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 the reduction of seismic risk but their origin is not recent, indeed, sev− eral 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 ground stratigra− phy and topography, masonry units and mortar, vaults and horizontal floors, connections and tie−rods, new and existing construction. All these aspects represent a codification of earthquake−resistant techniques used in seismic zones in accordance with best practice, still extraordinarily relevant when compared with both recent standard recommendations about structural details and with the performance observed during the 2016 and 2017 earthquakes. FIGURE 1. Location of Norcia and Ischia in Italy.

A common source for the destructive earthquakes in the volcanic island of Ischia (Southern Italy): insights from historical and recent seismicity

“…As for the whole of Italy (Crescimbene et al 2015), seismic risk has not been adequately perceived by the inhabitants of the island, until 21 August 2017 when a M d = 4.0 (M W = 3.9) earthquake stroke the island. The occurrence of this recent earthquake, after 134 years of almost complete seismic silence, has brought out again the problem of the relatively high seismic risk for the island (Briseghella et al 2019;De Natale et al 2019;Marotta et al 2019). Based on the current national seismic hazard map provided by the Istituto Nazionale di Geofisica e Vulcanologia (http:// esse1.…”

Investigation of Rubble-Masonry Wall Construction Practice in Latium, Central Italy

“…In this instrument the carbonate is exposed to hydrocloridic acid and the pressure increase related to the released carbon dioxide is measured, hence estimating the mortar carbonate percentage at about 11% (Figure 6c). Such low presence is an indicator of a seismic risk awareness lower than in other areas such as that of Norcia [19]. Based on previous results, a proportion of 1 lime part by 9 sand parts will be intentionally used when manufacturing the unretrofitted and retrofitted walls to be tested on the shake table [13].…”

Development of parametric seismic fragility curves for historical churches

“…1), within the boundaries of Marches, Umbria, Latium and Abruzzi regions (Mazzoni et al 2018). The affected area experienced several earthquakes such as that of 1859 in Norcia (Marotta et al 2019), that of 1979 in Valnerina and that of 1997 in Umbria-Marches (Sorrentino et al 2018), which required restorations and interventions. Besides masonry and reinforced concrete ordinary buildings, Central Italy is characterized by a building portfolio rich of historical constructions, in fact as much as 4325 unreinforced masonry (URM) churches were inspected during the 2016-2017 seismic sequence (Penna et al 2018).…”