Compressive strength of bricks

Discussion in 'Builders' Talk' started by BuildMore, Sep 7, 2021.

  1. BuildMore

    BuildMore New Member

    Need some advice, please.

    Trying to design some tall brick columns that support a lot more bricks above a lintel. Need to understand how much weight a single brick (at the bottom of the column) can take before failing. I'm not planning to build a single brick column, but understanding how much a single brick can take will help with my calculations.

    My bricks are rated at around 10 N(ewtons)/mm2. The bricks are 215 x 102.5 mm, total surface area of 22,037 mm2. So I think that means the most a single brick can support 220,375 N, evenly distributed. That equates to around 22,464 Kg or around 22 Tonnes.

    This seems far too much, as a maximum load before fracture. Where have I made a mistake?
  2. AnotherTopJob

    AnotherTopJob Screwfix Select

    I think that's correct (in theory). Obviously an even bed of mortar is essential to spread the load to avoid any point-loading.
  3. rogerk101

    rogerk101 Screwfix Select

    Which then begs the question of what the compression strength of the mortar is, and, unlike with bricks, which are pretty standardised, there are so many variables in mortar that the whole calculation exercise is pretty pointless. Mortar with what type of cement, and what type of sand ... with what ratios ... with what amount of water ... how fresh it was when it was laid ... how quickly did it dry ... was it whacked by the brickie or laid gently ... etc, etc. Each of the above factors could reduce the compression strength by a factor of two, and a few of them together would change it by an order if magnitude!
    What exactly is it you're trying to achieve with your calcs?
  4. stevie22

    stevie22 Screwfix Select

    You are spot on in your thought process, but the area is only 22,037 (you've gained a 10) so 2.2 tonnes. These are pretty weak bricks and for a load bearing pier you would normally use much stronger bricks (they are available up to 100N. Note however that this value is a country mile from what your brick can carry as part of a column.

    A load of factors come into play:

    Brick strength, mortar strength, pier cross section, pier height, load configuration and , quality of bricks, quality of laying.

    This is why SEs get the big bucks

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