Launching Gantry System is designed according to features of precast concrete simply supported beam. Today, we take one example of segmental box girder Launching Gantry. This method of launching gantry system composes of main beam, nose beam, front support leg, rear support legs and temporary legs, trolley and transverse shifting mechanism etc.
Suspension construction of whole span in segments is adopted. Front and rear support legs bear all the external force. Erection procedure as following:
Trolley feed the segmental girder below the segmental launching gantry system.
Beginning from the pier cap, lifting the girder and suspend it onto the main beam and one by one lifting all girders and suspend.
After roughly adjust and accurate adjust positioning, finish temporary pre-stressing.
Permanent pre-stressing inside the box girders is conducted.
Front and rear support legs jack the hydraulic cylinder to lower the segmental launching gantry system 200mm, transfer the stress of crane and piers.
Dismantle the spreader and suspender, finish the girder erection.
