The Section List doesn't recognize the Tapered Section.
When dealing with bridge columns that have tapered sections, it's common to use Tapered sections in Properties > Section > Section Properties. However, as indicated in the title, Tapered Sections are not supported in the Section List of Rebar Input for Column Section.
[ Tapered Section Dialog ]
[ Piers with Tapered Sections ]
To perform seismic performance evaluation, it's necessary to obtain moment-curvature curves for the top and bottom of the bridge column based on its behavior. To create these curves, you need to input the reinforcement details for the section. To do this for Tapered Sections within the Section List's limitations, you'll need to make some modifications to your bridge column modeling.
Since the locations where moment-curvature curves are needed are at the top and bottom of the column, you should divide your column into smaller elements within the range of the tapered section, as shown below, and then assign regular sections.
[ Section Properties Dialog ]
[ Dividing the Column into Smaller Sections and Applying Regular Sections ]
By splitting the top and bottom sections of the column and applying regular sections to them, you can ensure that the Section List in Rebar Input for Column Section recognizes the sections.
[ Rebar Input for Column Section Dialog ]
When the yield effective stiffness of the bridge columns obtained through the moment-curvature curve is defined through the Seismic Perform > Demand > Generate Section Effective Stiff. function, the P1-Tapered section is not applied because it is defined based on the section assigned to the element. Therefore, additional definition of the Tapered section is required utilizing the Properties > Section Manager > Stiffness .
[ Section Manager > Stiffness Dialog ]