CPS House Jacketing to Strengthen RC Beams

Beta Scope

•  Structural analysis of existing RC Frame using SCIA Engineer
• Existing RC Beams capacity check and identifying overstressed beams
•  Evaluation of repair options including FRP, HPC and traditional jacketing
•  Design of structural jacketing to strengthen RC Beams
•  Preparation of repair method statement
•  Specifications of materials suitable for jacketing and corrosion inhibition

Background

Beta Design Consultants were commissioned by the Client Boultbee Brooks Real Estate to prepare the structural design to strengthen the RC beams that are found to have inadequate capacity to support the addition of a new office level to their two storey office building.

Beta Design Consultants worked with the Client, the Client’s Project Manager TFT Consultants, the Client’s nominated contractor CRL Repairs and the Client’s appointed Project Structural Engineer Clarkebond. The building, CPS House, is located in the town centre of Cheltenham.

Beta Design Consultants established existing loading on the column using SCiA Engineer. They established capacity of existing beams and design forces following the addition of the new office level.

Beta Solution

This allowed us to propose a strengthening option. We considered FRP, HPC and traditional jacketing. Traditional jacketing was proposed as the reduced capacity of the existing beams, due to carbonation and low compressive strength, meant that the section does not have sufficient concrete strength to mobilize FRP strength. A combined option of FRP plates for tension and HPC in compression was also considered, but was dismissed due to concerns related to debonding between FRP and concrete and separation between HPC and concrete. Jacketing was recommended and this proved to be a good proposal when corrosion inhibition needed to be implemented.

Practical Details

Beta Design Consultants worked with the material suppliers (Mapei) to specify flowable concrete and corrosion inhibitor with a short lead time to ensure quick procurement of the right products. Mapegrout Hi-flow was specified for the flowable concrete suitable for jacketing.

Beta Design Consultants produced a detailed construction method statement to ensure works were carried out in a safe, practical and correct sequence.