The reporting of story shears (storey shears in the UK) has been enhanced. This enhancement was first introduced in release 2023 Service Pack 3.

In all previous releases horizontal Dir1/ Dir2 Shear forces (values and arrows) could be displayed in the Results View for any selected Loadcase or combination via the Sway Drift and Story Shear Ribbon group, to give an indication of the distribution of lateral load within the structure. The same nodal shear values were also summed in each level to produce the “Inter Story Shear” and “Cumulative Story shear” tables available in the Review View > Tabular data.

Following customer feedback, reporting of story shears has been enhanced with new reporting options as described below. For more details see the new Help Topic Understanding story shears and story forces.

• Changes to previous results:

  • Results View - the previous “Dir1 Shear” and “Dir2 Shear” values are calculated and displayed in a similar manner, but are now termed “Story Forces Dir 1” and “Story Forces Dir 2”, as shown in the picture above.

    • The sign and direction of the force arrows is also changed to generally reflect that of the applied lateral load (positive if the arrow acts in the selected building direction and negative if it acts against the selected building direction), since the general intention is to indicate where/ how load enters the members of the lateral system. The location of the force value text is also adjusted to the center of the arrow. Together these changes produce a generally clearer view of the forces as illustrated in the picture below.

• Tabular Data Tables - the previous Review View > Tabular Data result tables “Inter-story Shear” and “Cumulative Story Shear” are renamed to “Story Forces” and “Story Shears” respectively and moved to the Model and Results > Tabular Data view. This is more logical as it places them with the other similar data tables for displaying analysis results.

  • [TSD-14708] - while there is no change to the calculation of Story Forces (other than the change of sign noted above), the calculation of Story Shears is enhanced in this release to correctly include horizontal load applied between levels, such as point and line loads applied to columns between levels.

• New Results - the following new results and results display are now available:

  • Story Forces Dir 1/ 2 - together with the individual local story force arrows/ values, the tabular story force values (which are the totals for each level) are now also displayed in the Results view, indicated by large blue colored arrows adjacent to the model. This is illustrated in the pictures below for the model shown - a five story building with Diaphragm Loads applied at each level in Dir1 only, resisted by a lateral system of A- brace pairs in each story and in two frames parallel to the load direction. This example covers the most common situation of lateral loads - e.g. wind and seismic - being generally applied at levels.

• Story Shears Dir 1/ 2 - new “Story Shear” values can now be selected for display in the Results View as illustrated in the picture below for the same model shown in the pictures above. Individual shear arrows/ values are shown for each set of braces / wall panels. These are cumulative - i.e. in a particular story they include the contribution of the force in each set of braces / wall panels of the stories directly above. The shear arrow is located slightly below each level to indicate the members/ story it refers to. Additionally, the tabular story shear values (which are the totals for each level) are now also displayed in the Results view by large blue colored arrows adjacent to the structure.

• Wall/ Braced Bay Story Shears - these new results are available both graphically in the Results View and tabulated in the new Model and Results > Tabular Data view > “Walls/Braced Bay Story Shears” table, as shown in the picture below. They give the magnitude of cumulative horizontal shear resisted by walls and braced bays at each floor level resulting from the horizontal component of all loads applied to the structure for any selected Loadcase or combination. In the Results view they are shown with blue colored arrows in each wall panel/ braced bay in the model for each level.

• In the Results view, the “Wall/ Braced Bay Story Shears” can be selected for display in one of three direction options; Dir 1, Dir 2 and In-plane. The latter option gives values in the plane of each individual wall panel/ braced bay. This is useful for models with walls/ braced bays not aligned with the building directions, as illustrated in the picture below.

  

• Limitations - as the name implies, the scope of these new Wall/ Braced Bay Story Shears results is limited to wall and braced bay lateral systems (of single braces and the currently available brace pairs). Moment frames are not explicitly considered.

  • This is illustrated in the example shown below of a model with a mixture of braced bays - of single braces in a single frame - and moment frames - comprised of two columns and connecting beams in two frames - together resisting lateral forces in Dir 1. Cumulative story shear values are calculated/ displayed for the nodes of the moment frame columns in each level. However, they are not combined to produce a single moment frame “bay” value and no value is shown for the moment frames in the Results View > Wall/ Braced Bay Story Shears results.

• The Result View > Wall/Braced Bay Story Shears options only display arrows + values for the braced bays in this example. However, the Tabular Data view’s “Wall/Braced Bay Story Shears” result table does include values titled “Not captured by walls and braced bays” which are the total shear values for each level generated in the moment frame columns, as shown in the picture below.

  • This would also be the case for the (usually small) amount of shear that can typically develop in continuous columns (or other systems) that are not part of the lateral system, due to displacements from lateral loading in structures with floor diaphragms.