1. Control the positioning of prestressed tendons
Lay the prestressed reinforcement strictly according to the design requirements, and ensure the accurate laying position, so as to achieve no twisting and straight plane. When the tension end is set, the prestressed tendon and the anchor plate should be ensured vertical, and the pressure plate should be fixed firmly after the column is installed to prevent displacement when the mixed soil is poured.
Check the correlation with the non-prestressed tendons is based on the coordinate position of the curved prestressed tendons. When the prestressed tendons conflict with the non-prestressed tendons or other pipes, ensure that the prestressed tendons are laid according to the design position, and the position of the ordinary steel bars is properly adjusted. The correct prestressed pipe position is strictly prohibited to cut the steel bars no matter how adjusted. In the actual construction, if there is a large displacement of steel bars in two parts, we can use the same type of tic-bar reinforcement to strengthen this part, and the requirements of curve coordinates should be met when making and arranging steel bars in the construction process.
Before lashing the made steel bars, the position of the steel bars and the edge line of the beam should be marked on the cushion layer, and the lashing should be tied in the order of the overlapping of the steel bars, the special bracket should be firmly welded on the stirrup in the beam according to the design position of the steel strand, and several special brackets should be arranged in the steel cage, and the steel strand bundle should be slowly placed in the process of pulling by the end and transporting by the other end. Then the screw reinforcement and pressure plate and other components are installed. The upper steel bar is inserted into the prestressed bar in turn, and fixed firmly after checking the position.
The important basis to ensure the quality of the prestressed system is the installation quality of the prestressed reinforcement and the crossing pipe, and the construction process should be strictly controlled. Only in this way can the wave pipe be ensured without plugging, leakage, deformation and displacement after pouring concrete.
Before use, strictly check the pipe to see if there is damage, repair can be repaired in time, can not be repaired abandoned, the end of the bellows must be removed before installation, careful inspection, so that the pipe positioning is accurate, to prevent left and right movement, floating and sinking phenomenon, the position deviation control within the specification requirements.
During the operation of electric welding near the pipeline, it is necessary to cover the corrugated pipe with wet sack or thin iron sheet to avoid damage to the bellows. During the construction process, pay attention to the corrugated pipe to avoid contact with sharp objects such as iron parts, so as not to scratch.
When pouring concrete, try to avoid the contact between the vibrator and the crossing pipe.
2. Control the quality of grouting operation
In post-tensioned prestressed concrete members, the joint work problem of structural concrete and the corrosion prevention problem of prestressed tendons are solved by filling the space between the pre-stressed tendons and the pre-stressed tendons with pressure grouting. If the prestressed tendons are in the state of multi-span bending and non-horizontal tilting and stripping, the space for the existence of cement slurry is formed after the evaporation of the water in the slurry. Here the prestressed tendons lose protection.
The corrosion damage of prestressed concrete columns is very sensitive under high stress, and the safety and durability of prestressed concrete structures are affected by the section defects of the corroded parts of prestressed tendons.
Therefore, the anti-corrosion performance of prestressed tendons, the safety performance and durability of prestressed structures are directly affected by the quality of grouting.
Therefore, the quality problems such as the shrinkage of the cement paste after hardening and the separation of the pore wall, the cement slurry is full at the end, there are gaps, and the strength of the cement slurry after hardening does not meet the standard requirements should be paid enough attention and solved in time.