An experimental study on the flexural behavior of local prestressed steel–concrete composite continuous box beams

Abstract

The flexural bearing capacities of three composite continuous box beams with different prestressing degrees were tested and studied to investigate the influences of local prestressing bundles on the deflection, relative slip of interface, strain, and redistribution of the internal force of the steel–concrete composite continuous box beam. Results show that the arrangement of local prestress can not only improve the bending stiffness at the mid-span of the composite continuous box beam, but also significantly enhance the ductility. In the design process of the local prestressed composite continuous box beam, the influence of the slip at the middle support should be fully considered, and the deflection could not be taken as a control factor. The internal force redistribution of the local prestressed continuous box beam is lower than that of the ordinary continuous box beam, but it still has good plastic internal force redistribution. The number of prestressing bundles in the negative moment region is the main factor that affects the internal force redistribution of the middle support.

Fatigue Experiment Study on Internal Force Redistribution in the Negative Moment Zone of Steel–Concrete Continuous Composite Box Beams

“…Based on the experiment of Zhang et al [ 22 ], nine 1:8-scaled models of continuous composite box beams were fabricated according to the Chinese code (JTG 3362-2018) [ 28 ]. FSCB-0 was used for the static comparison test, and FSCB-1 to FSCB-8 were used for the fatigue tests.…”

“…Previous studies have shown that the formation of the plastic hinge will cause obvious internal force redistribution at the middle support of continuous composite box beams [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Table 6 shows the measured force (not including self-weight) at the middle support under the target number of loading cycles, with an applied static load of 340 kN.…”

“…Wu et al [ 21 ] studied the feasibility of improving the crack resistance of composite beams by releasing the interfacial slip effect within the negative bending moment zone. Zhang et al [ 22 ] studied the redistribution of the internal force of a steel–concrete composite continuous box beam and found that the influence of the slip at the middle support should be fully considered. Su et al [ 23 ] studied the redistribution of shear stress under prestressing force in the negative moment zone.…”