Difference between King Post Truss & Queen Post Truss
Concept about King Post Truss
In the case of the roof structure and bridge frameworks, the king post truss has been used. The king post truss is simple in design, having higher strength and also being economically efficient. The king post truss has been made with steel or timber, two principal rafters and a vertical central post, which helps to create the triangular structure.
Discuss the key components of the King Post Truss
Rafters
The rafters are the sloping members of the king post truss, which help to form the sides of the triangle. The rafter helps to resist the load of the roof and transmit the loads to the verical king post.
King posts
The king post helps to strengthen the roof truss and also helps to transfer the roof load to the foundation structure.
Tie beam
The tie beam of the king post truss helps to resist the outward thrust from the rafters. Thus, the tie beam helps to prevent the roof from spreading outwards.
Struts
In some cases of the king post truss, diagonal struts have been added. These components help to support the rafters, as well as enhance the load-bearing capacity.
Discuss the applications of the King Post Truss in the construction project
Construction of bridges
In the case of timber bridges or steel bridges, the king post truss has been applied.
Construction of pavilions and public structures
In case of the open-air structures, including park shelters, pavilions or gazebos, the king post truss has been used. This king post truss helps to provide an aesthetic visibility of the public structures.
Used in industrial sectors
The king post truss has also been used in the large-span industrial buildings because of its higher load-bearing capacity.
Concept about Queen Post Truss
The queen post truss can span a longer distance in the construction structure. In the case of the roofing system that requires a medium span, the queen roof truss can be used.
The queen post truss consists of two vertical posts, which provide support to the roof and other types of external loads in the construction structure.
Discuss the key components of the Queen Post Truss
Top Chord
The top chord of the queen post truss helps to form the upper edge of the roof truss.
Bottom Chord
The bottom chord of the queen roof truss helps to connect the end of the roof truss. This bottom chord helps to keep the queen posts from spreading apart.
Struts
The struts of the queen post truss help to make the connection between the queen posts and the top chords. This strut helps to distribute the load and also helps to prevent bending.
Queen Posts
The queen post helps to transfer the loads from the top chord and is located at the third of the span.
Rafters
The rafters of the queen post truss help to form the slope or pitch of the roof.
Soffit
The soffit helps to provide an interior appearance and also has a waterproofing feature.
Purlins
The purlins of the queen post truss help to provide intermediate support to the roof materials.
Discuss the applications of the Queen Post Truss in the construction project
Used in bridges
The queen post truss is appropriate for small and medium-sized bridges, as it helps to support the weight of vehicular and pedestrian traffic.
Used in residential buildings
In the case of the houses, along with pitched roofs, the queen post truss has been applied. The queen post truss helps to provide aesthetic appeal to the residential buildings.
Used in agricultural buildings
The queen post truss has been used in barns and agricultural structures and allows for the wide open spaces in those structures.
Key differences between King Post Truss and Queen Post Truss
There are several key differences between the king post truss and the queen post truss, which are as follows:
Based on the length of the span
The king post truss has been applied in the case of the length of the span is about 5 to 8 meters. Whereas, the queen post truss has been applied in the case of the length of the span is about 8 to 12 meters.
Based on the vertical post
In the case of the king post truss, one vertical post has been provided at the centre of the roof structure. On the other hand, in the case of the queen post truss, the two vertical posts have been provided on the two sides at a distance.
Based on the necessity of the straining beam and straining sill
In the case of the king post truss, the straining beam and straining sill are not essential. Whereas, in the case of the queen post truss, the straining beam, strut, rafter, tie beam and straining sill are essential.
To learn more, watch the following video tutorial.
Video Source: Engineering Motive
Based on the connection of the top ends of the rafters
The top ends of the rafters in the king post truss have been connected to the ridge pitch. On the other hand, the top end of the rafters in the queen post truss has been connected with the heads of the queen posts.
