Summer 2021 | Vol. 3 | No. 2 W Failure Modeling of Post-Tensioned Concrete Bridges By Sammy Miles illiam Hartt, professor emeritus at Florida Atlantic University (Boca Raton, Florida, USA), has been studying post-tensioned (PT) bridges and modeling their tendon failures. PT construction is relatively new (<100 years old) and is commonly used because of its ability to change the integrity of bridges. PT construction has been evolving since it was first developed, in response to integrity issues that have been identified. However, there have been several failures within a few years of construction that have highlighted the need to better predict—and prevent— failures from occurring. PT construction has many advantages, including allowing longer spans, reduced construction time, thinner sections with a more streamline appearance, improved crack control, and overall cost savings compared to conventionally reinforced structures. 1 It generally consists of seven wire strands, in which six high-strength, high carbon steel wires conforming to ASTM A416 2 are spirally wound around a straight wire. These wires are subsequently stressed and relax over time. They generally use grouted tendons, comprising a number of seven wire strands. However, these strands can corrode and fracture from improper storage, construction issues such as water exposure during construction, and grout issues (including excess mix water, storage temperature, and storage time and Cl– contamination), 3 leading to tendon fail-ure and (if unaddressed) structural collapse. Failure Modeling of Post-Tensioned Concrete Bridges …………………… 1 New Study Examines Minority-and Women-Owned Businesses in Rail …………………………………………………………………………………… 2 View from the Hill: INVEST in America ………………………………………… 3 In-Service Assessment of Pile Wrapping Systems Using Sensors ……… 4 Composite Technology Partners Celebrate Reopening of Maine Bridge …………………………………………………………………… 8 Coating NYC’s Tribeca Bridge and Beyond …………………………………… 10 New Composite Bridge Showcases Sustainable Solution ……………… 13 California Commission Approves $2 Billion in Infrastructure Projects 15 NACE/SSPC Infrastructure Education Course Schedule ………………… 16 NACE/SSPC Infrastructure Reports & Standards ………………………… 19 NACE/SSPC Infrastructure Books ……………………………………………… 19
Infrastructure Insights Summer 2021: Page 1
