In the construction industry, a “girder truss” is a type of truss that is used to support the weight of other structural elements, such as roof trusses, floor joists, or beams. Girder trusses are typically made from wood or steel and are custom-designed and built to fit the specific requirements of the building. They are used in both residential and commercial construction and serve several important purposes, including providing structural support for the building, distributing the weight of the roof or floor evenly across the walls, and allowing for longer spans without the need for additional support columns or walls.
Composition and Structure
Girder trusses are typically made from the following materials:
- Wood: Wood girder trusses are the most common type of truss used in construction. They are typically made from dimensional lumber, such as 2x6s or 2x8s, that are custom-cut and assembled to fit the specific requirements of the building.
- Steel: Steel girder trusses are sometimes used in commercial or industrial construction. They are typically made from steel channels or I-beams that are custom-cut and assembled to fit the specific requirements of the building.
Functionality
Girder trusses serve several important functions:
- Support: Girder trusses provide support for the weight of other structural elements, such as roof trusses, floor joists, or beams, ensuring that the building is stable and secure.
- Weight Distribution: Girder trusses distribute the weight of the roof or floor evenly across the walls, reducing the risk of settlement or shifting over time.
- Spanning Ability: Girder trusses allow for longer spans without the need for additional support columns or walls, providing greater flexibility in the design and layout of the building.
Types of Girder Trusses
There are several types of girder trusses commonly used in construction:
- King Post Truss: King post trusses are a type of girder truss that consists of a single vertical member (the king post) with two diagonal members (the rafters) extending from each side to the top of the truss. They are typically used in small or medium-sized buildings with relatively short spans.
- Queen Post Truss: Queen post trusses are a type of girder truss that consists of two vertical members (the queen posts) with two diagonal members (the rafters) extending from each side to the top of the truss. They are typically used in medium-sized buildings with longer spans than king post trusses.
- Howe Truss: Howe trusses are a type of girder truss that consists of vertical members (the king posts and queen posts) with diagonal members (the web members) extending from each side to the top of the truss. They are typically used in large buildings with long spans and heavy loads.
Installation
The process of installing girder trusses typically involves the following steps:
- Design: The design of the girder truss is finalized, taking into account the specific requirements of the building and the desired structural characteristics.
- Construction: The girder truss is constructed on-site or prefabricated off-site and installed according to the design specifications.
- Installation: The girder truss is installed in the building, with the ends of the truss bearing on the walls and the intermediate supports.
- Connection: The girder truss is connected to the walls and the other structural elements using nails, screws, or other fasteners, ensuring that it is stable and secure.
Maintenance
Proper maintenance is essential for preserving the functionality and integrity of girder trusses:
- Girder trusses should be inspected regularly for signs of damage, wear, or deterioration and repaired or replaced as needed.
- Girder trusses should be cleaned periodically to remove dirt, dust, and debris and to prevent the growth of mold or mildew.
- Girder trusses should be painted or treated as needed to protect them from the elements and to maintain their structural integrity.
Conclusion
Girder trusses are an essential structural element in construction, providing support for the weight of other structural elements, distributing the weight of the roof or floor evenly across the walls, and allowing for longer spans without the need for additional support columns or walls. By properly selecting, installing, and maintaining girder trusses, construction professionals can ensure the stability and integrity of the buildings they construct.
