Which term describes the ratio of unsupported height to thickness?

• A. P-Delta effect
• B. Hydration
• C. The ratio of unsupported height of the panel to its thickness
• D. P-Delta ratio

Answer: (C)

The main idea is the height-to-thickness ratio, a measure of slenderness for a panel. This ratio, describing the unsupported height of the panel relative to its thickness, is a direct way to gauge how slender the panel is and how it might behave under loading. In tilt-up construction, a larger height-to-thickness ratio means more slender panels, which are more prone to bending, buckling, and the effects that arise from lateral displacement under axial load (P-Delta effects). That makes this descriptive term the best fit because it precisely names the quantity being discussed. The P-Delta effect refers to the additional moments created by lateral displacement under axial load, not the ratio itself, and hydration is unrelated to this structural concept.