In the realm of fracture mechanics, natural stone is frequently overlooked, as often considered the material of the past. This oversight poses a significant challenge to the preservation of historical structures, which commonly rely on such materials. Presented paper addresses fracture parameters of two selected marble types through composite methodology combining experimental, analytical and numerical methods. Specifically, three initial crack geometries, often encountered in historic structural elements, were analysed. In correspondence, three different fracture modes were studied respectively – opening mode I and mixed-modes I/II and I/II/III. In addition to assessment of qualitative and quantitative fracture parameters, the important objective of this research was evaluating the influence of crack geometry on different mechanical properties and offering insights into the complex brittle behaviour often exhibited by marble. The underlying aim of this study was the contribution to the expertise regarding marble under load within the context of cultural heritage, as many of these structural elements suffer substantial structural deterioration phenomena.

The estimation of the fundamental frequency in historic masonry towers remains a challenge due to uncertainties in material properties, structural configurations, and boundary conditions. Empirical formulations provided by national codes and literature are often used, in order to avoid experimental tests, which can prove costly, especially in tall towers. This study uses the concept of rank aggregation, based on the Plackett-Luce model, to enhance the prediction of fundamental frequency in bounded historic masonry towers. By integrating eight different empirical formulations based on geometric parameters, the methodology optimally combines the different laws to generate a new aggregate estimate. This rank aggregation strategy is trained on an extensive historic tower dataset and then validated through an experimental dataset coming from a number of Italian towers. The resulting reference ranking list demonstrates the effectiveness of the Plackett-Luce model in prioritizing the most reliable formulations while minimizing variance. This study further enhances fundamental frequency estimation by fitting datasets to distributions, ensuring a robust and adaptable framework for ranking empirical formulations, which is a relevant parameter for the seismic assessment of these cultural heritage assets.

All FRP structures represent by now a solid reality in the field of structural engineering. In fact, almost all potential applications have already been investigated through in-depth studies, except for seismic performance. The research aims to make a contribution to improving the current knowledge level on the item with reference to an all FRP multi-story building with respect to structures built with traditional materials. The analysis is carried out considering an equivalent (with the same cross sections) steel structure. This research is also in view of future potential comparison with respect to an optimized steel structure (with transformed strengths and deformations). The present study is realized by comparison between modal analysis and participating masses, fundamental period and elastic spectrum response in the case of FRP and steel materials. The investigation starts from a well known all FRP spatial structure build in Italy (L’Aquila), after 2009 earthquake emergency, and already analyzed inside the European TC 250 WG 4 in view of the next Eurocode dedicated to all FRP structures.

Marble is a fundamental material in world’s built cultural heritage. However, often affected by environmental influences, it is subjected to compositional, chemical, and structural degradation over time. The restoration of marble elements is thus an essential process for preserving the built heritage; yet the long-term structural performance and durability of rehabilitated marble components remain insufficiently studied and understood. This study investigates the mechanical behaviour of two marble types, in pre- and post-restoration, with a particular focus on three different notch configurations and the complex marble/adhesive interfaces under applied loads. Through a systematic analysis combining experimental and numerical methodologies, this research aims to unveil the principles governing collapse in restored marble structures. The findings provide key insights into the structural integrity of restored elements, contributing to the optimization of conservation techniques and the development of more durable restoration strategies.

Accurately calculating displacements from sensor data is crucial in structural engineering, yet it presents significant challenges due to inherent errors and noise in sensor data. This study presents a comparative analysis of two displacement derivation methods, one based on velocity data and the other on acceleration data. Deriving displacements from acceleration data involves inherent errors due to double integration, while velocity-based calculations suffer from considerable background noise owing to instrument sensitivity. To assess and compare the performance of both approaches, a Python-based simulation was developed to model the free vibration response of a simply supported reinforced concrete (RC) beam. Two scenarios were considered: one using the analytical solution of the damped vibration equation, and another based on Newmark’s method for numerical time integration. Synthetic acceleration and velocity data generated from both scenarios were used as input to derive displacement via integration. These derived displacements were then compared to the original displacement values from the model. Results show that displacements obtained from velocity data closely match the original model values, while those derived from acceleration data exhibit larger deviations due to cumulative integration errors. Both methods, however, can complement each other when used in combination, offering valuable cross-validation. These findings reflect the outcomes of the first phase of a two-stage research effort. In the next phase, the methodology will be validated through laboratory experiments using real sensor data obtained from a physical RC beam specimen instrumented with accelerometers and velocimeters.

Structural control health monitoring (SCHM) is strategic for safety and conservation of historic buildings and monuments. Currently there are available different techniques to obtain reliable results, and they could be invasive or not invasive. The dynamic monitoring, which is global not invasive one, is particularly efficient. In this field, the use of accelerometers to detect fundamental frequency, damping coefficient and modal shapes is common. These dynamic parameters are useful to understand residual stiffness and damages. This study proposes some results on a recent technique with warless velocimeters, named tomograph - easy to apply and rapid in giving outputs – with whom is possible to record ambient vibrations and to transform these in dynamic parameters by OMA (operational modal analysis) approach. The study focuses a review founded on four selected cases studies – Katmandu, Venice, Ragusa (Italy), L’Aquila (Italy) - which have been chosen due to a specific rationale. In detail, they are all monuments with complex structures, in seismic or sensitive areas, with the need to understand general dynamic characteristics and dominant modal shapes. Findings are addressed to outline benefits and/or criticisms in using results for rapid strategy intervention in monuments and historic constructions.

Dynamic characterization is essential for understanding structural behavior and ensuring integrity. Structural Health Monitoring (SHM) using ambient vibration analysis offers a non-invasive, rapid, and effective approach for assessing historic structures. This study presents a case study on Venice’s historic masonry arch bridges, evaluating their structural conditions through synchronized Tromino sensors. These bridges are not only critical for pedestrian mobility but also represent valuable cultural heritage, making their preservation a priority. A network of Tromino sensors was strategically deployed on each bridge to capture ambient vibrations induced by wind, pedestrian traffic, and environmental factors. The recorded signals were processed using advanced spectral analysis and peak-picking techniques to extract key dynamic parameters, including natural frequencies, mode shapes, and damping ratios. These insights provide a deeper understanding of structural behavior, enabling the detection of potential damage and deterioration trends over time. Results confirm that ambient vibration monitoring is a reliable and effective technique for evaluating bridge conditions, offering early warnings of structural changes without invasive testing. The collected data also aids in the calibration of numerical models, improving predictive accuracy and facilitating Machine Learning applications for long-term structural health assessment. By applying this methodology to multiple case studies, this research highlights the potential of SHM in preserving cultural heritage. The proposed approach enhances structural evaluations, ensuring the longevity and safety of historic bridges while advancing modern engineering practices in infrastructure monitoring and conservation.

The dynamic identification of horizontal diaphragms turns out to be one of the most difficult challenges in Civil Engineering and specifically in the field of Structural Health Monitoring (SHM). Characterising these macro-elements is important for the overall assessment of the building structural behaviour. This information is particularly valuable for unreinforced masonry constructions, often characterized by deformable diaphragms. Ambient vibration testing (AVT) could be very useful to obtain modal parameters without affecting the structure and describing the operating conditions of the entire system. The present work focuses on the AVT and Operational Modal Analysis (OMA) of a traditional Venetian slab, consisting of timber floor finishing with terrazzo flooring, in Ca’Tron, a significant noble palace overlooking on Canal Grande and valuable example of gothic architectural style. The slab was investigated at several acquisition points synchronously recording the response to ambient sources of vibration, through a passive seismic single station. A preliminary rapid processing of the data, through peak picking and Decò methodology allowed the identification of two modes, namely a transversal global mode and a vertical local mode of the floor. Their main modal parameters (i.e. natural frequencies, damping ratios and mode shapes) are presented and discussed.

Geophysical surveys are widely used to reconstruct subsoil seismo-stratigraphic structures with a non-invasive approach. In this study the geophysical surveys were carried out with the aim to characterise the San Giorgio Cathedral in Ragusa (Italy) and the area on which it is built from a dynamic point of view. A 3D subsoil model was realised through the integration of two active (i.e., seismic tomography and multichannel analysis of surface waves) and one passive seismic technique (horizontal to vertical spatial ratio). The instrumentation used for the latter method consists of a tromograph (Tromino®), which is also employed for the characterisation of the building, focusing on the façade and the dome, by means of an ambient vibration test, processed through the standard spectral ratio and frequency domain decomposition methods. Integration of the 3D model, showing the distribution of areas with different physicomechanical characteristics, enables identifying anomalies that are likely attributable to the remains of the ancient Byzantine church of San Nicola. Four lower modes mainly involving the two investigated macroelements are identified. The experimental results outline the advantages of the use of the tromograph both for soil and structural characterisation, especially for massive masonry buildings located in areas with high seismic hazard.

Fibre-reinforced polymer composites in general, and especially glass fibre-reinforced polymer (GFRP), have increasingly been used in recent decades in construction. The advantages of GFRP as an alternative construction material are its high strength-to-weight ratio, corrosive resistance, high durability, and ease of installation. The main purpose of this study is to evaluate the response of GFRP under dynamic conditions (more specifically, under seismic loads) and to compare the performance of this composite material with that of two traditional building materials: reinforced concrete and structural steel. To this aim, a finite element analysis is carried out on a two-dimensional frame modelled with steel, reinforced concrete (RC), or GFRP pultruded materials and subjected to a seismic input. The dynamic response of the structure is evaluated for the three building materials in terms of displacements, inter-storey drift, base shear, and stress. The results show a good performance of the GFRP frame, with stress distribution and displacements halfway between those of RC and steel. Most importantly, the GFRP frame outperforms the other materials in terms of reduced weight and, thus, base shear (-40% compared to steel and -88.5% compared to RC).

Dynamic identification strategies and, in particular, Operational Modal Analysis (OMA) approaches demonstrated to be a significant source of information about the condition of an investigated building, as well as, repeated data acquisitions and processing methods, developed in the field of Structural Health Monitoring (SHM), have been successfully used to track the evolution of this condition over time. Nonetheless, planning a cost-effective ambient vibration monitoring campaign is still an open challenge as several uncertainties must be considered to ensure a beneficial trade-off between number of sensors or set-ups and quality of the information collected. This is particularly important when dealing with historical masonry buildings. The present work discusses the preliminary results of a project, currently under development, whose aim is the definition of optimised protocols for data acquisition and processing for built cultural heritage dynamic identification and monitoring, with specific focus on the Venetian palace typology.

The present study describes an approach to boost the cost-effectiveness of the Operational Modal Analysis (OMA) application to historic buildings, through the optimisation of the trade-off between the number of required sensors and the quality of the information provided by them. Such an approach, currently under development and testing, considers a limited level of knowledge and relies on extensive simulations to assess the effect of the sources of uncertainties on the dynamic behaviour of the structure. In particular, the work focuses on a specific building typology, namely the noble palace overlooking Canal Grande in Venice, dating back to Gothic period. To this end, a prototype is defined based on the most relevant typological and morphological features of this typology, and its Finite Element (FE) model is generated. A Monte Carlo simulation technique is employed to sample several different instances from pre-set probabilistic functions for each stochastic variable. An Optimal Sensor Placement (OSP) algorithm is used to rank different recommended locations for a reduced number of sensors under these parameters’ variation, producing an optimal overall topology for the network. These considerations open future developments in view of a possible protocol applied to this historical building typology.

Sonic tests are well-known non-destructive analysis technique (NDT). Independently or in combination with other examination techniques, they are widely used to understand and qualify structural elements and their mechanical properties, detect the presence of inner voids and flaws, and control the effectiveness of the structural consolidation. This paper presents the results of the combined analysis method, merging different NDTs such as visual inspection and sonic tomography mapping for columns in San Marco Basilica in Venice, Italy. The aim of the study was to assess the structural properties of these elements and to understand and locate the potential ongoing mechanical deterioration. Tomography maps were constructed in selected horizontal and vertical sections, for more profound study with three-dimensional analysis approach. The performed analysis confirmed the suspected mechanical deterioration in all studied stone elements. Most of the areas that exhibit low sound velocity, overlap with the highly deteriorated exterior zones previously identified though the visual surveys. The NDT approach allowed the identification of the types of structural deterioration, and their profound study in three-dimensional space.

Ten years after the earthquake that affected central Italy in 2009, noninvasive investigations were carried out in L'Aquila on the Basilica of Santa Maria di Collemaggio. These were conducted to characterize the ground from a site-response point of view. The study consisted of 11 ambient noise recordings using the Nakamura technique and distributed along two profiles: one longitudinal to the central nave and one transverse. Analyzing the results, it was possible to determine the frequency of the vibration of the ground. After comparison with data from previous literature, it was possible to graph the contrasting sections of the impedance of the subsoil up to about 300 m depth (bedrock) drawing on a passive seismic survey from the single station. Furthermore, sonic tests were performed on the 14 octagonal columns of the central nave. The data were compared with those collected 10 years earlier (post earthquake) and with postearthquake structural restorations. The new tests show an increase of velocity in the resistant sections of the pillars subjected to the structural consolidation. (C) 2021 American Society of Civil Engineers.

This work describes an approach for combining local and global non-destructive techniques for the structural characterization and conservation assessment of cultural heritage buildings. An experimental investigation program was conducted on the south vault of St. Mark's Basilica in Venice, involving historical investigations, a damage survey, sonic tests, and ambient vibration measurements. Recorded data were employed to assess the material and structural properties of the vault and to characterize the observed damage pattern. The study of the correlation between results of sonic tests and ambient vibration measurements has shown how, in complex structural typologies, the information provided by both these two kinds of tests are necessary in order to effectively characterize the structural behaviour, which is strongly influenced by the complexity of geometry and restraint condition. Experimental results have been used for the validation of a numerical model adopting a non-conventional approach. The procedure is based on comparing numerical simulation of ambient vibration response in terms of the frequency content of acceleration signals. This approach can be performed using only a limited number of measured acceleration signals, proving to be useful and cost-effective. The work aims to provide helpful insights into the combined use of non-destructive tests for the efficient structural characterization and safety assessment of heritage structures.

The aim of this paper is to identify, also through micro tremor analysis and numerical analysis, the collapse’s mechanisms of the Nepalese wood-masonry monuments damaged by the 2015 seismic event that struck Kathmandu and its valley. The research analyses two case studies: The Radha Krishna and the Bhimsen Temples.After a careful anamnesis based on visual inspection and hypotheses on the temple’s structural behaviour, a global dynamic ambient test (micro tremor) was carried out for qualitative characterisation of the structural system, residual stiffness and strengths.First, numerical models have been calibrated on mechanical parameters present in literature. The difference between experimental results and numerical model values is higher than 100% in the Radha Krishna temple and 70% in the case of Bhimsen temple. Considering this results, the models were calibrated on the experimental results. The modal analysis shows important mixed effect of torsional and flectional mode in the case of the Radha Krishna temple while in the Bhimsen temple local effects prevail. The capacity curve of Radha Krishna temple shows behavior close to collapse at 0.26 g, while the Bhimsen temple presents important damage at 0.3 in Z direction and 0.23 in X direction.

The proposed research focused on the maintenance and structural check of the first all FRP (Fiber reinforced polymer) pultruded construction built in Italy in the 2018. The proposed steps have been mainly in the frame of the joint’s efficiency evaluation from the local point of view, and in that of visual inspection from a general point of view. By the way, the joint made by bolts are the more potential weak part in these type of constructions. The construction – all FRP made unless steel bolt – has been the consequence of a specific call and is built in the Iuav University Campus in Venice. The structural check is developed through cyclic in situ analysis of the joint bolted efficiency, specifically by means moment toque value applied evaluation and visual damage detection also considering closed formulas already available both for all FRP bolted joints and similar ones as well as connections made by steel and wood. Bolt monitoring is managed by means of a controlled tightening torque wrench which is used to detect the tightening torque for each bolt in the structure. To calculate the friction coefficient used, it was chosen to use the experimental formula on the determination of the µ. For the research, it was decided to use two different friction coefficients to calculate the tightening of the knots. The final aim of the research is to show the results of the structural controls and discussed in the framework of the general performances foreseen for all FRP structures.

The aim of this paper is to identify, both through microtremor analysis and visual inspection, the collapse mechanisms of the Nepalese wood‐masonry monuments damaged by the 2015 seismic event that struck Kathmandu and its valley. The research analyses two case studies as the “Radha Krishna” temple located in Teku, a district in Kathmandu, and the “Pancha Deval complex” in Pashupati area. More specifically, after a careful anamnesis based on visual inspection and hypotheses on the temple's structural behaviour, global nondestructive testing (microtremor) was carried out for qualitative characterization of the structural system. The visual damage survey allowed to identify the recurring collapse mechanisms in the two case studies with the identification of typical Nepali expected damage. The case of Radha Krishna temple denotes a Nepali collapse mechanism typical in the corner of temples made of timber masonry, in which the mechanical contribution of the timber is manifested through columns and windows. The ambient vibration analysis carried out by tromograph device and microtremor evaluation allowed to dynamically characterize the two bases by identifying the peak frequencies both for Radha Krishna and for Pancha Deval complex. With the same device, the two historic constructions have been also studied in evaluating local modes and frequency. In the Pancha Deval complex, a relationship between damage, frequencies, and the amplification of the base was observed. In detail, the five buildings have similar damage and similar first frequencies (2.72–2.9 Hz). The most damaged sides are those with the frequencies close to the base (2.05–2.38 Hz).

The objective of this work is present the results of ambient vibration measurements obtained in two different Nepal missions (October 2016 and October-December 2017). The object of the research is the comparison of the dynamic behavior, through the measurement of the ambient micro tremor, of two monumental Hindu masonry buildings (Bhimsen Temple and Pancha Deval complex) damaged by the 2015 Gorkha earthquake. The methodology used involves a meticulous study of the building through visual inspection and the use of a tromograph for the survey of structures in elevation. The results obtained show, in the case of Jagannath temple, a relationship between the high level of damage and the asymmetrical disposition of the roof beams.In the case of Pancha Deval complex, the AVMs show an interaction between the structure and the ground.

The research explores the capabilities of frames of pultruded FRP profiles as seismic strengthening for masonry walls. A programme is currently in progress at the IUAV University of Venice, consisting of in-plane shear tests on half-scale panels. The selected masonry type is traditional, i.e. clay bricks and lime mortar joints. The goal is to assess the effectiveness of the strengthening system with respect to the undamaged condition of masonry. A particular focus is on the connection system between the panel and the frame, i.e. epoxy adhesive connection and bolted joint. The results will be implemented in FEM analyses and analytical models to predict the system's and the joints' shear strength.