The connection between box culvert is one of the most important elements to the quality of underground pipeline.
There are two common connections are widely used in projects. One is connecting with the longitudinal steel bar, the other one is connecting with male & female joint (without steel bar).
1.Connecting with longitudinal steel bar.
Build a hole for the steel bar when precast the box culvert, and connect each box culvert withthe steel bar and tension the bar, then box culverts are connected into one whole pipeline. This process used to compress the rubber gasket, seal the gap and resist the differential settlement of the ground.
the longitudinal connection could be two box culvert, and also could be used in multiple box culverts to improve efficiency.
Anchoring fasten method in longitudinal connection as drawing below. there is the hole in the anchoring sheet. after the tensioning of steel bar is done, and anchoring work has been finished, fill concrete grout into that hole to prevent the steel bar from going rust.
Longitudinal steel bar connection could be "All in one connection " or "Adjacent connection", diagram as below:
2. connecting with male & female joint (without steel bar)
Connecting with male & female joint (without steel bar), rely on the rubber gasket between the gap of male & female joint to seal.
This kind of connection could be used in Jacking-in project.
If we want to enlarge the distance of jacking, steel joint box culvert would be a better option.