TRUSSES AND ITS APPLICATION

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.

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

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.

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.

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.

IMAGES OF TRUSSES

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.

TRUSS ANALYSISFollowing 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.

TRUSS ANALYSISApplication of trusses-

Roof of factory shade. Ware house Railway platform Garage shed transmission towers Crane truss Bridge Truss Sport Stadium Truss

HOW TO SOLVE A TRUSS PROBLEMFor 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.

HOW TO SOLVE A TRUSS PROBLEMFor 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.

EXAMPLE OF A QUESTION

CONTINUE

CONTINUE

Done by :Milan Joshi BE/50024/15Bhairvi Singh BE/50036/15Asman BE/50054/15