This paper presents the comparative results of the static and dynamic monitoring of damaged masonry macro-elements. The structural health monitoring (SHM) has been carried out over 3 years. The crack opening displacement of the main shear cracks of the overturning mechanisms of the façade, of the bottom walls of transept and the cracks of the arches was monitored using extensometers. Moreover, dynamic sensors for measuring accelerations were used and through the registration of each major seismic vibration event, a modal identification of output-only systems was carried out; the main frequencies were identified. This work highlights the structural damage detection methodology and shows the differences between global and local damage detection techniques. The static monitoring presents the displacement trend of each monitored main crack with its respective temperature–time history. The results of both long-term monitoring systems are compared to develop the reliability and the correlation of the static and dynamic parameters over 3 years. Static and dynamic monitoring are useful to check both the level of damage and the degradation of the cracking survey, to evaluate the interaction with the safety measures, and also to analyze the stability of signals by varying the intrinsic and environmental conditions such as temperature. This research reveals a good reliability between the static and dynamic results, particularly on the detection of the effect of a safety intervention. Moreover, the results highlight the limits and merits of each monitoring system.

This paper presents part of the diagnostic activities performed for the subsequent major restoration work of the Rialto Bridge in Venice. The document analysis, the visual inspection, and the destructive tests on extracted masonry samples have proved to be the first important steps for an initial structural assessment and for the characterization of the materials. Moreover, the tensile stresses of the tie-rods, which connect the two sides of the shops structures, have been measured by means of dynamic tests. To study the local and the global dynamic behavior of the bridge structure and its overlying shops structures, a dynamic monitoring was performed. The data were acquired through ambient vibrations test to measure the dynamical properties (mode of vibration, frequencies, displacements, and damping ratios) of the historical construction using a modal identification of output-only systems. The main natural vibration sources were pedestrian traffic, wind, and wave-motion of the Grand Canal. Modal identification was carried out through poly-reference least square complex frequency-domain (pLSFC) estimator. Finally, of the variations of the boundary conditions and the structural interaction between the bridge and the shops, structures on the modal shapes are evaluated through a finite element model. The global structural health monitoring was carried out to define the real dynamic behavior of this important bridge.

Compared with other diagnostic techniques, which are limited to the local investigation, the structural dynamic monitoring allows to obtain information about seismic response and vulnerability of structures, in their whole. The experimental modal analysis evaluates the dynamic parameters such as frequencies, vibration modes and damping coefficients. For historic buildings, due to their heterogeneity and complexity, these data are not yet readily available. The possibility of applying the simplified procedures for the dynamic identification of the different historic structural typologies is, therefore, strategic to obtain useful information to apply the design criteria and the structural verifications in the seismic field. Besides the simplified procedures allow an optimization both on the execution time and on the costs. The paper provides some hypothesis of simplified dynamic monitoring procedures through the reduction/optimization of the accelerometric sensors used for three case studies, which differ in structural typology such as Churches, Towers and Palaces.

Historical churches, in the most of cases, are characterised by the presence of annexes and rigid diaphragm that influence their seismic response. Therefore, this research aims to investigate the disadvantages and the benefits which emerge during the horizontal dynamic actions between these structures. This study presents some analyses carried out on the Gesu Church in Mirandola, which was damaged by the 2012 Northern Italy earthquake.The first fundamental steps have been the geometrical, material and in particular the seismic damage survey. An undamaged finite element model of the actual configuration of the Gesu church with a perfectly connected annex was created and was also considered the same model as an isolated structure. Through these FE models preliminary modal dynamic analyses were conducted in the linear elastic field. Subsequently non-linear static analyses were carried out to investigate the ultimate capacity of the building.The churches are characterised by large halls without internal thorn walls, slender walls, pushing elements and lack of intermediate horizontal connection. All these factors lead each macroelement to have an independent dynamics, showing the absence of box-like behaviour. Since the roof trusses are one of the few structural elements that can determine a better global behaviour, it has been decided to perform the same numerical analyses even in the FE models without the roof, then considering the extreme case of a not effective simply supported roof. (C) 2015 Elsevier Ltd. All rights reserved.

damaged by Emilia-Romagna earthquake sequence of May 2012. The research suggests solutions for the rehabilitation of a masonry historic building that presents a serious damage pattern. The solutions includes the base isolation of the global structure. Through the historical analysis, the damage survey and the mechanisms analysis were defined the macro-structure of the palace. Subsequently, was generated different configurations based on the aggregation or separation of the five macro-structure identified. The separation of these proposed projects is done through the use of seismic isolators and dampers. It was carried out a simplified finite element model and the linear elastic dynamic modal analysis was performed to evaluate the main modes of vibration of each configuration, which correspond to the higher values of percentage of participating mass. Finally a response spectrum analysis was performed with the use of data of the earthquake of 29 May 2012. It going to evaluate the seismic behavior of all the configurations.

We show the preliminary seismic monitoring of a historical church in L'Aquila (central Italy), which was strongly damaged by the 2009 seismic sequence. This structure, S. Maria del Suffragio church, suffered the collapse of a great part of the dome during the April 6th 2009 Mw 6.1 earthquake. In this paper, recordings of ambient noise and local earthquakes have been analyzed. The seismic data were recorded by means of a dynamic monitoring system (19 mono-directional and 3 tri-directional piezoelectric accelerometers) and of two velocimeters, with all the instruments installed into the church. The aim of this research is the evaluation of the performance of the accelerometers of the monitoring system in case of low-amplitude vibrations. Simple techniques of analysis commonly employed in the seismic characterization of buildings have been applied. The reliability of the in-situ data was evaluated and the main modal parameters (natural frequencies and damping ratio) of the church were presented.

The aim of this study is to evaluate the influence of SFRC repairs of different thicknesses on the mechanical performance of RC slabs, especially with respect to the crack pattern and level of cracking load. To understand the influence of SFRC, in terms of performance and variation of cracking load after repairing, a comparison with a reinforced concrete slab without fiber reinforcement was made. The study shows also the mechanical characterization of SFRC through conventional testing, to evaluate compressive strength, fracture energy, tensile strength and toughness. Concerning the application of SFRC on the concrete slab surface, the bond was improved by removing a small amount of superficial material. Finally, the experimental results on cracks distribution, displacements and level of cracking load are shown.

The first experimental dynamic parameters of a large spatial FRPs (Fiber Reinforced Polymers) pultruded structures are presented in this research. This construction is a temporary structure realized to accommodate future restoration work and to cover a historic church of Santa Maria Paganica stroked and partially collapsed by 2009 L'Aquila earthquake. The covering structure is an all FRP spatial-reticular with elements made by pultrusion process, connection plates by bag molding process and steel bolts. The dynamic behavior was analyzed using the ambient vibrations test to measure the mode of vibration, frequencies, displacements and damping ratios of the structures using a modal identification of output-only systems. The operational modal analysis OMA has been carried out to identify the modal characteristics through poly-reference Least Square Complex Frequency-domain (pLSFC) estimator.

This paper presents a first program of non-destructive tests carried out on two medieval façades and inside the main rooms of Palazzo Ducale in Venice, i.e. the room of Maggior Consiglio and the room of Scrutinio. A probably multiple leaf load-bearing brick masonry and an external cladding of polychrome stones compose these façades under investigation. The aim of the tests concern the improvement of knowledge about the construction technique and the mechanical features of these important historical facades. The program was set up after a preliminary historic investigation. Non-destructive and minor-destructive investigations (i.e. pattern surveys, endoscopic tests and georadar test) on the inner sides of the two walls of the area under examination were carried out for the analytical determination of the construction technique and structural characteristics, not clearly inferable from the literature.Due to the complexity of the structure and the transformations undergone in seven hundred years of life, and to the very limited investigable areas of the internal surface, the results of investigations cannot be extended to the entire structure. Nevertheless, these tests provide valuable clues to give a correct interpretation of the construction technique and to contribute to identify the possible mechanical properties, which provide knowledge about the health state of the building.

A CGF Panel (Concrete Glulam Framed Panel) is a concrete panel with a glued laminated timber frame. The experimentation on this new construction system at LabSCo (Laboratory of Strength of Materials) of IUAV University of Venice, inspired a wide research on buildings made of this construction system investigating in different aspect of building behaviour: particularly about mechanical property of the materials, mechanical of the system and building physics. This paper presents the results of quasi-static in-plane tests on single panel and configurations of some different panels. The tests in the laboratory are used for measuring the in-plane strength and stiffness of individual panels and wall sections consist of some panels in order to verify and measure the behavior of the connections between the various parts of the single panel and the connection between the panels. Thanks to the results obtained it was possible carry out the FE model to calibrate the characteristics in relation to experimental data. Finally, in order to compare this constructive system with the well known X-lam systems, on the basis of the calibration of the models we were able to set up a comparable FE model with those of the X-lam wall described in the publication: "Quasi-Static and Pseudo-Dynamic Tests on XLAM Walls and Buildings " inherent in the SOFIE project coordinated by the CNR-IVALSA (Italian National Research Council - Trees and Timber Institute)

The Church of Gesù and the tower of the Cathedral were stricken and damaged by Emilia-Romagna earthquake sequence of May 2012. This paper presents the procedure for the structural identification of the most widespread types of religious monuments. The dynamic behavior was analyzed using the ambient vibrations test to measure the dynamical properties (mode of vibration, frequencies, displacements and damping ratios) of the constructions using a modal identification of output-only systems. The operational modal analysis OMA has been carried out to identify the modal characteristics through poly-reference Least Square Complex Frequency-domain (pLSFC) estimator. The global structural health monitoring was carried out to define the real dynamic behavior of the damaged constructions that are subjected to different mechanism. These researches are useful for the structural rehabilitation and to define the possible changes in the structural behavior.

The paper shows the results of monitoring activities to check the structural response and the level of damage of two historic monument of LAquila: San Pietro di Coppito and Santa Maria Paganica, that were damaged by the main earthquake of April 2009. The diagnostics operation was planned and carried out in situ and in laboratory to verify the integrity of the residual stiffness of the structures and to define the mechanical parameters of the material. The mechanical characterization of materials was carried out through destructive tests on samples, taken directly on site, and micro-destructive tests through single and double flat jacks. To give a first qualitative assessment of overall was used sonic test (non-destructive test) on the main macro-structure. The global structural health monitoring (SHM) was carried out through ambient vibrations to define the real dynamic behavior in serviceability state and to calculate - via a modal identification of output-only systems-the dynamic parameters (mode of vibration, frequencies, displacements and damping ratios). The aim of this research is to prove the reliability of different diagnostic methodologies, the real extent of global and local damage and the extent of the residual stiffness of the macro elements of the structures (façade, tower, walls of nave, transept) that are subjected to different mechanism of failure.

The paper shows the approach toward the construction of a very large Pultruded Fibre Reinforced Polymer (PFRP) temporary structure realized to accommodate future restoration work and to cover a historic church stroked and partially collapsed by 2009 LAquila earthquake. The aim regards the analysis and evaluation of seismic performance of that structure made by very light and elastic-brittle material, as FRP material, in a moment in which there is a loss of technical recommendation for specific calculation in seismic field, indeed actually some deepening already present in literature allows only static field. The covering structure is an all FRP spatial-reticular with elements made by pultrusion process, connection plates by bag molding process and steel bolts. The PFRP structure covers more than 1050 meters squares surface with 32 meters height and only 100 kN weight. Detail performance of first part of PFRP structure through mode vibrations and involved percentage mass deduced by numerical approach with discussion of employments perspectives of PFRP material in seismic zones than traditional material are showed.

The aim of this research regards the evaluation of mechanical performance of a prototype panel made by steel fiber reinforced concrete, SFRC, on the top, and fiber reinforced pultruded sandwich panel, GFRP, on the bottom, subjected to combined moment-shear actions through four-bending test. Two different mechanical solutions were used for the connection of the panels. A first steel connection previously designed and a second one with resin applied uniformly on the surface of GFRP panel. The SFRC-G panel involves the analysis of the weakness of GFRP material due to its very low deformability, the risk of the local instability and the elastic brittle behaviour till the collapse, while steel is obviously characterized by elastic-plastic curve. However in the test proposed the ultimate limit state (SLU) involves first of all the loss of bond strength between materials. The panels length/thickness ratio has been previously designed to give prominence to flexural-shear combined actions and in verifying the connections capacity.

The research showed focus on the performance comparison between two equivalent frame structure. i.e. the first one made by steel and the second one by all frp (fibre reinforced polymer ) pultruded material. The structure adopted for the analysis is a traditional two floors frame made by connections between columns and beams. The connection has been assumed rigid to simplify the comparison, already very hard and to point out on the overall structural answer of the two different cases. The reason why of the investigation is related to teh need to deep detail the eventually structural benefits in presence of FRP material. However the success is related to a very reduced weight of FRP material (with weight equal to 1600-1800 kg/m3) linked to a not negligible performance in term of strength and durability, even if also the easy employment play a very important rule. The two storeys frame were subjected to static and dynamic actions to analyse also in comparison the response

The City Hall of Mirandola was stricken and damaged by Emilia-Romagna earthquake sequence of May 2012. This paper presents the procedure for the structural monitoring control of a masonry historic building that presents a serious damage pattern. Structural monitoring was carried out with transducers installed to control the serious cracks that regards the main volumes of the building. The global structural health monitoring was useful to define the actual condition of the dynamic behavior of the damaged construction that are subjected to different mechanism. Ground penetrating radar allows to detect the depth of the cracks and the condition of the masonry. These researches are useful also for the structural future rehabilitation and to define the possible changes in the structural behavior.

During the seismic event of May 2012 in the Emilia-Romagna Region (Italy), several cultural heritage structures collapsed or were severely damaged. This paper gives a description of the damage/collapse mechanisms observed on some of these buildings. The Church of Gesù, the City Hall and the tower of the Cathedral in Mirandola (MO) were analyzed. In particular, this article focuses on the behavior analysis of a church, a palace and a bell-tower, mainly masonry construction, that are the most widespread types of protected monuments proposed in the Italian code as simplified models for the verifications on the entire cultural heritage of a prior assessment of the seismic risk. The survey permitted to detect the most significant damage, mainly related to the cracks of the masonry and to understand the different collapse mechanisms.

In May 2012, two major earthquakes occurred in Emilia Romagna region in Northern Italy, causing widespread damage. The hypocentre of the second one, strokes Mirandola where is located the Gesu Church investigated in this research. The church has a long and important annex to the south built during the same period of the church. This paper addresses how the important annex influenced the seismic response of this historical church and how, more generally, this kind of asymmetric mass can influence the behavior of historic churches. The final considerations are based on the comparison between the structural damage pattern survey and modal and seismic FE analysis. A FE model was constructed considering four different configurations: (i) isolated church, (ii) the church with the presence of the real annex with a perfect connection, (iii) the church with the presence of the same annex but with an interface between the church and the annex and (iv) this last configuration with the stiffness degradation of the interface. Firstly the dynamic modal analysis and subsequently the seismic spectral analysis were performed. The results indicate that the annex's presences play a significant role in the dynamic response of the church and affect the distribution of damages for the whole building. The results of the seismic simulation are in agreement with the observed damage. (C) 2014 Elsevier Ltd. All rights reserved.

The paper presents a critical analysis of the structural response and the level of damage of a historic tower of Santo Stefano of Sessanio that was hit by the main L Aquila earthquake of April 2009. A FE model was constructed to simulate the structural behaviour during the seismic event. The presence of a reinforced concrete slab in the upper part of the tower probably cause a different dynamic behavior compared with the lower masonry circular walls. Have also been investigated boundary conditions at the base, the different mechanical property of masonry and the contribution of the stiffness of the wooden floors.