Structural behaviour of indeterminate continuous reinforced concrete beams with shear reinforcement and asymmetric loading

Despite statically indeterminate continuous reinforced concrete beams being commonly used in most reinforced concrete structures, a limited number of studies have been conducted to explore their behaviour. In addition, there have been no studies that have investigated asymmetric loading ratios on multi-span continuous beams. To address this, two nominally identical indeterminate continuous reinforced concrete beams were tested, and their behaviour was evaluated using discrete and distributed sensing. The beams had two spans, were continuous across the central support, and had a point load applied at the centre of each span. The applied load on each span was increased at the same rate up to a service load of 200 kN (approximately 60 % of first yield). After that, the load on one span was held constant while the load on the other span was increased until failure. There was a 12 % difference in load carrying capacity despite the beams being nominally identical, which was thought to be due to the formation of a shear hinge in one of the beams. Crack development, which may have been influenced by shrinkage behaviour, may have played a role in the formation of the shear hinge. The Canadian concrete code (CSA A23.3) shear prediction, which predicted a ductile flexural failure, was found to be unconservative, with both beams being shear critical. The beam with the shear hinge had the lower test-to-predicted ratio of 0.72. • Tested reinforced concrete continuous beams with three supports and two spans. • 12 % difference in load carrying capacity despite being nominally identical beams. • Canadian reinforced concrete design code shear prediction may be unconservative. • Shear hinge prevented full central support moment capacity being achieved. • Cracking behaviour contributed to differences in ultimate behaviour.