Support Conditions

Depending on their functions, the supports of beams are classified as

  1. Simple support
  2. Roller support
  3. Hinged or Pinned support
  4. Fixed support

Simple support

A simple support offers only a vertical reaction. Horizontal moment or rotation of the member are not prevented at this support (Example Masonry Wall).

Roller support

A roller support is similar to simply support. It offers only a vertical reaction. Rollers are provided in between the member and the support to facilitate free horizontal movement of the member at the support. In the case of long beams and trusses, roller support is provided at one end to avoid temperature stresses in the members (Example: Roller bearings for trusses).

[Note: Roller supports are not to be provided at both the ends of beam, especially when it is subjected to inclined or horizontal forces.]

Hinged or Pinned support

A hinged support will offer a vertical reaction and a horizontal reaction. Both vertical and horizontal movements of the members are prevented at this support. But the end is not restrained against rotation at hinged support [Example: Single riveted lap joint].

Fixed support

A fixed support offers a vertical reaction, a horizontal reaction and a moment reaction called fixed end moment. The member is restrained against any movement and rotation at this support. [Example: Built in end of beam, welded joints].

 

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