Title:
Development Length of Glass Fiber-Reinforced Polymer Bar Based on Nonuniform Bond Stress Distribution
Author(s):
Cheng Wu, Hyeon-Jong Hwang, and Gao Ma
Publication:
Structural Journal
Volume:
123
Issue:
4
Appears on pages(s):
335-348
Keywords:
bond strength; development length; glass fiber-reinforced polymer (GFRP) bar; pullout test; splice test
DOI:
10.14359/51750660
Date:
7/1/2026
Abstract:
There are various studies on the development length of glass fiber-reinforced polymer (GFRP) bars in concrete, and current design codes specify the development length of GFRP bars. While the existing methods rely heavily on statistical analysis of collected experimental data, the applicability of these methods is often disputed. Thus, a theory-based analysis method with broader applicability is urgently needed. In this study, the previously proposed nonuniform bond stress distribution model is modified to estimate GFRP bar development length. The unit bond strength and nonuniform bond stress distribution were considered in the model. In addition, a new parameter to account for the effect of surface characteristics of GFRP bars on the development length was introduced. The proposed method was applied to 169 existing test specimens to predict the development length or tensile stress of GFRP bar splices. The predicted results were compared with the existing test results and the predictions of current design methods, including ACI CODE-440.11-22, CSA S806-12, CSA S6-19, and JSCE. The results showed that the prediction accuracy of the proposed model was comparable to that of ACI CODE-440.11-22, showing the average ratio of the test results to GFRP tensile stress predictions as 0.99 and coefficient of variation (COV) as 0.198.
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