Shape-finding rigid connection method and its application in steel truss suspension bridges

To overcome the difficulties of establishing rigid connections between segments of steel truss suspension bridges, in this study a shape stiffness connection (SFRC) method is proposed and an attempt is made to apply it to the Kahaluo Jinsha River Bridge (a steel truss suspension bridge in Sichuan, China). First, the basic principles using the unstressed state approach are elucidated and the proposed method is validated by leveraging the deflection theory. Insights from practical projects substantiate the accuracy of the proposed method. The influence of secondary dead loads on the rigid connection timing during the lifting process is investigated. The results show that this method does not affect the internal force state of the structure at completion stage, and ensures the rigid connection forces are consistently below 200 kN, thereby reducing the difficulties in forming rigid connections. In addition, the optimal timing for rigid connections advances with the increase of the secondary dead loads. A functional relationship between the secondary dead load proportion and the percentage of lifted segments to the total girder segments after completing the rigid connection is established. Through applications to additional real-world bridges, the reliability of the predictive equation is further confirmed. These findings highlight the potential advantages of the SFRC method in practical engineering projects.