Improving the Flexural Strength of Bowed Marble Panels through Mechanical Treatment
Post War architecture
Historic Preservation and Conservation
This research examined the conservation options for thin marble cladding as used in Post War architecture in the United States. The phenomenon of bowed marble panels was studied as early as the 1910s, and literature on the topic became more prolific in the 1990s following early catastrophic failures of entire Post War building façades less than 20 years after construction due to little knowledge of material properties. The current hypothesis is that thin marble panels deform due to the disaggregation of calcite grains from environmental hysteresis. Prominent case studies include the Amoco Building in Chicago and Finlandia Hall in Helsinki, with the more historical example of the bowed marble enclosure tablets of New Orleans’ above-ground cemeteries. Replacement is the current conservation strategy, which compromises the aesthetics of the marble, and comes at a huge monetary cost. This is detrimental to the historic fabric, especially as the buildings constructed in this era reach 50 years, making them eligible for the National Register of Historic Places. The research presented investigated methods to stabilize and strengthen deformed marble panels where preservation of existing historic fabric is the preferred mode of treatment. Through an examination of the literature of the mechanical reinforcement of concrete slabs and masonry panels, a method to improve the flexural strength of bowed marble panels can be developed and tested through the procedures outlined in Nordtest Method: NT BUILD 499, testing for bowing potential, and ASTM C880-98, testing flexural strength.