Long span shelving – support material

[HopperParticipant @hopper]

Posted by Puddleglum on 29/05/2023 20:54:58:

Posted by martin haysom on 29/05/2023 20:39:22:

could put more than one beam from side to side to increase load capacity

Yes, minimum of 2, maybe 3 or 4. Working out what the minimum needed would be.

Depends entirely on what you plan to store on the shelf. A row of motorbike petrol tanks would be ok with one beam and a sheet of plywood attached to the wall of the shed. A row of truck gearboxes would need a lot more.

[PuddleglumParticipant @puddleglum]

Posted by Mike London on 29/05/2023 23:32:06:

Have you considered "Dexion"?

Deep angle section without the weight. For extra strength bolt two lengths together back to back to create "T" section.

Can be found second hand quite cheaply, from various sources. I use it all over the workshop.

Hadn't considered it as assumed designed for compression loading. Gut feel a thin material that the holes would be the weak points for lateral flexion failure.

But my goal was to try to get more meaningful than gut feeling

[PuddleglumParticipant @puddleglum]

Posted by John Doe 2 on 29/05/2023 23:59:48:

You could go for 4 supports but I would advise that you go for 5, which would mean you would never need to worry about overloading, nor about the shelf sagging between the supports.

Assuming an inset of 20mm from each end; the shelf support centres will need to be at;

20mm

760mm

1500mm

2240mm

2980mm

As measured from one end

As above – there isn't scope for intermediate supports – has to be single span supported either end only

[PuddleglumParticipant @puddleglum]

Posted by Hopper on 30/05/2023 06:43:52:

Depends entirely on what you plan to store on the shelf. A row of motorbike petrol tanks would be ok with one beam and a sheet of plywood attached to the wall of the shed. A row of truck gearboxes would need a lot more.

As above, maybe 200kg distrubuted unevenly across the shelf. Might be less – a safety factor always good.

[martin haysomParticipant @martinhaysom48469]

Posted by Hopper on 30/05/2023 06:43:52:

Posted by Puddleglum on 29/05/2023 20:54:58:

Posted by martin haysom on 29/05/2023 20:39:22:

could put more than one beam from side to side to increase load capacity

Yes, minimum of 2, maybe 3 or 4. Working out what the minimum needed would be.

Depends entirely on what you plan to store on the shelf. A row of motorbike petrol tanks would be ok with one beam and a sheet of plywood attached to the wall of the shed. A row of truck gearboxes would need a lot more.

the OP did specify the weight .

[John Doe 2Participant @johndoe2]

Posted by Puddleglum on 30/05/2023 09:30:31:

Posted by John Doe 2 on 29/05/2023 23:59:48:

As above – there isn't scope for intermediate supports – has to be single span supported either end only

Ah, missed that.

I'll get my coat…….

[HopperParticipant @hopper]

Posted by martin haysom on 30/05/2023 09:58:15:

Posted by Hopper on 30/05/2023 06:43:52:

Posted by Puddleglum on 29/05/2023 20:54:58:

Posted by martin haysom on 29/05/2023 20:39:22:

could put more than one beam from side to side to increase load capacity

Yes, minimum of 2, maybe 3 or 4. Working out what the minimum needed would be.

Depends entirely on what you plan to store on the shelf. A row of motorbike petrol tanks would be ok with one beam and a sheet of plywood attached to the wall of the shed. A row of truck gearboxes would need a lot more.

the OP did specify the weight .

Ah yes. It seemed so long ago…. 200kg. My apologies. Spread over the full 3 metres length, not that great, especially if you put the heavier items near the ends. If the shelf is going to be the usual sort of 600 to 750mm wide, I wouild try three beams, one on the wall, one on the outer edge and one in the middle.

Easy enough to rough test before construction. Place your three beams together on the ground with a brick under each end. Stand two hefty blokes in the middle and observe the sag (of the beams, not the hefty blokes). I can't imagine two blokes sagging three 40x20x1.6 box sections overly much. (Provided they are oriented narrow side up. Laid flat they might bend a bit.)

[David Millar 3Participant @davidmillar3]

My very rough, back of an envelope, no responsibility implied or offered, gives a circa 6mm deflection on 3 no. 50*50*3mm SHS, 3m long, carrying 67kg per metre.

[Peter Cook 6Participant @petercook6]

Posted by Puddleglum on 29/05/2023 19:13:19:

Posted by Peter Cook 6 on 29/05/2023 18:50:56:

There are several free beam calculators on the internet that will let you do deflection calculations. You can test out various materials and cross sections without risking your box section – or the bodies you hang from it!

It might be I'm a bit thick – but the ones I found required all sorts of parameters I haven't a clue about. Unless you could kindly point me in the direction of a simple one…?

The one I use is at Free Beam Calculator | ClearCalcs

it needs – besides the obvious (length, position of supports, distribution of load etc)

Young's Modulus of the material – steel is 200,000 Ali 68,000 others are on the web.

Area of Cross Section of the beam – basic geometry or for more complex shapes the calculator below will give you the area.

Second Moment of Area (Moment of Inertia) calculator for most shapes at Free Moment of Inertia & Centroid Calculator | SkyCiv

Hope this helps.

 

 

Edited By Peter Cook 6 on 30/05/2023 12:04:38

[Howard LewisParticipant @howardlewis46836]

The essential thing is that the stiffness of the beam is proportional to the width of the beam and the cube of the depth

(B x D^3 ) / 12 so the depth of the support has by far the greater influence on stiffness, and therefore deflection under load..

A poiint load will have a greater effect than a Unifromly Distributed Load.

Effectively, a single heavy item will produce a localisewd deflection rather than a duistributed load.

A number of heavy items will be very rough approximation to a high UDL.

Obviously a box section , for the same stiffness, can be shallower than an L section..

Howard

[PuddleglumParticipant @puddleglum]

Posted by David Millar 3 on 30/05/2023 11:51:22:

My very rough, back of an envelope, no responsibility implied or offered, gives a circa 6mm deflection on 3 no. 50*50*3mm SHS, 3m long, carrying 67kg per metre.

Thank you – this helped me understand the online calculator linked by Peter

[PuddleglumParticipant @puddleglum]

Posted by Peter Cook 6 on 30/05/2023 12:01:57:

Posted by Puddleglum on 29/05/2023 19:13:19:

Posted by Peter Cook 6 on 29/05/2023 18:50:56:

There are several free beam calculators on the internet that will let you do deflection calculations. You can test out various materials and cross sections without risking your box section – or the bodies you hang from it!

It might be I'm a bit thick – but the ones I found required all sorts of parameters I haven't a clue about. Unless you could kindly point me in the direction of a simple one…?

The one I use is at Free Beam Calculator | ClearCalcs

it needs – besides the obvious (length, position of supports, distribution of load etc)

Young's Modulus of the material – steel is 200,000 Ali 68,000 others are on the web.

Area of Cross Section of the beam – basic geometry or for more complex shapes the calculator below will give you the area.

Second Moment of Area (Moment of Inertia) calculator for most shapes at Free Moment of Inertia & Centroid Calculator | SkyCiv

Hope this helps.

Edited By Peter Cook 6 on 30/05/2023 12:04:38

Thanks for this Peter – I think I've got my head around it and could get figures v similar to David's rough calcs – which gives me some confidence I'm not messing it up too badly

[Maurice TaylorParticipant @mauricetaylor82093]

Hi, I’ve just tried Hopper’s suggestion only using 4 x 2 timber 3m long . I used 3 pieces side by side ,2 people (approx total weight 150kg) stood in the middle ,only very slight deflection.

Maurice

[Andrew EvansParticipant @andrewevans67134]

I have made some great shelves with keyclamp and scaffolding boards. Very easy to use, strong and cheap. You can paint or wax the boards.

[Author]

Posts