Identification of Cracks

Question 1:

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

A).

• This cracks are formed due to flexural failure of a beam.
• Flexural strength, also known as modulus of rupture, or bend strength, or transverse rupture strength is a material property, defined as the stress in a material just before it yields in a flexure test.
• The flexural strength represents the highest stress experienced within the material at its moment of rupture.It is measured in terms of stress.
• In this Beam failure, concrete is crushed and reinforcement is exposed.
• Concrete spelled beyond reinforcement which is a sign of rupture.
• Top portion of beam looks safe because of flange advantage of slab.
• Its form of Flexural failure to reversal of stress during earthquake.
• During stress reversal, support top experiaences and bottom experiences tension.
• Top compression is managed by slab advantage.
• Bottom tension was not satiesfied by provided reinforcement.
• Since the reinforcement got yielded, it can not be repaired.

B).

• This cracks are formed due to the mistakes done in concreting and honeycombing in concreting.
• Cracks are formed along Beam-Column edge.
• Crack seems to have developed through structure as it looks much wider.
• Beam looks separated from the columns at the joint.
• To avoid cracks in the concrete, avoid using high slump concrete.
• Its beam pull out failure due to insufficient development length of reinforcement in joints.
• During Earthquake, The Horizontal movement of structure makes this condition worse and detached the beam member from column.
• Providing anchorage length between two existing concrete is very difficult.
• So this failure is not repairable.

C).

• This cracks are formed due to the Beam-Column joint Failure.
• In the Strong Column-Weak Beam design, beams are expected to form plastic hinges at their end and develop flexural overstrength beyond design strength.
• Cracks in the beam developed through its entire width.
• Slab also developed more cracks along the beam width direction.
• The damage occurd only in joint zone first.
• Slab participated to its best to handle the tension.
• The joint can be strengthened.

Question 2:

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

A).

• This cracks are formed due to flexural failure of a beam.
• Colmuns have the most important role in the structure.
• In this failure, Concrete damaged all around the column face.
• Beams are looking safe.
• The location of the building looks at the edge of the building.
• It is soft storey failure, Technically plastic hinge formation.
• Based on the development of crush of concrete, it can be repairabale or non-repairabale.

B).

• This crack will form due to the shear strength of Column.
• Concrete develpoed complete breakage diagonally.
• Lateral loads are carrying by vertical elements such as columns and shear walls.
• Lateral loads are generated by wind load, earthquake loads from retaining structures.
• Shear reinforcement spacing looks wider.
• Inadequate shear reinforcement compels concrete takes all shear stresses.

C).

• This cracks are formed due to short column failure.
• Short column is classified base upon slenderness Ratio.
• Failure of Column usually occurs due to anyone of the following stresses developed in the column.
• There are two slabs connected to columns, probably one at mid height of column.
• The wooden piles might be Post failure support after column failed, providing temporary prop to avoid collapse of the entire structure.