Meaning of A and B in the base-plate thickness formula In the standard formula, identify A and B correctly (column supported on a base plate).

Introduction:
For steel columns on base plates, plate thickness is often sized using a bending strip model. Two parameters A and B appear and correspond to how far the plate projects beyond the loaded area in the major and minor directions.

Given Data / Assumptions:

• Column (steel) bearing on a rectangular base plate.
• A and B appear in the thickness expression.
• The loaded area equals the column footprint (or bearing area after deductions).

Concept / Approach:
The plate bends as cantilever strips beyond the column face under bearing pressure. Therefore, the controlling geometry is the projection length in each direction, not the overall plate dimensions or the column's total size. The symbols generally denote: A = larger projection and B = smaller projection beyond the column face.

Step-by-Step Solution:
1) Determine column footprint on the plate.2) Compute plate projections (half-plate minus half-column dimensions) in both directions.3) Assign A to the greater projection and B to the lesser projection.4) Use these in the thickness formula to estimate required plate depth.

Verification / Alternative check:
Checking plate bending by strip method or finite strip confirms projection lengths govern fiber stresses.

Why Other Options Are Wrong:
Options (a) and (b) refer to overall sizes; thickness depends on projection beyond the loaded area, not the raw dimensions.

Common Pitfalls:
Substituting overall plate size for projections; ignoring grout thickness and bearing uniformity assumptions.

Final Answer:
Both (c) and (d) of above.