Project no. 6279
BE Collective were commissioned upon recommendation by Australian Concrete Xray (ACX) to undertake inspection and reporting for a dilapidated reinforced concrete structure at a commercial greenhouse facility in Brisbane. The commission scope was to provide quantitative advice as to repair options/costs, and also indicative replacement cost for consideration by the Client’s Board.
Spalling of the aging concrete was prolific. Spalling is typically caused by the corrosion of the steel reinforcement as a result of the ingress of chlorides &/or carbonation of the concrete. In the worst instances heavily corroded reinforcing was visible due to delamination of cover concrete. A total of 13 areas were noted during our inspection as having exposed reinforcing with significantly damaged concrete coincident in several locations.
Reinforced concrete beams were deemed beyond cost effective repair, but could potentially be supported by new structural steel framing. Based on the test data, carbonation had also degraded the protective barrier to the steel reinforcing. The slabs also exhibited some spalling, however it was deemed these elements could be remediated and maintained to provide further functional life.
Due to the significant extent of reinforcing corrosion and concrete degradation, BE Collective estimated extensive remediation works would cost in the order of $200,000. Based on construction unit rates of $1,500-$2,000/m2 a new-build replacement cost was estimated as being in the order of $190,000-$250,000 excluding contingency and builders margin. From a whole-of-life perspective it proved more cost-effective to demolish the existing concrete structure and rebuild.
