Introduction to Trusses

Introduction to Trusses

Roof trusses. Image credit myrooff.com

Roof trusses. Image credit myrooff.com

ZIMSEC O Level Combined Science Notes: Introduction to Trusses

  • A truss is a supporting framework for a roof, bridge or any other large structure
  • Box and rectangular truss frameworks are inherently weak and susceptible to shear force
The rectangular truss is weak when subjected to shear forces

The rectangular truss is weak when subjected to shear forces

  • The rectangular truss structure can be strengthened by attaching a diagonal tie to it as shown above
  • The result is triangular shaped trusses
  • Because of their inherent strength trusses are always made up of triangular shapes
A simple truss showing the triangular nature of trusses

A simple truss showing the triangular nature of trusses

  • The diagram above shows an example of a simple truss
  • The load is prevented from falling by attaching a piece of wire to the cantilever beam
  • The compress forces in the truss can only act laterally (horizontally)
  • It plays no direct part ┬áin holding this load but it keeps the truss extended
A slightly more sophisticated truss

A slightly more sophisticated truss

  • The diagram shows a slightly more sophisticated truss
  • It was made by adding an extra piece to the truss
  • The topmost wire is in tension and the bottom most beam in still in compression
  • These two parts hold the entire truss up
  • The weight of the load is now supported by the upward action of the tension in the middle wire
  • and the compression the diagonal piece (the one to the right in the diagram above)
A truss trellis

A truss trellis

  • More and more pieces can be added to make an even more complicated truss ( a trellis)
  • The diagonal parts of the trellis support the load
  • The horizontal wires parts support the trusses
  • All the beams resist shear
  • The trellis is lighter because unnecessary (neutral components are reduced)

To access more topics go to the Combined Science Notes page.

By |2017-01-17T11:12:25+00:00June 13th, 2016|Notes, O Level Science Notes, Ordinary Level Notes|1 Comment

About the Author:

He holds an Honours in Accountancy degree from the University of Zimbabwe. He is passionate about technology and its practical application in today's world.
%d bloggers like this: