Treating Distress and Failure in Historic Terra-cotta Facades

摘要

Originally acclaimed for being lightweight, economical, and efficient as compared to traditional stone, terra cotta was a common facade element on many late- 19th and early 20th century commercial buildings. Architectural terra cotta consists of molded or extruded clay shells that are fired after an initial air drying. Units may be left plain for a natural stone appearance, or, more often, glazed with neutral stone colors or different effects. Commonly used in transitional steel-frame buildings with projecting decorative elements, most historic terra cotta includes metal anchorage that is critical to its structural stability, providing resistance to gravity loads and overturning. This anchorage typically consists of ferrous hooks, bars, or rods attached to the steel structure or backup masonry. Terra-cotta units were frequently partially filled with mortar or masonry to provide increased restraint and augment structural bearing capacity.