Nonlinear Finite Element Analysis of Concrete Structures

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inforcement bar modelling. The influence of the shear stiffness
that might be attributed to reinforcement bars will receive particular
attention. As discussed previously in section 4.3, relative
displacements parallel to a crack plane result mainly in
local bending of the bar as well as in local crushing of the
concrete in the vicinity of the bar. However, these phenomena
are not simulated in the program. Instead it is possible to consider
some bar shear stiffness and the present section evaluates
the use of such a shear stiffness. Obviously, use of the original
shear modulus G of the bar material is expected to overestimate
the bar stiffness parallel to the crack plane and
therefore the modulus KG is applied where 0 < K < 1. T e influence
of different K-values is investigated in the following.
For this purpose we consider a quadratic panel with uniform
thickness as shown in fig. 1. It appears that reinforcement bars
are located in two directions perpendicular to each other. This
isotropic reinforcement consists of deformed 0 8 bars (nominal
2
area = 53.3 mm ) with a distance of 100 mm. This corresponds to
a reinforcement ratio = 0.666%. A uniform tensile loading corresponding
to the force F is applied and the reinforcement forms
the angle a to the loading direction. For a = 0, 10°, 20 , 30
and 40
this arrangement was tested by Peter (1964), and of
special interest are the vertical displacement