Due to the growing significance of structural theories concerning the composite structure
analysed and designed plastically, this paper introduces a new optimisation method
for controlling the plastic behaviour of a full-scale composite integral abutment
bridge by employing complementary strain energy of residual forces that existed within
the reinforcing rebars. Composite bridges are structures made of components such as
steel and concrete, which are frequent and cost-effective building methods. Thus,
various objective functions were used in this work when applying optimum elasto-plastic
analysing and designing the composite integrated bridge structure that was tested
experimentally in the laboratory. In contrast, the plastic deformations were constrained
by restricting the complementary strain energy of the residual internal forces aiming
to find the maximum applied load and the minimum number of steel bars used to reinforce
the concrete column part of the structure. The numerical model employed in this paper
was validated and calibrated using experimental results, which were considered inside
ABAQUS to produce the validated numerical model, using concrete damage plasticity
(CDP) constitutive model and concrete data from laboratory testing to solve the nonlinear
programming code provided by the authors. This paper presents a novel optimization
method using complementary strain energy to control the plastic behaviour of a full-scale
composite integral abutment bridge, with the original contribution being the incorporation
of residual forces within reinforcing rebars to limit plastic deformations. Following
that, a parametric investigation of the various optimisation problems revealed how
models performed variously under different complementary strain energy values, which
influenced the general behaviour of the structure as it transitioned from elastic
to elasto-plastic to plastic; also results showed how the complementary strain energy
value is connected with the amount of damaged accrued in both concrete and steel.
