Transverse reinforcement (ties/spirals) pitch limits in reinforced concrete columns What is the code-based limiting pitch for transverse reinforcement of a column?

Introduction:
Transverse reinforcement (ties or spirals) in columns restrains longitudinal bars against buckling and confines the core concrete, improving ductility. The maximum pitch (spacing) is limited to ensure effective confinement and to prevent bar instability between ties.

Given Data / Assumptions:

• Reinforced concrete column with properly detailed ties/spirals.
• Normal seismic demand is assumed (non-special confining reinforcement).
• Standard bar sizes and cover are provided.

Concept / Approach:

Codes specify that the tie pitch shall not exceed certain limits tied to the member size and bar diameters. The governing maximum pitch is the least of specific expressions so that confinement is effective regardless of bar sizes or column dimension.

Step-by-Step Solution:

Verification / Alternative check:

Detailing examples and experimental data show that exceeding these limits reduces confinement efficiency and increases risk of longitudinal bar buckling in compression zones.

Why Other Options Are Wrong:

Options A, B, and C give only individual caps; the governing requirement is the least of them. Option E introduces a non-standard multiplier (twenty), which is not the conventional limit.

Common Pitfalls:

Using a single limit and ignoring the other caps; not reducing pitch near beam-column joints or where special confining reinforcement is required.

Final Answer:

least value of the above