Engineering a construction method to allow rapid removal of existing superstructure components, and erection and installation of new prefabricated components. The contractor’s preference was to use mobile cranes to complete all removal and erection work, in order to avoid the higher costs of more specialized equipment and to maximize flexibility on the job site. It is rare for mobile cranes to be set up and operated on a bridge structure, as the weight of a crane plus the load it is lifting will far exceed the design live loads for bridges. To add to the challenge, the schedule requires cranes to be set up both on the existing structure and on newly installed superstructure components.
Entuitive enabled the use of cranes for all removals and erections by individually analyzing both the existing and new structure under more than 3,000 crane load cases. This work was made possible through the development of a parametric model of the structure which facilitated both the analysis and the drawing production. Sixty-six removal and erection plans were detailed, using cranes with capacity between 145 and 200 tonnes to replace 1.15 km of the Gardiner Expressway.