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The Basilica of Maxentius, the largest vaulted space built by the Romans, comprised three naves, the outer ones covered by barrel vaults and the central, the highest one by cross vaults. It was built on a sloping site, resulting in a possible structural vulnerability at its taller, western end. Two naves collapsed in the Middle Ages, leaving only t...
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... The destruction of buildings is a complex process in which natural and anthropogenic causes both play significant roles in their long and gradual deterioration (Stiros 2020). Researchers have visualized the consequences of seismic activity in the region as one factor of deterioration and damage, such as in the Roman port city of Ostia (Marra et al. 2020) and the Basilica of Maxentius (Albuerne 2016;Albuerne and Williams 2017). Tsunami events have also damaged Roman harbors over the past centuries (Goodman-Tchernov and Austin 2015). ...
Roman concrete is one of the most fascinating materials ever invented by humankind. Understanding the historical context and details of the production of ancient Roman concrete (ARC) is necessary to comprehend its nature. Recently, the interest in researching ARC has grown considerably, leading to several projects to describe its production. Remarkable properties were
attributed to ARC, with durability emerging as one of the most relevant but also the most misunderstood. The reasons for the durability of Roman structures are still under investigation,
and various hypotheses have linked its durability to the microstructure, or its chemical and mineralogical composition. In this literature review, historical facts contextualize ARC and detail
the specific materials and methods used for production. It also becomes clear that the chemical, mineralogical, and mechanical characterization of ARC has begun to link research from different
disciplines, providing an overview of this material, and exploring some of the unexplained facts that could potentially improve today’s concrete technology.
... However, in addition to these structural deformations driven by external actions, further geometrical irregularities, considered in respect of a hypothetical design geometry, can frequently be observed in heritage structures. These geometrical irregularities can arise from a variety of factors, including errors or inaccuracies during the original construction [1], short-term deformations that occurred during the building process (such as deformation of centering, mortar settlement, etc. [34]), damages that were sustained and subsequently incorporated during construction (e.g., settlements induced damages), as well as any subsequent modifications made to the structure over time [33] and, lastly, deliberate design choices such as optical corrections typical of monumental buildings [20] or technical features such as slight tilting for water management. Both structural deformations and non-structural geometrical irregularities are relevant for a comprehensive structural analysis of a heritage building. ...
Masonry vaults are common structural elements in heritage buildings that, given their long lifespan, are susceptible to the accumulation of damages and deformations from diverse actions such as overloads, support movements, seismic action, etc. The use of 3D point clouds from terrestrial laser scanners and structure from motion photogrammetry survey to investigate these deformations can offer valuable information for structural assessment and conservation, particularly when historical information is limited. The analysis of the deviation measured between the surveyed as-built point cloud of a vault and a reference geometry could reveal deformation patterns. Those, compared with recurring damage mechanisms discussed in literature, can provide a preliminary identification of the damage mechanisms affecting a structure, and the evaluation guide the recognition of the underlying action. The aim of this paper is to investigate how to generate different reference geometries and the impacts of their choice as reference geometry for the identification and quantification of different deformations. Deviation analyses were performed on the main vaults of two different churches with different reference geometries (i.e., geometries derived from the survey and geometrical primitives fitted on point-cloud), and the results were discussed by comparing the deviation maps obtained with the crack pattern and the already known deformations of the buildings.
... These remains are limited, unique, and non-renewable resources, making their conservation even more critical (De la Torre and Mac Lean 1997). Many of these structures have deteriorated over the years, losing structural integrity and suffering deterioration, leading to partial or total collapse (Albuerne and Williams 2017;Autiero et al. 2021;Ruggieri et al. 2018). As a result, ruins often exhibit isolated structural elements, such as arches, individual walls, columns etc., which are highly vulnerable. ...
The proposed research work presents a comprehensive approach to assessing the seismic vulnerability of archaeological sites. This approach aims to be a quick and easy-to-use investigation procedure that enables accurate and large-scale evaluations. While the methods employed are well-established in the literature and have been widely applied to buildings, this study contributes by proposing a structured framework that integrates different assessment procedures at different levels of analysis, specifically tailored to archaeological sites. The analysis is divided into three stages within the conceptual framework: (i) the application of the Masonry Quality Index; (ii) seismic vulnerability assessment and prediction of expected damage; and (iii) analysis of individual walls’ structural response through strength domain, capacity and fragility curves. Specifically, the study explores and adapts four Vulnerability Index methods, i.e. GNDT, Formisano, Vicente and Ferreira methods, to suit the specific characteristics of archaeological sites. To this end, a simplified procedure is proposed to estimate the conventional strength in the methods’ forms. The comparison of the index-based methods is then crucial for critically evaluating the reliability of vulnerability estimations. The paper illustrates the application of this framework through a detailed case study, i.e. the archaeological site of Wupatki Pueblo in Arizona (US), demonstrating its effectiveness in evaluating the seismic risk and defining the vulnerability distribution of the site. Consequently, this approach facilitates the identification of the most sensitive areas, which necessitate further investigation, providing useful outcomes for the decision-making process concerning the conservation and protection of archaeological sites.
... The investigation of geometrical irregularities and deformations in historical buildings has long been recognized as an important part of the knowledge process to reach a comprehensive understanding of the history and pathology of a structure [2]. It proved to be able to provide plenty of information useful in many fields from history of architecture to structural engineering [3]. With the technological advancements, surveying instruments have improved in accuracy and capability, enabling the collection of a greater amount of detailed metric data. ...
Masonry vaults are common elements in heritage buildings and, due to their age, may accumulate damages and deformations due to various actions like overloads, support movements, earthquakes, etc. The use of terrestrial laser scanners and structure from motion photogrammetry survey to study these deformations can offer valuable information for structural assessment and conservation, especially when limited knowledge of buildings history is available. The analysis of the deviation between the surveyed point cloud and a reference geometry can reveal deformation patterns and aid the damage detection and action evaluation on the structure. This paper aims to explore the role of the reference geometry to provide a reliable and more accurate identification and quantification of deformations. Deviation analyses will be performed on the vaults of the main nave of two different churches with different reference geometries (i.e. geometries derived from the survey and geometrical primitives fitted on point-cloud) and the results are discussed comparing the deviation maps obtained and the already known deformation and caused.
... In this approach the structure is considered as an assembly of rigid bodies, and a few input data, rather easy to be evaluated, are required for calculations, that is the geometry and materials' weight density. For this reason, the method is widely used for structural assessment of historic buildings, including those of Roman origin [3,[5][6][7]. According to the Safe theorem, the structure is safe (i.e. in static equilibrium with acting forces) if a thrust line (TL), representing the compressive forces flow, can be drawn inside its thickness. ...
... In this paper, the seismic vulnerability of the ruined colonnades is assessed exploiting both the linear and nonlinear kinematic approaches, to compute both the load-bearing capacity, that is the capacity to withstand horizontal forces which activate the collapse mechanism, and the displacement capacity. To decrease their vulnerability, a targeted strengthening intervention which does not exist in the literature has been conceived, because more traditional interventions, such as steel ties or buttresses, or the many innovative systems proposed by researchers, such as systems based on the application of fiber reinforced composites materials (FRP and FRCM) or techniques such as the Reticulatus method [ 33 , 34 ], can hardly be applied to remains in archeological sites [35][36][37][38] and cultural heritage assets as they must mandatorily satisfy the principle of reversibility, compatibility and minimum visibility. ...
The recent discovery of a Thermopolis in Regio V of the archaeological site of Pompeii in December 2020, still completely intact and complete with decorations and kitchenware, has recalled the important role of archaeological sites that preserve and pass on the historical, artistic and architectural value of populations. Therefore, it appears even more evident, that there is the need to identify suitable methodologies to preserve intact the archaeological heritage, consistent with their peculiar characteristic of being in a state of ruin and, therefore, even more vulnerable to external actions, such as those induced by an unexpected earthquake, as compared to a complete building. Moreover, the very fact of being a protected heritage, also necessarily requires the use of special interventions such as not to alter the structures themselves and to guarantee reversibility. In this context, in this paper the seismic vulnerability of the remains of the colonnade of the forum of Pompeii is evaluated with the methods of kinematic analysis that allows the identification of the collapse mechanisms activated by an earthquake. To increase the capacity to withstand seismic actions, a non-invasive, reversible and non-impact reinforcement system has been proposed and validated carrying out numerical analyses conducted by means of a calculation code developed specifically for the study of these structural types consisting of an assemblage of rigid blocks.
... There are, however, numerous masonry constructions that present a level of tensile strength at joints exerting a resistance against separation of masonry blocks. An important category of vaulted structures exhibiting some tensile strength is ancient Roman construction made of Roman concrete, as exemplified by the remains of the Basilica of Maxentius in Rome (Giavarini 2005, Albuerne & Williams 2017. ...
Continuous arches and vaults made of cohesive materials with low but nonzero tensile strength, such as Roman concrete, are a common feature in historic and monumental structures, many of them sited in earthquake-prone regions. The effect of tension capacity on the dynamic behaviour of masonry vaulted structures has scarcely been studied. We describe a series of shaking table tests on model-scale, continuous circular arches of 1m span, with the aims of assessing the effect of tensile capacity on mechanism formation, evaluating the structures’ lateral acceleration capacity and comparing their performance to that of voussoir arches. While tested arches fail by forming a four-link mechanism like the no-tension voussoir arch, significant differences in behaviour between continuous and voussoir arches are observed, including: differences in hinge positions; higher accelerations required to initiate rocking; cracking of material required to form hinges; inability of hinges, once formed, to close and move to a different location (travelling hinges). Conventional limit analysis, whose basis includes an assumption of zero tensile strength, is a suitable analytical tool for voussoir arches, but is shown to be inaccurate when applied to arches having a modest tensile capacity. The experimental observations are modelled using nonlinear finite elements Abaqus/Explicit dynamic analysis algorithm, from commercial software Abaqus 2017. By applying the concrete damage plasticity numerical material law, good agreement is obtained between the tests and the numerical predictions, supporting the formation of collapse mechanisms that significantly differ from the mechanisms observed for no-tension arches. Finally, the numerical model is upscaled to study full-size arches with a span of 4m, obtaining results that align with the experimental observations and do not agree with observations and models for the no-tension voussoir arch, evidencing the need to account for tensile capacity of vaulted structures when assessing their dynamic capacity.
... The second phase, carried out using numeric-type interpretative tools or computations performed manually, as in the case of the city walls under study, is aimed at retracing the timeline of events that caused damage to the construction, and allows estimating the magnitude and the main direction of the external action, which is the cause that provoked the surveyed damage. The numerical tools suited for the analysis of ruins in archaeological sites, such as the sites analyzed in [2][3][4], present in literature, rely on FEM [5,6], DEM [7][8][9][10][11][12] or rigid-block models [13][14][15][16][17][18][19][20][21] as well as equilibrium approaches [22][23][24][25]. However, they need input data regarding the material properties [26,27] and data on the life-cycle of the structure necessary to reduce the material strengths that are not always available in cases of archaeological artifacts. ...
During the archaeological excavations carried out in the summer of 2017, it was immediately observed that the three uppermost courses of the two leaves of the city walls in the north area of Pompeii were staggered by 10 cm from the underlying ones. This arrangement cannot be attributed to a “building error” but, more probably, to a subsequent event. Ruling out the initial hypothesis of a damage due to the historical earthquake in 62 AD or, in any case, to a seismic event, the authors have performed some numerical analyses, in order to investigate the possible cause of that damage, that seems to be compatible with the action exerted by the pyroclastic flows provoked by the 79 AD eruption of Mount Vesuvius, that is the only other important event recorded in that period. This paper reports on the construction technique and the historical phases of Pompeii's city walls construction and presents the investigations of the crack pattern and the performed numerical assessments. The method used herein has allowed the timeline of the events that caused that damage to be retraced, as well as proving that a damage mechanism different from the translational one, that was observed directly on-site, could not have been caused by a thrust, provoked by the windy flows, in the magnitude that has roughly been computed by the authors. If the hypothesis of the block displacement of the city walls is corroborated also by other future investigations, this damage would be the second one attributable to the eruption of Vesuvius, the first one being the lack of the first floors of the buildings, a damage already attributed to the thrust action of the windy flows by volcanologists.
... Furthermore, masonry structures belonging to architectural heritage (Paradiso, Galassi, and Sinicropi 2014a;Galassi, Dipasquale, Ruggieri, and Tempesta 2018) often occur as ruins (Aguilar et al. 2015;Albuerne and Williams 2017;Ruggieri et al. 2018;Sassu et al. 2013) composed of structural members detached from the original structure, therefore more easily vulnerable, such as individual walls, entablatures, arches or even punctual elements such as columns. To preserve these artifacts (Bogoeva-Gaceva et al. 2007;Dolce et al. 2001;Jurina 1997;Loccarini et al. 2016;Paradiso et al. 2013;Rovero, Focacci, and Stipo 2013;Sinicropi et al. 2014;Galassi 2018a, Galassi 2018b) located in archaeological sites, special tools are necessary to assess the actual vulnerability against possible external actions such as foundation settlements (where the soil is not properly compacted) and earthquakes. ...
... For analyzing the stability of the concrete barrel vaults of the Basilica of Maxentius in Rome, Italy, Albuerne and Williams (2017) used the thrust line analysis (Heyman 1995) and graphic statics. For the analysis of the cross vaults of the central nave, thrust line analysis was combined to the slicing technique introduced by Poleni (1748) to subdivide the entire vault into ideal arches. ...
Ancient masonry constructions in archaeological sites are often ruins or remains of wider portions. Therefore, archaeological artifacts generally occur as a discontinuous set of walls or columns detached from the original context. The absence of most of the original structural portions makes them much more vulnerable. Indeed, even if their current existing condition is an indicator of their equilibrium condition under gravitational loads, this condition is not sufficient to guarantee their preservation in the case of an unexpected earthquake. Furthermore, the cracking patterns and collapses make them even more vulnerable. For these reasons, the vulnerability of ruins should be addressed as regard to the possible failure mechanisms that can be activated by seismic actions. Accordingly, in this article a novel and targeted numerical tool for seismic vulnerability assessment of remains in archaeological sites, that considers collapse mechanisms occurrence as the main cause of masonry constructions being lost, is presented. Results of the numerical procedure proposed are compared with the results obtained by the canonical formulation of virtual works. Finally, the seismic vulnerability level of selected masonry constructions in the archaeological sites of Pompeii and Arpino (Italy) has been assessed by the use of this procedure.
... The need for preserving, restoring and consolidating architectural and monumental heritage [1,2], as well as ruins in archaeological sites [3][4][5][6], is the reason for the development of innovative materials and techniques for strengthening and repairing them [7][8][9][10][11][12][13][14]. In this framework, masonry arches, vaults and domes are typical and recurrent structural elements of architectural heritage that need to be preserved. ...
In recent years fiber-reinforced polymers (FRP) have been widely used for strengthening masonry structures. In particular, in the case of masonry arches, the use of FRP sheets increases load-bearing capacity by limiting or preventing the occurrence of tensile cracks that could activate collapse mechanisms. The effectiveness of the strengthening intervention depends on the bond between FRP and substrate, due to the shear and normal stresses that occur in the bond interface, so much so that the typical failure mode of an arch reinforced with narrow FRP sheets at the intrados is exactly delamination. In this paper a predictive numerical procedure of the combined mode I and mode II failure is proposed. Numerical results provided by this procedure are compared to the experimental results on in-scale arch models taken from a recent work of the author.
