The role of UHPC in Column Retrofit Options

On a recent project in Mumbai, the 28-day concrete results were not achieved on a few columns. Concrete of 80 MPa strength were registering just about 55 MPa. The client had NDT tests conducted that reaffirmed the low strength of concrete. Typical concrete jacketing suggested substantial column size increase, which was not acceptable.

The client approached UHPC India Pvt Ltd for a solution and we suggested UHPC jacketing, which would result in limited increase in the column cross-section. These columns were retrofitted using a 70mm thick UHPC jacket to meet the intended loading requirements and specifications. 

The process of jacketing involved chipping off a nominal concrete cover of the existing column, followed by addition of a few vertical and horizontal shear rebar by epoxying them into the existing columns. Formwork was then placed around the periphery of the column and UHPC was poured from the top. The high flowability and self-levelling characteristics of UHPC facilitated the smooth filling of the thin jacket.

This utilization of UHPC demonstrates the versatility of UHPC as repair and retrofit material not only safeguarding the structure against potential vulnerabilities but also prolonging their lifespan.