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Structure Modelling
35
elastic phase permanence (E);
formation of a plastic hinge due to reaching the moment value limit (P);
collapse of the section after exceeding the maximum allowable rotation value (R).
Please note that the shear force characteristics are constant along theelement due to
the concentrated actions in the nodes. These are calculated so as to guarantee
the’equilibrium with the moments developed at the ends.
With regards to the shear resistance check, this is performed by comparing the calculated
shear value, which is compatible with the equilibrium of the element on the basis of the
moments developed at the ends, with that limit. If this check is not satisfied, and the
shear resistance is less than that calculated then theelement will be evaluated as
collapsed, and hence no longer able to support forces, due to the fragile breakage
mechanism hypotheses.
Please note the dependence of the maximum resistance limits (for bending and shear) on
the normal compression strain. It follows that these comparison values are not a constant
property of theelement. They can vary during the analysis, following redistribution of the
actions towards the elements which contribute together tothe total equilibrium of the
structural system.