Movable formwork cast-in-place concrete box girder prestressed pipe blockage
The cast-in-place beam is constructed by penetrating the steel bundle into the bellows and then pouring the concrete. When the tension is applied, the first end is equipped with a jack, and the steel strand is swayed to observe whether there is a blockage. If there is clogging, use the irrigation method to detect the blockage: inject water from the grouting hole, calculate the approximate position of the blockage according to the amount of water injected, and drill the hole with a hammer to see if there is water flowing out to determine the specific position. Re-research measures to remedy the situation.
The main reason for the blockage of the pipeline is that the pipe joint is not handled well, there are small holes in the pipe wall or the concrete is not vibrated when the concrete is vibrated, and the slurry is leaked when the concrete is poured, and the mortar or cement leaking into the pipe The pulp has solidified. Precautionary measures: Before installing the bellows, carefully check for small holes. If it is found to be wrapped with tape, it is important to note that after the bellows is installed, when installing the top plate steel, use electric welding, and must be taken under the solder joints. The shielding measures prevent the welding slag from falling onto the bellows and burning through the bellows; pay attention to the joint installation quality of the bellows, the joint should be firm and smooth, without deformation, and the tape should be wrapped tightly without leakage.
Once the pipe is blocked, if the position is ascertained, if the blockage is not serious, the pipe can be cut from the outside of the beam. After the pipe is dredged, the iron sheet is lined at the opening of the bellows and then sealed with high-grade epoxy resin concrete. .
The above contents are compiled according to the problems encountered by the students in the actual work, for reference, if there is any problem, please communicate and correct in time.
Prestressed tendon installation of cast-in-place concrete box girder with movable formwork