Continuous Slab–Beam Systems – Bending Moment Signs for Filler Joists Identify the correct sign convention for bending moments in filler-joist construction at typical locations along end and interior spans.

Introduction / Context:In continuous flooring systems with filler joists, bending moment signs follow the usual convention: sagging is positive and hogging is negative. Recognizing where moments are positive or negative is crucial for placing bottom and top reinforcement appropriately.

Given Data / Assumptions:

• Continuous spans with joists or beams supported over multiple supports.
• Sign convention: sagging (+) at midspan, hogging (-) over supports.
• Load primarily uniformly distributed.

Concept / Approach:

For a continuous system, moments reverse sign between spans and supports. End spans exhibit sagging near midspan and hogging near the interior support, while interior spans sag at midspan and hog at interior supports.

Step-by-Step Solution:

Verification / Alternative check:

Classical slope–deflection or moment distribution methods produce the same sign pattern, confirming the qualitative picture.

Why Other Options Are Wrong:

• Options a to d are all correct individually; only option e captures the complete set.

Common Pitfalls:

Mixing sign conventions or forgetting that support regions in continuous members attract top reinforcement due to negative moments.

Final Answer:

All the above