Identification of Cracks

Q1. ) What is the mode of failure or damage of the beams in the figure above ? Would you characterize the case as damage or as a failure ? Are the damages repairable? Elaborate.

1. 

Ans :-

• This crack will develop as a result of a beam failing flexurally.
• The stress in a material just before it yields in a flexure test is the flexural strength, also referred to as the modulus of rupture, bend strength, or fracture strength. The material's maximum internal stress at the time of rupture is represented by the flexural strength.
• Stress levels are used to measure it. At the bottom and top of the beam, there is main steel to prevent this kind of failure.
• The harm can be repaired.Find a nearby welder or metal shop and ask for angle iron that has been cut and drilled to the length of the damaged beam that needs to be repaired.
• Eliminate any current pipes, wires, etc. that pass through the beam.
• Before doing so, make sure to turn off the water, electricity, etc.c
• hanger must be pryed away from beam.On the jack and the temporary post, mount the angle iron.
• Set up the angle iron, then raise the jack gradually until it is wedged against the damaged beam.
• Remove the temporary post before screwing the angle iron into the beam.Reconnect any previously disconnected wires or pipes, then turn on the water and power.

2.

• These cracks developed as a result of construction errors and concrete honeycombing.
  
• Avoid using high slump concrete to prevent cracks in your concrete.
  
• Less cracking occurs in concrete with a moderate slump (less than 5 inches).
  
• Only high slump concrete that has been designed to prevent segregation and bleeding of the concrete or that contains concrete admixtures can be used.
  
• To increase slump while decreasing the addition of water content, concrete admixtures like water reducers or super plasticizers can be used.
  
• Air entertained concrete can also be produced to increase slump especially when concrete is to be subjected to freeze and thaw cycles.
• The honeycombing occurs when the fine mortar fails to thoroughly fall and fill the gaps created by the coarse aggregate.
• As mentioned previously, poor concrete consolidation is usually the top cause of honeycombing, along with poor vibration, improper ratio of fine to coarse aggregate, dry concrete and construction conditions that are not up to standard.

3.

• This cracking is a result of the failure of the beam-column joint. In the strong column-weak beam design, beams are anticipated to develop flexural overstrength beyond the design strength and form plastic hinges at their ends.
• High shear demands are placed on the joint core by the high internal forces developed at plastic hinges, which lead to critical bond conditions in the longitudinal reinforcing bars passing through the joint.The bond performance of the bars anchored in a joint has a significant impact on the shear resisting mechanism.

* QUESTION 02 :- *

1. 

Answer :-

• This crack will develop as a result of a column failing flexurally.
• Out of all the structural components of a building, columns play the most significant role.
• According to the fundamental principle of civil engineering, columns should fail after beams and other components have been damaged.
• Compared to columns and column-beam joints, beams appear to be less susceptible to damage during earthquakes and their damage appears to have less of an impact on performance, according to the performance of existing buildings in earthquakes.

2.

• This crack will develop as a result of a column failing in shear.
• Vertical components such as columns and shear walls carry the lateral loads in a structure.
  In the absence of shear walls, these lateral loads are supported by columns.
• Winds, earthquake loads, retaining structures, etc. all produce lateral loads. Based on the shear forces applied to them, shear links are given to columns.
• To further increase the shear capacity, the columns' sizes are increased in the shear direction.

3.

• The short column failure is what caused these cracks to form.
• Failure in Short Columns occurs as a result of yielding; we refer to this as CRUSHING.
• Slenderness Ratio, which is the ratio of the effective length (Length between point of zero moments) and least lateral dimension of the column, is used to categorize short columns.
• Any of the following stresses that develop in the column can lead to failure of the column.
• Short columns will only fail when a column develops a direct compressive stress, or we can also say that short columns will typically fail when there is a direct compression or crushing.