Abstract:
Design of large span continuous bridges and building structures supporting high
magnitude concentrated loads using capacity design concept should consider the presence
of shear in beams. Current Ethiopian design code (ESEN 2015) specifications for design
of continuous composite beam do not fully consider effect of reduction in maximum moment
capacity due to the presence of shear. This may result in the uneconomical section design.
In this paper, using finite element analysis, moment-shear interaction property was
investigated, shear-moment interaction curves developed and the maximum shear and
moment values estimated for 21 continuous steel concrete composite beam models.
Independent variables were cross-section of steel beam ೢ
௧ೢ
ratio values 90,120 and 150
as well as concrete slab reinforcement ratio ( 𝜌௦
) of 0, 1%, 2.5% and 3%. Section of the
beam around middle support regions were studied. Geometric non-linearity, material non linearity and full shear connection conditions were modeled. Model validation done using
experimental test results obtained from literature review.
Analysis results disclosed that finite element model’s maximum load value obtained was
95.6% similar with corresponding maximum load of experiment data. Under combined
effect of moment and shear, 𝜌௦ of concrete slab and the ೢ
௧ೢ
significantly influenced the
ultimate load and failure modes of composite beams, all FEA output values fall outside the
moment–shear interaction curves suggested in Ethiopian Building Code. Moment–shear
interaction curves varied little with the increasing of slab reinforcement ratio (𝜌௦
) than
increase in values of web cross-section slenderness ratio ( ೢ
௧ೢ
).
