Dear All,
I'm asking a very rudimentary thing. When we define property, How does staad use this? Does it only account for weight calculation? How does it account the stiffness of members? It seems to me staad accounts individual member stiffness's for their respective deflection instead of the structure as a whole. I did single line model of a portal pier frame with a stiff pier and given the size as 11m(wide) and 1.5m(thick). Even then it showed deflection of the piercap over the pier shafts which shouldn't. Logically deflections should be beyond the edges of pier shaft.
If you define a property, weight and stiffness of that property is considered during the analysis of a whole model. If you could attach your model, we could try to explain what is happening with it.
Piershaft_with P1 0.9x1.2.std
Please check
When you are using the beam members, the connectivity is maintained at the connection of the center lines only. So even if the pier shaft has high dimensions, it does not mean that pier cap is connected to the pier shaft all along its width - instead these members are connected at the centerlines only, so that's why you see a bigger pier cap deflection than expected.In this case, I would recommend you to model the pier shaft using the plate element, then mesh that plate and connect the pier cap to the nodes of the meshed plate to maintain the proper connectivity along all width of the plate shaft.
ok. what about the extraction of moments at base of pier shaft. won't it be inplane moments.? and support conditions of the plate element be the same, i.e. fixed support? I have attached a sample model. Please reviewstiff piershaft.std