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Strengthening of Pre-Damaged Columns exposed to Fire using FRCM
Al-Momani, Bashar
Al-Momani, Bashar
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35.232-2025.45a Bashar Al-Momani.pdf
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Description
A Master of Science thesis in Civil Engineering by Bashar Al-Momani entitled, “Strengthening of Pre-Damaged Columns exposed to Fire using FRCM”, submitted in November 2025. Thesis advisor is Dr. Farid Abed. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).
Abstract
Fabric-Reinforced Cementitious Matrix (FRCM) systems have recently emerged as an effective method for strengthening and repairing concrete structures. This technology embeds textile reinforcement within an inorganic cementitious mortar, creating a durable composite. Unlike traditional epoxy-based Fiber-Reinforced Polymers (FRP), FRCM maintains structural integrity at significantly higher temperatures, offering notable advantages for fire-prone applications. This study evaluates the performance of poly-paraphenylene-benzobisoxazole (PBO)-FRCM as a retrofitting solution for fire damaged reinforced concrete (RC) short columns. Seven circular RC columns, each 1.2 meters tall and 200 mm in diameter with a 1.5% reinforcement ratio, were tested under axial compression. Two columns served as control samples and were not exposed to fire, while five columns were exposed to fire for 133 minutes in accordance with ASTM E119, then repaired with two layers of PBO-FRCM. Variables included concrete type as normal (NSC) or Ultra-high performance concrete (UHPC), pre-fire wrapping with FRCM or FRP, and the presence of a cement-based insulation system prior to fire exposure. The findings demonstrated that post-fire strengthening plays a significant role in restoring the original capacity of the tested normal concrete specimens. Repairing the fire-exposed column, which lacked both insulation and wrapping, recovered 68% of its axial capacity. Pre-fire FRCM strengthening combined with insulation improved the post-fire axial behavior to similar levels to that of the unwrapped control specimens, but the axial capacity remained about 17% lower than that of the unheated FRCM-wrapped control column. PBO-FRCM effectively
improved the axial performance of the UHPC column, where its axial capacity was 183% higher than that of the unrepaired counterpart. However, relative to the nominal
capacity predicted by ACI ITG-4.3R, the repaired column retained only 36.5% of the original capacity. Analytical predictions based on international codes closely aligned
with experimental findings, yielding experimental-to-predicted capacity ratios of 1.13–1.30 for control columns and 1.17–1.50 for fire-exposed columns, reflecting uncertainties associated with modeling post-fire material degradation.