Structural steel design – lacing/batten system for built-up columns In built-up steel columns, the lateral system provided to carry shear and keep components acting together is commonly made of which rolled sections?

Introduction / Context:
Built-up columns (such as pairs of channels, angles, or I-sections combined) require a lateral system—lacing or batten plates—to ensure the individual components act as one member and to transfer shear between them. The question asks which rolled shapes are commonly used to form that lateral system.

Given Data / Assumptions:

• Member is a built-up steel column.
• Lateral system must resist shear and prevent relative displacement between components.
• Standard rolled products are available.

Concept / Approach:
Lacing is often made from flats or angles arranged in single or double systems; battening may use plates or channels where feasible. The governing code requirements address slenderness of lacing bars, spacing, end connections, and shear transfer capacity.

Step-by-Step Solution:
Identify common lacing shapes → flats and angles.Identify common batten/lateral connector shapes → plates and sometimes channels as stiff connectors.Conclude that flats, angles, and channels are all used in practice for the lateral system.

Verification / Alternative check:
Design handbooks and steel codes illustrate lacing with flats/angles and battening with plates or short channel pieces, confirming all the listed rolled sections are used.

Why Other Options Are Wrong:

• Each single shape alone is not exclusive; practice includes multiple rolled shapes.
• “None of these” is incorrect because the listed sections are indeed used.

Common Pitfalls:
Confusing flange cover plates (for bending strength) with lacing; the latter is specifically for shear and to maintain component alignment.

Final Answer:
All the above