Blockwork Compressive Strength and High Loadings

[sithlord382]

Hi,

I had a question regarding loadings and load bearing walls.
If I have a steel beam with an end reaction of 180kN, would a 3m high wall comprising of 7.3N/mm2 blockwork as the inner leaf be suitable to use? I would assume a concrete padstone of approximately 900mm long x 100mm wide x 300mm deep would need to be installed for the beam to bear onto.

However is there any written guide lines as to what the maximum end bearing load can be taken by 7.3N/mm2 blockwork, before it must be beefed up to 10.3N/mm2?

KR

Sithlord

 

[Greenalleycat]

That's a big ol point load. I'm not aware of any such clauses in our codes but of course YMMV. I would imagine it comes down to you working out the demand and the capacity and beefing it up if you have to. Limiting value would be bearing of the beam on the concrete core of the block work I would imagine

Is this just landing on top of the end block or is it a dedicate column?

How good is the foundation beneath? I'd be wanting to avoid having any settlement directly beneath the beam end. Though a 3m high wall should be very stiff and able to handle that.

 

[sithlord382]

Hi Greenalleycat,

In terms of limiting values, the beam bears in the plane of the wall onto the wall, therefore I am proposing to have the ends of the beam to bear approx 600mm-700mmm onto the wall, as opposed to typical 150-200mm. Just to be clear the beam will sit on the top of the blockwall and it is not a dedicated column.

We are planning on piling down 12ms, with 600mm deep ground beams for the walls to sit onto

 

[JLNJ]

Most masonry codes have maximum bearing values. I think for the US it's 1/3*f'm.

A 900 mm bearing block is quite long. You would need to think about whether the bearing fully and equally distributes the load along the entire length (I suggest it does not). Once you successfully figure out how to mount the beam (no eccentricity) and design the bearing plate/block then you need to chase that load down to the foundation. The code has provisions to check the buckling of compression elements such as walls. And you must account for doors or windows nearby as they prohibit the load from "spreading out".

For such a large load, there is no "rule of thumb" which you can employ to avoid all calculations and load path considerations. I'm guessing that you will need to stiffen the steel to properly "even out" the load so that it's applied uniformly, and, even then, 10.3N/mm2 block might not be strong enough.