Editing Structural engineering (section)

===Catenaries===
{{Main|Tensile structure}}

Catenaries derive their strength from their form and carry transverse forces in pure tension by deflecting (just as a tightrope will sag when someone walks on it). They are almost always cable or fabric structures. A fabric structure acts as a catenary in two directions.
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===Seismic base isolators===
{{Main|Vibration control}}

[[Base isolation]] is a collection of structural elements of a building that should substantially [[decouple]] the building's [[superstructure]] from the shaking ground thus protecting the building's integrity and improving its [[seismic performance]]; see, e.g., the shake table testing of a kind of ''' seismic base isolators''' called [[Earthquake Protector]]s. This technology, which is a kind of seismic [[vibration control]], can be applied both to newly designed buildings and to seismic upgrading of existing structures. Normally, excavations are made around the building which is separated from its foundation. Steel or reinforced concrete beams replace the connections to the foundation, while under these, the isolating pads, or '''seismic base isolators''', replace the material removed. While the [[base isolation]] tends to restrict the transmission of the ground motion to the building, it also keeps the building positioned properly over the foundation.
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