Non linear Behavior of Hogging Moment Zone of Inclined Web Steel box Composite Girder

Abstract:

Two experiments for inclined web steel box composite girder were carried out to investigate the non elastic behavior of the hogging moment zone at the intermediate supports of continuous girder. Tests were made of the deformation of the girder along the longitudinal direction, strains distribution on various sections, formation and propagation of concrete cracks, slips between steel girder and concrete and bearing capacities of these experimental specimens. Experiment results show the specimens behave non linearly most time though they behave linearly at the beginning of the loading. Additionally, the reinforcement ratio affected the mechanical behavior of the inclined web steel box composite girder significantly. The stiffness of the composite girder with less reinforcement ratio decreased rapidly and caused steel yield earlier, while excellent mechanical behaviors were presented in inclined web steel box composite girder with proper reinforcement ratio. Comparison between the testing results and relatively designing method of composite girder indicates that the simplified discounting stiffness method in code GB50017 2003 for calculating the deflection of inclined web steel box composite girder is safe and feasible. Large bearing capacity reservation exists in inclined web steel box composite girder when the bearing capacity with concrete crack width 0.2 mm is taken as its normal service state bearing capacity.

Key words:steel box composite girder; inclined web; hogging moment zone; concrete cracking