Influence Law of Axis Deflection on the Mechanical Properties of Steel Stranded Short Slings in Arch Bridges

Most cable arch bridge damage accidents are caused by bridge collapse due to fracture of the short sling of the arch bridge. The service life of the short sling is much lower than the design life, mainly resulting from the action of vehicles and temperature, and the arch rib and the bridge floor will have relative displacement along the bridge direction, which leads to the emergence of bending stress due to the different axes at both ends of the short sling, forming local stress concentration. The stress concentration is coupled with corrosion to accelerate the damage to the sling. To study the influence of shaft deflection on the mechanical properties of short slings of steel strands in arch bridges, this study analyzes the distribution law of the shaft deflection angle of arch bridge slings under the action of vehicle and temperature loads for a medium-bearing arch bridge with a main span of 560 m. The results show that under different vehicle and temperature loads, the axial deflection angle of the short sling is the largest, and the closer it is to the center of the span, the smaller the axial deflection angle. The static and fatigue properties of 1, 3, 7, 9, 12, 19, and 27 strands of whole bunch extruded strand slings were simulated and analyzed under a 0.45σb force when the axial deflection angle of the strand slings was 0 mrad, 10 mrad, 20 mrad, and 30 mrad. The results show that the ultimate tensile properties, breaking strength, and fatigue life of the strand slings decreased to a certain extent with increasing shaft deflection angle. The accuracy of the finite element models is verified by the ultimate tensile test and the fatigue test. This study explores the bending deflection results of the short slings of arch bridges due to the different axes of the upper and lower anchorages and provides the necessary theoretical support for the design and fatigue life estimation of the short slings of arch bridges.