The maximum ratio of span to depth of a slab simply supported and spanning in two directions, is

ANS:C - 35

A maximum ratio of span to depth of 35 implies a relatively long span compared to the depth of the slab. This suggests that the span of the slab is significantly greater than its depth. While there may not be a strict limit on this ratio, it is uncommon to have such high ratios in typical structural design practice. Here are some considerations:

1. Structural Efficiency: A higher span-to-depth ratio can result in a less structurally efficient design. The slab may be more prone to deflections and may require additional reinforcement or thicker sections to meet strength and serviceability requirements.
2. Deflection Control: Excessive deflections can occur when the span-to-depth ratio is too high. Deflections can affect the functionality of the structure and may lead to cracking or other serviceability issues.
3. Buckling Considerations: High span-to-depth ratios can also lead to instability issues, such as buckling. The slab may be more susceptible to buckling under certain loading conditions, especially if the slab is slender.
4. Code Compliance: Design codes and standards often provide recommendations or limits on the maximum span-to-depth ratio for slabs to ensure structural safety and performance. While the exact limits may vary depending on the specific code or standard used, ratios much higher than 30 are uncommon.

In summary, while there may not be a strict limit on the maximum span-to-depth ratio for slabs, a ratio of 35 is unusually high and may raise concerns regarding structural efficiency, deflection control, and stability. It's advisable to consult relevant design codes, standards, and structural engineering principles to ensure the adequacy and safety of the design.