Reuse of Existing Piles Study – Hwy 417-PPT Presentation

PPT Presentation

Pdf Summary

The study evaluated whether existing piles at the Woodroffe Avenue and Richmond Road bridges on Ontario Highway 417 could be reused during rapid bridge replacements. Corrosion concerns and seismic performance requirements could otherwise necessitate supplemental deep foundations, adding cost and construction time.<br /><br />Investigations included exposing piles beneath wingwalls, cleaning them by abrasive blasting, and assessing corrosion through visual inspection, pit-depth measurements, ultrasonic testing, and soil analyses. The team mapped pitting and estimated cross-sectional area loss. Measured pitting rates were 0.11 mm/year at Woodroffe and 0.07 mm/year at Richmond, while calculated average site corrosion rates were 0.015 mm/year and 0.007 mm/year, respectively. The study recommends using a conservative rate of 0.015 mm/year for both sites and other nearby bridges.<br /><br />The in-situ assessments enabled the design team to validate the piles’ predicted 75-year service life. The estimated cost of supplementary investigations was $400,000, compared with projected construction savings of $1.65 million from avoiding additional piles and abutment modifications—an estimated net saving of $1.25 million. Reusing the piles would also reduce impacts on the public and the environment.

Keywords

bridge pile reuse

Ontario Highway 417

corrosion assessment

rapid bridge replacement

seismic performance

deep foundations

ultrasonic testing

service life validation

cost savings

environmental impact