Selection of a Structural System for a Three-Tower Suspension Bridge of Maanshan Yangtze River Highway Bridge

Abstract

A three-tower suspension bridge has an additional middle tower and a main span when compared to the conventional two-tower suspension bridge. Restriction between main cable and middle tower top is weaker, and the force difference in the main cables on the two sides of the middle tower is large when one main span is fully loaded and the other one is not loaded. The main structure of the Maanshan Yangtze River High way Bridge over the left branch is a three-tower suspension bridge with main span arrangement of 2 × 1080 m. Four different structural systems could be chosen for a three-tower suspension bridge, which are: girder integral with the tower, girder pinned at the tower, half float system and full float system. The slip resistance stability of main cable, whole bridge structure stiffness, middle tower strength, stiffening girder internal forces, cable internal forces, reactions at the bearings, capabilities of resisting wind and earthquake, and so on are compared for these four structural systems. Results show that the girder integral with the tower is better than other structural systems and therefore is adopted for the Maanshan Yangtze River Highway Bridge.