Nonlinear Finite Element Analysis of Concrete Structures

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ted horizontal displacements grossly overestimate the experimental
values. However, the agreement for vertical displacements
is fair even though the tension stiffening effect is not considered
and the predicted failure loads are in very close agreement
with the experimental results.
5.2. Thick-walled closure
This section deals with the analysis of a model of a thickwalled
closure for a reactor pressure vessel. The testing of
this closure model termed LM-3 (Lid Model-3) is described in
detail by the writer and Andersen in (1977a) and some selected
results have been presented by them in (1975) and in (1977b,
The considered closure is a structure where large triaxial compressive
stresses as well as cracking are present. It represents
therefore a unique opportunity to evaluate the applicability of
the program. The influence on the predicted structural behaviour
of different failure criteria and post-failure behaviour is investigated.
The geometry, loading and boundary conditions of the LM-3 closure
are shown in fig. 1, where all quantities are in mm. It
appears that the closure is loaded by a uniform pressure and
that the forces through a heavy steel flange are supported by
struts. These 40 struts are loaded uniformly in compression and
the inclination to vertical is as an extremely good approximation
fixed during loading. A steel liner assures tightness, and
Fig. 5.2-1: Configuration and loading of the LM-3 closure.