I am playing around with a simple beam analysis in STAAD (version 20.07.11.82) with only member dead load case (1.0 gravity load factor).I initially had it modeled as a 2-member beam fixed at a midspan joint. Then I changed it to a single member. The results were the same for each case.I am trying to analyze a built-up steel section (prismatic general). I calculated the section properties by hand and defined the section in STAAD. And I am getting an extremely large maximum deflection from STAAD. c. 2400-inchesMy hand calculations (5wL^2 / 384EI) are only c. 6-inches.When I changed the section property definition to a W-beam from the section database, STAAD's maximum deflection is spot-on to my hand calculations. c. 28-inchesIn both cases, the maximum moment and bearing reactions are as expected (verified by hand calcs). And I've tried using the " SET SHEAR " command, but that doesn't seem to have any effect.Does anyone have any ideas what's going wrong with my prismatic section deflection analysis?...thanks for any input...
0284.1548-StrongB-ONLY.std