Flexural Performance of Post-Combined Ultra-High Performance Concrete Composite Bridge Deck with Grouped-Stud Arrangement

Abstract:

To investigate the effects of grouped-stud arrangement on the mechanical performance of the post-combined UHPC （ultra-high performance concrete） composite deck， bending load tests and finite element parametric analysis based on the UHPC plastic damage model were conducted for a composite deck specimen with averagely spaced studs and a post-combined composite deck specimen with grouped-stud connection. The test results show that the failure characteristics of these two specimens are UHPC plate crushing and steel U-rib bottom yielding. The elastic flexural stiffness of the specimen with grouped-stud connection and the one with averagely spaced studs are 232 kN·mm^-1 and 213 kN·mm^-1 respectively， and the bearing capacity are 2 154 kN and 2 049 kN respectively. The maximum interface slip value of these two specimens is less than 0.2 mm before the U-rib yielding. These two specimens have the same strain distribution and strain development pattern. The cross-sectional strain distributions of the specimens approximately obey the plane section assumption. The parametric analysis results show that there is no significant change in the bearing capacity and elastic bending stiffness when the grouped-stud hole spacing is increased from 600 mm to 1 200 mm. When the grouped-stud hole size is the same， the hole spacing has no significant effect on the bonding state of UHPC bonding interfaces. The 600 mm spacing of grouped-stud holes can better ensure the safety of studs and the cross-sectional combination effect than the 1 200 mm arrangement. Comparing the flexural performance of parametric models， the longitudinal spacing of 600 mm combined with the 2×3 grouped-stud arrangement in the hole is more favorable to improve the stress state of the post-combined steel-UHPC composite deck under positive bending.