Which of the following applies to unfilled hollow masonry piers supporting a beam?

The statement that the unsupported height cannot exceed four times the least dimension is rooted in structural engineering principles designed to ensure stability and prevent buckling of masonry structures. When dealing with unfilled hollow masonry piers, the structural integrity of the pier is primarily dependent on its geometry. Limiting the unsupported height to four times the least dimension helps ensure that the potential for lateral instability is minimized and that the load-bearing capacity remains effective.

In engineering practice, the least dimension of the pier is a critical factor because it relates directly to the width or thickness of the pier. This relationship is vital for maintaining sufficient resistance against forces that can cause buckling. By adhering to this dimensioning rule, builders ensure that even under load, the pier will not fail due to excessive height relative to its width.

The other options either do not capture this important structural guideline or impose incorrect limitations that don’t align with engineering standards for hollow masonry.