? Elaborate.

ANS:-

Beam column connection failure is the mode of failure in the above figure.

• Formation of plastic hinge at underisable locations.
• The joint is not supported to beam thr weak link between 4 components (2 beams and 2 columns).
• These elements are subjected to very high shear force during seismic activity.
• If these cracks are left unattended will lead to loss of strength and collapse.
• Shear failure governs in the beam column.
• Formation of plastic hinges must occur at the end of the beams not at the column and beam connections.
• It is also caused due to inappropriate detailing.

2 A)

Shear failure of column: It follows the mechanism of weak column and strong beam. Longitudinal steel has buckled due to large compression forces.

2B)

Confinement failure of the column:

This is caused due to inappropriate detailing of plastic hinge location.Under ductile response to earthquakes high compression dtrains should be accepted from combined effect of axial force in bending moment.Adequate closed spaced well detailed transevered reinforcement needs to be done to avoid spoiling of concrete followed by instability of compression reinforcement.It should also be done to check the resistance longitudinal reinforcement against buckling.

2C)

Short column effect:

It is caused due to influence of partial height infill increasing column shear force(short column effect) which causes undesirable mode of deformation.It happens due to ignoring the stiffening effects of non structural partial height masonary infill built hard up against the column.The shorter column attracts higher shear force which often leads to deformation or collapse.