07-17-2010, 04:53 PM
Hi all!
You can use either Linear Links or Multilinear Plastic links, depending on your needs. (Go to "Define" Menu --> "Link Support Properties"). I'd say that if you're modeling for service limit state analysis, you would try to keep your bearings away from "yielding", so you could use Linear links, entering U1, U2 and U3 rigidity data. You'd be still in a linear approach. If you have share keys placed in such way that you avoid bearing yielding, you should add a Gap link to simulate the shear key. I would never use models from posts #4 and #5, because they increase secant rigidity and lead to erroneous bearing behavior. The increased rigidity must be provided by the Gap link. Multillinear Plastic links should be used only in Time History analysis cases, if share key collapse is considered. The bearings in this case would be responsible for transferring all horizontal forces from deck to foundations. I would still choose for U1 a linear behavior, and for U2 and/or U3 a Hysteretic behavior according to the desired scenario.
Once links are defined, the easier part is to draw them, first of all creating nodes to represent your bearings and your share keys, 2 per element. Afterwards, using "Draw" --> "Draw 2 joint link" and choosing the desired property, place your links accordingly.
Regards!
You can use either Linear Links or Multilinear Plastic links, depending on your needs. (Go to "Define" Menu --> "Link Support Properties"). I'd say that if you're modeling for service limit state analysis, you would try to keep your bearings away from "yielding", so you could use Linear links, entering U1, U2 and U3 rigidity data. You'd be still in a linear approach. If you have share keys placed in such way that you avoid bearing yielding, you should add a Gap link to simulate the shear key. I would never use models from posts #4 and #5, because they increase secant rigidity and lead to erroneous bearing behavior. The increased rigidity must be provided by the Gap link. Multillinear Plastic links should be used only in Time History analysis cases, if share key collapse is considered. The bearings in this case would be responsible for transferring all horizontal forces from deck to foundations. I would still choose for U1 a linear behavior, and for U2 and/or U3 a Hysteretic behavior according to the desired scenario.
Once links are defined, the easier part is to draw them, first of all creating nodes to represent your bearings and your share keys, 2 per element. Afterwards, using "Draw" --> "Draw 2 joint link" and choosing the desired property, place your links accordingly.
Regards!