E-Liberary Pakistan: Various types of Roof trusses for various spans

In Architecture and Structural Engineering, a truss is a structure comprising one or more triangular units constructed with straight slender members whose ends are connected at joints referred to as nodes.
External forces and reactions to those forces are considered to act only at the nodes and result in forces in the members which are either tensile or compressive forces.
Moments (torsional forces) are explicitly excluded because, and only because, all the joints in a truss are treated as revolutes.

In this article, we are going to discuss the various types of roof trusses in wood and steel and their uses in various kinds of construction.

King Post roof truss (spans upto8M)

Queen Post Truss (spans upto 10M)

Howe Truss (spans upto 6M to 30M)

Pratt truss (spans upto 6M to 10M)

Fan Truss (spans upto 10M to 15M)

It is made of steel.
Fan trusses are form of Fink roof truss.
In Fan Trusses, top chords are divided into small lengths in order to provide supports for purlins which would not come at joints in Fink trusses.
It can be used for spans from 10-15m.

North light roof truss (spans upto 20M to 30M)

When the floor span exceeds 15m, it is generally more economical to change from a simple truss arrangement to one employing wide span lattice girders which support trusses at right angles.
In order to light up the space satisfactorily, roof lighting has to replace or supplement, side lighting provision must also be made for ventilation form the roof.
One of the oldest and economical methods of covering large areas is the North Light and Lattice girder.
This roof consists of a series of trusses fixed to girders. The short vertical side of the truss is glazed so that when the roof is used in the Northern Hemisphere, the glazed portion faces North for the best light.
It can be used for spans from 20-30m.
Used for industrial buildings, drawing rooms etc.

Quadrangular Roof Truss (for large spans)

Large Span Trusses

Large span trusses