What are the differences between the Load Analysis View, Results View and Check Member deflections?
QuestionI appear to get up to three different deflection values depending on whether I am looking in the Results Scene View, Load Analysis View or if I right-click a member and Check or Design. What is the difference between each of these deflection results?
Results ViewThe results view will display global deflections. (Absolute deflection - i.e how far a node has moved in comparison with its original position).
Slab loads are decomposed into frame members, the structure is analysed based on this loading. This will produce one set of deflection results showing how far each node moves in the whole structure.
Run an Analysis for the loadcases or combinations you wish to review.
Go to the Results Scene view
Select the loadcase/combination or envelope you wish to see the results of
Select the appropriate Deflection you wish to view for the required direction
Adjust the scale if required.
This allows you to exaggerate the displacements and locate areas that are deflecting the most
Text can also be enabled at each node point in the results ribbon
Load Analysis View
The Load analysis view displays relative deflections - relative to the member ends. These are also often termed "local" deflections. They are deflections from a straight line drawn between the member end nodes in the final displaced position. Thus generally for beams in 3D models these local deflections will be lower, since for example they will not include the vertical deflections of supporting columns. Note that deflection due to the rotations of member end nodes in the global analysis is included otherwise neither deflections nor forces would be correct.
The exception to this is single span cantilevers for which the rotation of the node at the fixed end is assumed to be zero and thus for these the load analysis deflections do not include the effects of either the global translation or rotation of the node at the connection to the supporting member.
Load analysis results are based on the same solver results used for the Results View, however, since deflections are local, there is no vertical translation deflection component at the support locations (nodes) - thus the deflection values refer to how far the beam is deflecting between the support points, this being the deflection that is generally required for beam span/deflection ratio checks. This deflection is also the value reported when you hover the cursor over a member when viewing deflection within the Results Scene view.
Check MemberIf the beam is non-composite then the deflection results should match the results shown in the Load Analysis View.
If the beam is composite, then Check Member takes into account the composite effect of the slab. Post analysis design checks are applied, so unlike the Results Scene view and the Load Analysis view, the section is considered with stiffer properties, taking into account the effect of the slab properties working with the beam section and hence reducing deflections.