A feature has been added in RC-PIER per the request from Caltrans. This feature is about how the out-of-plane reactions to external loads from superstructure are distributed to pier columns in an integral pier.

For those loads which have both vertical and out-of-plane components, the out-of-plane components of the reactions in piers columns will be proportional to the vertical components of reactions based on in-plane analysis.

For those loads which have no vertical components, but out-of-plane components, RC-PIER offers two options thru Analysis Tab -> A/D Parameters -> Load Distribution Tab:
(1) Evenly distributed into columns
(2) Proportional to the vertical reactions from analysis of self weight.