Formwork supporting system for bridge construction

A formwork supporting system for bridge construction comprises a steel bar, channel steel, a sand box support, an I-shaped steel main beam and an I-shaped steel distribution beam which are sequentially arranged from bottom to top, the I-shaped steel main beam and the I-shaped steel distribution beam are perpendicular to each other, and a construction platform is in lap joint with the I-shaped steel distribution beam. A rotatable C-shaped clamp is arranged at the mutual lap joint position of the I-shaped steel main beam and the I-shaped steel distribution beam, the rotatable C-shaped clamp comprises a horizontal base, an L-shaped rotating piece and a lead screw connected to the L-shaped rotating piece in a threaded mode, a vertical side rod of the L-shaped rotating piece is rotatably connected with the horizontal base, and the lead screw penetrates through the horizontal side rod in a threaded mode. The transverse I-shaped steel main beam and the longitudinal I-shaped steel distribution beam are fixed through