Design a built-up column $10\text{ m}$ long to carry factored axial l…

Question

Design a built-up column $10\text{ m}$ long to carry factored axial load of $1080\text{ KN}$. The column is restrained in position but not in direction at both ends. Provide single lacing system with bolted connections. Assume steel grade Fe 410 bolts of grade 4.6

i) Design the column with two channels placed back to back

ii) Design the column with two channels placed toe to toe

Which of the two system is economical.