ENGINEERING MECHANICS EXPERIMENT NO.7
OBJECTIVE:
To determine the reactions of a Simply Supported Truss.
APPARATUS:
Weight Balance, weights, hanger.
Figure 7.1: Simply Supported Truss Apparatus
THEORY:
A Truss is a triangulated system of members that are
structured and connected in a way such that they only incur axial force. These
members are considered two-force members as the forces are only applied at
either end of the member, resulting in either a compression or tension force.
They are commonly used as bridge designs, given their ability to efficiently
span long distances.
PROCEDURE:
Step#1: Place
the truss on the set of weighing balances.
Step#2: Adjust
the balance measuring to zero by adjusting the screw. Step#3: Apply point load with the help of steel hook at:
• Mid span of the truss as shown in the
figure.
• L/4 distance as shown in the figure.
Step#4: Record the value of R1
and R2 on the balance
scale provided on both supports.
Step#5: Now apply three point loads at L/4 distance as shown in the figure.
Step#6: Repeat Step 1.
|
Load |
Analytical
Result |
Practical
Result |
Percentage Error(%) |
|||||
S.No.
|
F1 (N) |
F2
(N) |
F3
(N) |
R1
(N) |
R2
(N) |
R1 (N) |
R2
(N) |
R1
|
R2
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CALCULATIONS:
Calculate the reactions when one, two and three point loads
are applied on the truss.
PRECAUTIONS:
1. The
Truss should remain in a straight line that is should not lose its alignment
(get curved) in direction perpendicular to the loading plane.
2. Accuracy
of the weighing balance.
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 sides when the distance changes from both ends.
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