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The ability to shift our internal state to meet expected environmental demands fundamentally molds our experience of and interaction with the world, supporting learning, speech comprehension, and social behaviors. Such dynamic attending relies on (1) temporal expectations to guide neurobehavioral state shifts and (2) sufficient state flexibility to allow for these shifts. When the latter goes awry, we may struggle to increment our attention when faced with challenge or decrement arousal despite quiescent conditions. Whereas previous literature on dynamic attention emphasizes the role of temporal expectancy, little research examines the interplay between state flexibility and temporal processing. The present thesis aims to fill this gap in scientific knowledge by addressing both temporal processing and state flexibility in relation to dynamic attention. To do so, we measure sensorimotor synchronization and brain responses to rhythmic auditory stimuli to examine temporal processing, whilst considering the influence of diverse stressors on one’s ability to shift states via self-reported lifestyle factors and emotional wellbeing.In an experiment using both behavior and electrophysiology, Chapter 1 identifies a potential neural marker of auditory temporal processing. Chapter 2 subsequently provides an integrative review elucidating the influence of psychological and physiological stressors on brain state and state flexibility through allostasis. Chapter 3 then lends support to the arguments outlined in Chapter 2, describing an experiment in which chronic stress burden was found to correlate with resting cortical state. Lastly, a collaborative systematic review in Chapter 4 highlights the therapeutic potential of voluntary regulated breathing as a means of stress-reduction. Cumulatively, this research emphasizes the importance of neurobehavioral state flexibility in dynamic attention and its modulation by varied stressors. This synthesis illuminates the extensive yet underappreciated interconnectedness of brain, body, and behavior and urges a reconceptualization of stress, health, and the brain to lead future research and application.

This paper discusses the experimental qualification process of Fabric Reinforced Cementitious Matrix (FRCM) composites with Polyparaphenylene BenzobisOxazole (PBO) textiles. FRCMs consist of fiber textiles incorporated within inorganic cement or lime mortar matrices and have emerged as composite materials suitable for the retrofit of unreinforced masonry structures. The Italian Ministry of Infrastructures and Transportation and the European Organization for Technical Assessment have developed guidelines defining standard tests to certify the FRCM mechanical properties for qualification and acceptance purposes. This paper presents part of the experimental qualification results for PBO-FRCM composites with two PBO textiles (unidirectional and bidirectional) applied to two different masonry substrates (clay bricks and tuff blocks), considering tensile, bond and durability behavior. Direct tension tests were carried out on PBO textiles and FRCM specimens, with or without textile lap splices. Single-lap tests allowed determining the bond properties of both FRCMs on clay-brick and tuff-block masonry substrates. The stability of the tensile properties with respect to degradation induced by environmental actions was evaluated by performing direct tensile tests also on FRCM specimens conditioned in humid, saline, and alkaline environments, or subjected to high-temperature stress.

This paper presents a comprehensive experimental campaign performed on natural stone masonry wallettes jacketed with 14 different combinations of mortars, meshes, and connectors. After characterizing the mortars and the bare masonry, diagonal compression tests were performed on three specimens for each jacketing solution. The performance of a fiber-reinforced, high-performance mortar without reinforcing mesh was investigated, considering its application to one or both sides of the wall, with and without connectors. Then, two different fabric reinforced cementitious matrix solutions were tested, using unidirectional or bidirectional textiles. Finally, the effects of FRP mesh spacing, mortar composition, and connector type and density were explored on reinforced plaster applications. The test outcomes were analyzed in terms of failure mode, tensile strength, and corresponding shear deformation capacity. All combinations proved effective at increasing the tensile strength compared to the bare masonry, with ratios between 1.9 and 4.7.

Researchers and practitioners widely employ simplified Equivalent Frame Models (EFM) for reproducing the in-plane governed response of unreinforced brick masonry (URM) structures, as they typically represent an acceptable compromise between numerical accuracy and computational cost. However, when considering URM structural systems with irregular opening distribution, the definition of the effective height and length of deformable components (i.e. pier and spandrel elements) still represents an open challenge. In this work, the influence of irregular distribution of openings on the predicted lateral response of full-scale URM façades was investigated. To this end, several geometrical combinations characterised by various degrees of irregularity were considered and idealised according to commonly employed EF discretisation approaches. Then, after a preliminary calibration process against experimental tests on both individual piers and a full-scale building façade, EFM results were compared with micro-modelling predictions, carried out within the framework of the Applied Element Method and used as a benchmark. Although in specific irregular configurations using some discretisation approaches, macro and micro-models converge to similar results, non-negligible differences in terms of initial lateral stiffness, base-shear and damage distribution were observed with other EF schemes or opening layouts, thus indicating that a careful selection of appropriate criteria is indeed needed when performing in-plane analyses of URM systems with irregular opening distributions. Finally, building on inferred simulated data, potential solutions are given to overcome typical EF discretisation issues and better approximate micro-modelling outcomes.

This paper explores and validates the use of ground shaking scenarios generated via 3D physics-based numerical simulations (PBS) for seismic fragility studies. The 2009 L’Aquila seismic event is selected as case-study application, given the availability of a robust and exhaustive post-earthquake database, gathering observed seismic damages detected on several building typologies representative of the Italian built environment, and of a validated numerical model for PBS ground shaking scenarios. Empirical fragility curves are derived as a function of different seismic intensity measures, by taking advantage of an improved statistical technique, overcoming possible uncertainties in the resulting estimates entailed by data aggregation. PBS-based fragility functions are compared to the corresponding sets of curves relying on updated ShakeMaps. The predictive capability of the adopted simulation strategies is then verified in terms of seismic damage scenarios, by respectively coupling PBS- and ShakeMap-based fragility models with the corresponding ground shaking scenarios. Comparison of observed and predicted damage distributions highlights the suitability of PBS for region-specific seismic vulnerability and risk applications.

In this paper, empirical fragility curves for reinforced concrete buildings are derived, based on post-earthquake damage data collected in the aftermath of earthquakes occurred in Italy in the period 1976–2012. These data, made available through an online platform called Da.D.O., provide information on building position, building characteristics and damage detected on different structural components. A critical review of this huge amount of data is carried out to guarantee the consistency among all the considered databases. Then, an in-depth analysis of the degree of completeness of the survey campaign is made, aiming at the identification of the Municipalities subjected to a partial survey campaign, which are discarded from fragility analysis. At the end of this stage, only the Irpinia 1980 and L’Aquila 2009 databases are considered for further elaborations, as fully complying with these criteria. The resulting database is then integrated with non-inspected buildings sited in less affected areas (assumed undamaged), to account for the negative evidence of damage. The PGA evaluated from the shakemaps of the Italian National Institute of Geophysics and Volcanology (INGV) and a metric based on six damage levels according to EMS-98 are used for fragility analysis. The damage levels are obtained from observed damage collected during post-earthquake inspections through existing conversion rules, considering damage to vertical structures and infills/partitions. The maximum damage level observed on vertical structures and infills/partitions is then associated to the whole building. Fragility curves for two vulnerability classes, C2 and D, further subdivided into three classes of building height, are obtained from those derived for specific structural typologies (identified based on building height and type of design), using their frequency of occurrence at national level as weights.

Unreinforced masonry (URM) buildings with cavity walls, typically constituted by the assembly of a loadbearing inner leaf weakly coupled to an outer veneer with no structural functions, are widely present in a number of regions exposed to tectonic or induced seismicity, including the Groningen province (The Netherlands), which has lately experienced low-intensity ground shaking due to natural gas extraction. Recently, experimental evidence has shown that the lack of seismic details, and, above all, the presence of large ground floor openings, makes these structures particularly vulnerable towards horizontal actions. In this endeavour, advanced discrete element models, developed within the framework of the Applied Element Method (AEM), are employed to investigate numerically the impact of ground floor openings percentage on the dynamic behaviour of cavity wall systems representative of the typical Dutch terraced houses construction, namely low-rise residential URM buildings with rigid floor diaphragms and timber roof. Firstly, the model is validated through comparison with a shake-table test of a full-scale building specimen, tested up to near-collapse. Then, a comprehensive numerical study, which featured several combinations of ground-floor openings and the application of various acceleration time-histories up to complete collapse, is undertaken. The ensuing results allowed a comparison of the fragility associated with each of the considered openings layouts, showing how the presence of large ground floor openings may significantly increase the seismic vulnerability of typical URM Dutch terraced houses.

The homogeneity of standard Italian railway stations in terms of period of construction (second half of the 19th century), architectural and structural features, typical dimensions and morphology (...

This paper illustrates the derivation of an empirical fragility model for residential unreinforced masonry (URM) buildings, calibrated on Italian post-earthquake damage data and compatible with the key features of the Italian national seismic risk platform. Seismic vulnerability is described by fragility functions for three vulnerability classes, then refined based on the building height. To this aim, a clustering strategy is implemented to merge predefined building typologies into vulnerability classes, based on the similarity of the observed seismic fragility. On the other side, a specific procedure is built up to determine the vulnerability composition of the exposed URM building stock, starting from national census data. The empirically-derived model was implemented into the national seismic risk platform and used, together with other vulnerability models, for assessing seismic risk in Italy. The results presented in this paper, consisting of refined typological fragility curves and fragility curves for vulnerability classes, can be also exploited for estimating both expected seismic damage and risk in sites with similar seismic hazard and building inventory.

The seismic performance of existing unreinforced masonry (URM) buildings is considerably affected by typology and level of effectiveness of both construction details and structural components, especially if not originally designed for resisting earthquakes. Within this framework, the use of advanced numerical approaches that are capable of duly accounting for such aspects might improve significantly the assessment of the global response of URM structures. In this article, the applied element method is thus employed for simulating the shake table response of a number of full-scale building specimens representative of cavity wall terraced house construction, used in a number of countries exposed to tectonic or induced seismicity, accounting explicitly for the influence of the presence of both rigid and flexible diaphragms, degree of connections among structural members, and interaction between in- and out-of-plane mechanisms. Although the models slightly underestimated the energy dissipation in some specific cycles prior to collapse, the predicted crack patterns, failure modes, and hysteretic behaviors have shown a good agreement with their experimental counterparts.

The overall seismic resistance of unreinforced masonry (URM) systems that exhibit box-behavior mainly relies on the lateral force capacity of structural components. Despite the fact that it is wide...

This paper discusses the results of a unidirectional shake-table test carried out on a full-scale unreinforced clay-brick masonry building with chimneys. The specimen embodied construction details representative of old detached single-storey houses of the Groningen province in the Netherlands, without any specific seismic-resistant detailing. The house featured a typical Dutch gambrel roof that allowed for living space above the attic floor, with high gables that were vulnerable to out-of-plane excitation. The floor consisted of timber joists and planks, resulting in a flexible diaphragm. Two clay-brick chimneys were included to investigate the performance of falling non-structural masonry elements in earthquakes. A cumulative incremental dynamic test was performed up to collapse conditions, using input ground motions compatible with induced seismicity scenarios for the examined region. The paper summarises the key characteristics of the specimen and the observations from the shake-table tests, illustrating the evolution of the structural and non-structural damage, and the dynamic response of the building. The attainment of significant damage limit states is correlated with experimentally defined engineering demand parameters and ground-motion intensity measures for the performance-based seismic assessment of unreinforced masonry buildings. All data from the tests are available upon request on www.eucentre.it/nam-project.

A unidirectional shake-table test was performed on the half-scale prototype of a natural stone masonry building aggregate, to investigate the seismic performance of this type of historical construction and to assess the effectiveness of two retrofit solutions. The specimen represented a building aggregate with two adjacent three-storey units, connected along one side as if they were built at different times. Double-leaf stone masonry with undressed blocks and river pebbles was used for the walls. Timber floors constituted flexible diaphragms in their planes. Roofs with different timber truss configurations and heights covered the two units. Improved wall-to-diaphragm connections and tie rods were pre-installed, although initially not fastened, on the prototype. Both retrofit systems were activated after significant damage was reached testing the unstrengthened specimen. This paper describes the seismic behaviour of the prototype, focusing on the effects of the retrofit interventions on damage mechanism evolution, lateral displacement demand, hysteretic response, and dynamic properties degradation.

Structural design of unreinforced masonry buildings in The Netherlands, recently exposed to low-intensity ground motions induced by gas extraction, was not originally conceived for earthquake-resis...

Several architectural configurations of unreinforced masonry residential buildings are designed according to the different methods proposed in the Italian code: rules for the so-called simple mason...