Hi there,So as the subject of the discussion suggested, I have modelled my construction deck using plate element in STAAD Pro and assigned various vertical load (eg: construction load, selfweight, SDL etc.) and the deck is supported by diaphragm wall at the edge and kingpost/deckpost in the middle of the deck. For ease, I used pinned support for all the supports.However, all my loadings assigned are vertical (in y-direction) and i have checked in the post processing "static check results", all my loadcases have zero Fx, which means i supposed to have zero reactions at all supports. But, when im extracting the reactions from the supports, some of them have reaction in Fx (horizontal) direction. Even when I am looking at single loadcase like Selfweight, some of the support have Fx reaction. This has been bugging me for a while. Hereby attached the std. file, hopefully some of you can help me on this. Thanks.Construction Deck_pin_1.0EI_v8.std
You can have non zero horizontal support reactions even if the loading is only vertical. This is because the structure is subjected to lateral sway due to unsymmetry in loading as well as geometry.
For example for the load case 1, you will see lateral displacements like the ones noted below0.006 inches of diplacement at node 13586 in X direction0.013 inches of displacement at node 14172 in Z direction
However since there is no hozizontal loading applied on the structure, algebraic summation of all the horizontal support reactions in any direction would be equal to zero.
Understood and thanks for the prompt reply!! However, I also tried to replace all the pinned support by roller support and found out that some of the supports (support at the middle of the deck that represent the kingpost) did have different vertical reaction of up to 800kN while some have zero/insignificant difference. This is what makes we worry. I couldn't explain to myself why this happens too.