Empirical Coastal Atmospheric Corrosion of Masonry Metal Wall Ties

Abstract

Not counting domestic dwellings, it has been estimated that in Australia alone, some tens of thousands of masonry buildings and structures have exceeded their design life, with many of these being at risk of partial (or worse) collapse from falling or dislodged masonry. This has significant implications for human life but also for the urban environment and economic health of building owners, managers, and insurers and for local and national economies. This risk can mainly be attributed to the slow deterioration of masonry under atmospheric and other environments and the corrosion of so-called wall ties. Wall ties are relatively thin pieces of steel that tie the outer leaf of masonry walls to the stabilized inner leaf. The problem is likely severe for scenarios such as cyclonic and earthquake events, as they cause area-wide damage and the potential wide-spread loss of human life—losses that could be prevented by timely intervention. This paper reports on the in situ inspection of two case study buildings and the data obtained from controlled wall tie corrosion field trials, which are used to develop predictive models of structural response. These models will inform practical tools that will be developed for building assessment, cost-effective monitoring, and rectification, assisting in the management of existing masonry buildings.