A roof truss provides support for a roof.
In architecture or structural engineering, a truss system is an arrangement of wooden or steel support beams configured in a triangular shape. Typically, the horizontal ends are connected to other trusses in the system. Truss systems are often used in the construction of utility buildings, bridges and towers. They are also commonly used in stage and display projects.
The sloped or common style is one of the two most common truss designs.
One of the advantages of the truss system is its simplicity. The triangle carries loads only at its joints or nodes. A triangular structure is stable and doesn’t need extra support to prevent it from collapsing like a rectangle would. Force calculations are easy because only compression and tension forces are present. This limits the number and direction of forces that must be considered when determining the forces in a truss member.
Buildings often use truss systems made from steel beams.
Despite its simplicity, a wooden truss system is extremely strong. A truss system is stronger than a beam because it can dissipate forces throughout its structural members. The use of truss systems in construction remained popular even after other stronger materials became available. Truss systems are easy to build because they consist of few parts. They tend to be lightweight and very inexpensive because only beams and joints are needed.
Truss systems can span great distances and dissipate forces throughout the structure with load bearing only at the ends. This can be very convenient in the construction of both residential and commercial buildings because non-load bearing walls can be placed at intervals between the two ends of the truss system. This allows flexibility in wall spacing and allows for easy removal if necessary.
There are some disadvantages to truss systems, which is why they are not used on all roof structures. In situations where more space is needed in the roof area, such as attic rooms, truss systems can take up a lot of space. Truss systems are more difficult to place than beams. They must be mounted on the ground and lifted with a crane, while rafters can be built quickly and without special equipment. On roof systems with many shape irregularities, truss systems may not perform well.
Many variations on the truss system are available to combat some of the drawbacks and make the system capable of handling different load requirements. In the case of utility towers, a three-dimensional truss system can be used to make the structure vertically stable and able to withstand high winds without tipping over. Another example of a variation on the truss system is the use of a cantilevered truss in bridge construction to allow for long span truss systems.