Abstract: Structural steel-concrete composite beams used for building and bridge constructions are commonly subjected to simultaneous actions of positive and negative bending. However, there are relatively few numbers of experimental tests on this aspect; hence more behavioural researches on composite beam under negative bending are needed. This paper investigates the behaviour of steel-concrete composite beam under negative bending considering the load-deflection, shear connection and concrete-steel interface slip characteristics. Four composite beam specimens were tested under negative bending by carefully turning them upside down before a single point loading was applied at the mid span to simulate the mechanical behaviour of continuous composite beams at the internal supports, while another remaining two beam specimens were subjected to positive bending in order to compare some distinct behaviours between composite beams subjected to negative and positive bending. Experimental results showed that the arrangement of shear connectors influence strength and deformation characteristics of composite beams. The reduction of the stiffness of the shear connectors in the cracked concrete influences the composite beam stiffness and the overall negative plastic moment capacity. However, it was noted that for a composite beam subjected to positive bending the positive plastic moment capacity is effectively utilised. Finite elements models created using SAP 2000 software were used to validate the experimental results trends and vice versa.
Keywords: Composite beams, Negative bending, Load-deflection, Slip, Interaction, Finite element, SAP2000.
Title: Experimental Study of Steel-Concrete Composite Beams Subjected to Negative Bending by Point Loading at Mid-Span Considering Load – Deformation Characteristics
Author: Sylvester O. Osuji, Oziegbe I. Oria-Usifo
International Journal of Civil and Structural Engineering Research
ISSN 2348-7607 (Online)
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