Timber Raised Pond Strength

Cycle Designer

I'm building a raised timber pond for the garden and would appreciate some advice on the load bearing capability of the timber structure. The pond is 1.2m x 1.8m and 1.1m high, using 32mm T&G timber and a PVC liner. The corners are notched and fairly tight. It will hold 1650 litres of water.

I'm trying to work out the pressure on the structure walls and the load bearing capacity of the wood, and prove that the current design is up to it. Also, I wouldn't mind scaling up the design and would like to know how big I can go.

I've made a few calculations and would like to see if they match with anybody else!

listermint

32mm, Id say you would be stretching it tbh. That sounds like a large pond. Id be sizing up.

Even going for sleepers instead

kadman

If you are only using 32mm material. then your design is flawed.

Unless of course there is a whole lot more material incorporated in the design
that you have failed to mention.

If your 32mm material attaches to some other material, it may or may not work.

We dont know unless we have all the info.

Best design option would be interlocking vertical edge boards. As in current
method timber construction for log cabins, sun rooms ect.
And unless you have machine shop facilities, it would be tricky and time consuming.

Or flesh out the design you are thinking of.

But i reckon a kit build raised pond is the way to go for value.

kadman

This is what i,m talking about,

https://www.quickcrop.ie/product/raised-pond-with-liner-6ft-x-4ft

Jamesgrace

32 mm sounds too small -if you're buying it off the shelf I doubt it's good enough to hold up outside which will contribute to loss of strength too.

Cycle Designer

I am using the same sort of boards that Quickcrop use, with the interlocking ends. They go up to 6x6, I was wondering if that is strong enough and could I possibly go for a 8' span. As far as I know it is C16 grade timber.

kadman

Quickcrop engineers have no doubt already specced what they are selling.

Why not runa a larger design footprint by them.

Is your interlock identical to quickcrop.

c16 timber span tables with edge supporting loads as in timberframe tables,

is a different animal where your loads are not on the edge, but on the side face.

A 6x2 supporting a load on its edge , is not the same as a 6x2 supporting a load on its face.

Cycle Designer

It is the same timber that Quickcrop use. I've calculated the lateral stress on the timber due to hydrostatic force but I really need to know how to work out the bending strength of the boards and if they are capable. I am aware that timber joist span requirements are different.

kadman

http://www.awc.org/pdf/codes-standards/publications/wsdd/AWC-WSDD1986-ViewOnly-0301.pdf

http://www.coford.ie/media/coford/content/publications/projectreports/eurocodea520061031.pdf

Cycle Designer

Do you have anything that applies to modern EU timber grades, preferably metric?

kadman

Thought they would have been in Coford link?

Cycle Designer

Thanks, I'll run the eye over them, see if they tie in with my calculations.