Multi-level buildings – Case studies of premature deterioration, causes and repair

Durability of reinforced concrete structures became an integral part of design, construction and asset management in the latter part of the 20th century. Guidance on construction practices and materials is provided in documents such as the NCC/BCA (1), AS 3600 (2) and CIA recommended practices (3), which have evolved as understanding of reinforced concrete and its durability has improved. 

 This paper presents high-rise structures which have incorporated poor and/or previously recommended construction practices. These practices compromised asset life by enabling aggressive species to access reinforcement far earlier than would otherwise occur. Practical case histories of both conventional reinforced concrete and post-tensioned concrete deterioration through corrosion, and corresponding remediation strategies, are presented and discussed. 

This paper demonstrates how the interactions of specific design decisions, construction errors, and recommended practices from past decades have had unintended consequences requiring careful and specialised remediation.