Structural analysis and assessment of Guastavino vaulting

Abstract

This thesis studies the behavior and pathologies of the masonry tile structures built by the R. Guastavino Company in order to provide recommendations on their analysis and assessment. Structural analyses of two specific geometries - domes and barrel vaults - are carried out with equilibrium and elastic methods to determine how well each assesses the safety of Guastavino shells. Results show that stresses are relatively low in these structures, so they are unlikely to fail due to inadequate material capacity. The safety, then, is dependent on the stability of the structure rather than its material strength. Analysis of a Guastavino structure should demonstrate its stability, and graphical equilibrium analysis is well-suited to this task. Case studies of three Guastavino projects - the Grace Universalist Church, the Saint Louis Art Museum, and the Army War College - provide examples of pathologies specific to masonry tile structures and demonstrate how they were successfully or unsuccessfully analyzed and rehabilitated in the past. Guastavino shells exhibit behavior similar to other masonry structures, but have an additional characteristic that sets them apart: soffit tiles can debond and fall as a result of cracking or water damage. Falling tiles pose a serious mortal danger but do not necessarily threaten a structure's safety. Nonetheless, they elicit dramatic structural repairs and retrofits. The case studies present an opportunity to critically evaluate structural interventions with an understanding of masonry tile vault behavior. By bringing both sensitive and unsuccessful rehabilitations to light, hopefully Guastavino shells will be protected from unnecessary retrofits in the future.