2.2. Battens

Battens Flat plates placed perpendicular to the axis to connect built-up sections.

Battens are flat plates that are used in the construction of built-up steel columns. Their main purpose is to connect different sections of the column, helping to maintain structural stability. By placing these plates perpendicular to the column axis, they effectively prevent buckling and help transfer shear forces within the assembled structure.

Think of battens like the cross braces in a wooden frame of a house. Just as those cross braces keep the frame from swaying during strong winds or earthquakes, battens provide extra stability to steel columns, ensuring they can handle loads without bending or breaking.

Design Guidelines: Minimum of three battens in the column length. Thickness and connections designed to carry transverse shear (typically 2.5% of axial load). Battens spaced to limit slenderness of individual component sections.

When designing battens, there are several important guidelines to follow. Firstly, it's essential to include at least three battens along the length of the column to ensure effective stabilization. The thickness of these battens, as well as how they are connected to the column, must be adequate to handle the transverse shear forces they will experience, which are typically calculated as 2.5% of the axial load. Additionally, the spacing between battens should be managed to prevent any individual component section from becoming too slender, which could increase the risk of buckling.

Imagine you're assembling a tall bookshelf. If you only use a few small brackets to hold the shelves in place, the books on those shelves might cause it to lean or topple over. However, by using multiple, appropriately-sized brackets spaced out evenly, you ensure the shelves can support the weight of the books without bending or collapsing. In the same way, designing battens properly ensures that a steel column can support loads safely.

Parameter Lacing Batten Orientation Diagonal Perpendicular Function Prevent buckling, transfer shear Prevent buckling, transfer shear Common Use Tall/lighter build-ups Shorter/stockier build-ups

Lacing and battens serve similar overall functions in structural engineering: both are designed to prevent buckling within built-up columns and transfer shear forces. However, they differ in their orientation and specific applications. Lacing typically runs diagonally between the sections of a column, which is often used in taller, lighter structures to add stability against twisting forces. On the other hand, battens are positioned perpendicularly and are more suitable for shorter and stockier structures, providing stability without the complexity of diagonal bracing.

Consider a tall, thin tower that sways in the wind. By using diagonal supports (lacing), it can resist the wind's forces effectively. Now, think of a short, stout building where you might not need those diagonal supports; instead, horizontal connections (battens) will suffice to keep it stable under heavy loads. Both types of support are crucial, but they are chosen based on the structure's height and overall design.

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