RAPID BRIDGE REPLACEMENT OF CONCRETE RIGID FRAME BRIDGES UTILIZING HEAVY-LIFT CONSTRUCTION TECHNIQUE

摘要

A rapid bridge replacement (RBR) method was designed and used for the replacement of the Highway 401 twin overpasses at Cornwall Centre Road in Cornwall, Ontario. This RBR project was the first heavy-lift and move of large, approximately 1400 tonne, reinforced concrete rigid frame bridges in Ontario. The new structures were prefabricated in staging areas near the sites and moved to their final locations by specialized heavy-lift construction equipment, comprising self-propelled modular transporters (SPMTs). For the westbound lane structure, a segmental approach where a top rigid frame component and two bottom footing components were constructed separately and connected at their final location was adopted to reduce the weight of the structure due to limited space available for SPMTs. For the eastbound lane structure, the entire rigid frame integrated with footings was constructed and transported by specially configured SPMTs and lifting system that included climbing jacks to lower the entire structure 1.5 m to its final position after transportation. A three-dimensional, linear elastic finite element analysis was utilized for design due to the high skew (51.5°) of the rigid frames to ensure the strength and stability of the structures during lifting and transportation, and their final backfilled service condition. The cost for RBR construction was approximately 25% higher than that of the conventional construction. However, the project confirmed that it is feasible to use the RBR method of construction for complex rigid frame bridges to significantly reduce the duration of traffic impacts for the construction of these types of structures.