Quasi-static responses estimation of a cable-stayed bridge from displacement data at a limited number of points

Cable-stayed bridges are one kind of long-span bridges and are widely used. The girder of a cable-stayed bridge is slender and connected to the pylon with a cable. The girder of the cable-stayed bridge is subjected to a significant compressive force compared to other bridge types because of cable tension. The compression force can cause buckling failure of the girder. When a cable or girder fails, the equilibrium condition of the entire bridge is changed. For these reasons, it is important to monitor the structure condition to proactively detect bridge defects. In many cases, the acceleration or displacement of the structure is used to detect the defects. If as much displacement information as the degrees of freedom can be obtained, it is possible to estimate the condition of each of the members of the structure. However, as only a limited number of displacements can be acquired, SRALD 1.0 was proposed in order to overcome such limitations. In this research, SRALD 1.0 is used to analyze the responses of a cable-stayed bridge using a limited number of displacements. Limited numbers of displacement responses are used to estimate deformed shapes of the structure. In addition, the cable tension, axial force, and bending moment of the girder are estimated to analyze the characteristics of SRALD 1.0. Finally, the application of SRALD 1.0 was validated by comparing its algorithm with spline interpolation method, which is widely used to show the deformed shape of the structure.