Authors:

Abstract

Steel jacketing has become an attractive strengthening technique for reinforced concrete (RC) columns due to ease of construction and less space requirement. The steel cage consists of angle sections placed at corners and held together by battens at intervals along the RC column height. A numerical investigation of the effective use of steel jackets as a strengthening technique in RC columns is presented in this paper. First, the finite element models of the strengthened column were developed and validated using past experimental data. Then, with the validated model, six sets of steel jacket sections with modified cross-sections such as batten spacing, batten thickness, batten width, end batten width, L angle thickness and steel jacket height were tested under constant axial and lateral loading to understand the effectiveness of steel jackets as the strengthening technique. AnunstrengthenRC column were also analysed to compare the performance of a similar column strengthened by steel jackets with modified parameters. It was shown that strengthening RC columns with steel jackets was effective in enhancing the lateral performance of the columns and resulted in a more stable load-displacement curve with lower strength degradations as compared with the un-strengthened ones. Additionally, it was found that the most effective method to increase the lateral strength and ductility is increasing the L angle thickness. On the other hand, increasing the steel jacket height also increases the lateral performance, however, it was identified that increasing the jacket height is effective only up to 1/3rd of the RC column height. Finally, the obtained results for each parameter were compared to study the behaviour of each component of the steel jacket towards lateral strength and ductility improvements.

Keywords: Concrete damage plasticity model, Lateral performance, Non-linear finite element analysis, RC column, Steel jacket, Strengthening technique