RSJ Flexi Post Bolt Down

The RSJ Flexi Post Bolt Down is a specialist support post designed for Armco barrier systems where a degree of flexibility is required to absorb impact without transferring excessive force into the ground fixings. Unlike standard rigid posts, the flexi post allows controlled movement on collision, reducing the risk of damage to both the barrier and the surface it is anchored to.

Manufactured from high-quality rolled steel joists (RSJ) and hot-dip galvanised to BS EN ISO 1461 standards, the RSJ Flexi Post Bolt Down offers outstanding durability and corrosion resistance. Its bolt-down design makes it ideal for fixing onto existing concrete surfaces, such as car parks, warehouses, and industrial yards, where excavation is not practical.

Key Features of the RSJ Flexi Post Bolt Down:

• Impact-absorbing design – built to flex under impact, reducing damage to the barrier and surface.
• Bolt-down fixing – securely anchors to concrete surfaces without the need for excavation.
• Heavy-duty steel – manufactured from robust RSJ steel for long-lasting performance.
• Hot-dip galvanised finish – ensures resistance to rust and weathering in harsh environments.
• System compatibility – works seamlessly with all Armco beams and accessories.
• UK manufactured – produced by Armco Barrier Supplies for guaranteed quality.

Typical Applications:

• Multi-storey and surface car parks.
• Warehouses and distribution centres.
• Service yards and loading bays.
• Industrial sites requiring impact-absorbing safety systems.

FAQs – RSJ Flexi Post Bolt Down

1. What is the advantage of a flexi post over a standard RSJ post?
The RSJ Flexi Post Bolt Down is designed to absorb impact by flexing, reducing stress on the barrier system and the concrete surface fixings. This minimises long-term maintenance costs.

2. Can the RSJ Flexi Post Bolt Down be used outdoors?
Yes. Each post is hot-dip galvanised to BS EN ISO 1461 standards, ensuring excellent resistance to rust, corrosion, and weathering in outdoor environments.

3. Is the RSJ Flexi Post Bolt Down compatible with all Armco beams?
Absolutely. The RSJ Flexi Post Bolt Down is fully compatible with the complete Armco range, including 1.3m, 1.9m, 3.5m, and radius beams.

Transferring Impact

In an off-highway Armco-type crash barrier, the beam provides the continuous restraint line, while the post transfers impact loads into the supporting substrate (typically reinforced concrete for bolt-down applications). A bolt-down post configuration is commonly selected where excavation is undesirable or impossible (for example, warehouses, factories, yards and car parks).

Within this family, an RSJ Flexi Post (bolt down) is an H-section (RSJ) post configured with a controlled deflection mechanism so that under impact, it yields in a predictable, limited way rather than behaving as a purely rigid cantilever.

What “Flexi” means mechanically (and why it matters)

A conventional rigid bolt-down RSJ post aims to stay elastic as long as possible. Under a forklift or vehicle strike, the system response is dominated by:

• high peak reaction forces at the base plate and anchors,
• localised concrete stress at the fixing points,
• potential permanent deformation of the post/beam or anchor pull-out if the substrate or fixings are marginal.

By contrast, a flexi (limited-deflection) post introduces compliance—commonly via an engineered interface (for example, rubber shock absorption elements or a spring-steel deflection feature, depending on manufacturer and model). A published example of a flexi-post arrangement describes the upper part of the post mounted into a rubber shock absorber allowing limited deflection, with consequent reductions in applied forces and anchor bolt forces.

The practical implication: instead of transmitting the full impulse into the anchors and slab as a spike load, a flexi post spreads and moderates the load over time and displacement, improving survivability of the base fixings and adjacent concrete in lower-speed, frequent-impact environments.

Benefits over traditional rigid bolt-down posts

Below are the principal engineering and operational advantages, with an emphasis on why they appear in the real world.

Lower peak loads into anchors and concrete

A key design intent of flexi/deflecting posts is reduced demand on anchorage and slab. For example, spring-steel bolt-down posts are described as flexing under impact and putting less stress on the fixing and concrete floor slab.

Similarly, rubber shock-absorbing flexi-post systems reduce anchor bolt forces and reducinge the risk of damage to floors.

Why this matters: rigid posts often “win the battle and lose the war” they may restrain a vehicle effectively but at the cost of slab cracking, anchor damage, or difficult reinstatement.

Reduced secondary damage (barrier, floor, and vehicle)

Flexi bolt-down RSJ posts are “built to flex under impact”, reducing damage to the barrier and surface.

Spring/deflecting posts are also described as reducing the risk of damage to the floor, beam and the impacting vehicle.

Why this matters: in facilities with frequent minor strikes, the cost driver is often not the first incident but cumulative maintenance—replacing rails, repairing anchors, patching slabs, and managing downtime.

Better performance under frequent nuisance impacts

Rigid RSJ posts are strong, but if the operational reality is “lots of small hits”, a flexi post can be a more economical resilience strategy:

• fewer bent posts/rails,
• fewer anchor retightening/repairs,
• less slab spalling around base plates.

This is consistent with how product ranges position flexi/spring/shock-absorbing bolt-down posts as variants for specific impact and maintenance profiles.

Potentially reduced reinstatement complexity

Where a rigid post transfers high loads into the slab, remedial works can escalate into concrete breakout and reinstatement. By moderating peak loads, flexi posts reduce the likelihood that an impact becomes a civil repair job rather than a straightforward barrier component replacement. (This is a practical engineering inference from the documented reduction in anchor/floor damage risk.)