Steel Truss

STEEL TRUSSES

WITH RIVETED AND WELDED JOINTS

ROOF TRUSSES:

A truss is a structure comprising

five or more triangular units

constructed with straight

members whose ends are

connected at joints referred to

as nodes.

OR

A trusses consist of an assembly

of rigid but elastic members

jointed in form of triangles to act

as a beam.

Trusses mainly consist of FOUR elements:

Rafters to support the roofing material Purlins to provide intermediate support to rafters and Tie beam Strut

TYPES OF ROOF TRUSSES:

TRUSSES TYPE

FIGURE DETAIL APPLICATION

KING POST TRUSS

The spacing of the

king post truss is

limited to 3m centre

to centre.

Span- 5-8mts

Queen post truss

Span- 8-12 meters

Combination of king and queen post.

Span- 18 meters

Note: King post, queen post , combination of both , mansard truss

are essentially wooden trusses

TYPES OF ROOF TRUSSES:

TRUSSES TYPE

FIGURE DETAIL APPLICATION

Mansard roof truss

The upper pitch

(king post) varies

from 30 to 40 degree, and lower

pitch (queen post)-

60 to 70 degree.

COMPOSITE ROOF TRUSSES

The tension

member are of steel

and compress

member are of

timber.

Steel truss When exceed by Span- 10 meters

and timber truss

become heavy and

uneconomical.

STEEL ROOF TRUSSES:

Steel roof trusses are for lager span as compared to wooden trusses.

Steel roof trusses are mainly fabricated with sections.

The angle sections are jointed together by rivets , welding or nuts and bolts.

Gusset plates are also used in connections.

Recently gusset plates are replaced by welding the members directly.

Steel trusses are fabricated from roll steel structural members such as channels, angles, T- section, circular and plates.

STEEL ROOF TRUSSES:

Steel angle section trusses

ADVANTAGE OF STEEL ROOF TRUSSES OVER TIMBER TRUSSES:

Steel trusses are more commonly used these days for all spans small or large since thy are :

a) More economical

b) No span restriction, while timber trusses are suitable for only up to

15-18 meters.

c) Light in weight and Easy to construct or fabricated in any shape.

d) Fire proof and termite proof

e) More rigid

f) Permanent

g) The sections of steel trusses are readily available in the required

dimensions, resulting in minimum wastage.

h) Steel trusses are easy to install.

STEEL ROOF TRUSSES :

Steel roof trusses are used in industrial buildings, work shops and auditoriums for covering. Main types of roof covering are corrugated sheets, slate and tiles etc . The sheet are fixed on longitudinal member provided in between two trusses.

TYPES OF STEEL ROOF TRUSSES :

The various shapes of these along with their suitability for different span ranges, are shown in figure:


KING POST TRUSS

QUEENPOST TRUSS


FINK TRUSS

FINK TRUSS WITH CAMBER

COMPOUND FINK TRUSS


FAN TRUSS

HOWE TRUSS


HOWE SIX PANELS TRUSS

PRATT OR N- TRUSS GENERALLY USED FOR BRIDGES

DETAILS OF STEEL ROOF TRUSSES :

Steel Truss

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