203 x 203 x 46 Universal Column

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Where the 203 series starts, and the usual answer when a 152 column has run out of room.

203 x 203 x 46 dimensions and weight

Approximate total weight by length — this is what determines how the column is offloaded and lifted into place.

What is a 203 x 203 x 46 used for?

Here the series steps up from domestic to substantial. The 203 x 203 x 46 appears in larger house projects, basement conversions and light commercial work, and it is the usual move when the calculations say a 152 will not do, or when the storey height is simply too great for one. The section is properly square, 203 by 203, so it resists buckling about as well in one direction as the other. For a column that symmetry is the point. A beam is held along its length by the floor it carries; a column standing in the open has nothing holding it, and it will fail whichever way it is weakest.

The most common domestic use of a column this size is the steel goal post frame — a beam over the opening with a column carrying each end down to the foundations — which covers when you need one and how the frame is put together.

Why a column is not just a beam stood on end

A universal column is close to square — this one is 203mm deep by 203mm wide — while a universal beam of similar weight is much deeper than it is wide. That difference is the whole point. A beam is designed to resist bending across a span, so depth is what it needs. A column mostly carries load straight down its length, and its enemy is buckling sideways, so it needs similar stiffness in both directions rather than a lot in one.

It is why swapping a UB for a UC of the same weight is not a like-for-like substitution in either direction, and why columns are specified by section rather than by weight alone.

What decides the size

Three things govern a column, and only one of them is the load.

• Effective length. How tall the column is between points where it is genuinely held. A tall unrestrained column carries far less than a short one of the same section.
• End restraint. How the column is fixed top and bottom. A column pinned at both ends behaves differently from one built in, and the assumption made in the calculations has to match what actually gets built.
• How the load arrives. A beam framing in on one side applies its reaction off-centre, which adds bending to the compression. Two beams balanced either side do not.

This is why there is no column equivalent of a span table, and why we do not publish one. A 203 x 203 x 46 that is comfortable in one position can be inadequate a metre taller or with a different connection at the top.

Grades, lengths and finishes

The 203 x 203 x 46 is normally supplied to BS EN 10025-2 in S275JR or S355JR. S355 is the higher strength grade and is increasingly the default across the supply network; if your calculations specify one grade, tell us, because the two are not interchangeable. Mill certificates can be supplied with the order on request.

Columns are supplied cut to your lengths rather than as standard mill lengths, and we can arrange:

• Welded base plates, cap plates and cleats — the parts that make a column installable
• Drilling and holes for holding-down bolts and beam connections
• Cutting to size — supplied ready to install
• Painting and priming, including intumescent coatings for exposed columns
• Galvanising for external or exposed positions

Base plate details matter more on a column than almost anything else we are asked to fabricate. The plate spreads the whole load into the foundation, and the holding-down bolt positions have to be agreed before concrete is poured rather than after.

Delivery

A 6m length of 203 x 203 x 46 weighs approximately 275kg. At that weight the beam needs mechanical offload at the kerb and, in most cases, mechanical assistance to get it into position. We deliver direct to site across London, the South and the Midlands, with HIAB lorry crane offload available on request. Columns are usually needed inside the building rather than at the kerb, so if the route in is tight — a terraced passage, a stairwell, limited headroom — tell us at quote stage and we will plan the delivery around it.

Other sizes in the range

Also searched as: 203x203x46, 203 x 203 x 46 UC, UC 203x203x46, 203×203 UC46. Universal columns are also called UC sections, I-sections or, loosely, steel posts — and older drawings may show them as UB or “universal bearing pile” sizes, which are a different section entirely.

• All universal column sizes
• Universal beams (UB) — where the load spans rather than bears straight down
• RSJ beams
• Steel hollow sections — often the alternative where a column is on show

Common questions

Dimensional data shown is nominal and for guidance. Column sizing depends on effective length, restraint and loading, and must come from a structural engineer.