Question

Define the Pin connected truss.

Mention three types of truss?

Answer 1

• Truss elements are also called "two-force member". Here Two-force member is a structural component where forces can only be applied at both ends or nodes.
• Truss elements are inter-connected by it's nodes to form a stable configuration. These joints are generally pinned connection.

  Reason for pinned connection:-

• We know truss elements can either in compression or tension hence it can't be in bending .hence the moment because of applied force has to be released somehow.
• For this reason the joints are connected as pinned connection that's only the force is allowed to transfer from truss elements to another but not the moment and hence it's released.

[Moments gets released meaning the joints don't provide any restrictions to rotation hence no moment.]

Types of truss:-

1. Pratt truss
2. Warren truss
3. North light truss

(There are different types of truss but only 3 are given as asked in the question.)

1. Pratt truss(N truss)

Pratt truss are normally used in long span building ranging from 20-100m in length.

In normal Pratt truss the diagonal truss elements are in tension because of gravity loads.hence these types of truss are generally used when gravity load are predominant.

There are also some modified pratt truss shown in the diagram below.

2.Warren truss

In this types of truss the diagonal elements are alternatively in compression and tension .it has fewer elements than Pratt truss.

Here all the truss elements are of equal span length.

Hence the load is distributed through these equilateral triangle to spread out the loads on the structure.

Diagram Is shown below.

3. North light truss

These are used for short span structures unlike Warren and Pratt truss.

They allow for maximum benefit from natural lighting by the use of glazing on steeper pitch which generally faces north to reduce the solar gain.

The use of North light truss to increase the natural daylighting can reduce the operational carbon emissions of buildings.

Diagram is shown below.