Title:
Assessment of Shear Capacity of Fiber-Reinforced Polymer Deep Beams Using Different Methods
Author(s):
Md Shah Alam
Publication:
Structural Journal
Volume:
118
Issue:
6
Appears on pages(s):
237-250
Keywords:
arch action; concrete design; deep beam; design guidelines; fiber-reinforced polymer (FRP); shear strength
DOI:
10.14359/51733079
Date:
11/1/2021
Abstract:
Fiber-reinforced polymer (FRP) reinforcing bars have been demonstrated as a viable substitute to steel-reinforced reinforcing bars owing to their favorable properties of non-corrosive and magnetic neutrality. Design code and guidelines for concrete members reinforced with these reinforcing bars have been proposed by the Canadian Standards Association (CSA) and ACI. Recent researches suggest that these methods do not account for some of the shear design parameters appropriately. One of them is the shear span-depth ratio (a/d), which has a significant effect on the shear capacity of FRP-reinforced members. This paper presents the assessment of the shear design methods of CSA and ACI for calculating the shear strength of FRP-reinforced concrete members. The accuracy of these methods for predicting shear capacity are assessed using 328 test results of rectangular beams and slabs that were studied in existing publications. The samples were reinforced for flexure only using FRP reinforcing bars, and there were no shear reinforcements. It was seen that the shear capacities predicted by applying the CSA and ACI procedures are conservative and widely scattered, mainly for deep beams (a/d < 2.5) due to the lack of proper implementation of this parameter. This is partly due to the arch action for this type of beam. The variations of shear strength for these beams are investigated. Based on this investigation, modifications of CSA and ACI guidelines have been proposed for members with a/d < 2.5 using a data set of 38 specimens. The proposed modifications have been verified using a data set of an additional 65 specimens. The proposed modifications were found to improve the results significantly for beams with a/d < 2.5 and provide uniform predictions over a wide range of d and a/d.