Carl J. Larosche, Principal, Wiss, Janney, Elstner Associates, Inc.
Concrete is a material that continues to surprise us in many ways. Understanding the root cause(s) of distress and the methodology for determining the causation can and often does change direction. Mr. Larosche will provide three case studies involving concrete deterioration, corrosion and the potential impact on ductility and unanticipated consequences in design of reinforced concrete elements. The case studies highlight concrete material and chemical reactions, the influence of corrosion on the ductility of reinforced concrete structures, and will conclude with lessons learned with precast double tee elements.
In terms of the impact on corrosion affecting ductility, prior research studies by others have reported reduced ductility potential when corroded reinforcing bars were evaluated in a standard tension test; however, prior research had been limited in regard to the influence of corroded bars embedded in reinforced concrete elements. Based on past research results, reinforcing bars with section loss from pitting corrosion were judged to have reduced load-carrying capacity and ductility relative to non-corroded bars. The reduction in capacity was expected, as the actual area of steel (considerable amount of section loss) was reduced. Nevertheless, there was concern that the ductility findings of the standard tension test did not represent conditions in a reinforced concrete section.
Finally, Mr. Larosche will conclude with a discussion involving investigation of precast elements. To facilitate the architectural desires, precast engineers typically employ garages designed as shear elements with support of precast columns and inverted tee beams supporting precast concrete double tee beams. In an effort to reduce precast costs, designers have widened double tee widths, increased span lengths, and attempted to optimize materials. As a result, a number of structural concerns have occurred
About our Speaker: Carl J. "Chuck" Larosche, PE, F.ACI
Chuck is a Principal in the Austin office of Wiss, Janney, Elstner Associates, Inc. (WJE), an employee-owned architectural and engineering firm, where he leads the Structural Engineering Practice Area Group. With over thirty years of experience, Chuck is an industry leader in the fields of preservation and restoration of historic and existing structures, structural design, and investigation and evaluation of existing structures and materials; however, Chuck is equally well known for his contributions to the field of engineering and mentoring young engineers as he is for his engineering capabilities.
Mr. Larosche's diverse background includes structural design, investigation, and evaluation of existing structures and materials. He has successfully combined his broad construction background with his knowledge of material behavior in existing structures to provide rare insight and knowledge in the area of conventional reinforced concrete, pre-cast and post-tensioned concrete, masonry, and steel evaluation, including strengthening and repair of these materials.
Chuck received his Bachelors of Science in Civil Engineering and his Masters of Science in Structural Engineering from the University of Texas at Austin. His field of study was structural engineering with an emphasis on corrosion related distress. Prior to joining WJE, Chuck founded his own firm, Sparks, Larosche & Associates.
Mr. Larosche is a professional engineer registered in the State of Alabama, Arizona, Colorado, Florida, Idaho, Louisiana, Missouri, New Mexico, Oklahoma, and Texas and is currently in compliance with the respective Board of Professional Engineers’ Continuing Education Competency Program. Mr. Larosche is also a Certified Welding Inspector with the American Welding Society
