Sources: Federal Highway Administration; CP staff
As part of its Long Term Bridge Performance Program, geared to studying and collecting field data on structures completed since 1960, FHWA has delivered its first timeline tracking materials progress, “National Changes in Bridge Practices for Reinforcing Bars.”
The agency reached out to the National Concrete Bridge Council to better understand important rebar developments. A “Reinforcing Bars” timeline traces specifications from 1910 through 2015, and calls out development of specialty reinforcements to address issues related to corrosion and/or higher tensile strength. Specialty reinforcing bars include epoxy-coated, galvanized, dual-coated, low carbon-chromium, and stainless steel.
Most recently, the document cites the issue of new or fully revised standards: ASTM A775, Standard Specification for Epoxy-Coated Steel Reinforcing Bars; ASTM D3963/D3963M, Standard Specification for Fabrication and Jobsite Handling of Epoxy-Coated Steel Reinforcing Bars; and, ASTM A1094/A1094M, Standard Specification for Continuous Hot-Dip Galvanized Steel Bars for Concrete Reinforcement. It also references ASTM A1035/A1035M, Standard Specification for Deformed and Plain, Low-Carbon, Chromium, Steel Bars for Concrete Reinforcement, to which have been added types CL and CM, available in grades 100 and 120 and formulated with lower chromium contents than the current type CS.
“National Changes in Bridge Practices for Reinforcing Bars” can be obtained here. The SAFTEA-LU highway bill-seeded Long Term Bridge Performance Program targets a representative, nationwide sample of highway bridges to help engineers and practitioners better understand structure performance. FHWA officials envision a collection of data-driven tools, including predictive and forecasting models to help bridge owners optimize structure management.