A Pre-compressed Spring Isolator is a necessary position that spring isolators must take to account for installation and construction considerations.
For example, in large scale building applications, pre-compressed spring isolators in their base building assemblies effectively locks the design load displacement. This allows construction to progress without the adverse effects of relative height changes in the structure, as the load on spring gradually increases during construction. Once the design load on the isolator is achieved, the pre-compression system is released, allowing the spring to operate as an isolator.
Engineering Dynamics gives significant consideration to the design phase of the project to ensure there is a robust procedure to access and release the pre-compression mechanism(s).