Hi RachaelSelby
How are you loading this beam ie:- single point load, uniformly distributed load, several point loads or combination of both. Secondly is the beam simply supported
or built in as this will make a difference to the formula
you need to use.
I will assume for the moment that it is a simply supported
beam with a central point load.
therefore stress = M*y/I
where M= bending moment
y= distance from beam surface to the neutral axis
I= second moment of area of the angle.
a word of caution here if the load applied does not go through the centroid of the angle then there will be twisting of the beam. Also the second moment of area will be different depending on which of the legs is horizontal or vertical.
So to calculate the maximum point load the beam can take at the centre you need get your design stress into the above formula and transpose to find M the bending moment :-
M=stress*I/y now calculate M from the stress and I and y
now M = W*L/2
where W=max point load at beam centre
so once you have the max bending moment M you divide it by the length of the beam and multiply by 2 and this will give you W.
regards
desertfox
