Structural Engineering

Aerospace Biological Civil Geotechnical Mechanical

FRP-Confined RC Columns with Transverse Steel Confinement: From Finite Element Modeling to Reliability-Based Calibration of Design Equations

Michele Barbato headshot
Seminar Speaker
Michele Barbato, Ph.D
Seminar Date
Wednesday, Mar 2, 2022 - 12:00 pm
Seminar Location - Room
Speaker Bio

Dr. Michele Barbato is a Professor in the Department of Civil & Environmental Engineering at the University of California, Davis. He is also co-director and co-founder of the UC Davis Climate Adaptation Research Center, and director of the CITRIS Climate Initiative of the CITRIS and the Banatao Institute. He received his Summa Cum Laude “Laurea” degree in Civil Engineering from the Sapienza University of Rome (Rome, Italy) in 2002, and his M.S. and Ph.D. in Structural Engineering in 2005 and 2007, respectively, at the University of California, San Diego. He is a licensed PE in Louisiana and in Italy. 

Dr. Barbato is an expert in both traditional and innovative construction methodologies and materials, with particular emphasis on new recycled and green materials. His research includes modeling, analysis, and design of structural and infrastructure systems subject to earthquake, wind, storm surge, and wildfire hazards. He is active in the development of performance-based methodologies in earthquake, wind, and hurricane engineering, as well as in multihazard applications. Dr. Barbato’s research also embraces nonlinear finite element modeling and analysis of structural systems, random vibration theory, structural reliability analysis, multihazard assessment and mitigation under current and changing climate conditions, and life-cycle cost optimization of resilient/sustainable structures subject to multiple hazards. Dr. Barbato’s research aims to develop safer, economic, and more rational design procedures, accounting for natural and man-made hazards, which support the development of sustainable infrastructures and more resilient communities under current and changing climate conditions.

He is the author of more than 200 technical publications. He received the 2007 ICASP10 Overseas Student Scholarship, the 2009 ASCE Moisseiff award, the 2011 European Association of Structural Dynamics Junior Research Prize, the ISSE-12 Best Paper Award for Young Experts, the 2020 ASCE Sacramento Section Fredrick Panhost Structural Engineer Award, and the 2020 Walter L. Huber Civil Engineering Research Prize, as well as several teaching and service awards. He was elected SEI Fellow and EMI Fellow in 2019, and ASCE Fellow in 2021. Dr. Barbato has served as the Chair of the ASCE EMI Dynamics Committee in 2017-2020 and of the ASCE SEI Multihazard Mitigation Committee in 2018-2021, and is currently the Chair of the ASCE SEI Performance Based Design of Structures Committee, an associate member of the ASCE 7-22 Wind Loads Subcommittee, and a member of the EMI Board of Governors. He is an associate editor of the ASCE Journal of Architectural Engineering, ASCE Natural Hazards Review, ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems: Part A-Civil Engineering and Part B-Mechanical Engineering, and the specialty editor in Earthquake Engineering and Structural Engineering for the Journal of Research on Engineering Structures and Materials.


External confinement of reinforced concrete (RC) columns with fiber-reinforced polymer (FRP) wraps is a technique extensively used for strengthening and retrofit of structurally deficient columns. Due to modern design codes’ requirements, new RC columns tend to have higher amounts of both longitudinal and transverse steel when compared to older columns. The confinement effect produced by the externally-bonded FRP acts simultaneously with the confining mechanism of the existing internal reinforcing steel, thus increasing the vertical load capacity and ductility of the member. The transverse steel confinement contribution can be significant, although it is generally ignored in existing design guidelines for FRP wrapping, potentially leading to over-conservative retrofit design. For these structures, the concurrent confinement effects of FRP and steel needs to be properly quantified and modeled in order to represent the actual mechanical behavior of FRP-confined columns.

An FRP-and-steel confined concrete material constitutive model for use in finite element (FE) analysis is developed and validated against experimental data available in the literature. This model is able to accurately model the combined confinement effect of FRP and internal steel reinforcement on the structural monotonic, cyclic, and/or dynamic response of FRP-confined RC columns. This newly developed confined concrete model is used to propose a modification to the ACI 440.2R-17 design equation of FRP-confined RC circular columns subjected to axial loading. The proposed design equation is calibrated through a rigorous structural reliability analysis approach, in which the probability distribution of the axial capacity model is generated via Monte Carlo simulation based on advanced nonlinear FE response analyses. The proposed design equation is thoroughly validated for multiple realistic combinations of design parameters’ values. A practical design procedure based on the newly proposed design equation is also presented using a realistic application example.


Scroll Up