Historical Building Codes issued after the strong Italian earthquakes of Norcia (1859) and Ischia (1883)

Abstract

Building codes are a fundamental part of the overall strategy for reduction of seismic risk but their origin is not as recent as one can expect, because several historical examples are available. After the 1859 Norcia (Central Italy) and 1883 Ischia (Southern Italy) earthquakes two standards were issued, which can be considered a remarkable attempt to improve the performance of ordinary unreinforced masonry structures by regulating architectural configuration and structural details. Both documents contain interesting observations about stratigraphy and topography, masonry units and mortar, vaults and horizontal floors, connections and tie-rods, new and existing constructions. All these aspects represent a codification of the rule of art in seismic zones, still extraordinarily relevant when compared with both recent standard recommendations about structural details and with the performances observed during the 2016 and 2017 earthquakes.