Bridge operating agencies

From the main beam and side beams, divided into single girder and double girder bridge bridge categories. Single girder bridge by a single span girders and located on both sides of the end beam composed of two dual-beam bridge girders and by the end beam components. Main beam and side beams rigidly connected to the wheels at both ends with end beam for supporting the run on the elevated bridge. Main beam welded rails for lifting trolley. Bridge girder structure type more typical are:
1 box-shaped structure
(1) Hand Pallet Truck box-shaped double beam is widely used in a basic form, the main beam from the upper and lower flange plates and sides of the vertical web composition, trolley rails arranged on the flange plate on the center line, and its simple structure, easy to manufacture, suitable for mass production, but the larger self.
(2) Partial rail box double side rail box girder and single girder cross-section are from the upper and lower flange plates and unequal thickness of primary and secondary webs composition, trolley rails arranged in the main webs top box Short body stiffener save where partial rail box girder by a single wide-flange box girder instead of two main beams, weight smaller, but more complex manufacturing.
2 four truss structure
The four combined into a closed space plane truss structure, the upper surface of the horizontal truss generally paved walkway plates, light weight, stiffness, but compared with other structures, size large, more complex manufacturing, fatigue strength is low, has been less production.