using Gap-Element to model compression only behaviour of strip foundation
using Gap-Element to model compression only behaviour of strip foundation
(OP)
My first time post here.
I am having a problem getting non-linear gap element to work in my SAP2000 (V17.1.1).
I have a simple RC portal frame with a lateral point load pushing the structure over. I have assigned the gap elements to the bottom of column to model compression-only behaviour of the strip foundation. I have set assigned non-linear behaviour in U3 direction with stiffness of 12000KN/m and gap of 0. U1 and U2 is fixed.
How come I am still getting a tensile force on one of the column>
Please help
I am having a problem getting non-linear gap element to work in my SAP2000 (V17.1.1).
I have a simple RC portal frame with a lateral point load pushing the structure over. I have assigned the gap elements to the bottom of column to model compression-only behaviour of the strip foundation. I have set assigned non-linear behaviour in U3 direction with stiffness of 12000KN/m and gap of 0. U1 and U2 is fixed.
How come I am still getting a tensile force on one of the column>
Please help





RE: using Gap-Element to model compression only behaviour of strip foundation
You have assigned non-linear behaviour to U3 direction, assuming that would correspond as default to Z direction... but it is not. With links, U1 represents its own longitudinal direction, while U2 & U3 are transversal directions.
You can check the orientation of your link displaying its local axes. In your case, the vertical direction corresponds to U1, so that's the value that should be assigned with the non-linear behaviour.
Or you could change the orientation of local axes to make U3 the vertical one.
RE: using Gap-Element to model compression only behaviour of strip foundation
RE: using Gap-Element to model compression only behaviour of strip foundation
In order to achieve compression-only behaviour at the link, should I be setting the gap length to 0? I don't quite know what this parameter represents when assigned as a single link (in comparison to double link).
RE: using Gap-Element to model compression only behaviour of strip foundation
If you set it to 0, the link shall be non-linear from the very beginning.
I can't see any difference between 1-joint and 2-joints links regarding this feature.
RE: using Gap-Element to model compression only behaviour of strip foundation