Jump to content
msc0433

Pallet racking bowing problems

Recommended Posts

Hi people I have pallet racking 10 foot long with a 8 foot tank on it and it is 20 mm lower at the end of the 8 foot tank then goes back up at the end of the stand. Should I empty the tank and add extra bracing from the ground to the top rack of the pallet racking and if so could a middle leg be welded on to the middle of a pallet rack or what would be the best way to straighten the beams to hold the weight of a 8 foot tank. Any ideas appreciated and buyers beware of pallet racking Thanks. Mark

Link to comment
Share on other sites

3m is a long span (well just extra 300mm to regular 2.7m). You can go up in size of beam ie. thicker. My rack fabricator recommended not to add extra uprights since they are not designed for that ie. could make a potential stress point. They're metal, so a bit of give, just make sure no cracks in the welds.

Guess comes down to what you are comfortable with...

Link to comment
Share on other sites

Go for thicker grade beams, and you may as well get shorter lengths while your at it.

If that's not economical, a good work around is to put a sheet of 19mm ply under the tank - stiffened by two longitudinal wooden ribs.

If your worried, draining the tank half way down will take the bow out until you can fix it.

Link to comment
Share on other sites

Spoke to the people that sell the racking and have been told that the beams are built to withstand 17 mm of flex in them. I have measured mine and they are flexing 15 mm. Have been told to centralise tank so will be a spare foot at each end and should improve the problem. Thanks. Mark

Ps beams are rated at 1.6 ton for the length and thickness I have

post-1266-14711631333125_thumb.jpg

Edited by msc0433
Link to comment
Share on other sites

IMO

Centralising the tank will no reduce deflection, probably increase it. It will make the water level in your tank appear level but.

Ply will not give any significant advantage, it is just not that strong under the loads and will deflect itself.

The steel is not at risk of breaking as it can take the movement but the tank is.

I have two options.

1. Get stronger beams

2. You could camber the beams so that instead of dropping down 15 mm, they have an initial bend upwards of say 8 mm, then when the tank fills and the steel deflects the total downwards movement = 15 - 8 = 7 mm. Need a good metal worker to ensure he does not yield the steel and may well void any guarantee from the manufacturer.

I would also drain about half the tank, and that should about half the deflection.

(I am assuming the bars were not initially bent when you got them)

Link to comment
Share on other sites

Rembr they are designed for pallets which are 1200 wide, so no probs with flex over that distance for indiv. pallets, but still bow. Best to go next size beam, but could cost more than the whole rack?

Thick board of form ply or just structural ply will at least reduce some of the flex tankside, or perhaps 3 x2 hardwood rails 3m lengths, just a thought.

In another post on similar topic, I said I was not comfortable with my rack beams' bow spanning, 1200 wide by two 6 x 2 x 30" on ( str. ply base), so put them back on individual stands.

In hindsight, matey down the gc has 9 x 800s or wider with fair bit of bow, but not over 3 m lengths

Link to comment
Share on other sites

bolting some 6mm thick x 100mm wide steel strip to the outside of each beam would fix that up.. if you want a patch up job, I would also be concerned that those long spans are flexing outwards aswell, measure the width at the end and at the point of greatest deflection...

personally I would get stronger shorter beams, or swap the entire rack for a unit with more appropriate spans

Or just get a proper tank stand built..

Its not just about holding the weight, most aquariam stands are built way over kill, because deflection will destroy a tank,

Link to comment
Share on other sites

I think I'm going to sell the tanks first then get rid of racking and start again all brand new If anyone can give me a quote on 2 stands which are 2 tier both capable of holding 6 x 2 x 2 tanks. So 4 tanks and 2 stands and will sell off what I have in the photo and start again as not worth the risk or trouble of mucking around with what I have. Thanks. Mark

Link to comment
Share on other sites



×
×
  • Create New...