Fiber-reinforced polymers (FRP) reinforcements have become one of the most used construction materials during the last decade. ACI Committee 440 is leading the writing of design standards and guidelines and is sponsoring these full sessions. Four 2-hour sessions will highlight and collect the most recent research, development, and application of FRP reinforcement in the concrete industry. Numerous important topics related to external and internal FRP reinforcement will be presented.
(1 Identify the new acceptance criteria (AC521) developed under IBC Section 104.11 on how FRP bars and meshes as secondary reinforcement of non-structural concrete members are evaluated to show compliance with the provisions of the IBC;
(2) Summarize how reliability analysis of compression-controlled flexural FRP reinforced concrete members are designed using CSA S6, CSA S806, and ACI 440.1r standards;
(3) Recognize how GFRP reinforcements are used in seawall concrete application, and assessment of life-cycle analysis compared to conventional steel-reinforced caps;
(4) Explain how to provide evidence for proposed draft code provisions that can be practically implemented in typical design situations; and identify situations in which proposed draft code language may require modification;
(5) To learn about the structural design used for GFRP-RC piles. Field-collected data on pile resistance, stresses, and integrity are presented;
(6) To learn how to calculate and predict the shear strength design models for fiber-reinforced concrete deep beams.
This session has been approved by AIA and ICC for 2 PDHs (0.2 CEUs). Please note: You must attend the live session for the entire duration to receive credit. On-demand sessions do not qualify for PDH/CEU credit.
Building Code Compliance of FRP Bars and Meshes Used as Internal Reinforcement for Non-Structural Concrete Members
Presented By: Mahmut Ekenel
Affiliation: ICC Evaluation Service, LLC.
Description: Advances in technology have opened doors for building construction with new materials that are lightweight, efficient, noncorrosive, and reliable in terms of durability without a sacrifice in strength and performance. One of these technologies is the use of FRP bars and meshes in concrete members as internal reinforcement. Although FRP bars as structural reinforcement in concrete members have been successfully utilized in building and bridge projects (i.e., slabs, beams, etc.) for the past three decades; recently, there has been an interest in using FRP bars and meshes as secondary reinforcement for non12 structural concrete members such as plain concrete footings, concrete slabs-on-ground, and plain concrete walls in lieu of code-compliant conventional temperature and shrinkage steel reinforcement. Because the use of FRP bars and meshes as secondary reinforcement is not within the provisions of the International Building Code (IBC), the predominant building code in the United States, an acceptance criterion (AC521) has been developed under IBC Section 104.11. This paper explains the requirements of AC521, and how FRP bars and meshes as secondary reinforcement of non-structural concrete members are evaluated to show compliance with the provisions of the IBC.
Reliability of Compression-Controlled Flexural FRP Reinforced Concrete Members Designed Using CSA S6, CSA S806, and ACI 440.1R: Comparison and Resistance/Strength Factor Calibration
Presented By: Fadi Oudah
Affiliation: Dalhousie University
Description: The use of fiber reinforced polymer (FRP) in structural engineering applications is challenged by the need for increasing the market competitiveness of FRP as compared with conventional reinforcing material. The market competitiveness of FRP can be enhanced by optimizing the design provisions of FRP reinforced concrete elements in relevant design codes and standards using structural reliability methods. The objectives of this research are to (1) evaluate and compare the reliability of compression-controlled flexural concrete members reinforced internally using FRP designed using the Canadian Highway Bridge Design Code (CSA-S6-19), the Design and Construction of Building Structures with Fiber-reinforced Polymers Standard (CSA-S806-17), and Design and Construction of Structural Concrete Reinforced with FRP bars Guideline (ACI440.1R-15); and (2) recommend FRP material resistance factor and strength reduction factor for the respective codes/standards based on a unified target reliability approach. Reliability analysis using Monte Carlo simulation indicates that the reliability index associated with a flexural design using ACI440.1R-15 is about 20% greater than the average reliability index of similar beam and slab sections designed using CSA S6-19 and CSA S806-17 (equates to 150 times greater probability of failure for sections designed using CSA S6 and CSA S806). The recommended material resistance factors for CSA S6 and CSA S806 and the strength reduction factor for ACI 440.1R based on the reliability analysis conducted in this research are 0.80, 0.85, and 0.75, respectively, for a unified target reliability indexes of 4.0 and 3.1 for beams and slabs, respectively. Structural designs based on the recommended values yield consistent reliability indexes among the three codes/standards.
Assessment of GFRP-RC Seawall Caps Using Life Cycle Cost (LCC)
Presented By: Roberto Rodriguez
Affiliation: University of Miami
Description: Traditional seawall construction and maintenance present a challenge to municipalities due to their reduced service life in aggressive marine environments. Combined with the challenges associated with climate change, there is a need to deploy new material technologies to provide more economical and safe solutions. In 2020, a seawall replacement project in Florida was constructed utilizing glass-fiber-reinforced polymer (GFRP) reinforcement as part of the concrete seawall cap construction. This provided an opportunity for the analysis of economics using Life Cycle Cost (LCC) methods. Field recorded data collected by the contractor on productivity rates were combined with the materials cost to perform this study. Structural capacity of the seawall cap in relation to demand is quantified to provide a comparison to the steel reinforcement alternative. When compared to steel reinforced seawall caps, the GFRP counterpart outperformed the steel-reinforced counterpart of several return period analyses. This article also provides an overview of the GFRP quality acceptance procedure carried out and provides an overview of other projects that have implemented composite reinforcement for this application type in the past.
Implementation of GFRP-Reinforced Concrete Draft Code Provisions
Presented By: Isaac Higgins
Affiliation: Mackin Engineering
Description: The American Concrete Institute (ACI) currently has an approved design guideline for FRP-reinforced concrete - ACI 440.1R-15 Guide for the Design and Construction of Structural Concrete Reinforced with FRP Bars. Work is in progress to develop a consensus-based design code for GFRP-reinforced concrete consistent with ACI 318-14 where possible. The code language is expected to generally follow the principles developed in the ACI 440.1R-15 Guide, with a number of significant changes that have resulted from more recent research (e.g., changes to design limits) and the need to develop provisions in areas that ACI 440.1R-15 does not address (e.g., requirements for torsion). The proposed changes have not yet been vetted in practical design situations, so their impact is still to be fully explored. Design examples consistent with proposed draft code language have been developed and their solutions examined to understand the impact that proposed code language may have on the design of GFRP-reinforced concrete members. This paper discusses selected design examples to: (1) provide evidence for proposed draft code provisions that can be practically implemented in typical design situations; and (2) identify situations in which proposed draft code language may require modification.
Design and Driving Performance of Two GFRP-Reinforced Concrete Piles
Presented By: Roberto Rodriguez
Affiliation: University of Miami
Description: Glass fiber reinforced polymer (GFRP) reinforcement shows promise as an alternative to other non-corrosive reinforcing systems for coastal marine application. Designers are reluctant to use new material systems without guidance or case studies demonstrating successful implementation. For the case of precast concrete piles, the current practice is prestressing with carbon steel strands. In this paper, a seawall replacement project in South Florida allowed for the demonstration of the use of reinforced concrete (RC) piles using GFRP bars and spirals. The field performance of the GFRP-RC piling system was validated by collecting data during driving by means of a pile driving analyzer (PDA). The measured internal stresses in the pile were compared with code requirements and concrete compressive strength determined from laboratory tests. The structural design used for these GFRP-RC piles and field-collected data on pile resistance, stresses, and integrity are presented and discussed in this paper.
Assessment of Shear Strength Design Models for Fiber-Reinforced Concrete Deep Beams
Presented By: Ahmed Bediwy
Affiliation: University of Manitoba
Description: Deep beams are common elements in concrete structures such as bridges, water tanks and parking garages, which are usually exposed to harsh environments. To mitigate corrosion-induced damage in these structures, steel reinforcement is replaced by fiber-reinforced polymers (FRPs). Several attempts have been made during the last decade to introduce empirical models to estimate the shear strength of FRP-reinforced concrete (RC) deep beams. In this study, the applicability of these models to predict the capacity of simply supported deep beams with and without web reinforcement was assessed. Test results of 54 FRP-RC deep beams and 31 steel/FRP-FRC deep beams were used to evaluate the available models. In addition, a proposed model to predict the shear strength of FRP-FRC deep beams was introduced. The model was calibrated against experiments conducted previously by the authors on FRP-FRC deep beams under gravity load. The model was capable of predicting the ultimate capacity with a mean experimental-to-predicted value of 1.04 and a standard deviation of 0.14.