In reinforced concrete design as per civil engineering practice, a pedestal is a compression member whose effective length does not exceed its least lateral dimension by more than which multiple?

Introduction / Context:
In reinforced concrete (R.C.) structures, compression members are classified based on their geometry and effective length because buckling risk and design assumptions depend on slenderness. Very short compression members that primarily carry load in direct compression are termed pedestals, while longer members are designed and detailed as columns with slenderness considerations.

Given Data / Assumptions:

• Member type: reinforced concrete compression member.
• Classification depends on effective length relative to the least lateral dimension.
• We seek the limiting multiple that defines a pedestal.

Concept / Approach:

Standards and textbooks define a pedestal as a very short compression member where slenderness effects are negligible. The commonly adopted criterion is that the effective length (distance between points of contraflexure for buckling about the critical axis) does not exceed three times the least lateral dimension. Within this limit, design may treat the member as a block in direct compression with appropriate detailing for load transfer and bearing.

Step-by-Step Solution:

Verification / Alternative check:

Design manuals distinguish pedestals (stubby supports under base plates, beams, or walls) from columns. The 3-times rule is widely cited in R.C. design guides to separate direct-compression behavior from potential buckling behavior.

Why Other Options Are Wrong:

• 12, 16 times: These are slenderness-type limits suitable for columns, not pedestals.
• 8 or 6 times: Still too large for the pedestal definition; buckling effects can be non-negligible.

Common Pitfalls:

• Confusing effective length with clear height; boundary conditions affect effective length.
• Ignoring load transfer and bearing checks even for short pedestals (e.g., bearing stress under base plates).

Final Answer:

3 times