Nonlinear Finite Element Analysis of Concrete Structures

- 8 -
arbitrarily located reinforcement bars and membranes. Linear
displacement fields are used in all elements resulting in perfect
bond between concrete and steel. Based on Galerkin's method,
the fundamental equations in the finite element displacement
method are derived in section 4.1. Readers familiar with
the finite element method may dwell only with the important section
4.2.2 dealing with different aspects of consideration to
cracking, with the introduction of section 4.3 where reinforcement
elements are described, and with the general computational
schemes as given in section 4.6.
The very important section 5 contains some examples of analysis
of concrete structures. The following structures were analysed
up until failure and compared with experimental data:
(1) panels with isotropic and orthogonal reinforcement loaded by
tensile forces skewed to the reinforcement. The analysis focuses
on aspects of reinforcement bar modelling and in particular
on simulation of lateral bar stiffness;
(2) a thick-walled closure for a reactor pressure vessel. It
represents a structure, where large triaxial compressive
stresses as well as cracking are present. The influence of
different failure criteria and post-failure behaviours is
investigated;
(3) beams failing in shear. Both beams with and without shear
reinforcement are considered, and of special interest are
aggregate interlock, secondary cracks, influence of the magnitude
of tensile strength, and dowel action;
(4) the Lok-Test which is a pull-out test. The influence of the
uniaxial compressive strength, the ratio of tensile strength
to compressive strength, different failure criteria and
post-failure behaviours are investigated and special interest
is given to the failure mode.
Moreover, this section shows that a finite element analysis may
offer unique possibilities for gaining insight into the loadcarrying
mechanism of concrete structures.
Finally section 5 demonstrates that the AXIPLANE-program in