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BEARING PLATE DESIGN

BEARING PLATE DESIGN

BEARING PLATE DESIGN

(OP)
I AM TRYING TO DEIGN A BEARING PLATE TO SUPPORT BUG TRUSS ON A BUTTRESS , THE DETAIL IS ATTACHED WITH THE POST, I TRIED DESIGNING IT AS A BASE PLATE BUT I HAVE A HUGE LOAD ON IT (17000 KN) AXIAL COMPRESSION ,CAN ANYONE PROVIDE ME WITH A DESIGN PROCEDURE FOR THAT??? i am just asking about the outer plate.

RE: BEARING PLATE DESIGN

.1 Please turn off your Caps Lock Key. Some people consider all caps to be shouting.

.2 It's a large load, but it is also a large base plate. If uniformly distributed over the area, the pressure is about 6.25 MPa. I would follow the usual procedures for base plate design.

.3 Why is the bolt spacing unsymmetrical? And why 1649 mm for overall size of plate? Your plan shows dimensions differing by miniscule amounts. It will be the source of considerable confusion on the job. I suggest symmetrical bolt spacing dimensions and rounding the overall dimension to 1650, or better still, 1600.

BA

RE: BEARING PLATE DESIGN

I would also point out that your stiffeners seem rather small to spread out that type of load. Their aspect ratio is around 1:1, I would of expected that they extend further up the column so they spread out the load and have more vertical plate at the outer edge. They can simply be checked as a cantilever plate for combined shear and moment.

For the baseplate follow a normal procedure, you may need to take advantage of a good thickness of very high strength grout under to further distribute the loads to the concrete if you cannot satisfy the concrete bearing checks directly under the plate.

If this doesn't work you could cast in a section of column under the baseplate and distribute the force via a lot of shear studs welded to the cast in item, make it as long as is required.

RE: BEARING PLATE DESIGN

What circumstances justify the use of such a complicated and expensive attachment of truss to foundation? Why not simply use a base plate with stiffeners as required and forget about the upper base plate, the piston plate and the elastomeric disc?

The note "Bigger holes provided to facilitate rotation and deflection in all directions" is misleading. The detail may allow for some rotation, but it does not result in zero moment and it does not facilitate movement at right angles to the connected member. It is a semi-rigid connection.

BA

RE: BEARING PLATE DESIGN

(OP)
Thank you guys for the useful responses. :)
the plate in discussion is only the upper plate because the other parts are already designed and tested on the site.
i will try to design it using the yield line theory because the base plate calculations resulted in a 120 mm plate and my supervisor refused that ( i assumed that the plate is bearing on a concrete slab and not on another steel plate).

the thing is i am having a problem trying to identify the yield lines for the upper plate (the plate above the ear plate) so i could use some help from you guys in this area ;).

and BAretired you can read about the advantages of using this detail in this article

http://cosmecinc.com/Pot%20Bearings

Thank you :)

RE: BEARING PLATE DESIGN

malikasal,

I thought you were talking about the bottom bearing plate when you said "outer plate". I now understand you are talking about the upper plate which is labeled "Baseplate" on your section.

It seems to me that the 110 mm thick "Piston Plate" should suffice to spread the column load over the Elastomeric Disc, so it isn't clear to me what you are expecting the upper plate to do or why you believe the 50 mm plate shown might not be adequate.

Thank you for the article. I will read it with interest.

BA

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