This thesis deals with the behaviour of Partially Encased Composite (PEC) and
Concrete Filled Tubes (CFT) subject to cyclic loading by means of experimental and
numerical investigations. It addresses a number of design and assessment issues
regarding the ductility capacity and ultimate response of PEC and CFT beam-column
elements.
Experimental results from ten tests including seven cyclic tests on PEC members and
three cyclic tests on CFT members are presented. The set-up, instrumentation and
member configuration are described followed by a full description of the experimental
results. The composite members were subjected to cyclic gradually increasing lateral
displacements along with varying levels of axial load simulating various gravity
effects. Particular attention was given to the ultimate failure mode. To this end, in
order to enhance their ductility, six of the seven PEC specimens were provided with
special transverse links with the purpose of delaying the onset of local buckling. The
effects of these improved details are discussed with regards to their influence on
ductility as well as other structural response parameters.
Numerical Finite Element models developed to simulate the response of the
specimens are proposed and validated against the experimental results. This allowed
for a more detailed assessment of local buckling effects in composite members.
Furthermore, the FE models were used to conduct parametric studies on key design
aspects related to the stiffness, capacity and ductility of composite members.
Based on the experimental results and numerical studies, the implications of the
finding of this work on design consideration for PEC members and CFT members are
discussed.