Identify the FALSE statement from the following, pertaining to the design of concrete structures.

The relevant cross-sectional details of a compound beam comprising a symmetric $${\rm I}$$-section and a channel section (with welded connections), proposed for a steel gantry girder, are given below (all dimensions are in $$mm$$)

$$(a)$$ Determine the depth of the centroidal axis $$\overline y $$ and the second moment of area, $${{\rm I}_{xx}}$$ and $${{\rm I}_{yy\,\,eff}}$$ of the compound section. For computing $${{\rm I}_{yy\,\,eff}}$$ include the full contribution of the channel section, but only the top flange of the $${\rm I}$$-section.

$$(b)$$ Determine the maximum compressive stress that develops at a top corner location on account of a vertical bending moment of $$550.0$$ $$kN$$-$$m,$$ combined with a horizontal bending moment of $$15.0$$ $$kN$$-$$m.$$

Consider the following two statements related to structural steel design, and identify whether they are True or FALSE.

$${\rm I}.\,\,\,\,\,\,$$ The Euler buckling load of a slender steel column depends on the yield strength of steel.
$${\rm II}.\,\,\,\,\,\,$$ In the design of laced column, the maximum spacing of the lacing does not depend on the slenderness of column as a whole.

Identify the most efficient butt joint (with double cover plates) for a plate in tension from the patterns (plan views) shown below, each comprising $$6$$ identical bolts with the same pitch and gauge.