Title: Implications of ACI 440.11 Code Provisions on the Design of GFRP-RC Footings

Author(s): Zahid Hussain, Antonio Nanni

Publication: Structural Journal

Volume:

Issue:

Appears on pages(s):

Keywords: building Code; footing; GFRP reinforcement; reinforced concrete; shear

DOI: 10.14359/51742142

Date: 7/31/2024

Abstract:
The first edition of ACI 440.11 Building Code was published in September 2022, where some code provisions were either based on limited research or only analytically developed. Therefore, some code provisions, notably shear and development length in footings are difficult to implement. This study, via a design example, aims at a better understanding of the implications of code provisions in ACI 440.11-22 and compares them with ones in CSA S806-12, thereby highlighting a need for reconsiderations. An example of the footing originally designed with steel reinforcement was taken from the ACI Reinforced Concrete Design Handbook and redesigned with GFRP reinforcement as per ACI 440.11-22, and CSA S806-12. A footing designed as per ACI 440.11-22 requires a thicker concrete cross-section to satisfy shear requirements, however, when designed as per CSA S806-12 the required thickness becomes closer to that of the steel-reinforced concrete (RC) footing. The development length required for a GFRP-RC cross-section designed as per ACI 440.11-22 was 13% and 92% greater than that designed as per CSA S806-12 and ACI 318-19 respectively. Also, the reinforcement area required to meet detailing requirements is 170% higher than that for the steel-RC cross-section. Based on the outcomes of this study, there appears to be a need for reconsideration of some code provisions in ACI 440.11-22 to make GFRP reinforcement a viable option for RC members.