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

Alessandra Marotta,Domenico Liberatore,Luigi Sorrentino

doi:10.4401/ag-7986

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.

Highlights

The urban development of several municipalities located in seismic areas is closely linked to the occurrence of strong earthquakes [Penta, 1964; Reitherman, 2006a; Tobriner, 1984]
In Italy, the history of the city of Norcia and of the island of Ischia (Figure 1) is relevant, because ad hoc standards were enacted on the basis of post-earthquake observations, as discussed below
1965; Mascarenhas, 2004; Rossa, 1998; Ruggieri, 2017), and the “Instructions for Engineers commissioned in South Calabria” by the Borbone government in 1784 [Grimaldi, 1863; Ruggieri, 2017; Vivenzio, 1788]

Summary

INTRODUCTION

The urban development of several municipalities located in seismic areas is closely linked to the occurrence of strong earthquakes [Penta, 1964; Reitherman, 2006a; Tobriner, 1984]. França, 1965; Mascarenhas, 2004; Rossa, 1998; Ruggieri, 2017), and the “Instructions for Engineers commissioned in South Calabria” by the Borbone government in 1784 [Grimaldi, 1863; Ruggieri, 2017; Vivenzio, 1788] All these regulations are unquestionably a first fundamental, qualitative, step towards the more complete quantitative standards of the twentieth century, such as those issued after the 1906 San Francisco earthquake [Reitherman, 2012] and the 1908 Messina and Southern Calabria earthquake [Sorrentino, 2007]. The cases of Norcia and Ischia are outstanding examples of accurate analysis of observed buildings performance during seismic events, used as the basis for detailed recommendations for new constructions and for an accurate selection of repair measures for existing buildings. Www.vigilfuoco.tv) and b) Ischia, after the 2017 earthquake (photo courtesy of Antonio Formisano). 2

SEISMIC EVENTS PRECEEDING AND FOLLOWING THE NORCIA AND ISCHIA BUILDING CODES

THE 1860 NORCIA BUILDING CODE

THE 1884 ISCHIA BUILDING CODE

Findings

CONCLUSIONS