PSI - Issue 44

Mariateresa Guadagnuolo et al. / Procedia Structural Integrity 44 (2023) 766–773 Guadagnuolo et al. / Structural Integrity Procedia 00 (2022) 000–000

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1. Introduction Chimney stacks are the witnesses of the past in many countries and therefore are protected as cultural heritage. Their shape and geometry mainly depend on the architectural language of the building time, fireplaces' evolution, historical period, and geographical area (Fig. 1). Most were built of unreinforced brick or stone masonry, and are very slender. The chimney stack collapse is frequent seismic damage in buildings, yet remains one of the most disregarded items. Many post-earthquake reconnaissance reports state that chimney stacks underwent heavy damage and failures, even under slight earthquakes, because they are typically the tallest component in buildings and experience large amplification of ground motion (Giaretton et al. 2018; McDonald 2018; FEMA 2010). During an earthquake, most tend to break at the roofline level and fall either through the roof or outward onto adjacent buildings or public pavements. Therefore, in addition to the loss of cultural heritage, their failure can yield huge damage to the underlying building, and is hazardous to public safety (Guadagnuolo et al. 2018; Dhakal 2010).

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Fig. 1. Chimney stacks: (a) Louvre Museum in Paris, (b) Dutch Parliament in The Hague.

The seismic behavior of chimney stacks depends on several features, i.e. cross-section geometry, height above the roof, location within the building, roof slope, building height, weathering, and decay of structural materials (Monaco et al. 2021). Chimney stacks mostly behave like cantilevers when undergoing seismic actions, and earthquakes typically cause cracks at the roofline, or in intermediate sections. After cracking, they commonly tend to behave like rigid blocks that can overturn. Despite the numerous researches concerning historic masonry buildings, few of them specifically deal with the seismic analysis of chimney stacks (Maison and McDonald 2017, 2018; Giaretton et al. 2017; Derakhshan et al. 2019). The existing literature is rather limited, partly because their danger underestimated for a long time. Sometimes, their rigid block behavior is analogous to the out-of-plane overturning response of masonry walls, which has been widely studied (Abrams et al. 1996; Casapulla and Argiento 2017; Cappelli et al. 2018; Doherty et al. 2002; Gesualdo et al., 2014; Lagomarsino, 2015). Lately, the seismic behavior of some non structural protruding masonry elements (gables, merlons, etc.), more like chimney stacks, was analyzed in research papers (Cattari et al. 2014; Giresini et al. 2016; Ferretti et al. 2018; Gesualdo et al., 2019; Guadagnuolo et al. 2019). Some standard codes today require the seismic verification of non-structural elements, and then of chimney stacks (FEMA 2010; 2012a; 2012b; MIT 2018). This paper concerns the seismic safety assessment of masonry chimney stacks to contribute to their protection and conservation. A specific procedure to study overturning failure mechanisms is developed and presented. The behavior is studied through the linear and nonlinear kinematic approaches. The filtering effect due to the underneath building structure, which modifies the ground seismic input, is considered through floor response spectra. The procedure is then applied to the high chimney stacks of the Royal Palace of Carditello, a dwelling built-in 1787. This allows focusing on the main parameters influencing the seismic safety of many historic chimney stacks. 2. Kinematic analysis of chimney stacks: Carditello Royal Palace The Royal Palace of Carditello is on the outskirts of San Tammaro, a town in the province of Caserta. The complex was built at the behest of Ferdinand IV of Bourbon in 1787 and was intended both as a royal residence and