Structures

Field Investigation of Ultra-High Performance Concrete Piles

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Abstract

In response to the recent calls for increasing service life of bridges and optimizing structural systems by the American Association of State Highway Transportation Officials (AASHTO), a field investigation was conducted in Iowa to evaluate the application of Ultra-High Performance Concrete (UHPC) on two test piles. Comparing other pile materials, UHPC has excellent durability characteristics and very high compressive and tensile strengths. The UHPC piles were designed with dimensions and weight similar to that of a reference steel HP 250×85 pile. The first test pile (P3) was 13.7 m (45 ft) long while the second test pile (P4) consisted of two 4.6 m (15 ft) sections welded end to end at a structural steel splice. Both piles were driven into a Wisconsin glacial till. The surface was characterized using a Standard Penetration Test and a Piezocone Penetrometer Test. Driveability analysis was conducted using Wave Equation Analysis Program (WEAP). The responses of both piles during installation and subsequent five restrikes were monitored using a Pile Driving Analyzer (PDA) with subsequent signal matching analyses using CAse Pile Wave Analysis Program (CAPWAP). Immediately after all restrikes, a vertical static load test was performed on P3. Both driveability analysis and PDA confirmed that the maximum pile stresses were well below the allowable driving limits. No visible structural damages to both piles were observed during driving and restrikes. The analytical results reveal that the axial resistances of P3 and P4 increased by about 98% and 70%, respectively, in 6 days after the end of driving. Comparing the axial resistance determined from the static load test based on the Davisson failure criterion, the axial resistance of P3 was about 3% over-estimated using PDA and 6% under-estimated using CAPWAP. The field test verifies the performance of UHPC piles and facilitates the application of UHPC on production piles.

Keywords: pile, load test, WEAP, PDA, CAPWAP, UHPC

How to Cite:

Ng, K. W., Garder, J. & Sritharan, S., (2016) “Field Investigation of Ultra-High Performance Concrete Piles”, International Interactive Symposium on Ultra-High Performance Concrete 1(1). doi: https://doi.org/10.21838/uhpc.2016.54