Concrete beam supported on 26mm bar……WHAT??
Having been working on the RC detailing drawings it wasn’t until I saw the shear quantity of steel and the congestion that I realised the magnitude of the work faced by the steel fixers. I noticed too that the interface between the pile s and the ring beam was by a poxey couple of 26mm bars. This has got me thinking that the next level of concrete is not held up by the connection between the piles and the ring beam.
In this case my thoughts are that the ring beam is in fact a whaler beam and the intermediate beams are acting as props. In this case the whaler beams are being loaded by the deformation of the piles and is acting like a compression ring. The load is then transferred into the beams axially loading them and putting them in to compression rather then acting as first thought purely in bending.
This theory is supported by the pile shape arrays (monitoring system) clearly showing that the piles are in bending and have in fact deformed by up to 6mm in some cases. In addition when looking at the distribution of the steel through the beams the steel is fairly evenly spaced. My thoughts are that the top and bottom steel is in fact designed to act in tension and compression in order that they can be axially loaded and resist buckling upwards or downwards. All comments, thoughts and pearls always welcome.
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How deep is your excavation now???
No pearls I’m afraind…and not much wisdom either
Those’ll be 25 or 28mm dia bars I’d have thought?
Confuserd on the support to the grillage beams – I thought there was a plunge column involved in there somewhere?
As for how the grillage is working laterally…If I remember the wall to wall span was about 25m You say that the wall inward deflection is 6mm – that’ll give you a strain . The stiffness of concret is about 30GPa – that’ll give you an implied compressive stress
….all up a compressive stress of N/m^2 or so …. what’s the crushing strength concrete—the clue is in the grade
…so frigthening?….I think not…..the reason for the reinforcement ………I think not even more…….