How is a one-way slab defined?

• A. When the long end to short end ratio is less than 2
• B. When the long end to short end ratio is equal to 2
• C. When the long end to short end ratio is greater than or equal to 2
• D. When it can carry vertical loads from all directions

Answer: (C)

A one-way slab is defined as a slab that primarily spans in one direction and is efficient at carrying loads along that direction. The specific criterion stating that the long end to short end ratio is greater than or equal to 2 helps to categorize the slab as one-way. This ratio indicates that the slab is significantly longer in one direction compared to the other, which means that the bending moments and shear forces a slab experiences will be predominantly along the longer span.

In practical terms, this means that for a slab to be considered one-way, it typically will have a longer dimension at least twice as long as the shorter dimension. As a result, the reinforcement in the slab can be placed predominantly in the direction of the longer span, which optimizes material use and supports efficiency in construction.

The other options do not accurately reflect the definition. A ratio less than 2 suggests that the slab does not have a pronounced direction of span, which would imply that it is more likely a two-way slab capable of carrying loads in multiple directions. A ratio equal to 2 does not sufficiently establish the characteristics of a one-way slab since it needs to indicate that the span is notably greater. Lastly, the option stating that the slab can carry vertical loads from all directions describes