A guide to RSJ Beams

  • 29.08.23
  • Construction Products

From size to cost and project management insights, learn about RSJ beams in this blog to ensure a cost-effective, efficient, and safe construction process.

RSJ beams and girders are an undeniable staple of steel construction and have helped establish and sustain entire cityscapes worldwide.

Relatively lightweight, incredibly sturdy, and always reliable, RSJ beams can provide you with the overall structural integrity to ensure your construction requirements remain stable indefinitely.

But before you invest, there are some key considerations to evaluate, such as the size, costs, and general industry insights regarding RSJ beams and girders.

Let’s explore.

What to Consider Before Investing in RSJ Beams for Your Construction Project

RSJ Beams

What is an RSJ?

RSJ stands for “rolled steel joist” and are long beams made from hot or cold-rolled steel. Common across structural steelwork for buildings and other large structures, RSJ beams are utilised in construction for their distinct properties that provide longevity, design flexibility, building speed and space efficiency.

As part of the global structural steel market valued at $105.57 billion in 2022, RSJ beams have had a pivotal place in the construction industry since patented by Alphonse Halbou in 1849.

RSJ also gets called “I-beams” or “H-beams”, which is the universal reference due to the shape of the cross-section that appears like a capital letter “I” or “H”.

The strength of RSJ beams comes from the different elements that create their signature cross-section shape. RSJ beams are not limited to horizontal positions and can be employed to reinforce structures while providing pillars for other structural elements to connect.

RSJ beam core strength comes from the central web, while the flanges provide the integrity to withstand heavy loads and bends. However, not all structures or applications suit RSJ beams, especially when the girder gets exposed to bidirectional bending, twisting and torsion loads.

With these structural requirements, we suggest using hollow steel sections instead to withstand torsional loads.

What size RSJ do I need?

The size of your RSJ beam will depend on the length of the beam and the weight your beam is supporting. RSJ beam sizes also depend on the intended span length.

You can calculate the beam depth by dividing the span length by millimetres, 18mm-20mm for the primary beam and 15mm-18mm for the secondary.

Before investing, please consider the following factors that will influence your RSJ beam size:

– The intended weight to support.
– The span length impacts the size and strength requirements.
– The steel material quality and RSJ beam profile (I-beam or H-beam).
– The acceptable bending and deflection limits.

Many factors contribute to the size of the RSJ beam you might need. However, we have listed a general rule of thumb beneath to give you a rough idea of the dimensions you may need based on average loads and span lengths.

All these tools are manufactured to ISO 9242 specifications from superior steel, oil-hardened, and tempered with high-quality ground law faces.

What size RSJ do I need for a 2m span?
127mm x 76mm x 13kg/m. This dimension is the smallest suitable universal beam size.

What size RSJ do I need for a 2.5m span?
127mm x 76mm x 13kg/m again for 2.5m. But anything between 2.5m and 3m should be 152mm x 89mm x 16kg/m.

What size RSJ do I need for a 3m span?
152mm × 89mm × 16kg/m.

What size RSJ do I need for a 4m span?
178mm × 102mm × 19kg/m.

What size RSJ do I need for a 4.5m span?
203mm × 102mm × 21kg/m

For RSJ beams over 4m, the design should be enlisted by an experienced engineer and comply with industry regulations.

What size RSJ do I need for a 5m span?
203mm × 102mm × 23kg/m.

What size RSJ do I need for a 6m span?
254mm × 102mm × 25kg/m.

What size RSJ do I need for a 7m span?
305mm × 102mm × 28kg/m.

What size RSJ do I need for an 8m span?
356mm × 127mm × 33kg/m.

What size RSJ do I need for a 9m span?
406mm × 140mm × 46kg/m.

What size RSJ do I need for a 10m span?
406mm × 178mm ×54kg/m.

A qualified engineer should provide the necessary structural calculations to determine the appropriate size of the RSJ beam you need for your construction project. Supporting the intended weights while complying with your local or national building regulations is essential in ensuring you build a safe and legal structure.

Failing to recognise the correct RSJ beam for your construction project can potentially lead to dangerous structural instability and catastrophic safety concerns.

How much does an RSJ cost?

The average cost of an RSJ beam up to 46kg/m is around £200, while the cost to install will be a further £300. Per kilogram, RSJ beams, on average, will cost you £3.50.

Therefore in the UK, the average RSJ installation for a standard project will be around £1500-£2500.

Speak to leading UK steel specialists for your RSJ beam solutions

At Hickman & Love, we’re a quality-assured steel stocklist provider with accreditations across CARES and CPSA while remaining a proud MPA British Precast Member.

We’ve been a respected and trusted name in the steel and concrete industry with highly trained staff skilled in the latest welding and steel fabrication techniques for the past 80 years.

For more information on how our RSJ beam solutions can bolster your next construction project, get in touch.

For further information or to order please call +44 (0)121-557-2191 or email enquiries@hickmanandlove.co.uk we look forward to hearing from you. Or like us on Facebook to keep up to date with projects and news.


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