Increased Substructure Felxibility of Column-Top Isolation Systems


Abstract eng:
As seismic isolation continues to gain popularity for its ability to significantly reduce earthquake damage, retrofit applications are still limited due to significant construction expenses. Foundation work and excavation of a seismic gap, as well as installation of an additional rigid diaphragm lead to high project costs which often limit isolation retrofit to historical buildings. To mitigate these expenses, some designers have begun installing the isolation layer on the tops of the first level columns without the use of an additional rigid diaphragm. This type of installation also negates the need for excavation; however, designers typically design practically rigid support columns in an effort to limit any flexibility below the isolation plane. While this is practical for new construction, this may not be feasible for a retrofit application. This study considers the behavior of a column-top isolation system when subjected to varying substructure flexibilities. Large flexibility leads to end rotations in the isolation bearings during ground motions. To investigate this behavior, experimental cyclic testing of a column-bearing subsystem was done at McMaster University. The results are investigated and compared against a bearing model which accounts for changes in lateral stiffness and buckling behavior under both translational and rotational degrees of freedom, which was implemented in OpenSees. Experimental results show that flexible substructures can significantly reduce the lateral stiffness of elastomeric bearings and the end conditions must be accounted for to reasonably estimate the isolation period.

Contributors:
Conference Title:
Conference Title:
16th World Conference on Earthquake Engineering
Conference Venue:
Santiago (CL)
Conference Dates:
2017-01-09 / 2017-01-13
Rights:
Text je chráněný podle autorského zákona č. 121/2000 Sb.



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 Record created 2017-01-18, last modified 2017-01-18


Original version of the author's contribution as presented on USB, paper 2573.:
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