Parametric Analysis on Incrementally Launched Construction for Concrete Box Girder

The structural behavior of incrementally launched bridges in the construction stages depends on different parameters. Internal force of main girder is influenced by the dead load and stiffness of main girder, the length and stiffness of launching nose. Parametric analysis on the effect of internal force of an 8x60m-span concrete continuous box girder bridge was carried out. The results show that bending moment increases following the increase of weight and stiffness of corresponding segment of main girder. The phenomenon is even more obvious in the negative bending moment region of main girder segment nearby the launching nose. The bending moment of main girder reduces significantly when the stiffness ratio among launching nose and main girder is less than 0.15. While, the negative bending moment of main girder reduces significantly when the length ratio among launching nose and main span is more than 0.58.