Study On The Deformation And Stress State Of HTY Asymmetric Skew Half-through Steel Tube Arch Bridge

Abstract:HTY Bridge is an asymmetric skew half-through steel tube arch bridge with a span of1-90m. The longitudinal dislocation of two arch ribs is15.4m, and arch ribs and hangers to the longitudinal directionand transverse of the bridge are not symmetrical. There are four rows, each row has two supports in whole bridge. The angle of intermediate supports in line with the beam axis is43°. The beam of the HTY Bridge belong to the floating system longitudinally.The structure and the deformation and stress state of the bridge are very complex. In this paper, the deformation capacity and mechanical performance of the HTY Bridge under constructing state and completion state were analyzed, and the mechanical properties of the bridge under live load, using vertical hangers system or inclined hangers system, were compared and researched. The main work and results are as follows:1. According to the structural characteristics of the HTY Bridge,the finite element simulation method of the HTY Bridge was studied. The space grillage method was adopted to simulate the vertical and horizontal beam system. The arch rib steel tube and concrete at the foot of arch was simulated by space beam element.2. The suspender force of each arch rib under dead load was given after study. Because the arch to the direction longitudinal and transverse direction is asymmetrical, the forces in hanger of single arch acting the direction longitudinal horizontal force is difficult to balance. The forces in hanger of two arches given by this paper to the horizontal forces acting on floating beam is almost zero, single arch boom to the unbalanced force acting on the direction longitudinal is smaller, and unbalanced torque caused by two arch hangers reverse direction of horizontal force is smaller on the beam, it can be balanced by transverse horizontal force of supports.3. The construction process of the HTY Bridge was Optimized. The paper analyzes the deformation and stress state of the HTY Bridge both under construction state and worst-case of live load. The calculation results reveal that in the process of construction, only tension suspenders before removing support, or tension suspenders before and after, the results show that both methods are feasible, the working conditions of the bridge are safe, and the alignments of the bridge can meet the requirements.The strength and stiffness of the bridge also meets the requirements when the main forces act on the bridge.4. The deformation and stress state of the HTY Bridge under additional forces loads were analyzed and researched. The results reveal that the deformation and stess of the beam under temperature loads is approached to that under worst-case of live load. The maximum of transverse horizontal displacements in the main arch caused by Wind loads is48.6mm; The deformation and stess of the bridge have been less affected by non uniform settlements5mm of supports. The stress state of bridge is good when the main forces and additional forces act on the bridge together.5. The mechanical properties of the bridge under live load, using vertical suspender system or inclined hangers system, are compared and researched. The results show that the internal forces and displacement of main girder have a small difference in two hangers systems, but comparing with vertical suspender system, the peak internal forces and displacement of arch rib in inclined hangers system are smaller.The results of this article provide design basis for HTY Bridge, and are of reference value to other similar bridges. This paper has220graphs,14tables and64references.