What is an alternative to using deformed bars, as stated in the regulations?

Using plain bars for spirals is an alternative to the use of deformed bars according to construction regulations. Plain bars can serve effectively in applications where the enhanced bonding and mechanical interlock provided by deformations are not essential. When used for spirals, especially in applications such as column confinement, plain bars can still provide adequate structural support and meet the required design specifications.

The primary role of spirals in reinforced concrete is to confine the core concrete, enhance ductility, and prevent buckling of longitudinal bars. Since spirals are typically tightly wound, the lack of deformation on the bars does not significantly undermine performance in these capacities, making plain bars a viable option. This adaptability is particularly useful in situations where minimizing stress concentration is critical.

The other alternatives have different primary functions or characteristics that make them unsuitable for this specific application. Wire baskets and small rebar ties are generally not considered substitutes for deformed bars in terms of their form and function in the structural integrity of concrete elements. Prestressed cables, while effective in prestressing applications, cannot replace deformed bars directly in the context of reinforcement for concrete elements that require tension and shear resistance provided by traditional rebar.