PG40 80×80 mm Eight Slot Aluminium Strut Profile Square Column

OEM / ODM Available Free Sample Available ISO 9001:2015 EN 755-9 RoHS REACH

An 80 x 80 mm eight slot standard wall PG40 aluminium strut profile square column. Equal stiffness about both axes, so it cannot be installed the wrong way round. For legs, masts and gantry uprights.

Wholesale Price $8.60 - $13.40 / m per m

Material	Aluminium
Alloy Grade	6063-T5
Temper	T5
Section Size	80 x 80 mm
Slot	8 x 10.2 mm groove, 8 mm mouth, 40 mm pitch, 2 slots per face on all four faces, M8
Length	6 m stock, cut to drawing to +/-0.5 mm
Tolerance	EN 755-9 / GB/T 6892, wall +/-0.15 mm
Surface	Mill finish / clear anodised / black anodised
MOQ	200
Lead Time	18-28 days after deposit for mill finish
Loading Port	Shanghai / Ningbo
Supply Ability	250 t per month
Payment Terms	T/T 30% deposit + 70% before shipment \| L/C at sight
Trade Terms	FOB \| CIF \| EXW
Certifications	ISO 9001:2015 \| EN 755-9 \| RoHS \| REACH

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Structural framing · PG40 square column

A PG40 80 x 80 mm eight slot aluminium strut profile is a square column section on the 40 series groove system. Eight 10.2 mm grooves with an 8 mm mouth are cut on a 40 mm pitch, two on each face. The corners carry 5 x 5 mm bores and the web carries a 12 mm bore tapped M14 at the end. It weighs about 5.80 kg/m and is supplied in 6063-T5.

A square section is the right shape for a post because a post does not know which way the load will come from. The 80 x 80 has about 130 cm4 about both axes, so it cannot be installed the wrong way round and it does not need to be checked in two orientations. That makes it the default choice for legs, masts, gantry uprights and any member whose load direction is not yet fixed.

80 x 80 eight slot section: two grooves per face on a 40 mm pitch, symmetric about both axes.

Why a square column is the safe answer

A beam is designed against a known load direction, so a rectangular section can be tuned to it. A column is different. A column carries axial load, and the axial load is not what usually breaks it — buckling is. Buckling always happens about the weaker axis, which means a rectangular column is only as strong as its narrow direction.

That is why a 120 x 80 section used as a post is a false economy: it has the same weight as a section with more balanced stiffness but only one strong direction, and the post will buckle about the 80 mm axis regardless of how much material there is in the other one. The 80 x 80 square removes the whole problem.

Section	Weight	Stiffness, weak axis	Weak axis relative to 80 x 80
80 x 80 eight slot	approx. 5.80 kg/m	approx. 130 cm4	Reference
120 x 80 ten slot	approx. 6.00 kg/m	approx. 180 cm4	1.4 x, at 3 per cent more weight
90 x 90 eight slot	approx. 7.60 kg/m	approx. 230 cm4	1.8 x, at 31 per cent more weight
100 x 100 eight slot	approx. 9.20 kg/m	approx. 380 cm4	2.9 x, at 59 per cent more weight

For a column, compare the weak axis, not the strong one. A 120 x 80 section is stiffer than an 80 x 80 in one direction and about the same in the other, which is why it is a beam and not a post. If the load direction is genuinely unknown, a square section is the only honest choice.

Buckling, in one page

A short column fails by crushing: the stress reaches the yield strength of the material and the section simply squashes. A long column fails by buckling, at a load far below the crushing load, because a small sideways imperfection grows until the column bends over. The load at which that happens is given by Euler’s formula, and the only section property in it is the second moment of area.

For this section in 6063-T5, with a Young’s modulus of about 70,000 MPa and 130 cm4 about both axes, the buckling load falls with the square of the free length. At short lengths the crushing load governs; above about 2 m buckling takes over and the capacity drops quickly.

Free length	Slenderness ratio	Crushing load	Euler buckling load	Safe load at 3:1
1.0 m	41	approx. 236 kN	Not governing	approx. 78 kN
1.5 m	61	approx. 236 kN	approx. 399 kN	approx. 78 kN
2.0 m	81	approx. 236 kN	approx. 224 kN	approx. 75 kN
2.5 m	102	approx. 236 kN	approx. 144 kN	approx. 48 kN
3.0 m	122	approx. 236 kN	approx. 100 kN	approx. 33 kN
4.0 m	163	approx. 236 kN	approx. 56 kN	approx. 19 kN
5.0 m	203	approx. 236 kN	approx. 36 kN	approx. 12 kN
6.0 m	244	approx. 236 kN	approx. 25 kN	approx. 8.3 kN

The table is for a pin ended column, which is the conservative assumption. Fixing the ends raises the capacity, but a bolted profile frame is rarely rigid enough at the joints to justify treating a post as fixed, and assuming pinned ends is the safe engineering habit.

A 6 m post carries about a tenth of what a 2 m post carries. Same section, same material, three times the length, one tenth the capacity. Nothing else in structural design falls away that fast, and it is why tall frames are usually braced rather than built from bigger posts.

What to do when the column is too tall

The instinct when a post is not strong enough is to step up a section size. On a column that is usually the wrong answer, because the capacity falls with the square of the length and only rises with the section’s stiffness. Doubling the section stiffness buys about 41 per cent more capacity; halving the free length buys four times.

Brace itA diagonal brace in one plane halves the effective free length about the weak axis and quadruples the capacity. On a tall frame it is nearly always cheaper than a bigger post.

Support itA horizontal member at mid height, tied back to something rigid, does the same job as a brace and often serves another purpose at the same time.

Fix the baseA post that is genuinely fixed at the base behaves as though it were shorter. A heavy base plate with four bolts into a floor is worth more than a section size on a tall post.

Only then step up a sizeIf the post must stand free and unbraced, then a larger section is the only remaining option. Go to the 90 x 90 rather than the 120 x 80, because the column needs balance rather than depth.

Frequently asked questions

Why a square section rather than a rectangular one?

Because a column buckles about its weaker axis. A rectangular section’s capacity as a post is set by its narrow direction, so the extra material in the wide direction is largely wasted. A square section is equally strong in both directions and cannot be installed the wrong way round.

How tall can an 80 x 80 post be?

It depends on the load. At 3 m the Euler load is about 100 kN and the safe load at a three to one factor is about 33 kN. At 6 m the safe load is only about 8.3 kN. The capacity falls with the square of the length, so height is the dominant variable.

Is it strong enough for a mezzanine or a platform?

Only with the buckling check done properly and the frame braced. An 80 x 80 post at 2.5 to 3 m is a sensible leg for a light platform; above that the frame needs bracing or a larger section. Send us the leg height and the load and we will run the check.

Does the slot reduce the column capacity?

Slightly, and it is already allowed for in the 130 cm4 figure. The more important effect is that the slots give the bracing and the platform members somewhere to bolt, which is what actually keeps the column stable.

Can I bolt two together to make a bigger post?

Yes, and it is a common way to build a heavy post from standard parts. Two 80 x 80 sections bolted face to face give roughly four times the stiffness of one, which is a better return than stepping up a size. The joint has to be bolted at the 40 mm pitch along the full length, not just at the ends.

Send the leg height and the axial load

Tell us how tall the post is and what it carries. We will run the buckling check and say whether the section works, needs bracing, or genuinely needs a larger size.

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