Fatigue and Fracture Performance of a Pedestrian Bridge with a Circular Steel Tube Girder

Pedestrian bridges with I-shaped girders exhibit frequent construction errors and difficulties in the construction of curved sections because the bridges are composed of straight girders mounted on piers. Therefore, a pedestrian bridge utilizing circular steel tubes as the main girder, which is easy to construct and more economical, is proposed to resolve these problems. When steel pedestrian bridges are used for long periods, fractures can occur owing to fatigue in the joints between the main girder and the bottom support. Full-scale circular steel tube joint test units were fabricated and subjected to two million cycles of fatigue performance tests and one million cycles of fatigue fracture tests to quantify the fatigue behavior of a new pedestrian bridge design comprising circular steel tubes. Finite element analysis (FEA) was used to verify the results of the fatigue fracture tests. The proposed pedestrian bridge exhibited excellent stability in terms of fatigue behavior. Moreover, the fatigue fracture of the bridge was successfully predicted using FEA.