The Following File Contains Details About Truss, its types and analysis of Truss by both Method of Joints and Method Of Sections with examples

2. PRESENTATION
CE-215L
STRUCTURAL ANLYSIS LAB
INSTRUCTED BY ENGR MUHAMMAD SALMAN
PRESENTED BY GROUP-232

3. TRUSS
S.NO TOPICS PRESENTED BY
1
Introduction,
Types and Uses Of
Trusses
Asmar-ud-Din
2
Analysis Of
Trusses, Types Of
Analysis
Muhammad Talha
3 Method Of Joints Hammad Shoaib
4
Method Of
Sections
Tariq Ullah
Table Of Contents
Group Members
S.NO NAME REGISTRATION NO
1 Asmar-Ud-Din 19pwciv5272
2 Muhammad Talha
19pwciv5212
3 Hammad Shoaib
19pwciv5298
4 Tariq Ullah
19pwciv5249

4. INTRODUCTION
A truss is the structure composed of slender members joined together at their end
points.
Usually the joint connections are formed by bolting or welding the ends of members
to a common plate , called Gusset Plate.
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Gusset Plate

5. TRUSS
What is the difference between truss and frame as both formed by connection of
members?

6. Classification Of Truss
TRUSS
Truss
Simple
truss
Compound
Truss
Complex
Truss

7. TRUSS
Truss
Plane
Truss
Bridge
Truss
Roof
Truss
Space
Truss
Tower
Truss

8. Examples Of Roof Truss Examples Of Bridge Truss
TRUSS
Scissors Truss
Howe Truss
Pratt Truss
Pratt Truss
Howe Truss
K Truss
Warren Truss
Fink Truss

9. TRUSS
Electric Tower
Roof
Tower Crane
Bridge
Truss In Practical life

10. Roof Truss
TRUSS

11. Bridge Truss
TRUSS

12. Structural Analysis
Analysis is the prediction of performance of structure under load or
other external effects.
During analysis we calculate the
• Internal Actions
• Stresses (Flexural, Shear, Axial, Torsional etc.)
• Deformation
• Translation and Rotation
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13. Analysis of Trusses
There are some assumptions to make during truss analysis
• The members are joined together by smooth pins.
• All loadings are applied at joints only.
Because of these two assumptions, each truss member acts as an axial force
member, and therefore the forces acting at the ends of the member must be
directed along the axis of the member. If the force tends to elongate the member,
it is a tensile force (T), whereas if the force tends to shorten the member, it is a
compressive force (C). In the actual design of a truss it is important to state
whether the force is tensile or compressive.
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14. TRUSS
Analysis
Methods
Method Of
Joints
Method Of
Sections

15. Determinacy Of Truss
Since all the elements of a truss are two-force members, the moment
equilibrium is automatically satisfied.
Therefore there are two equations of equilibrium for each joint, j, in a
truss. If r is the number of reactions and b is the number of members
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b+r=2j , Statically Determinate
b+r>2j, Statically Indeterminate
b+r<2j, Unstable
NOTE
If b + r < 2j, a truss will be unstable, which means the structure will
collapse since there are not enough reactions to constrain all the
joints.

16. TRUSS
Example-1

17. TRUSS
Example-2

18. Example-3
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19. Method Of Joints
The method of joints consists of satisfying the equilibrium equations for
forces acting on each joint
F x =0, F y =0
Procedure For Analysis
The following is a procedure for analyzing a truss using the method of joints
1. Determine the support reactions.
2. Draw the free body diagram for each joint. In general, assume all the
force member reactions are tension (this is not a rule, however, it is
helpful in keeping track of tension and compression members).
3. 3. Write the equations of equilibrium for each joint.
4. If possible, begin solving the equilibrium equations at a joint where only
two unknown reactions exist. Work your way from joint to joint, selecting
the new joint using the criterion of two unknown reactions.
5. 5. Solve the joint equations of equilibrium simultaneously, typically using
a computer or an advanced calculator.
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20. TRUSS
Example
Reference
Structural Analysis by R. C. Hibbeler

21. TRUSS
By taking Joint A,
Y
X
FAG
FAB
4kN
30°
A
+ F y =0; 4-FAGsin30°=0
FAG =8kN(C)
+ F x =0; FAB -8cos30°=0
FAB= 6.93kN(T)

22. By Taking Joint G,
TRUSS
+ F y =0; F GB-3cos30°=0
FGB =2.60kN(C)
+ F x =0; 8-3cos30°-FGF=0
FGF= 6.50kN(C)
30°
G

23. By Taking Joint B,
TRUSS
+ F y = 0; F BF sin60°-2.60sin60°= 0
FBF =2.60kN(T)
+ F x = 0; FBC +2.60cos60°-6.93=0
FGF= 4.33kN(T)
60° 60°
B
FBF
6.93kN FBC
Y
X

24. Method Of Sections (Ritter Method)
If the forces in only a few members of a truss are to be found, the method of
sections generally provide the most direct means of obtaining these forces.
The method is created by the German scientist August Ritter (1826 -1908).
This method consists of passing an imaginary section through the truss, thus
cutting it into 2 parts.
Provided the entire truss is in equilibrium, each of the 2 parts must also be in
equilibrium.
The 3 equations of equilibrium may be applied to either one of these 2 parts to
determine the member forces at the “cut section”
 A decision must be made as to how to “cut” the truss
In general, the section should pass through not more than 3 members in which the
forces are unknown
When applying the equilibrium equations, consider ways of writing the equations
to yield a direct solution for each of the unknown, rather than to solve
simultaneous equations
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25. Example
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26. TRUSS

27. TRUSS