Strength capacity of a bolted pole
You can model a bolted/twin pole in the Poles database by creating a new record, increasing the dimensions and strength of the corresponding single pole. Bolted poles are usually rectangular and the increased dimensions are obvious.
According to Busck the strength of a bolted pole is doubled in both directions. See section 9.1 in https://busck.co.nz/wp-content/uploads/2015/09/here..pdf
Two poles with only a cross-arm between them ie not braced, have a capacity of twice a single pole in both longitudinal and transverse directions.