Abstract
ACI 440.11 is silent on defining the relationship between the minimum thickness of GFRP-RC solid non-prestressed one-way slabs and their clear span. Therefore, in study 1 a relationship between minimum thickness and span of GFRP-RC slabs is proposed. Slabs were analyzed as simply supported, one-end continuous, both end continuous, and cantilever. Based on the outcomes of this study, a relationship between the minimum thickness of GFRP-RC one-way slabs and their span is provided. Additionally, the first study aims to analyze practical considerations in the design of GFRP-RC beams based on ACI 440.11. Results are reported in terms of challenges to the designer when implementing design, meeting serviceability, and detailing requirements.
The second study was carried out to investigate the effect of stirrup confinement on the bond strength provisions. The experimental program involved testing 16 full-scale GFRP-RC beams subjected to a four-point bending test. The test parameters comprised lap splice length and stirrup spacing in the lap spliced zone. The results indicated that GFRP stirrups increased the bond strength, decreased bar slippage, and increased splitting stress. Suggestions are provided to include the effect of confinement on the bond strength provisions.
The Code provisions in ACI 440.11 are based on the flexural theory that applies to slender members and may not represent the actual structural behavior when the shear span-to-reinforcement depth ratio is less than 2.5. The Strut-and-tie method can be a better approach to design deep members; however, this chapter is not included in the Code. Therefore, this study was carried out to provide insights into the use of STM for GFRP-RC deep members and to highlight the necessity and framework for the inclusion of a new Code chapter.