Elastomeric isolator connection

[Olivaw]

I'm designing the connections of a seismic elastomeric isolator, but I'm having problems with yielding of the base plate. I'm getting about 1 3/4'' thick. What I've seen so far on other connection details of isolators, is about 3/4'' thick.

I'm using AISC Design Guide 01. For base plate yielding of round HSS and pipes you use 0,8 times the diameter. But since there is a lot of compression on top of isolators, it results on a lot of moment on the base plate. I can't get it lower than 1 3/4'' thick. It makes me think that Im not using the right approach to design the connection. But I haven't been able to found an specific example on elastomeric isolator connection design.

If any on you have experience designing these type of connections, please share any advice.

 

[HTURKAK]

The subject formulas at AISC Design Guide 01 is applicable for HSS ( round or rectangular) . In your case , you may calculate the bearing stresses assuming rigid base assumption and design the base plate for bending and shear. I would prefer FEM modelling .




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