When the Virginia Port Authority needed to replace three ship-to-shore (STS) container cranes, the challenge was dismantling the cranes at their existing height along the waterfront. Working with our strategic partners, Crofton Industries (Crofton) and RLT Engineering (RLT), Engineered Rigging (ER) assisted in the execution plan and selection of the lifting equipment needed to meet the operational requirements of the project.
RLT devised a concept and strategy to safely hold the main boom and trolley beam of the crane in place while it was cut free from the portal gantry legs and then lower that entire section to the bottom seaside and landside cross beams for dismantling. The group determined that four (4) 200-mton strand jacks, from Engineered Rigging’s rental fleet would provide the lifting capacity to safely secure the load during the cutting process and then control the lowering sequence from the 150’ elevation.
First, a structural analysis of the STS crane structure was performed by RLT to determine if the gantry portal legs and main frame could support this lifting solution. With limited drawings and crane information, it was calculated that the entire upper section weighed approximately 600 tons inclusive of the main front boom, mast, backstay bracing, machinery house, trolley beams, hoist, trolley & spreader and operator cabin.
Engineered Rigging supplied the lift equipment from its rental fleet and installed the various components including the strand jacks, four hydraulic pumps, load anchors, wedges, strand and mounting grillage which would be used for lowering the main boom and trolley beam section. In addition, two certified equipment operators and technicians from Engineered Rigging were integrated into the on-site project team to support efforts throughout the process.
To ensure proper loading and load distribution, the ER crew engaged and checked the system before Crofton initiated the cutting procedures at the reinforced shoulder girders. Once the upper cross beams were free and clear, our technicians lowered the boom and trolley assembly until it was secure on the bottom landside and seaside cross beams. The loads for each jack were monitored throughout the lowering process by the SCC computer system to ensure the controlled loading and synchronized lowering. The Crofton crew then secured the boom segments to the bottom landside and seaside crossbeams so that the dismantling operations could begin.
The original strand jack system was then disassembled and re-assembled for the next portal crane. The cutting and controlled lowering process was repeated until the booms from all three cranes were safely lowered and secured by the Crofton project team.
The collaborative efforts of the three companies along with the specialized equipment technology proved to offer a successful, safe, innovative and cost-effective solution for the VPA project challenges. Engineered Rigging is proud to have contributed our heavy lifting expertise by supplying the right equipment and on-site technical support needed by this project.