Materials Performance

NOV 2017

Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.

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17 NACE INTERNATIONAL: VOL. 56, NO. 11 MATERIALS PERFORMANCE NOVEMBER 2017 Information on corrosion control and prevention The failed segment at Pier 22. Photo courtesy of Ali Abu-Yosef, Pivot Engineers. Tier 2 for further monitoring; and the remainder were tagged as Tier 3, which required no further action. Tier 1 pier repairs included installing new concrete drill-shaft foundations connected to the existing piers, which WisDOT says will provide adequate corrosion protection with a design service life of 75 years. "Only f ive [piers] were exposed to the corrosive f ly ash layer," Abu-Yosef says. "The repair engineer, Michael Baker International [Coraopolis, Pennsylvania], decided wisely not to rely anymore on steel piles, and instead installed concrete drill shafts. That transferred the loads from the pile caps to the concrete drill shafts. Because concrete is susceptible to premature distress in high-sulfate soils, they have installed inert sleeves around the drill shafts to isolate the concrete from the f ly ash soil." Tier 2 piers had monitoring probes and steel coupons installed in 2014. Data are collected from the probes during ty pical biannual bridge main- tenance inspections, and the probe data are supplemented by sec- tion loss measure- ments from the coupons. "What we did was install monitoring sen- sors to gauge corrosion rates using electrical resistance probes," Abu-Yosef says. "The probes contain a sacrif icial piece of metal. If it corrodes, a change in voltage is detected. That will tell you the corrosion rate over time. After three, f ive, and 10 years, it should give us an indication of how fast the corrosion is actually happening." The bridge reopened on January 5, 2014, just over three months after the Continued on page 18 NO SALT. NO RUST. ONE STEP.

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