Study on the Reasonable Alignment of the Steel Truss Concrete Composite Continuous Rigid Frame Bridge

The alignment of steel truss concrete composite continuous rigid frame bridge (STCR) has a significant influence on the distribution of internal bending force. In the negative bending moment section of STCR, the bottom chords are in compression state. These bottom chords are compression and bending members, which mechanical characteristics are somehow similar to that of the main arch of the open spandrel arch bridge. The bottom chord of STCR in the mid-span is in tension while the arch in the mid-span of open spandrel arch bridge is still in compression. On the basis of the method that determines the reasonable alignment of open spandrel arch bridge, a segmental pressure line method is proposed to determine the reasonable alignment of STCR. Results of the example show that the proposed method is simple and efficient, it can significantly reduce the internal bending force of each member, and improve the internal force distribution state of STCR.