EXPERIMENT NO.5
OBJECTIVE:
The purpose of the experiment is to determine support
reactions of a Simply Supported Beams.
APPARATUS:
Weight Balance, hanger, weights, ruler.
Figure 5.1: Simply Supported Beam
THEORY:
One common example of parallel forces in equilibrium
is that of a beam, because in most cases the forces are vertical weights due to
gravity. Hence the beam supports will develop vertical reactions to carry the
weights on the beam, and the self-weight of the beam itself.
For a beam on two supports there will be the two
unknown reactions, so two equations of equilibrium must be set up. It is
necessary to start by taking moments about a convenient point; if this point is
at a reaction then there is only one unknown force (the other reaction) in the
equation. The second reaction can then be found from vertical equilibrium.
PROCEDURE:
Step#1: Calculate
self-weight of the beam.
Step#2: Adjust
the weighing balances to zero with the help of by adjusting screw.
Step#3: Record
the reactions observed on the balance scale independently. The sum of the
reaction will give the self-weight of the beam.
Calculate the reactions on the beam due to
external/applied loads:
Step 1: Adjust the weighing balance to zero by adjusting screw,
when the beam is placed in the positions.
(a) As shown in figure 5.2
(b)As shown in figure 5.3
Step 2: Apply
the point load with the help of steel hook in hanging position:
o Mid-span of the beam (Figure 5.2) o L/3 distance (Figure 5.3)
Step#3: Record the value of R1 and R2 on the balance scale provided on the both edges for the two loading conditions.
o Now
apply two point loads
• At L/3 distance (Figure 5.4)
• At different distance (Figure 5.5)
o Record
the value of R1 and R2 on the both edges when
three point loads are applied.
o Now
apply three point loads
• At L/4 distance (Figure 5.6)
• At L/6 from both edge (Figure 5.7)
o Analytically
calculate R1 and R2 for one, two and
three-point load respectively keeping the same distances.
OBSERVATIONS:
CALCULATIONS:
Solve all the six cases for analytical results and
also plot shear force and bending moment diagram of all the six cases on paper
and using Microsoft Excel.
PRECAUTIONS:
1.
Accuracy of weighing scale.
2.
Horizontal beam should be maintained and
remained throughout the experiment particularly when load application and
measurement of reactions are made.
CONCLUSION:
Discuss
• The
change in value of R1 and
R2 when one, two and
three point loads are applied.
• The
ratio of load transfers on both side when the distance changes from both end.
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