ANS:C -

The design of a square flat slab involves considering the bending moments acting on the slab. The bending moment is a measure of the bending or flexural stress experienced by the slab due to applied loads. Let's denote:

• W as the total load per unit area on the panel (in force per unit area, such as pounds per square foot or kN/m²).
• D as the diameter of the column head (in the same unit as the span length).
• L as the span in two directions (in the same unit as D).

For a square flat slab supported on columns, the bending moments are generally calculated using simplified methods or more detailed structural analysis depending on the specific requirements and complexity of the structure. However, a common approach for design is to ensure that the sum of the maximum positive bending moment and the average of the negative bending moment meets certain criteria to ensure the structural integrity of the slab. The bending moments are influenced by factors such as loading, support conditions, and structural geometry. Without additional information about the loading conditions, support conditions, and structural properties, it's challenging to provide an exact formula for the sum of the maximum positive bending moment and the average of the negative bending moment. In structural engineering, design codes and standards are followed to ensure the structural safety and adequacy of the design. These codes provide guidelines for calculating bending moments and designing the slab accordingly. Common codes include ACI (American Concrete Institute) for concrete structures or AISC (American Institute of Steel Construction) for steel structures. For the specific design requirements you've mentioned, it's recommended to consult relevant design codes and standards or consult with a structural engineer to ensure accurate and safe design practices are followed.