> For the complete documentation index, see [llms.txt](https://docs.enercalc.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.enercalc.com/e3d-user-manual/interface/toc175916526/toc175916652/toc161393881-2/coupled-springs.md).

# Coupled Springs

How to assign coupled spring stiffness matrices to selected nodes for modeling substructures like bridge foundations.

Create > Constraints > Coupled Springs prompts you with the following dialog.

![](https://560001759-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FWNe8U6EBBBdUJHdb2X9G%2Fuploads%2Fgit-blob-e25dcc993608ae7d24845390cc3cc6d4655b3c13%2FCoupled%20Springs.jpg?alt=media)

It allows you to assign coupled springs to selected nodes. Coupled springs are useful in modeling/simplifying substructures such as bridge foundations. It is important to enter the coupled spring stiffness matrix in the appropriate units.


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