The hybrid-steel concrete connection for seismic behaviour
was studied using the numerical models. Finite element
analysis was employed as a numerical tool to investigate
the behaviour of joints. Concrete was modelled using 2D
elements, whereas truss elements are employed for steel bars.
The connection plates are modelled as 2D elements with steel
properties and the DIANA software was used as the modelling
tool. Comparisons with the experimental results indicated that
the finite element models used in this study were suitable,
and the corresponding investigation results were reliable.
The predicted results matched well with the experimental
observations. The connection plate modelled using 2D plate
elements and neglecting the concrete on either side of it showed
a satisfactory performance in the structural analysis. Based on
the parametric study results, the following conclusions can be
drawn
(1) The FE results showed that axial load was beneficial to the
joint’s performance. Axial load ratios N/Ag f 0
c = 0 to
0.3, influenced energy dissipation and story shears of the
joints adding in a better behaviour. However, an axial load
ratio beyond N/Ag f 0
c > 0.3 was detrimental to the joint’s
performance.
(2) Connecting plate thickness at joint influenced the energy
dissipation and deflections during the cyclic loading. The
increase in plate thickness gradually increased the energy
dissipation and strength of the joint. With ductility of
the joint remaining the same, the specimens showed an
optimum benefit of around 11% enhancement in strength
followed by better energy dissipation when plate thickness
was 14 mm. However, any increase in thickness beyond
14 mm, showed no marked improvement in energy
dissipation, and it also reduced the ultimate number of load
cycles attained.
(3) Continuation of beam bottom reinforcement increased the
ultimate strength of the specimens and reached an optimum
value of approximately 8% when the reinforcement was
0.75% of Ag. The specimens also showed good energy
distribution and smooth stress distribution. It was observed
form the FE analysis that beyond 1% of Ag, the advantage
almost ceased with no further enhancement in strength.