Abstract: The invention relates to a device for straightening bridges that have had their lower girders bent by trucks passing underneath having loads higher than the clearance afforded by the bridge. The invention contemplates using a threaded rod with two clamping members to engage both the bent beam and a rigid part of the bridge to as to gradually bend the beam back into alignment by rotating a nut portion on the rod so as to turn the rod and allow one clamping member to move slowly along the rod. The clamping members have a portion designed to engage the flange area and thereby allow firm engagement of the beam by the straightening device.