Support Reactions in Beams

In structural engineering, beams are commonly used to support loads and transfer them to the supports. The supports play a crucial role in providing stability and balance to the beam. There are different types of supports, each offering specific reactions depending on the nature of the load and the structural configuration. One of the most basic types of supports is a simple support.

Definition of a Simple Support
A simple support is a support that allows rotation but prevents translation in the horizontal and vertical directions. It is typically provided by a pin or a roller at the support location. This means that a simple support can resist vertical forces but cannot resist horizontal or inclined forces.

Reaction Normal to the Axis of the Beam
The reaction normal to the axis of the beam refers to the vertical component of the support reaction. In the case of a simple support, the only reaction it can offer is a vertical reaction. This reaction is normal (perpendicular) to the axis of the beam. Therefore, the correct answer to the given question is option 'B' - vertical.

Other Types of Reactions
While a simple support offers only a vertical reaction, other types of supports can offer additional reactions. Let's briefly discuss them:

1. Fixed Support: A fixed support prevents both translation and rotation. It can offer vertical, horizontal, and moment reactions.

2. Roller Support: A roller support allows translation but prevents rotation. It can offer only a vertical reaction.

3. Hinged Support: A hinged support allows rotation but prevents translation. It can offer only a vertical reaction.

4. Pinned Support: A pinned support allows rotation but prevents translation. It can offer vertical and horizontal reactions.

Conclusion
In summary, a simple support offers only a vertical reaction normal to the axis of the beam. It cannot provide horizontal, inclined, or moment reactions. Understanding the type of support and its reactions is essential for engineers to design and analyze beam structures accurately.