Reliability analysis of long-span CFST narrow arch bridge's stability

Tongwamen Bridge is a 238 m span, half-through, concrete-filled steel tubular (CFST) X-type arch bridge. The width of the deck is only 10 m, yielding a width-to-span ratio of 1/23. 8. The plane truss type section rib was adopted, which was made of two CFST chords and web member system. The lateral stability is the key issue to this bridge. Firstly, based on the CFST main theory, the method for performance functions of local stability failure mode is discussed, considering material performance, structure geometrical parameter and indefinite calculation model. Five performance functions of typical arch rib are put forward for a maximum load case. According to the analytical result, the reliability meets the necessity of object reliability index, bridge structure member of highway. Secondly, the response surface method is employed to obtain the reliability index of lateral stability. The arch ribs are safe enough to keep excellent stability. The calculated result provides the foundation that the plane truss rib would be a competitive solution for a long-span, narrow, CFST arch bridge.