Hi guys this is Civil Experience Blog and in this article, You will be learning about various types of beams mechanics used in civil engineering construction work based on different condition.

## Types of Beam

### Beam Definition

Beam is a structural member of a system having external loads at right angles to its axis

There are basically 6 types of beams used in mechanics. Beams used for finding out reactions on support are assumed to be massless and the support, if pinned or roller, are frictionless.

### Simply Supported Beam

Starting from the simplest of the beams

The **simply supported beam** rests on a pin and roller support. **Pin support** allows rotation and **roller support** allow rotation and lateral movement.

The deflected shape of the beam in 2D would look something like this on loading.

Simply Supported Beam has got **3 unknown reactions** which are vertical reactions at both the support and a horizontal reaction at pin support. We have **3 equilibrium equations** in which a resummation of forces in the vertical direction is zero, the summation of forces in the horizontal direction is zero and the moment about any of the support is zero, to find the 3 reactions.

Hence it is called a **statically determinate beam**.

### Overhanging Beam

Next, we are looking at an **overhanging beam** in which some portion of the beam extends from the support from one side.

The **deflected shape** of the beam on uniform loading between supports would look something like this, in which both the supports will allow rotation of the beam.

If the overhang is from both ends then the beam is supposed to be called, ** double overhang** and the deflected shape on uniform loading would look something like this.

These arrangements are also **statically determined** with** 3 unknowns **and **3 equilibrium equations**.

### Fixed Beam

Next is a **Fixed beam**, which has fixed or rigid supports from both ends.

Deflected shape due to uniform loading will look something like this in which *fixed supports will not rotate*.

Fixed support gives all **3 reactions** which are horizontal, vertical and moment at both supports hence a total of **6 unknowns**.

These unknowns cannot be found by **3 equilibrium equations**

Hence the arrangement is called **statically indeterminate**.

### Cantilever Beam

Next, we will see a **cantilever beam**, which is fixed on one side and free on the other side.

Deflected shape due to loading will look something like this.

This beam has got only **3 unknowns** hence they can be found by equilibrium equations making this beam **statically determinate**.

### Propped Cantilever Beam

Next, we will see a **propped cantilever beam **which is nothing but a cantilever beam with Roller support at the other end.

The deflected shape due to loading on the propped cantilever will look something like this.

As the total number of **unknown reactions are 4**, 3 from fixed support and one from the roller, it will be termed as a **statically indeterminate beam**.

But what if I tell you that a propped cantilever can be made statically determinate? This can be possible by introducing an internal hinge or pin. The internal hinge allows free rotation hence moment at that point is zero.

Beams to the left and right of the internal hinge can be treated like 2 separate beams for calculations. Deflections due to uniformly distributed loading this case would look something like this.

The slope abruptly changes on each side of the hinge. In the real world, a shear connection between 2 beams can be assumed as an internal hinge.

### Continuous Beam

Next comes a **continuous beam** that has 2 or more 2 spans. The support at the ends may be fixed, pinned or rolled. The ends can be overhanging or supported.

Deflected shape of the continuous beam unloading will look something like this.

The point to be noted here is that the intermediate support will not allow rotation of the beam hence there will be some amount of bending moment present at that support. As the **unknown reactions** in a continuous beam are more than 3, the reactions **cannot be statically determined**.

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## FAQ 1: what is Beam Definition?

Beam is a structural member of a system having external loads at right angles to its axis

## FAQ 2: Simply Supported Beam

The simply supported beam rests on a pin and roller support. Pin support allows rotation and roller support allow rotation and lateral movement. statically determinate beam.