Tremuri equivalent definition - eesd-epfl/OpenSees GitHub Wiki
An element with an in-plane response equivalent to the one of a Tremuri macrolement can be defined through the flag “-tremuri”. The input structure is:
-tremuri $h $L $t $E $G $fc $mu $c $Gc $beta
Where:
| h | height of the macroelement (dimension in the axis direction, x) |
| L | length of the section (dimension in local direction y) |
| t | thickness of the section (dimension in local direction z) |
| E | Young’s modulus of masonry |
| G | Shear modulus of masonry |
| fc | compressive strength |
| mu | friction coefficient defining the peak strength |
| c | cohesion (Mohr-Coulomb force criterion) |
| Gc | parameter defining the pre-peak deformability in shear (see Gambarotta-Lagomarsino model) |
| beta | parameter defining the post-peak response (see Gambarotta-Lagomarsino model) |
In order to obtain an equivalent response to Tremuri, the central section is made linear elastic and its integration length is set to 0.01h. The end sections, accounting for all the deformability of the element, are created equal, with a nonlinear behaviour, and feature the nonlinear correction term accounting for crushing. They are assigned an integration length of 0.495h each. This produces an intended elastic stiffness bias, adopted to replicate exactly the in-plane response of the Tremuri element.
As the tensile strength is zero, the element can give convergence issues, or non-uniqueness of the solution, when subjected to traction: the problem, when relevant, can be masked by the use of a negligible elastic response that never vanishes. Consistently with the “spandrel” element instantiation, the flag “tremuriSpandrel” can be used to adopt the same approach.
The shear model that is applied is the Gambarotta-Lagomarsino model as implemented in Tremuri. The shear area is assumed equal to the entire gross sectional area.
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