Question

The nature of bending moment developed at the intermediate supports of a continuous beam carrying downward loads is

• A. Sagging
• B. Hogging
• C. Sagging or Hogging
• D. Clockwise

Hint:

Use a simple visual aid for bending moments:
- Sagging = beam bends into a "smile" shape $\smile$ = Positive Moment. (Occurs mid-span)
- Hogging = beam bends into a "frown" shape $\frown$ = Negative Moment. (Occurs over intermediate supports and at fixed ends of cantilevers).

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks for the sign or nature of the bending moment that occurs over the interior supports of a continuous beam subjected to downward vertical loads.

Step 2: Detailed Explanation:
A

continuous beam spans over multiple supports. When downward loads (like gravity loads) are applied, the beam deflects.
- In the regions between the supports (in the spans), the beam tends to bend downwards, like a smiley face. This shape is called

sagging, and it corresponds to a

positive bending moment. This causes tension at the bottom fibers and compression at the top.
- Over the intermediate supports, the beam is bent upwards in a convex shape, like a frowny face. The support pushes up while the spans on either side sag down. This shape is called

hogging, and it corresponds to a

negative bending moment. This causes tension at the top fibers and compression at the bottom.
Therefore, the moments at the intermediate supports are always hogging moments for downward loads.

Step 3: Final Answer:
The nature of the bending moment developed at the intermediate supports of a continuous beam carrying downward loads is Hogging.