Title: Flexural Strengthening of RC Columns with Low Longitudinal Steel Ratio using GFRP Bars
Author(s): Mehdi Esfandi Sarafraz
Appears on pages(s):
Keywords: RC columns, GFRP rebar, ﬂexural capacity, NSM, seismic strengthening
This research describes the results of an experimental work that aimed to investigate the ﬂexural capacity of RC columns with low longitudinal reinforcement ratio that was strengthened with near surface mounted GFRP bars. The experimental program consisted of four square reinforced concrete columns, including one control specimen that were designed with a longitudinal reinforcement ratio below the minimum required ratio of 1% speciﬁed by RC design codes. Three of the four specimens were strengthened with diﬀerent ratios NSM GFRP bar. The specimens were tested under a combined axial compressive load and lateral cyclic displacement to evaluate this retroﬁt method for the ﬂexural improvement of RC columns. The eﬃcacy of the proposed strengthening method on the ﬂexural capacity, failure modes, hysteretic curves, energy dissipation capacity, and stiﬀness are discussed on the basis of the test results. The experimental results demonstrated that the contribution of GFRP bars to the ﬂexural capacity of RC columns was signiﬁcant. Also, an analytical procedure for calculating the bending moment capacity of RC columns strengthened with GFRP bars subjected to axial and lateral is proposed. The model accuracy is demonstrated by comparing the model predictions with the experimental results. The ﬂexural capacity calculated by this method were in good agreement with the experimental results.