Stretch-drawing method for prestressed ribs of concrete bridge

The invention discloses a method for tensioning a prestressed reinforcing rib of a concrete bridge, which comprises the following steps: A, determining primary stress and tensioning force according to the design requirement, and mounting a jack on two ends of the prestressed reinforcing rib; B, loading the jacks in stages to tension the prestressed reinforcing rib; C, when the loading reaches the designed tensioning force, holding the force for 5 to 30 minutes, returning oil, anchoring automatically, and moving back from the top to finish the tensioning for the first time; D, placing the prestressed reinforcing steel for 5 to 10 days; and E, repeating the steps B and C to finish the tensioning for the second time. The method for tensioning the prestressed reinforcing steel of the concrete bridge tensions two ends of the prestressed reinforcing rib and performs the tensioning for the second time so as to better ensure that the elongation and the effective prestressing of the prestressed reinforcing rib after t