A truss bridge is a bridge whose superstructure, or load-bearing portion, comprises connected triangle-shaped sections called trusses. In reaction to dynamic stresses, the connected elements (usually straight) may experience tension, compression, or occasionally both types of stress. The fundamental truss bridge types have straightforward designs that allowed engineers of the late 19th and early 20th centuries to analyse them easily. Because it makes optimal use of materials, truss bridges are inexpensive to build.
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See also: Different types of bridges, components, advantages and disadvantages
Truss bridge: What makes it a truss?
Trousse, which means “collection of things bound together,” is the ancestor of the word truss and dates back to roughly the year 1200. The word “truss” has frequently been used to refer to any grouping of components, including a cruck frame or a few rafters.
Truss bridge: Advantages
Following are some of the major benefits of a truss bridge.
Quick and simple installation
The fundamental benefit of trusses is that they may be used successfully without the need for expensive heavy machinery or extensive setup. They are also simple and quick to install. Typically, trusses are constructed at a factory before being shipped as a complete set to a construction site, where the building is then constructed. Trusses are frequently raised to the top of the wall using leverage, slipped into place, turned upright, and then secured.
Helps with load distribution
The roof’s weight is supported by them thanks to their triangular shape. Trusses help shift weight away from the centre and down towards the sides or legs. The outside walls thus bear the weight of the roof, which is advantageous for the inner walls. The inner walls can be erected and altered, changed to accommodate various requirements and preferences, or even eliminated altogether because they are not responsible for supporting the entire weight of the roof.
Spans more space
Trusses are able to span greater distances because of their triangular design. This makes them very practical. Triangular roofs retain their shape and are resistant to shift and sag, unlike square-sided roofs that frequently lose shape due to shifting or twisting. In addition to being stable, a roof that has a combined set of trusses can hold a lot more weight than a roof that has not been strengthened with trusses. Due to problems with weight distribution, roofs endure longer and need fewer repairs as a result.
Truss bridge: Types
Pratt Truss
For more than 200 years, trussing has been done successfully using the Pratt Truss. The diagonal elements are in tension, whilst the vertical members are compressed. As a result, the design can be made simpler and more effective by using less steel in the diagonal elements that are under tension. This has several benefits, including lowering the self-weight, lowering the cost of the building due to more effective members, and making the structure easier to construct.
Warren Truss
Another widely used truss structural system is the Warren Truss, which can be recognised by the way it is made up of equilateral triangles. A Warren Truss has the capacity to uniformly distribute the weight across a number of distinct members; however, this is typically only true when the structure is supporting a spanned load. The truss structure will experience concentrated forces under a point load, which is both its principal benefit and the source of its downside. The structure does not perform as well at dispersing the load uniformly among its parts in certain concentrated load circumstances. The Warren truss type is better for spanning loads because of this, but it is not appropriate for situations where the weight is concentrated at a single point or node.
K Truss
A slightly more intricate variation of the Pratt Truss is the K Truss. The vertical members have been reduced in length, which improves the structure’s resistance to buckling. But despite not being commonly used, it is a sturdy design and shares many of the same advantages and disadvantages as the Pratt Truss. The members’ inconsistent behaviour is one of its biggest drawbacks. Under certain stress conditions, a member may be in compression, whereas under others, it may be in tension.
FAQs
What strengthens a truss bridge?
The truss makes the highway stiffer and stronger, aiding in its ability to hold together against the varied stresses it faces rather than supporting it from above or below like a suspension bridge or an arch bridge would.
Are truss bridges long-lasting?
Truss bridges have a high strength-to-weight ratio, which makes them very efficient.
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