Modular ELS Mega Truss Skidding System

Under CKR KTW Contract, one of the key construction activities is a 370m long Underwater Tunnel at Kowloon Bay. In traditional construction method for this marine works, struts are installed above water by workers welding struts and assembly structs by boat. It hence leads to considerable safety risks relating to working at height, hot works, demanding of heavy lifting above water and downing of worker. To reduce these substantial risks, an innovative system, Modular ELS Mega Truss Skidding System, is adopted for assembling, transporting and installing the struts at the marine section. The whole system involves modular ELS mega truss, a hydraulic system for heavy lifting and skidding and a Design for Manufacture and Assembly (DfMA) platform and working tower. The first two layers of the ELS struts are symmetrically designed as a truss consisting of numerous modules, which are prefabricated at off-site yard and delivered to the site by barge. Quality control is hence ensure at factory fabrication. These DfMA components are then assembled at the loading point of a platform by bolt-and-nut connection and skidded along a rail with hydraulic jack to the designed location of the struts for installation. This hydraulic skidding system reduces the use of pontoon and lifting plants for the ELS installation and increasing productivity. Prefabrication also minimises the risks on site such as reducing welding works. The working tower serves as a safe access and working platform for workers, providing a safe and controlled environment.