Box Culvert Jacking

Box culverts can be jacked under surface infrastructure using techniques similar to pipe jacking. Box culvert installation can be used for underpasses, trafficable tunnels or water systems. Pre-cast or cast on site box culverts are jacked into position using high capacity hydraulic rams pushing from the launch side. Post tension jacks and cables are used to pull the culverts from the target side while excavation is carried out through the launch shaft portal. A “bond breaker” system is usually required to minimise the risk of dragging the surface structure in the direction of the jacking forces. The main benefit of this approach is that it offers an effective alternative to disruptive open cut techniques, conventional tunnelling methods being so close to the structures above. It also allows the above infrastructure to remain active during the course of work which significantly reduces potential disruption to services.