Serviceability deflection limits are set according to a beam: Question 7Select one:a.Elastic modulusb.2nd moment of areac.spand.load

1. Break Down the Problem

The question asks to identify which parameter relates to the serviceability deflection limits of a beam from the provided options: elastic modulus, second moment of area, and span/load ratio.

2. Relevant Concepts

• Elastic Modulus (E): A material property that measures its ability to deform elastically (i.e., non-permanently) when a force is applied. Higher elastic modulus indicates a stiffer material.
• Second Moment of Area (I): A geometrical property that measures an object's resistance to bending. It is a crucial factor in understanding beam deflection.
• Span/Load Ratio (L/W): This ratio helps in understanding the relationship between the length of the beam (span) and the loads applied to it, but it is not a direct measure of deflection limits.

3. Analysis and Detail

• Elastic modulus affects deflection but does not solely define serviceability limits.
• The second moment of area directly influences how much a beam will deflect under load.
• While the span/load ratio can affect deflection indirectly, it doesn’t encapsulate the direct mechanical properties that dictate limits.

4. Verify and Summarize

The primary factors for determining deflection limits in serviceability checks are generally based on the second moment of area and elastic modulus. However, the second moment of area is more directly associated with the limits of deflection in this context.

Final Answer

b. Second moment of area is the correct answer as it directly affects the deflection limits of a beam under serviceability considerations.