Mechanical behavior of steel truss bridge stiffened with rigid cables in construction stage

3D finite element numerical method was used to simulate the whole construction processes of steel truss bridge stiffened with rigid cables.Changing boundary conditions and imposing compulsory displacements on some nodes were applied to simulate system transformation and internal force adjustment respectively.Relaxing the longitudinal stiffness of an end of longitudinal girder was applied to simulate the effect of slotted holes.The internal forces and deflections were compared under six main conditions.Analysis result shows that rigid cables can participate in action with steel trusses more effectively through system transformation and internal force adjustment.Through internal force adjustment in longitudinal and lateral directions, the deviations of internal forces for the chords of middle truss and side truss, as well as that of midspan and sidespan, are less than 5%.Slotted holes set at both ends of longitudinal girder can avoid it taking part in longitudinal action prematurely, through which the internal force and deflection of main truss would increase by about 10%, while the maximum combined compressive stresses of longitudinal girder and floor beam would decline respectively from-271.1 MPa and-505.8 MPa to-63.0 MPa and-178.0 MPa, which are less than their allowable stress value 210 MPa.