@Blackstar123, you've got it spot on. I tried releasing one end of the member in the axial direction (to simulate a roller), under only vertical loading, and the end moments disappeared.
When I reinstate the x constraint, the end moments return, and because my structure will be welded at both...
@Celt83 that's a good point, the upper beam is restrained along it's length, that's what the shear plates are there for. In that case would you say the end moment is realistic?
People just love to jump on the 'you don't need a computer for everything' bandwagon without reading the content of the actual thread. I've done about 30 other such simple non-computer calcs for this design, and assure you I know when each is appropriate.
I am using a computer model because it is a much more complicated piece of grillage than that sketch shows, and it isn't just a simply supported beam, as I said in my OP. This beam has other members passing through it (into the page) and supports a tubular above it.
It requires computer...
It actually won't move side to side because of another member that runs into the page as we look, that's just a simplified sketch.
Good point about L being the clear distance between, perhaps a better way to model it is one Z support where the shear plate is and another where the end of the...
So at university we all learn that a simply supported beam with length L loaded with a point load P at mid-span will have a maximum bending moment at mid-span of PL/4 and always zero bending moment at the supports.
I have a case of a slightly complex piece of grillage, but one component is...
