non rectangular slabs

[oneintheeye]

how would you analyze a trapezodial slab? I am actually looking to determine loads transferred to the four sides rather than bending as my bending works on conservative but the beams supporting the slab fail assuming one way action (which its not).

 

[kslee1000]

Do a FEM analysis to figure out load distribution. Beware torsional effect.

 

[oneintheeye]

to give you more detail I have carried out a FEM analysis of my slab, I want to confirm the design by hand rather than take it as right (been burned before).

 

[kslee1000]

You are already half way there.
I will exam and sum the reactions along each edge. The results will give me a feel of how much load gets to each direction, and how the reactions/loads varies along a specific edge.
Now seperate the slab into strips to carry proportional loads (in each direction) by judgement.
Provide additional slanted/digonal bars at the corners to avoid premature cracks.

 

[csd72]

To get a general idea of loads, use the traditional yield line method to determine areas to be distributed to each wall.

Divide each corner angle into 2 and draw in the diagonal line. These lines will intersect at 2 separate points.
Draw a 5th line between these points of intersection.

This will give you 4 areas of floor to distribute to the adjacent walls.

As this is based on plastic yield lines it will give you a slightly different result from the elastic FEM method, but it is useful to check that you are in the right ballpark.