... all external force at working.Steps to install girders:1. Girder transporter feeds girders under the bridge,2. Lifting trolleys firstly ... pier is completed, remove slings and boom, the installing girders is finished.(3). Longitudinal movement to cross girdersSteps to cross ... the machine to move forwards about 27.1m, finish crossing girders Transverse movement flange position is obligate on the front, ...