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Published on: June 27, 2018
Integrated NSM and GFRP-reinforced ECC/UHPC techniques for strengthening deficient RC columns
Galal Elsamak1, Alireza Bahrami2, Mohamed Emara3
1Civil Engineering Department, Faculty of Engineering, Kafrelsheikh University, Kafrelsheikh, Egypt.
Scientific Reports
|May 27, 2026
Summary
This study enhances corroded reinforced concrete columns using near-surface mounted bars and advanced concrete jackets. Ultra-high-performance concrete with GFRP bars offered the most significant load capacity and energy absorption improvements.
Area of Science:
- Civil Engineering
- Materials Science
- Structural Engineering
Background:
- Corrosion of reinforcing steel significantly degrades reinforced concrete (RC) columns.
- Loss of structural integrity and load capacity necessitates effective strengthening techniques.
Purpose of the Study:
- To evaluate an innovative strengthening method for RC columns using near-surface mounted (NSM) bars and advanced composite jackets.
- To compare the effectiveness of engineered cementitious composite (ECC) and ultra-high-performance concrete (UHPC) as external strengthening layers.
Main Methods:
- Experimental testing of strengthened RC columns with various combinations of NSM steel/GFRP bars and ECC/UHPC jackets.
- Development and validation of finite element models (FEM) to simulate column behavior.
- Parametric study using FEM to investigate the influence of main reinforcement diameter.
Main Results:
- UHPC jackets provided superior confinement and load capacity enhancement compared to ECC jackets.
- NSM steel bars with ECC jackets increased load capacity by 25-32% and energy absorption up to 3.9 times.
- The combination of NSM GFRP bars with UHPC jackets yielded the highest performance, increasing load capacity by 49% and significantly improving energy absorption.
- FEM results closely matched experimental data, validating the strengthening approach.
Conclusions:
- The proposed NSM bar and external jacketing technique is highly effective for strengthening RC columns.
- UHPC offers superior performance over ECC for confinement and load enhancement.
- Increasing reinforcement diameter enhances column strength, though efficiency diminishes at larger sizes.
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