Title:
Reliability-Based Code Development for Carbon Fiber- Reinforced Polymer-Strengthened Circular Reinforced Concrete Columns
Author(s):
Juscelina Rosiane Ferreira, Peterson Araujo Quadros, and Sofia Maria Carrato Diniz
Publication:
Structural Journal
Volume:
121
Issue:
3
Appears on pages(s):
215-230
Keywords:
carbon fiber-reinforced polymer (CFRP) confinement; circular cross sections; design codes; existing structures; reinforced concrete (RC); reliability index; short columns; strengthening
DOI:
10.14359/51740490
Date:
5/1/2024
Abstract:
Concrete confinement using fiber-reinforced polymers (FRPs) has
been vastly used for strengthening of reinforced concrete (RC)
columns. The strengthening of RC columns belongs to the realm of
existing structures, which has been recognized as distinct from the
design of new structures. Code development efforts for the strengthening of RC columns should follow a reliability-based framework similar to the one used in the code development for new structures. In this process, a number of additional issues arise: the mechanical model of FRP confinement representing existing RC columns, the statistical description of the design variables, and the target reliability to be attained. In this study, the reliability levels of 288 axially loaded, FRP-RC short columns of circular cross sections,
strengthened according to ACI 440 guidelines, are assessed. Monte
Carlo simulation is used in the probabilistic description of column
strength and computation of the probability of failure. An FRP
confinement model that explicitly accounts for the presence of
transversal steel and attendant model errors associated to the estimation of ultimate stress and ultimate strain are used in the computation of the FRP-RC column capacity. The values of the reliability index are in the range of 3.92 to 4.61, satisfying the target reliability suggested for both new and existing structures. The research findings presented herein provide further support for the efforts of ACI Committee 440 in the development of standards related to the FRP strengthening of RC columns.