Simple Support

Definition

Simple support is a type of structural support that allows a beam or other structural member to rest freely while being able to rotate and translate in one direction. This type of support is commonly used in beams to create a balance between stability and movement, enabling them to carry loads without experiencing significant bending or shear forces at the supports.

5 Must Know Facts For Your Next Test

1. Simple supports provide vertical reaction forces but do not resist moments, which means they allow the beam to rotate freely.
2. In the case of uniformly distributed loads, the reaction forces at simple supports can be calculated by dividing the total load by the number of supports.
3. Simple support is often represented in diagrams as a triangle or a circle indicating where the support is located.
4. These supports are essential for structures like bridges, where they help in distributing loads evenly across spans.
5. Understanding simple supports is crucial for analyzing static systems and ensuring structures can withstand various forces without collapsing.

Review Questions

• How does simple support affect the behavior of beams under load?
  • Simple support allows beams to rotate and translate vertically while providing the necessary reaction forces. This means that when a load is applied to a simply supported beam, it can distribute the weight through its length without generating excessive bending moments at the supports. The freedom of rotation provided by simple supports helps maintain the beam's equilibrium under various loading conditions.
• Discuss how you would calculate the reaction forces at simple supports for a beam subjected to a uniformly distributed load.
  • To calculate the reaction forces at simple supports for a beam with a uniformly distributed load, you first determine the total load acting on the beam by multiplying the load intensity by the length of the beam. This total load is then divided equally among the supports if they are symmetrically placed. If there are multiple spans or asymmetric placements, you would need to use equilibrium equations (sum of vertical forces and moments) to find the exact reactions at each support.
• Evaluate the advantages and limitations of using simple support in structural design, especially in comparison to fixed supports.
  • Using simple support in structural design offers several advantages, such as allowing for ease of construction and material savings due to reduced moments at the supports. This flexibility can prevent damage from thermal expansion or contraction. However, limitations include their inability to resist moments, which may lead to deflections under heavy loads. In contrast, fixed supports can resist both vertical loads and moments but may introduce additional stresses and complicate analysis. Therefore, designers must consider the specific loading conditions and requirements when choosing between simple and fixed supports.

Related terms

Reaction Force: The force exerted by a support in response to an applied load on a structure, necessary for maintaining equilibrium.

Beam: A structural element that primarily resists loads applied laterally to its axis, typically supported at its ends.

Cantilever: A projecting beam or structure supported at only one end, allowing it to extend horizontally into space without external bracing.