Concrete cutting personnel in Inner MongoliaIn precast beam and T-beam construction, a specific process may be required based on different design philosophies. The process is as follows: first, a temporary support is set up at the pier top, followed by the placement of the precast box beams and T-beams on the temporary support. After the wet joint, wet hinge, negative bending moment tension, and grouting processes are completed, the temporary support is removed to complete the system conversion. In the past, brick and wood were used as temporary supports. Currently, two methods are generally employed:
1. The temporary support for sulfur mortar is pre-installed with heating wires, which melt the sulfur mortar through electrical heating to dismantle the temporary support and complete the system conversion.
2. Sand tube and sand box temporary supports: Select an appropriate diameter of steel pipe to manufacture the sand tube,焊接a steel plate plug at the bottom to prevent leakage, and leave bolt holes on the side, which are sealed with bolts. Fill the tube with suitable fine sand, with the top of the fine sand slightly lower than the diameter of the sand tube's piston. The piston can be made of concrete, wood, steel plate sealed steel pipe, etc., ensuring the piston top is 3-5cm higher than the sand tube. By loosening the bottom bolts, release the fine sand inside to dismantle the temporary bridge supports, thus completing the transition of the beam and slab system.
The temporary supports are constructed on prefabricated box girders and T beams. After the wet joints, wet joints, negative moment tensile forces, and grouting processes are completed, the temporary supports of the bridge are removed to complete the system conversion. After the overall production of the bridge, the temporary supports need to be removed, and the beams are placed on long-term supports to complete the overall construction of the bridge.
