Contents lists available at ScienceDirect Soil Dynamics and Earthquake Engineering journal homepage: www.elsevier.com/locate/soildyn Seismic damage survey and empirical fragility curves for churches after the August 24, 2016 Central Italy earthquake Lorenzo Hofer a, ⁎ , Paolo Zampieri a , Mariano Angelo Zanini a , Flora Faleschini a,b , Carlo Pellegrino a a University of Padova, Department of Civil, Environmental and Architectural Engineering - ICEA, Via Marzolo 9, 35131, Italy b University of Padova, Department of Industrial Engineering, Via Gradenigo 6a, 35131, Italy ARTICLE INFO Keywords: Amatrice 2016 Central Italy earthquake Churches Damage survey Masonry structures Seismic vulnerability ABSTRACT This paper presents the results of a damage survey conducted on a wide stock of churches in Central Italy, hit by the August 24, 2016 Amatrice seismic sequence. In the weeks following the mainshock, the authors performed a damage assessment of 196 churches in the area involved by the seismic event, aiming to identify damage me- chanisms and calculate damage index for each structure. Churches have similar characteristics within the analyzed area, with typical architectural elements, homogeneous structural types and similar construction materials. A discussion presents the main evidences observed during the survey and, lastly, empirical fragility functions are derived for this specific structural type. 1. Introduction Damage reports developed after recent earthquakes demonstrated that churches are vulnerable structures, such as many other historical buildings [1–3]. This leads to the consequence that a significant portion of the Italian cultural heritage is prone to seismic risk. Indeed, these structural types were often built with unreinforced stone masonry, having significant lack of construction details. Many researchers carried out seismic damage survey of churches after past earthquakes in Italy [4,5] and in other countries prone to seismic hazard [6–8]. In this paper the results of an extensive damage survey conducted on 196 churches hit by the August 24, 2016 Amatrice earthquake of moment magnitude M w 6.0 are presented. The epicenter of the M w 6.0 mainshock was lo- cated between the Municipalities of Accumoli and Amatrice (42.70°N–13.24°E), in the Lazio region, by the Istituto Nazionale di Geofisica e Vulcanologia seismic network [9]. The area between Lazio, Umbria, Marche and Abruzzo regions, struck by the 2016 Amatrice earthquake sequence, is significantly prone to earthquakes: in the last 20 years, other devastating events occurred with epicenters located at about 30 km far from the actual one (April 6, 2009 M w 6.29 L’Aquila event and 1997 Umbria seismic se- quence with a M w 5.97 mainshock). According to the Parametric Catalogue of Italian Earthquakes (CPTI15) [10], historical information reveals that the seismic activity in the Monti Sibillini area is frequent. In the past centuries, highly destructive events occurred indeed: from the eighteen century, a mean annual rate of about 0.25 events with mag- nitude M w > 4.0 was observed. Fig. 1 shows the macroseismic intensities (in terms of macroseismic intensity I O-MCS ) historically re- corded in the area of Accumoli. First evidences of damage induced by earthquake occurrences in the area of Accumoli were related to the effects of the July 1627 Monti della Laga event [11]. It was followed by the severe October 7, 1639 [12] Amatrice earthquake, that seems very similar to the actual seismic scenario. The Accumoli area suffered extensive damage also after the most destructive January 14, 1703, and was re-struck by the May 12, 1730 Valnerina event [13]. After about 150 years, these territories were hit again by the November 7, 1883 Monti della Laga earthquake, and in the twentieth century by other significant events, with I O-MCS 7–8 in 1916, 1950 [14]. Table 1 lists the historical events with macroseismic intensities at least equal to I O-MCS = 5, related to Accumoli Municipality from the 16th century. Along this paper, results of an extensive damage survey carried out on a stock of 196 churches in Lazio, Umbria, Marche and Abruzzo re- gions are illustrated. The aim of this work is to give a clear overview of the main deficiencies and collapse mechanisms of the macro-elements observed after the event. In the first part, a brief overview about the surveyed structures, visual inspection criteria and mainshock earth- quake scenario is provided. In the second part of the work, the most common structural types and damage observed are discussed. A key issue of this contribution is that the observed damage can be reasonably associated with the mainshock sequence, since no other significant aftershock occurred in the following 50 days, potentially leading to a remarkable damage increase hence, in such a way damage state prob- abilities can be directly linked to a scenario event. Lastly, empirical https://doi.org/10.1016/j.soildyn.2018.02.013 Received 4 November 2016; Received in revised form 29 August 2017; Accepted 8 February 2018 ⁎ Corresponding author. E-mail address: lorenzo.hofer@dicea.unipd.it (L. Hofer). Soil Dynamics and Earthquake Engineering 111 (2018) 98–109 Available online 04 May 2018 0267-7261/ © 2018 Published by Elsevier Ltd. T