2. WHAT IS TRUSS ?
A truss is a structure comprising one or more triangular units constructed
with straight members whose ends are connected at joints or nodes.
If all the bars lie in a plane, the structure is a planar truss.
The main parts of a planar truss.
TRUSS ANALYSIS
In other words, Trusses are designed to form a stable
structure.
3. DIFFERENT TYPES OF TRUSSES
There are tree types of Trusses:-
Perfect Trusses (m=2j-3)
Deficient Trusses(m<2j-3)
Redundant Trusses(m>2j-3)
Here m=members
j=joints
4. 1.PERFECT TRUSSES
A Structure that is made of members just sufficient to
keep it in equilibrium, When loaded without change of
shape.
m=2j-3
It is efficient and optimized structure.
5. 2.DEFICIENT TRUSSES
A structure that is made of members less than
sufficient that leads to change of shape when
load is added, leading to collapsing of structure.
m<2j-3
Not very efficient and optimized.
6. 3.REDUNDANT TRUSSES
A structure that is made of members more than
sufficient that doesn’t let the shape of the
structure to change.
m>2j-3
Very efficient and optimized.
8. ASSUMPTION IN TRUSSES
All members are straight and have uniform cross section.
All members have negligible weight.
All members are connected at joints through pin
connection which are frictionless.
The external force must be applied at the joints.
All members have axial force.
Couple movements which produce bending do not act on
the member of the truss.
9. TRUSS ANALYSIS
Following characteristics of Truss
* The members of the truss should be in a plane.
* Members are connected at their intersections by means of
frictionless pins or hinge.
* Loads and reactions are applied only at joint.
* The centroid of the members must coincide with centroid of
the joints.
10. TRUSSANALYSIS
Application of trusses-
Roof of factory shade.
Ware house
Railway platform
Garage shed
transmission towers
Crane truss
Bridge Truss
Sport Stadium Truss
11. HOW TO SOLVE A TRUSS PROBLEM
For method of Section
Draw a free body diagram.
Take an imaginary section to cut the truss into two pieces
in condition that the number of unknown forces doesn’t
exceed three.
Apply equilibrium equations on one piece of the truss.
∑V=0, ∑H=0, ∑M=0.
After determining all the forces, positive forces are
tension and the negative forces are compression.
12. HOW TO SOLVE A TRUSS PROBLEM
For method of Joints
Draw a free body diagram.
Find the equilibrium of the truss that is
∑V=0, ∑H=0, ∑M=0.
Select the joint whose number of forces doesn’t exceed
two and then study its equilibrium by using static
equations.
∑V=0, ∑H=0.
Go to next joint and follow the same procedure.
The Horizontal equation will be Tension and the Vertical
equation will be Compression.