Different types of supports |Mechanical engineering| Civil engineering| Strength of materials

The support is the structural element that provides opposite forces to the direction of applied loads. These structural elements carry whole weight of structure. Hence, understanding about support is essential to build safe structure. There are 5 types of supports used in analytical or numerical methods to analyze structures. These are listed below

1.  Roller support: The beam is supported by roller/wheel as shown in Fig.1.1.The reaction is always normal to support. The roller is free to rotate and move in horizontally.

Fig.1.1 Roller support

For structural analysis roller support is idealized having only one vertical reaction force as shown in Fig.1.2. The roller supports are used in bridges and mechanical components.

Fig.1.2 Roller support idealized in analysis

2.Simple support: The beam rests on rigid support without monolithic connection as shown in Fig.2.1. The simple support offers no resistance to rotation and horizontal movement. The reaction is always normal to support just like roller support. 

Fig.2.1 Simple support

Simple support is also idealized as having one vertical reaction force as shown in Fig.2.2. The simple support is a examples are concrete beam placed on masonry wall or vehicle wheels placed on road. 

Fig.2.2 Simple support  idealized in analysis

3.  Pinned support: The pinned support restricts the movement of beam in vertical and horizontal directions. But, offers no resistance to rotation. The beam pinned to support is shown in Fig.3.1.

Fig.3.1 Pinned support

Pinned support is also idealized as having one vertical and one horizontal reaction forces as shown in Fig.3.2. The door connected to hinge is an example for pinned support. Where vertical and horizontal displacements are restricted but allowed to rotate. Wheel and axle system is an example of pinned support.  

Fig.3.2 Pinned support  idealized in analysis

4. Fixed support: The beam is monolithically fixed to column is shown in Fig.4.1. The Fixed support restricts the movement and rotation in all direction. 

Fig.4.1 Pinned support

Fixed support is also idealized as having one vertical force ,one horizontal force and moment as shown in Fig.4.2. The cantilever beam supported end is  an example for fixed support. 

Fig.4.2 Pinned support  idealized in analysis

5.  5. Elastic support: The beam resting on compression spring is shown in Fig.5.1. The compression spring restricts the rotation and movement in horizontal direction.

Fig.5.1 Elastic support

Spring support is also idealized as having one vertical force as unknown as shown in Fig.5.2. The building resting on soil is an example for elastic support. 

Fig.5.2 Elastic support  idealized in analysis

Conclusion: The support reaction helps in evaluating bending moment and shear force of structural elements. The supports are the major contributors in designing member sizes of structure. The table below lists reaction forces of different types supports. 

Types of support	Label of support	Freed forces	Reaction forces
Roller		One horizontal One rotational	One vertical
Simple		One horizontal One rotational	One vertical
Pinned		One rotational	One vertical One horizontal
Fixed		None	One vertical One horizontal One rotational
Elastic		One horizontal One rotational	One vertical