In message , tony sayer writes
Crikey! I'm out of touch.
Recent lifting jobs here were a steel frame barn assembly and my sister's timber frame house which had to be hoisted over the telephone overheads.
I haven't seen a Tonout lorry recently but they were a common sight here on their way back to base.
Like this one...
In article , Andrew Gabriel scribeth thus
Thats the one!. I'd have thought that any idiot could see thats overbalancing but then again they seemed to have just an idiot driving it;!...
Please forgive my ignorance on this subject and bear with me whilst I ask a few (hopefully not too stupid) questions:-
What diameter rebar would you suggest for tying in the base to the vertical sides? And then what diameter for the horizontals between courses?
Not too sure how the dry mix works. Does it get the water to set it from the surrounding soil?
What ratio of sand cement should I use to bond the blocks together?
Are 140mm dense hollow blocks adequate for the sides?
Thanks
I'd use 25mm at 300mm c/s ... or space to suit your hollow blocks. Make up 'hokey sticks' wire then well to slab reinforcing so they become one during cast. Probably reduce to 3/4" for the vert bars as sides 'grow, tying well to the 25mm with at least 150mm overlap.
This is just what I would do ... I'm not a Structural Engineer.
Use good thickness mesh in slab .. ideally 2 layers with 50 mm spacers .. Here is pic of my recent job showing circular steel spacers.
The soil in heavy clay and the water table is quite high. The proposed internal dimensions of the tank are 2.85M x 1.5M x 1.5M deep and the top surface of the tank will be 0.25M below ground.
The research I have done so far suggests the best way to go is to use 100mm dense hollow cement blocks with 6mm rebar every 100mm vertically and filling each block with concrete mix. 6mm rebar would be placed between every course. Base to be 4" with A142 mesh.
Is this a reasonably sensible approach, given that I'm retired and have lots of time available.
And also how should I tie in the sides to the base?
Any guidance would be much appreciated.
I have a similar tank I built myself. Just a concrete base with some mesh with concrete blocks laid on their side for the walls. Laid the first course when the concrete was still green.
The top is cast in concrete with mesh. The supporting timber/shuttering for the top was constructed four or five cm below the top of the walls so that there is a step in the concrete that helps support the walls from falling inwards. It has to be dismantlable from inside. There is a manhole to get inside It was rendered inside, a cement fillet put round the base/wall juction and painted with fish pond paint.
It's so heavy, it won't float anywhere. In Winter when the ground is water logged it's always full of water anyway. You could lay some wall blocks "endways" if this worried you.
Are you sure? There were those that thought that the Mulberry Harbour caissons would never float when the water was pumped out before D Day, but they did :)
Andrew
Empty concrete swimming pools floating out of the ground is a well known phenomenon.
Before you do any work check with BCO, planners and the EA for what, if nay, permissions are required. The EA will not grant retrospective permission so you need to be particularly careful. It will not cost you much in time or effort and could save you a lot.
The difference in weight between full and empty is small in percentage terms compared with a swimming pool/buried fuel/septic tank. As the blocks are on their side, the walls are very thick and heavy compared with the volume of water. Put a few in endways if you are worried to grip the surrounding soil. Or/and leave the concrete base projecting beyond the walls.
You ever see a sewage manhole/inspection chamber "float out of the ground"?
I've seen an 'Onion' style septic tank emerge from the depths, and the owner said rather grudgingly that I had been right to say he should have put a thick ring of concrete round its neck :) He wasn't a happy bunny.
Andrew
That is unfortunately not correct, if it were to become empty .. and there was external water pressure - swimming pools can lift .... Hydraulics are very powerful.
Wrong quote Rick, I never said that
Andrew
Well, using the dimensions above, the internal volume would be a little over 6.4 m3, so that gives a maximum flotation of 6.4 tonnes empty. How much does the tank weigh?
Chris
Most cranes are fixed so that can't happen. I'd have thought it would be cheaper to take the back out of the garage in that case.
It was blamed on a computer failure.
Here's standing it up again:
Takes one crane to lift another I suppose;)...
I had seen one once where one of the outriggers found a void under the ground it was on, fortunately that showed up before any serious load was placed thereon;!...
In article , harryagain scribeth thus
What do you mean "fixed" in this context?...
In message , tony sayer writes
Strain gauges, tilt sensors, weight sensors etc. Tony. Then the computerised control tells you if you are near the limit and doesn't allow you to go over it. When I had a 150' mast taken down a few years ago the driver told me just how much each section weighed.
After shifting, with the help of 4 others, 10 tons of steel into a skip I found that the pain in my leg, that I'd had for a week was DVT, not sure if the exercise helped it or not! But I'm still here, for now. :-)
In article , Bill scribeth thus
Yes bin there dun that tho not 150 feet a 'lil less..
Got to be careful us olde 'uns;!..
I just wanted to hear what Harry's description of "fixed" was...
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