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The adoption of natural construction materials can help mitigate the environmental impact of the construction industry by reducing the amount of energy required and emissions. Among the natural materials, bamboo is a remarkable option, combining high mechanical resistance with a low specific weight and a very high growth speed; however, its application is limited by the absence of a suitable grading method. This paper aims at filling this lack by providing a strength-based grading methodology relying on a four-point bending test. Experimental results were processed considering bamboo both as a homogeneous material and as a non-homogeneous material and using the ANOVA test. Results show that statistical groups can be defined which are not based on the bamboo species, but on the values of the mechanical properties, hence supporting the appropriateness of strength classes. The bending tests used in this paper could be a crucial test for bamboo grading: it is easier to perform than a tensile test and it gives complete information on the change of material properties along the culm wall thickness. The study focuses on six different species of bamboo grown in Italy, for which little data is present in the literature. • Four-point bending test could be a crucial test for bamboo grading. • The flexural properties of six species of bamboo grown in Italy are discussed. • A strength-based grading methodology based on a four-point bending test is provided. • A classification scheme can be defined based on the mechanical properties of bamboo. [ABSTRACT FROM AUTHOR]

• Sodium chloride (NaCl) is the most used salt for anti/de-icing operations of pavements. • Three available variants of NaCl on the market: rock, solar and vacuum. • Evaluation of deicing performances and engineering characteristics of NaCl road salts. Winter road maintenance is a critical function of public works and transportation agencies in states with harsh winter climate or in cold regions. The use of salts represents a cost-effective snowfighting technique, having beneficial impact on public safety, essential mobility and travel costs. Nowadays, sodium chloride (NaCl), in its three available variants (rock, solar and vacuum pan salt), is by far the most widely used chemical for snow and ice control due to its abundance and low cost. There is a worldwide large variation in the actual price of NaCl due to several factors, but often the purchase cost, at the same logistical constraints, is mostly influenced by the origin of the extracted salt and by the demand for better performance expectations. The authors decided to analyze the emblematic case of Italy, a region where supplies from salt pans or port landings are equally widespread sales channels compared to salts from underground mines. Thus, the paper evaluated some fundamental properties of different rock salts, solar sea salts and vacuum pan salt directly supplied by salt storage sites of different Italian highway agencies, which manage comparable road networks (extension and traffic volume) exposed to similar harsh winter climates, following standardized and non-conventional testing procedures related to deicing performances and to engineering characteristics (hygroscopicity, spreading behavior, caking tendency). [ABSTRACT FROM AUTHOR]

Highlights • A novel indicator based on spectral entropy is proposed. • In damage detection of masonry buildings, SSE has been shown to be preferable to WE. • SE measure was used for damage detection in 3 buildings affected by earthquake. • Increment of damage does not necessarily results in an increase of signal's entropy. • Entropy estimate can differ if calculated with different physical quantities. Abstract One of the main drawbacks of using entropy-based indicators for damage detection is known to be their sensitivity to the energy introduced into the system. Indeed, energy supply can lead to a more deterministic behavior of the structure and thus to a reduction of the entropy. As a solution to these issues, in this paper an indicator based on two measures of spectral entropy is proposed to assess the occurrence of damage in masonry buildings, even in the presence of an external unmeasured input (e.g. minor seismic event). The proposed indicator was first validated by using a benchmark numerical model. Subsequently, the methodology was applied to dynamic response data from three monitored masonry buildings that were affected by the 2016–17 seismic sequence in Central Italy. [ABSTRACT FROM AUTHOR]

Abstract: The paper analyses the static behaviour and the seismic vulnerability of the Basilica of Santa Maria all’Impruneta near Florence (Italy). The static structural behaviour and the dynamic properties of the church have been evaluated using the finite element modelling technique, where the nonlinear behaviour of masonry has been taken into account by proper constitutive assumptions. A macro-modelling approach has been used based on the concepts of homogenisated material and smeared cracking and crushing constitutive law. Seismic vulnerability has been evaluated using a pushover method, and the results obtained with the nonlinear numerical model have been compared with the simplified schemes of limit analysis. The capacity of the church to withstand lateral loads is evaluated together with the expected demands resulting from seismic actions. The comparison of seismic demand vs. capacity confirms the susceptibility of this type of buildings to extensive damage and collapse, as frequently observed in similar buildings. The paper’s aim was to point out that advanced numerical analyses can offer significant information on the understanding of the actual structural behaviour of historic buildings. The methodology and the conclusions of this case study it is believed that are applicable to a wide variety of historic Basilica churches. [Copyright &y& Elsevier]

Abstract: In the first part of the present paper, a theoretical model to calculate the progressive bowing of marble slabs submitted to thermal cycles is presented. The model, developed within the framework of linear elastic fracture mechanics, takes into account the mechanical characteristics of the marble as well as the actual cyclic temperature field in the material. The slabs are subjected to a thermal gradient along their thickness (due to different values of temperature between the outer and inner sides of the slab) as well as to thermal fluctuation on the two sides of the slab due to daily and seasonal temperature excursions. This thermal action causes a stress field which can locally determine microcracks due to decohesion of grains. Stress intensification near the cracks occurs and leads to crack propagation in the slab. Such crack propagation under thermal actions is evaluated, and, considering different crack densities in the material and different boundary conditions in the slab, the corresponding deflection (bowing), which account for both elastic bulk deformation of the slab and for the deformation due to the crack presence, is calculated. In the second part of the present paper, the model is applied to the case study of the Pescara (Italy) court building. [Copyright &y& Elsevier]

• A complete characterization of "Scaglia Rossa" masonry is carried out. • The considered masonry monopolized constructions between 1950 and 60s in Central Italy. • Widespread damages and collapses were observed in the 2016 Central Italy earthquake. • Uniaxial compression, bending and shear-compression tests are performed on stone, mortar and walls. • The first quantitative indications were provided, filling a void in current bibliography. This paper outlines the complete characterization of masonry walls composed of "Scaglia Rossa", a typical stone of the Apennine area between the Umbria and Marche Regions in Central Italy. The study focuses the assessment of the mechanical behavior by means of an experimental campaign carried out in the laboratory of the Polytechnic University of Marche, where the samples of "Scaglia Rossa" masonry, obtained from the controlled demolition of three school buildings, were reconstructed with the same techniques of the 1950s-'60s, and then tested in order to identify both the constituent materials, stone and mortar, and the composite masonry. The experimental tests were prior to a numerical analysis implemented by the adoption of a nonlinear model capturing the cracking behavior. The main mechanical parameters were then calibrated by means of an optimization algorithm of Levenberg-Marquardt, considering a continuous approach with both (i) macro- and (ii) micro-modelling techniques and obtaining resistance parameters not deriving directly from the experimental tests. The comparison between the results obtained from the Levenberg - Marquardt algorithm by changing the parameters of the damage model based on data given by the experimental campaign allowed to confirm the validity of the approach used. [ABSTRACT FROM AUTHOR]

• A FE model calibration based on AVT and machine learning process is presented. • The dynamic parameters of the investigated tower are estimated via OMA techniques. • Different parameterization and modelling assumptions are employed for the updating. • The calibrated model accurately reproduces the real dynamic behaviour of the tower. Cultural Heritage preservation requires the combination of in situ investigations and accurate Finite Elements models in order to correctly interpret the empirical evidence and successfully apply advanced structural analyses for health assessment purposes, allowing to infer about the future evolution of the structural response and timely detect deviations from the expected behaviour. In this paper the actual dynamic behaviour of the Civic Tower of Ostra, Italy, is thoroughly investigated by means of a detailed numerical model built and calibrated using the experimental modal features estimated through field dynamic testing. To this end, a fully automated Finite Element Model Updating procedure based on genetic algorithms and machine learning is conceived and employed, allowing the successful estimation of the unknown material properties of the tower, considering both isotropic and orthotropic behavioural models for masonry. The results enabled to establish baseline information on the current structural condition of the heritage and to set performance standards that will serve to optimise the control of the structural integrity over time. [ABSTRACT FROM AUTHOR]

Abstract: This paper examines the interaction of successive historic construction phases in the church and monastery of Santa Maria Nova (Santa Francesca Romana) in Rome, built between the 8th and 20th centuries above the platform of the Roman temple of Venus and Rome, and their effect on the overall stability and conservation of the buildings. The North elevation of the building complex is better conserved, displaying the variety of materials and construction techniques used over the centuries, including the reuse of material, in a close relation with the local conditions. The discussion of the data collected through survey, archive research and architectural analysis identified the complex stratification, materials and techniques, allowing for the interpretation of the buildings, and providing the bases to inform any conservation work. The continuous process of construction, destruction, reconstruction and extension that emerges shows also techniques employed over the centuries to deal with pre-existing fabric while designing in a contemporary way, and their interfaces interest modern architectural technology, as well as conservation research and practice. [Copyright &y& Elsevier]

Abstract: The paper reports the results of a multi-disciplinary study carried out on a significant example of Modernist architecture, dating back to the Fascist period in Italy. The buildings of that period are as laboratories for architectural innovation and are characterized by the adoption of new constructive and technological solutions for the elimination of the decorative and functional element in order to obtain pure volumes. This characteristic feature caused in a great number of Modern buildings design errors and the deterioration of the unprotected elements. In order to safeguard this heritage it is necessary to have a thorough understanding of the materials and the techniques used. This can be achieved only through a multi-disciplinary approach on relevant case studies. The current study was carried out on the characteristic construction components of the main façade of a selected building, the stone cladding and the steel windows, to have a more thorough awareness of the techniques used and to verify the state of conservation. It was also possible to hypothesise conservation actions coherent with the material culture. [Copyright &y& Elsevier]

Abstract: This paper deals with the results of two environmental monitoring campaigns entailing the analysis of NO x levels registered before and after the renovation work of the “Umberto I” tunnel in Rome, Italy. The results of the data collection highlighted an efficient abatement of pollutants by the photocatalytic treatment of the tunnel vault with a cement-based paint, as evidenced through the lower concentrations found after the renovation. A NO x reduction of about 20% was calculated in the center of the tunnel (as an absolute comparison between the two periods), whereas a NO x reduction of over 50% was calculated in the same position, considering the reference data registered in the official stations of the city of Rome (Official Environmental Agency – ARPA). The duration of the monitoring campaigns performed seems to be considered significant from the statistical point of view, unlike all previous experiments which were carried out on the photocatalytic materials. This renovation project can prove out to be a very useful reference for the wide program for a sustainable upgrading of tunnels in Europe, according to the Directive 2004/54/EC on road tunnel safety. [Copyright &y& Elsevier]

• Mechanical characterization of stone masonry panels extracted from an existing building. • Investigation of the property evolution of masonry during cyclic compression tests. • A new analytical formulation is validated through 60 literature tests. • Increasing thickness and tensile strength of the FRM mortar positively affect the masonry shear strength. • FRM performance is lower for URM characterized by higher thickness and/or shear strength. Nowadays, the application of Fiber Reinforced Mortar (FRM) is widely used for the consolidation and rehabilitation of masonry structures because represents an effective solution in terms of reversibility and applicability. The paper illustrates the results of cyclic diagonal compression tests performed in situ on stone masonry specimens isolated from the walls of a historic building of L'Aquila (Italy). The tested stone masonry is representative of existing structures of the territories of the central Apennines in Italy. Only two of four panels were strengthened by FRM to provide also the reference value of the unreinforced masonry. The FRM comprised a glass-fiber grid embedded in a natural hydraulic lime (NHL)-based mortar applied as a coating to the masonry surfaces as well as carbon shear connectors. The tests were analyzed to derive the shear strength and the shear modulus of the masonry, as well as their evolution during the tests. Moreover, these tests were compared and integrated with a consistent number of experimental data collected in the current literature aiming to validate a new analytical equation for the estimation of the shear strength of the reinforced masonry, merely based on the properties of the unreinforced masonry and the FRM mortar. [ABSTRACT FROM AUTHOR]

Abstract: Approach to safety evaluations issued by modern codes is clearly based on quantitative assessment of performances. As a consequence, validated mechanical parameters and numerical models should be made available on large scale for practical applications. This is the background of the present paper that deals with a specific type of masonry largely used in Central Italy and particularly in Umbria and Abruzzo region, whose territory exhibits a relevant seismic risk. A research project focused on the shear behavior of masonry panels subjected to in situ diagonal compression tests has been issued. The project consists of two parts: tests were performed on unreinforced and reinforced panels. As to the unreinforced panels, focusing attention on the diagonal cracking failure mode, the experimental research allowed to provide representative values of the mechanical parameters adopted to define the limit strength domain of some typical masonry walls in old buildings of Umbria and Abruzzo. Conversely, reinforced panels were tested aimed at investigating the effectiveness of existing methods of repair. A comparison between traditional and innovative seismic-upgrading techniques has been made in order to characterize the behavior of historical masonry walls under different strengthening configurations. [Copyright &y& Elsevier]

Abstract: The Paderno iron arch bridge, erected in 1889 and still used as a combined road and rail bridge, is the most important monument of XIX century iron architecture in Italy. The bridge, with an arch span of 150m, has a total length of 266m between the abutments and about 2600tons of wrought iron were used in its construction. After a description of the historic structure, the paper presents the results of the experimental modal analysis of the bridge. The dynamic tests, performed in operational conditions (i.e. under traffic and wind-induced excitation) between June and October 2009, represented the first experimental survey carried out on the global characteristics of the bridge since the load reception tests (1889 and 1892) and suggested the opportunity of installing a permanent dynamic monitoring system on the bridge with Structural Health Monitoring purposes. [Copyright &y& Elsevier]

Abstract: Shear behaviour of masonry has been deeply investigated for a lot of masonry types. Nevertheless, there is still a lack of knowledge on the shear response of tuff masonry, which is widely spread in the existing building inventory in seismic areas like as Italy, Turkey, and Japan. To characterize the non-linear behaviour of the unit–mortar interface within tuff masonry, a series of direct shear tests were carried out. In this paper, both experimental results and empirical formulae are presented. Classical shear strength and deformation parameters along with shearing fracture energy and dilatancy were characterized. A shear response surface including both stress–strain diagrams and the frictional strength model is proposed. [ABSTRACT FROM AUTHOR]

Abstract: The recent earthquakes occurred in Italy (Umbria and Marche 1997 and Molise 2002) have shown that the collapse of masonry buildings is mostly due to out-of-plane actions, caused, for instance, by an inadequate interlocking between perpendicular walls. In this paper, a combined numerical–experimental analysis on in-scale unbonded masonry panels out-of-plane loaded is presented. Three different Series (A, B and C) of mortarless walls subjected to in-plane compressive loads and concentrated out-of-plane actions are considered. Series A is restrained at two perpendicular edges and subjected to an eccentric out-of-plane load, whereas Series B and C are constrained at the base and on both vertical edges and are subjected to an eccentric (Series B) or centered (Series C) out-of-plane load. Experimental tests are repeated in presence of three different vertical membrane compressive loads equal to, respectively, 7, 10 and 13kN. Two different numerical models, relying in an upper bound heterogeneous FE limit analysis and in a FE homogenized limit analysis approach, are employed to have a better insight into the experimentation conducted. The combined numerical–experimental information obtained shows that anisotropic masonry behaviour and vertical compressive loads are key aspects to consider to have a reliable prediction of both collapse loads and failure mechanisms. [Copyright &y& Elsevier]

On 13th March 1996 the dome of the St. Nicolo` Cathedral of Noto fell due to a post-seismic structural collapse. In order to study the soil–structure interaction a comprehensive laboratory and in situ investigation has been carried out to obtain a soil profile. In this paper the dynamic characterisation results and normalised laws are proposed to consider shear modulus decay and damping ratio increase with strain level. The existing foundations of the cathedral were investigated by means of excavations and tests on the stones and the mortar. In this way the foundations were subjected to visual inspections to detect their size and their embedment level. Now, the soil–foundation interaction has been analysed by means of the finite element code SOFIA, considering at this stage the superstructure weight through the influence area approach. In particular, the effects of the designed remedial work of the foundation have been studied, comparing the two configurations before and after the foundation improvement. [Copyright &y& Elsevier]

The collapse of the nave and dome of the Cathedral of Noto, S. Nicolo`, in a rainstorm in 1996 brought to light 18th century construction errors unique to this building. S. Nicolo` is the most prominent church in the city of Noto, a rich Baroque center in southeastern Sicily completely reconstructed after an earthquake in 1693. During the course of its construction and reconstruction between 1696 and 1950, S. Nicolo` was plagued by multiple earthquake failures and construction errors. This paper attempts to assemble the unwritten construction history of the church for the first time in English, and to address the question of how architects, engineers and builders responded to the problem of creating a seismically resistant building. [Copyright &y& Elsevier]