Continuous span beam with spring support reactions 1

[GreenJug]

Hello. I was curious about the support reactions of a continuous beam with 4 spans. The end reactions are pins but the middle three reactions are springs (i.e. they aren't pinned, they are simply bearing over a surface). Does the fact that these supports are springs affect the reactions? Please have a look at the illustration below. How would the reactions in a continuous span beam change with the three reactions in the middle as springs rather than pins?

Any help is greatly appreciated! Thank you.

 

[Celt83]

As the springs tend towards 0 stiffness the beam approaches the behavior of a single long simple span increasing the exterior pin reactions.

 

[GreenJug]

@Celt83

What if the springs were very stiff relative to the loads being applied?

 

[Celt83]

If they are very stiff and approach 0 settlement then they will act closer to true pin supports.

I think mastan2 will let you do spring supported nodes play around with it: Link

The mastan2 site also has a free textbook on matrix analysis.

 

[CANPRO]

The stiffness of the beam is another consideration. The support reactions will depend on both the spring stiffness and the bending stiffness of the beam. As the beam gets stiffer, the spring stiffness would need to increase to remain as effective.