In Narita City, Chiba, Japan, Denzai Engineering Corporation successfully employed an Enerpac JS-250 Jack-up system for the removal of a 150-ton overpass road bridge. This significant operation was carried out as part of the preliminary groundwork preceding a planned runway extension at Narita International Airport. By deploying the JS-250 towers mounted on Self-Propelled Modular Transporters (SPMTs), the bridge removal was executed overnight, effectively minimizing traffic disruptions on the bustling Higashi-Kanto Expressway.
The expansion of Runway B at Narita Airport necessitated the construction of a new grade-separated intersection connecting the Higashi-Kanto Expressway with the extended portion of Runway B. The removal of the bridge played a crucial role in facilitating the temporary rerouting of the Higashi-Kanto Expressway during the intersection’s construction.
The constraints of limited space ruled out the possibility of using a conventional crane for the bridge removal. Consequently, Denzai Engineering Corporation opted for the Enerpac JS-250 Jack-up system due to its exceptional lifting capacity, stability, and compact design. Two JS-250 towers were strategically mounted on each of two SPMTs, with a steel support platform positioned on top. This platform served as the foundation for supporting the 21-meter-long and 5-meter-wide bridge deck as it was skillfully elevated and transported to a designated rigging location near the Expressway.
The Enerpac JS-Series jack-up system operates as a versatile multi-point lifting system, featuring four jack-up towers, with one located beneath each corner of the load. The lifting frame of each jack-up tower contains four hydraulic cylinders that raise and stack steel barrels. The load ascends in increments as barrels are inserted via an automated system and assembled to form the lifting towers. Managed by a single operator, these towers execute lifting and lowering operations simultaneously, with the jack-up system’s synchronous technology ensuring the load remains perfectly balanced throughout the process.
