1. Select a pair of 15-in standard channels and design the bolted single lacing with steel Fy 36ksi for the channels in the column shown, using Fy=50 ksi. For connection purposes, the back-to-back distance of the channels is to be 15 in. PD 150 k and PL-350 k. Use LRFD method. PP. 20 t Par P. 15 15 in