BASF Construction Chemicals turned around a setback that had brought extension work at the Ministry of Finance building in Abu Dhabi to a grinding halt, allowing construction to resume in just three days.
Work was halted after it was discovered that the ground and basement floors of the new 10-storey structure had deflected in some areas as much as 200 mm.
Explains Paul Lowndes, regional marketing manager for BASF Construction Chemicals in the Middle East, Central Asia and Africa: “The extension consisted of the construction of a 10-storey building with two basements and a ground floor adjacent to the existing structure. Due to unforeseen circumstances, the basement one and ground floor levels of the building deflected, in some areas as much as 200 mm downwards. Construction was halted until the lower levels could be strengthened. Conventional solutions proposed demolition or major reconstruction. However, BASF proposed its Mbrace FRP Laminate system, which helped sub-contractor Nasa Structural Systems resolve the problem in under three days.”
Mbrace FRP Laminate is a ready-to-use pultruded carbon fibre laminate that provides a high tensile strength and is excellent for supplemental flexural reinforcement of concrete elements.
To reinforce structures with strong elements in tension, Mbrace Laminate replaces the traditional technique of plating with steel plates with use of extremely light materials that are easy to install. The system enables the amount of reinforcement to be calculated and placed in relation to the performance required, or the stress flow. Mbrace Laminate will then, depending on the application, increase load-bearing capacity, reduce deformation to the working loads by increasing rigidity, increase fatigue strength, and limit or cover the cracking states to increase durability.
Nasa Structural Systems came up with a solution to bring both slabs to their desired position without having to undertake major demolition and recasting. The concrete slabs were jacked up hydraulically and Mbrace FRP was installed to the soffit of the slabs to ensure they remained in their final position with the design strength intact.
Preparation of the slab soffits was undertaken by means of sandblasting to ensure an etched finish was achieved which would allow adhesion of the Mbrace adhesive to the concrete surface. This procedure also eliminated any oils, grease and/or laitance which could have impeded the installation process.
All works were completed in accordance with the UK’s Concrete Society Technical Report No 55 in less than three days, under three days, representing major cost savings for the contractor, says Lowndes, adding that load testing was completed successfully and showed an increase in the strength of the slabs.