Abstract:
Through a contractor-initiated Change Proposal by Facca Incorporated on a bridge contract for the Ontario Ministry of Transportation (MTO), as-tendered steel H-piles were replaced with newly designed prestressed/precast Ultra-High-Performance Concrete (UHPC) piles to support one abutment of the Lily River Detour Bridge in Northern Ontario. Six UHPC piles with 300 mm (~12â€) deep sections, based on previous successful development and testing of a tapered H-shaped pile at Iowa State University, were designed and installed on batter at one abutment. The opposite abutment was supported by six steel H-shaped battered piles driven to bedrock, as tendered. As the site contained occasional boulders and the design intent to drive the piles to bedrock, the UHPC piles were fitted with steel shoes for the first time. All piles were successfully installed using a D19-42 diesel hammer, reaching the targeted load bearing capacities. After the replacement bridge was constructed, the detour bridge was removed and the UHPC piles were extracted with a vibratory hammer to examine the conditions of the piles.
Since the above successful implementation of the first UHPC piles, Facca has continued to optimize the prestressed-precast UHPC piles to be a cost-effective solution for bridge foundations. The optimization considers the use of the supplementary cementitious materials to lower the carbon footprint of the UHPC mix, while maintaining the superior strength and durability properties.
This presentation will provide details of the innovative design of the piles, fabrication and driving of the piles, and pile splice design and testing. As well, a comparison of the environmental impact of the UHPC and steel piles will be provided, and future plans for design, testing and implementation.