The Engineering Behind Trusses

If we consider trusses from the point of view of engineering, the truss is basically a structure that consists of elements/members, which only takes compression or tension & there is no bending induced whatsoever. The members/elements are connected with the help of one gusset joint, which is either bolted, welded, or riveted in a certain way that only has axial forces induced in that structure. The actual reason behind the axial-forces is actually the reason that all the exterior or outer loads are used in a certain way that the effects appear to be in a form of the forces used on only the joints. In simpler terms, the truss is actually one structural member, which is basically assembled in a way that the forces are only applied on its ends.

truss engineering

Truss: In Engineering

Trusses or wood trusses that are commonly seen today are basically frames of triangulated lumber, which are actually bound together by galvanized steel’s connector plates, generally known as truss plates. In simple terms, trusses are actually a structure that has 2-force members & the two-force members are bonded in a manner that the entire thing appears to be a single object. Besides woodeb trusses there are also steel trusses that are widely utilized in construction.

In the typical context, the external forces & reactions to the forces are believed to only act at its nodes & result in the members’ forces, which are either compressive or tensile. For the straight members, torques (moments) are excluded explicitly because all the truss joints are considered as revolutes, which is important for its links to become two-force members.

The nodes and members in the planar truss, lies within one two-dimensional plane, while the space truss consists of nodes and members, which extend into 3 dimensions. The truss’ top beams are known as the top chords & are normally in compression, and the truss’ bottom beams are known as the bottom chords, which are normally in tension. Further, the truss’ interior beams are known as the webs & the areas found inside these webs are known as panels.


The truss typically consists of straight members that are connected at the joints, traditionally called the panel points. The trusses are normally made of triangles and the reason behind that is its design and shape’s structural stability. The triangle is considered as the simplest and easiest geometric figure, which won’t change its shape when its sides’ lengths are fixed. On the other hand, both the lengths and angles of one four-sided figure should be fixed in order to retain the shape. The truss is usually designed at the joint, which should be supported and that joint is commonly called as Munter Point.

Trusses, like most of the structures, are basically devices that are mainly used for load bearing and, then transferring the stress load from one point to another. For instance, the roof truss usually takes the roof’s weight or the snow & transfers the weight into the house’s load-bearing walls. Similarly, the bridge truss basically takes the entire weight of trucks and cars passing over the bridge & transfers the weight to the bridge’s piers. The main characteristics or feature of a truss is its efficient and clever way of carrying the load. The trusses are usually lightweight because the trusses take the advantage of the statics and geometry or mathematics laws.

Steel Trusses Manufacture: Setting the Standard

During the revamping or remodeling of the roof, it is always a better idea to make way for these steel roof trusses. These trusses render a reliable and durable support to the rest of the roofing materials.

The trusses are the triangular segments of the roof that are located at the base of particular roofing. Earlier, the households preferred the lumber system on which the entire roof used to be established. Nowadays, the more reliable and dependable truss-systems are in place.

Three Types of Commerical Trusses:

There are two types of steel trusses that are commercially available in the market, the flat (parallel) trusses and the pitched (common) trusses. Depending on your need, you can select one of them.
To identify and locate the roof trusses, move down to the lowest layer of your roofing. A caged structure of roofing segments would be exposed to you. This foundation structure is known as the truss-system. It consists of chords (outer trusses) and webs (inner trusses). While the chords offer an aggregated support to the stacked layers of the roofing architecture, the webs stabilize the individual chords.

The steel trusses are quintessential in the overall integrity of the roof as they hold the sheathing and the roofing material together. A weaker truss-system would be unable to carry the weight of bulkier tiles and rubber roofs.

Sometimes, the homeowners wish to replace their flat roofs with the pitched roofs in order to provide an added attic space. This can be achieved by replacing the old flat trusses with the pitched ones. Keep supervision of an expert in tact while performing the task. He would also guide you on your next course of action.

Along with the advantages that the roof trusses offer, there are certain drawbacks associated with them as well. The inculcation of these roof trusses in your roofing framework leaves the homeowners with a much lesser attic space. Also, the space of a particular room of the home may reduce owing to these triangular roofing segments.

However, the cheap labor cost complements the preference of such roof trusses over the traditional lumber system.

Truss Materials:

Trusses can also be made of aluminum, steel, or other materials. A lot of factors determine the suitability of materials for building trusses and discussed below are the uses, advantages, and disadvantages of timber and steel trusses.

Often after the construction of the house, timber rafters, because they look so good are not covered up. So besides being really strong, they also have a very appealing appearance. Compared to other materials, timber rafters are stronger over wider distances because of their considerable thickness.

The problem with timber is that it is vulnerable to damage by termites. In a place where these pests are a common cause of property loss, it is best to go for steel rafters that termites cannot eat Using steel also means you will save money on pest control.

Another problem that timber faces are that it expands quite a bit in the presence of moisture and this can affect the way timber rafters settle into each other. Steel, on the other hand, is resistant to expansion and contraction due to moisture and it doesn’t have to settle like wood. Steel also cannot rot like wood in moist places.

Wildfires are also a great threat to wooden rafters as wood is neither fireproof like steel nor fire retardant. But the disadvantage with steel rafters is that they look rather ugly and need to be covered. Since they have so many other benefits, their cost is near 20% more than that of timber rafters. Wood is still the first choice for termite-free places with less humidity.

The History of Trusses and Use

Wood trusses or trusses, which are so commonly seen in the present time, are actually triangulated lumber frames that are bound together with the help of connector plates of galvanized steel, commonly termed as the truss plates. In simpler terms, these are essentially a structure, which has two-for ce members and those members are assembled in such a manner that the whole thing looks like one single object. They are spreadly used in construction and for other purposes. Let’s trace a brief history of trusses and see how they made their way in our every day life.

metal trusses

Evolution of the Truss

In the modern times, the initial trusses were made using frames of light wood. They were constructed on the sites of construction using plates of plywood gusset or nailed boards at the joining areas. The truss structure has been around for a very long time. These were used by men since they started using log pieces. Centuries later, they were used with sawn lumber. Using the early trusses of timber ensured prolonged life spans and was cost effective as well, unlike the un-trussed lumber. However, they used to take a considerable amount of time in building on the site of construction.

History of Trusses

The history of trusses leads us back to the year 1952, in the Pompano Beach of Florida, the engineered wooden truss connected with metal plates was invented & patented. This interesting invention was a result of a long experimentation of the gusset plates of plywood and various combination & concoctions of staples, nails, screws, and glue. It was invented by A. Caroll Sanford who founded the Sanford Industries. This invention was very important and marked the truss industry’s beginning. This industry gained more and more popularity ever since and now it is changing commercial buildings, houses, and apartments. This industry is now a big part of the construction industry.

Application and Uses of Truss

The following are the common truss use and applications.

Buildings and Constructions

The most widely used trusses in the present times are the wooden one. They are used extensively in the commercial, residential, agricultural, and institutional construction. The higher strength-to-weight ratios of these provide greater flexibility and longer spans in the layouts of a floor plan. These can be conveniently designed and created in almost all sizes and shapes. Their uses can be restricted by shipping limitations, manufacturing capabilities, and handling considerations.

Wood truss in building

Post-Frame Structures

Component connections can be considered a very critical factor to the integrity of the framing system’s structure. In constructions with large and clear span wooden trusses, the critical connections are the connection & its strength between these & their support. Including the gravity-induced forces or the bearing loads, the connections must withstand strong forces that act perpendicular to that truss’ plane & uplift forces because of the wind. Wood posts enhance the advantage of direct, strong, yet cost-effective connections between walls and large trusses. These rests on many notches & stays bolted to a place. A special bracket or plate may also be included to improve the transfer capabilities of the connection load.

The handling, as well as the storage of the trusses’ raw material and component parts, is a crucial factor that contributes to the finished product’s overall quality. The lumber, prior to the process of manufacturing and during that process should be kept safe from snow and/or rain. In certain cases, one should also have to keep the humidity of the storage area under control. Often, the reason behind the failure of a system of the roof truss or wood floor is found to be improper handling during installation and delivery.