Exploration of a New Rigid-Frame Arch Bridge Constructed by Vertical Downrotation

Techno-economic analysis of the conventional concrete arch bridge and continuous rigid frame bridge was performed. A new rigid-frame arch bridge structure spanning over deep valley and river in mountainous areas was proposed based on the advantages of both above. Then its structural characteristics, downrotating vertically construction technology and techno-economic benefits were analyzed. For the rigid-frame arch bridge, half the arch rib is constructed in pillar on two banks respectively at first, and then two halves are rotated down vertically, close up and form a whole arch rib. The rigid-frame arch structure has been successfully applied in Gulu Middle School Overpass Bridge over Chongqing Yulin highway. The researches and engineering application show that the rigid-frame arch bridge is simple, safe and efficient in construction without broad constructing yards, and behaves good mechanical properties, structural integrity and aseismatic ductility. Its downrotating vertically construction method can be extended to large and medium span bridges constructed rapidly without scaffolding.