The correct answer is: Both (A) and (B).
Lacing bars are used in steel columns to provide lateral stability and to prevent buckling. They are typically placed at right angles to the longitudinal bars and are connected to them by ties.
The lacing bars must be designed to resist the bending moment and shear force due to the column load. The bending moment is caused by the weight of the column and any loads that are applied to it. The shear force is caused by the lateral loads that are applied to the column.
The lacing bars must also be designed to resist the buckling of the column. Buckling is a failure mode in which the column collapses due to lateral loads. The lacing bars help to prevent buckling by providing lateral support to the column.
The following is a brief explanation of each option:
- Option A: Bending moment due to 2.5% of the column load. The lacing bars must be designed to resist the bending moment due to the column load. The bending moment is caused by the weight of the column and any loads that are applied to it.
- Option B: Shear force due to 2.5% of the column load. The lacing bars must be designed to resist the shear force due to the column load. The shear force is caused by the lateral loads that are applied to the column.
- Option C: 2.5% of the column load. The lacing bars must be designed to resist the bending moment and shear force due to the column load. The bending moment is caused by the weight of the column and any loads that are applied to it. The shear force is caused by the lateral loads that are applied to the column.
- Option D: Both (A) and (B). The lacing bars must be designed to resist the bending moment and shear force due to the column load. The bending moment is caused by the weight of the column and any loads that are applied to it. The shear force is caused by the lateral loads that are applied to the column.