The Housing Authority appointed QP to design and supervise the structural strengthening works for the Binja Buqana residential complex in Mtarfa. This complex, housing a total of 80 apartments, was in a dangerous state due to shortcomings in both the original structural design and workmanship when originally constructed.
The design follows the analysis of structural defects by international firm Arup. QP subsequently assumed this analysis and carried out the structural design and supervision of the required remedial works to render this residential complex in a safe condition.
Throughout the execution of the project, the QP team faced several complex challenges intrinsic with retrofitting projects, the solution for which had to be approached with a sound knowledge of structural load paths and construction methodologies. For example, the basement columns supporting the transfer structure, including the transfer structure itself, were operating at a high level of stress with a safety factor less than unity. The distress level was evident in most of these structural elements at basement level. Laboratory tests had shown that concrete was of inferior quality with the inherent strength of concrete being approximately half the required design strength.
To address this issue, we designed strengthening works for the entire basement floor as well as the common areas. We also implemented cosmetic interventions on elements showing extensive deterioration and reinstated the structure to an acceptable level of durability.
Another challenge our team faced was that of significant degradation of the existing structure as a result of prolonged water infiltration. After removing the tiles on most terraces and common areas, it was noted that the screed was soaked through. Over time, structural deficiencies had developed in these areas. This required the complete reconfiguration of the drainage system on all terraces, replacing the stone cladding of all balconies and re-applying a new waterproofing system. The façade was also cleaned and re-pointed to avoid further water penetration through the bedding joints and improve the overall aesthetics of the buildings.
The total cost of the work was 2.3 million Euros.