OBJECT: TO DETERMINE SHEAR STRENGTH OF STEEL BARS

APPARATUS:

• Steel Specimen
• Shear Strength Apparatus
• UTM

THEORY:

SHEAR STRENGTH

1. SINGLE SHEAR
   

DOUBLE SHEAR

METHODOLOGY:

OBSERVATIONS:

• Diameter of Steel bar = ___________ mm
  
• Area of Cross Section = _______________ mm
  
• Failure load = _______________________ N
  
• Shear Strength = __________________ N/mm²
  

CALCULATIONS:

Shear Strength of Steel Bar

𝑟 = 𝑃/𝐴

FIGURE OF SHEAR SHACKLE APPARATUS

RESULTS: 𝝉 _____________________________ N/mm²

or

SHEAR TEST

AIM: Find out the Shear strength of a given specimen using UTM.

APPARATUS: A UTM, Specimen, shearing attachment, vernier caliper, etc.

THEORY: A type of force that causes or tends to cause two contiguous parts of the body to slide relative to each other in a direction parallel to their plane of contact is called the shear force The stress required to produce fracture in the plane of cross-section, acted on by the shear force is Called shear strength.

DIAGRAM:

PROCEDURE:

1. Insert the specimen in position and grip one end of the attachment in the upper portion and one end in the lower position
   
2. Switch on the UTM
   
3. Bring the drag indicator in contact with the main indicator.
   
4. Select the suitable range of loads and space the corresponding weight in the Pendulum and balance it if necessary with the help of small balancing weights
   
5. Operate (push) the button to drive the motor to drive the pump.
   
6. Gradually move the head control ever in the left-hand direction till the specimen shears.
   
7. Note down the load at which the specimen shears.
   
8. Stop the machine and remove the specimen.
   
9. Repeat the experiment with other specimens.
   

OBSERVATION:

1. Applied compressive force (F)=kgf.
2. Diameter of specimen=mm.
3. Cross-sectional area of the pin (in double shear) =(2𝜋𝑑2 / 4 ) mm²
4. Load taken by the specimen at the time of failure, W=…… (N)
5. Strength of the pin against shearing (τ)= 4𝑊 / 2𝜋𝑑2

PRECAUTIONS:

1. The measuring range should not be changed at any stage during the test.
   
2. The inner diameter of the hole in the shear stress attachment should be slightly greater than the specimen.
   
3. Measure the diameter of the specimen accurately.
   
4. The method for determining the shear strength consists of subjecting a suitable Length of steel specimen in full cross-section to double shear, using a suitable test rig, in a testing m/c under a compressive load or tensile pull, and recording the maximum load ‘F’ to fracture.
   

RESULT:

Shear strength of specimen = ——–

VIVA-QUESTIONS:

1. Does the shear failure in wood occur along the 45° shear plane?
   
2. What is shear stress?
   
3. What is single & double shear?
   
4. What is the finding of the shear test?
   
5. What is a unit of shear strength?
   

APPLICATIONS:

1. Shear failures of soils