Without bracing, a structure cannot stand against wind or seismic activity. It’s a ubiquitous part of the building process, and yet many traditional bracing systems require difficult logistics and time-consuming installation. Tension-only rod bracing offers an efficient alternative – ultimately saving time, effort, and costs.
You may know the basics of tension bracing – but how does it actually function? And is it really worth transitioning away from bracing methods that have been used for years?
In this article, we’ve taken an in-depth look at how different bracing systems work – both for the building and for the people creating it.
Traditional bracing systems for steel frame structures involve planning and calculations from structural engineers, complex logistics management, and precise installation on site. DonoBrace is the tension-only rod bracing system from Donovan Group that offers a different perspective.
How does bracing work?
Fundamentally, a bracing system uses compression and tension to stop the building falling over when sideways loads, such as winds, are applied. For example, two of the most common systems are angle bracing and wire rope bracing, neither of which prioritise usability or efficiency.
The angle steel brace, though antiquated, is one of the most recognisable bracing systems. Two lengths of steel, which can be upwards of 16 to 18 meters in length, are bolted to the main structure in an ‘x’ shape between portal legs. Although angle bracing functions in the same way as tension-rod bracing, it’s not nearly as efficient. The weak point of an angle brace system is in the bolted connection – which ultimately requires more steel to brace a building when compared to tension rod bracing.
An alternative to angle bracing is the wire rope tension bracing system, often associated with bridges. Two steel ropes, sized according to the structure’s capacity requirements, fitted with a dead-end and spliced wires that are wrapped back along the length of the steel rope.
Finally, there is tension-only rod bracing, with DonoBrace leading the system forward for Australasia. Using direct-action tension, a rod is connected through the DonoBrace, and then tightened to pull the portal legs to a square position. Similar to wire rope bracing, DonoBrace supplies multiple sizes to suit varying capacity requirements. Unlike an equal angle bracing system, the DonoBrace system provides flexibility in design and installation.
Transport and handling
In practice, tension bracing is a comparatively easy system to move around.
Equal angle bracing usually requires shipping long, heavy steel lengths in one piece, and a crane to place it at the site. Wire rope and other tension bracing systems can be shipped in more manageable coils and pieces. This usually means less weight and easier handling – resulting in overall lower transfer costs.
However, wire rope bracing systems often require greasing the cables before transit to protect the material. This means time-consuming cleaning is necessary before installation. Thick wire ropes for larger capacity projects can also be difficult to manage.
Tension-only rod bracing systems are designed with material efficiency in mind and therefore it is a complete system that doesn’t require greasing before transport or moving large rigid elements. DonoBrace is engineered for easy transportation and onsite handling, saving considerable time and effort while also optimising shipping costs.
Installation
To produce great work, you need a well-rounded perspective. The best products are developed based on feedback from every corner of an industry – the engineers, the builders and the manufacturers.
In an equal angle bracing system, not only do you need to lift dozens of 18-metre-long steel beams, but you also need to get your portal legs perfectly plumb and in position to place the rigid elements. It’s a system that requires unrealistic precision and little regard for the real conditions of preparing a site for bracing installation.
While wire rope bracing requires less effort to physically position the system, it can be a time-consuming process. You need to use chains with hook & eyes to temporarily brace the structure. Then, installers must manually wrap the wire tendons, which becomes more difficult with thicker wires and dead-ends.
Installing a tension-only rod bracing system is a highly efficient process. Little heavy lifting is required, no chain is needed before setting the bracing system, and the portal frame placement is far less important because the tension can be manipulated after installation.
Overall, DonoBrace makes installation faster, more straightforward, and limits the resources needed to get the system securely in place. It’s a process developed from real experience building steel frame structures. DonoBrace is simply unparalleled when it comes to on site usability and efficiency.
Planning and calculations
In traditional bracing systems, the structural engineer is responsible for completing the capacity calculations and identifying the bracing requirements.
Tension bracing, however, shifts much of the labour and responsibility from the structural engineer to the bracing system provider. When it comes to planning, this means structural engineers don’t have to spend as much time on crunching numbers for the bracing system.
With our tension-only rod bracing system, DonoBrace provides the calculations, CAD drawings, detail drops, example calculations, and the specifications to guide the installation. In practice, this means structural engineers only spend a few minutes specifying the DonoBrace system.
By taking the responsibility, we increase time-efficiency and eliminate risk for structural engineers.
So – Why tension bracing?
Because it does the same job for less – less weight, less time, less installation effort, less planning for structural engineers.
Why DonoBrace?
Because we do what we say on the tin. We have experience from every perspective of the building and manufacturing process – from on-the-ground installation to dealing with suppliers – and we know what matters most: products that live up to their promise, and people who do what they say they’ll do. We have the brains and the customer service to make sure your bracing system satisfies every requirement with maximum efficiency.
Learn more about tension bracing today and contact our product expert John Lawson.
Learn more about capacity and material usage with tension bracing, and how it works with rebuilds by reading our Part Two: Why Tension Bracing? follow-up blog.