Fabrication and Experimental Testing of Prestressed UHPC H-Piles under Flexural and Shear Loading

Abstract

UHPC is a high-strength, robust material that is well-suited for a wide range of structural applications. Driven piles as a replacement for normal steel HP sections is one such application. Three UHPC H-shaped cross-sections (12 in., 14 in., and 16 in. deep) were developed as part of an ongoing research project to be similar in weight and performance to conventional steel H-piles. The 12-inch, 14-inch, and 16-inch depth UHPC pile sections composed of 8, 10, 16 - 0.6 in. diameter prestressing strands correspondingly, were designed using first principles while considering the tensile capacity of UHPC. 13 full-scale piles ranging in length from 6'-6" to 24' were cast at two precast facilities, with two different UHPC mixes. Pile examples were outfitted with multiple internal strain gauges and monitored during the curing, detensioning, and post-detensioning processes to capture transfer lengths and short-term losses. These losses are measured against current ACI and AASHTO code requirements. To describe the structural performance of the piling sections, they were tested to failure under various combinations of flexural and shear loading. The findings and lessons learned from fabrication and large-scale flexural and shear testing of the pile specimens will be presented.