“In-Depth Façade Analysis of Steel Corrosion in Masonry”
- Gina Crevello (Echem Consultants LLC) | Paul Noyce (Echem Consultants LLC) | Irene Matteini (Echem Consultants LLC)
- Document ID
- NACE International
- CORROSION 2019, 24-28 March, Nashville, Tennessee, USA
- Publication Date
- Document Type
- Conference Paper
- 2019. NACE International
- Condition State Ratings, Preservation, Historic Steel Frame Masonry Clad Buildings, Corrosion of Steel Frame Construction
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- 16 since 2007
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Corrosion of steel within ‘vintage’ buildings circa 1880s to 1930s pose a health and safety risk to the public in major urban centers. Projecting masonry elements pose a particular concern when the underlying steel appurtenances and anchorage begin to corrode. Failed masonry has fallen from buildings, leading to death in worst case scenarios. While some signs of masonry cracking or displacement are usually visible prior to failure, the level of degradation of the embedded steel is not. With the equipment available to test these unforeseen conditions, methodologies exist to understand unobservable conditions to assist in condition state ratings of embedded steel. In many cities, building owners are being faced with large expenditures to strip and replace terra cotta or stone elements where the underlying steel is in fair condition.
This paper discusses a field-testing program where two full building elevations’ terra cotta clad steel appurtenances were evaluated for corrosion. The testing program assessed all steel components which projected from the structure with a bespoke, in-depth, testing program geared towards the development of condition state ratings for the elements of the facade. In addition, this novel approach provided valuable insight to more appropriate means of testing glazed brick and terra cotta assemblies, both of which can provide dubious results with surface mounted testing.
Corrosion of embedded structural steel in terra cotta clad buildings can pose life safety issues to pedestrians, as well as extensive maintenance and repair costs to the owner. Often times, the results of damages are evident on the façade however the degree of internal degradation of the steel is unknown. Traditional methods of material analysis include visual inspections and sounding surveys to determine quantifiable damage to the cladding, non-destructive evaluations to understand cracking of the terra cotta and water infiltration and laboratory testing to determine material performance properties of the terra cotta units. Stripping of masonry for probes to allow observations of the steel typically occurs when investigating steel frame conditions, but is often limited due to the time, cost and destructive nature of probing. In-depth corrosion testing programs can provide ample support to understand condition of the underlying steel.
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