Certain load-bearing structures with discrete structural components can be subject to the "zipper effect", where the failure of a single structural member increases the load on adjacent members. In the case of the [[Hyatt Regency walkway collapse]], a suspended walkway (which was already overstressed due to an error in construction) failed when a single vertical suspension rod failed, overloading the neighboring rods which failed sequentially (i.e. like a [[zipper]]). A bridge that can have such a failure is called fracture critical, and numerous bridge collapses have been caused by the failure of a single part. Properly designed structures use an adequate [[factor of safety]] and/or alternate load paths to prevent this type of mechanical cascade failure.<ref name="petroski">{{cite book| title=To Engineer Is Human: The Role of Failure in Structural Design| first=Henry| last=Petroski| year=1992| isbn=978-0-679-73416-1| publisher=Vintage| place=| url-access=registration| url=https://archive.org/details/toengineerishuma00petr}}</ref> | Certain load-bearing structures with discrete structural components can be subject to the "zipper effect", where the failure of a single structural member increases the load on adjacent members. In the case of the [[Hyatt Regency walkway collapse]], a suspended walkway (which was already overstressed due to an error in construction) failed when a single vertical suspension rod failed, overloading the neighboring rods which failed sequentially (i.e. like a [[zipper]]). A bridge that can have such a failure is called fracture critical, and numerous bridge collapses have been caused by the failure of a single part. Properly designed structures use an adequate [[factor of safety]] and/or alternate load paths to prevent this type of mechanical cascade failure.<ref name="petroski">{{cite book| title=To Engineer Is Human: The Role of Failure in Structural Design| first=Henry| last=Petroski| year=1992| isbn=978-0-679-73416-1| publisher=Vintage| place=| url-access=registration| url=https://archive.org/details/toengineerishuma00petr}}</ref> |