Civil Infrastructure Seminar Series: Renewal of Aging and Deteriorated Reinforced Concrete Bridges with Titanium Alloy Bars
Friday, December 7, 2018 - 12:15pm

DateFriday, December 7, 2018, 12:15 pm,

Location: Engineering Building, Room 310, 1930 SW 4th Avenue, Portland, OR, 97201

Abstract: Many older reinforced concrete (RC) bridges are identified as deficient in flexure and/or shear when applying modern design standards for their evaluation. The deficiencies most often are due to inadequate amounts of reinforcing steel and/or poor reinforcing details. To prevent the need for expensive replacements it is desirable to extend their service life by strengthening them. Titanium alloy bars (TiABs) offer a new opportunity to strengthen existing bridges that was not previously investigated. TiAB’s combination of strength, ductility, durability, and ability to form mechanical anchorages are essential characteristics for effective repair and retrofit applications. Round titanium alloy bars with a unique surface deformation were specially developed for strengthening applications. Research using TiABs to strengthen RC bridge girders in both flexure and shear was undertaken in the laboratory through full-scale tests. Using the findings, the flexural strengthening techniques were applied to a bridge overcrossing of a major interstate highway in Oregon. This first ever application of TiABs to a RC bridge was completed at a 30% cost savings compared to alternative designs. In addition to strengthening bridges for gravity loads, recent research findings demonstrate the ability of T to retrofit seismically deficient columns thereby transforming them into high-performance seismically resistant members. Based on this research, an LRFD design guide was developed and an ASTM material standard is now approved.

Speaker Bio: Christopher C. Higgins is a Professor and the Drinkward Professor of Structural Engineering in the School of Civil and Construction Engineering at Oregon State University. His field is structural engineering and he directs the Structural Engineering Research Laboratory at OSU. He holds a B.S.C.E. from Marquette University, M.S. from The University of Texas at Austin, and Ph.D. from Lehigh University. He is a registered Professional Engineer. Dr. Higgins has been at Oregon State University since 2000 where he teaches graduate and undergraduate courses and conducts research in structural, bridge, and earthquake engineering. He has received numerous teaching and research awards including: the Loyd Carter Award, Engelbrecht Faculty Award, the EERI/FEMA Graduate Fellow in Earthquake Hazard Reduction, and the AISC Special Achievement Award. Dr. Higgins’ research expertise is in experimental mechanics and he has extensive experience testing and evaluating structures subjected a wide range of loading conditions including: seismic, wind, ponded water, ocean waves, static, fatigue, and dynamic loads. He has conducted research on steel, concrete, timber, composite, hybrid, and polymer structural materials. Dr. Higgins and his research teams have successfully conducted experimental and analytical studies on hundreds of full-size laboratory and in-service structures and components. His research findings have been implemented into practice and adopted into design specifications.