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The strengthening of reinforced concrete columns by steel cages is one of various techniques available to increase ultimate column loads. Different researchers have shown the importance of the beam--column joint on the behaviour of columns strengthened by steel cages. This paper presents a parametric study using finite element models carried out with the aim of analysing the influence of the beam--column joint on the behaviour of axially loaded reinforced concrete columns strengthened by this technique. A design rule is proposed to provide a means of estimating the ultimate load capacity of column--joint assembly and recommendations are given concerning the design of the steel cage. [ABSTRACT FROM AUTHOR]

• Optical Fiber Sensing offers a valid alternative to existing shape sensing methods. • This technology can bring remarkable improvements to different fields. • This paper presents a review of the state of the art of Fiber Optic Shape Sensors. • The paper aspires to be an exhaustive guide for anyone interested in the field. Fiber Optic Shape Sensing is an innovative Optical Fiber Sensing Technology that uses a fiber optic cable to continuously track the 3D shape and position of a dynamic object (with unknown motion) in real-time without visual contact. This technology offers a valid alternative to existing shape sensing methods, thanks to a combination of advantages (including ease of installation, intrinsic safety, compactness, flexibility, electrically passive operation, resistance to harsh environments and corrosion, no need for proximity or computational or numerical models to reconstruct shape) that can bring remarkable improvements to the fields of Civil, Mechanical and Aerospace Engineering, Biomedicine and Medicine. A considerable research effort has been dedicated to this subject in the last twenty years. This paper presents an ambitious review of the current state of the art of Fiber Optic Shape Sensors (FOSS) based on Optical Multicore Fibers (MCF) or multiple optical single-core fibers with embedded strain sensors and provides a comprehensive analysis of a wide range of aspects, comprising: (1) existing alternative technologies; (2) an overview of optical fiber sensors (3) characteristics and advantages of fiber optic shape sensors; (4) historical achievements; (5) applications; (6) performance and error analysis; and (7) present and future perspectives. [ABSTRACT FROM AUTHOR]

• Edge and corner columns are most vulnerable to accidental events. • A test was carried out on a purpose-built full-scale RC building structure. • A corner-column was suddenly removed. • Alternative load paths were identified. The topic of robustness and progressive collapse of structures has attracted significant attention within the field of structural engineering recently. This is reflected by the rise in the number of scientific papers published in recent years as well as efforts in reviewing and developing codes for design. Although important numerical and experimental studies have been carried out to date simulating the sudden removal of columns to reproduce the possible consequences of an extreme event, most of these studies focus on subassembly systems and internal columns. Edge and corner columns are most vulnerable to accidental events. This paper gives the results of a test carried out on a purpose-built full-scale reinforced concrete building with a specially designed corner steel column used for the sudden column removal. The test was highly instrumented, involving 38 strain gauges, 38 displacement transducers and 2 accelerometers to monitor the vertical and lateral response. The results were used to analyse the dynamic performance of the structure after the sudden column removal as well as the alternative load paths (ALPs) mobilised during the test (i.e. flexural and Vierendeel action). The test showed a clear dynamic amplification of the strains and displacements (with high peaks); dynamic amplification factors (DAFs) were obtained accordingly. The load initially carried by the removed column was redistributed through the entire building system (not just the neighbouring columns). Tests on full-scale buildings, including the one described here, can be used to compile a database to validate codes and future numerical studies. [ABSTRACT FROM AUTHOR]

The most frequently used technique to construct reinforced concrete (RC) building structures is the shoring or propping of successive floors, in which the slabs are supported by the shores until the concrete acquires sufficient strength. A significant number of structural failures have been reported during construction in recent years leading in some cases to the progressive collapse of the whole structure. The collapse often starts with the local failure of a single element which could be due to errors in design or construction and/or due to accidental events. Although this is a well-recognized problem, studies on the effects of local failure in the shoring elements on the integrity of the shoring-structure system have not been carried out in the past. In this work advanced numerical finite element models were carried out of a three-storey RC building and its shoring system. Four scenarios of local failure were considered: sudden removal of a (1) shore, (2) joist and (3) complete shore line; and (4) incorrect selection of shores. The results indicated that the structure-shoring system was able to develop alternative load paths without dynamic amplification effects due to the large stiffness and redundancy of the system without compromising the integrity of the structure but leading to significant damage in the concrete slabs. Design recommendations are also given based on the results from this study, which pretend to be the first study to focus on the structural response and damage of a building structure under construction after the sudden failure of one or more shores. [ABSTRACT FROM AUTHOR]

This paper describes a study carried out in the ICITECH laboratories (Universitat Politècnica de València) on RC columns repaired on all four sides with cementitious-based mortars. A total of 18 specimens were tested, representing a group of square 20 × 20 mm 2 columns subjected to compressive axial loads. Different repair scenarios were considered in order to study the influence of the type of mortar used and the presence or absence of bonding agents between the mortar and the column concrete. The results obtained showed that bonding agents have no appreciable effect on the behaviour of the repaired columns. Of the two types of mortar used in the study (Classes R3 and R4), the columns repaired with the lower grade mortar (R3) were seen to behave better. The main novelty of this work lies in the fact that this is the first time that two types of mortar are compared in the repair of four column sides, in addition to the possible use of bonding agents between the mortar and the column. [ABSTRACT FROM AUTHOR]

The paper presents a machine learning (ML) based framework to predict the prestressing force reduction in prestressed reinforced concrete (PSC) box-girder bridges with unbonded tendons. In the field of road network safety, the reliable assessment of some bridge typologies, such as PSC box-girder bridges, depends on different aspects, among which the inaccessibility of internal unbonded tendons, the difficulty in measuring the effective prestressing force reduction over time, the design of an efficient structural health monitoring (SHM) system. To address the above issues, the proposed approach exploits the results of experimental tests on a scaled PSC box-girder to validate a nonlinear modelling strategy and, in turn, to generate a sample dataset for training different ML algorithms. To ensure generalizability of the proposed ML model, the variability of several parameters, including geometrical and mechanical properties, was accounted for. The obtained results, evaluated in terms of statistical metrics and through an eXplainability approach, revealed that the proposed surrogate model is able to predict the prestressing force reduction for this bridge typology, knowing the current prestressing force, the elastic modulus of the concrete, and the strain variation in specific cross-sections of the structure. The application of the framework on a scaled PSC box-girder experimentally tested, demonstrated its suitability for: i) estimating the prestressing force reduction without employing periodic and expensive onsite tests; and ii) providing the best strategy for employing a sensor-based SHM system. • A ML surrogate model to predict prestressing force reduction in prestressed concrete (PSC) box-girder bridges is proposed. • Experimental test of a scaled PSC box-girder, simulating an effective prestressing loss by removing prestressing cables. • Calibration of FE modelling strategy suitable for simulating prestress losses and generating data to train the ML model. • Use of eXplainability to define the most relevant features influencing prestress losses and indicate the best SHM strategy. [ABSTRACT FROM AUTHOR]

As buildings have to face more frequent and intense extreme events due to a changing climate and rising geopolitical tensions, the need for more robust structures that are insensitive to initial failures is now arguably more important than ever before. In this context, this article presents an in-depth analysis of the damage and failures that occurred during the partial progressive collapse test of a purposely built 15 × 12 m precast building with two floors. The building was designed to ensure load redistribution after the failure of single columns and also to segment parts of the structure from a larger initial failure that inevitably triggers a collapse. The ability of the structure to arrest collapse propagation was tested experimentally successfully isolating the collapse to the initially affected area. Based on visual inspections supported by computational simulations, failure mechanisms occurring in the collapsed area and damages in the upright part of the structure are analysed in detail in this article. Mechanisms that enabled the separation of the building in two parts are also studied. The presented results lead to an improved understanding of failure mechanisms causing collapse propagation and provide insights on how such propagation can be arrested. • Post-failure analysis of a full-scale partial collapse test is performed. • Combining inspections and simulations allows deeper investigation. • Different failure modes were observed for various building components. • Mechanisms enabling load redistribution and collapse isolation are identified. • Damages suffered by part of the building remaining upright were assessed. [ABSTRACT FROM AUTHOR]

This paper describes a study of the damage caused by corrosion to the reinforcement rebars of a 40-year old building used as a car park at a distance of 20 m from the sea. The corrosion levels of the building’s structural elements, including beams, joists and columns were analyzed by optical and electron microscopy. Carbonation depths and chloride contents (Volhard method) of the concrete cover were measured in situ . EDX was used to analyze the condition of the reinforcement surfaces and the morphology and composition of the oxides. A high degree of corrosion was observed in all the above elements, carbonation had reached the depth of the reinforcement in all the samples studied, and the concrete chloride levels were far in excess of the recommended maximums. The study of the reinforcement rebars revealed different types of oxides of varying morphologies, compaction and coloring according to chloride content. A comparison with previous studies allowed us to verify the presence of crystals of at least akaganeite, lepidocrocite and goethite. [ABSTRACT FROM AUTHOR]

A full-scale purposely built precast concrete building, designed to comply with robustness requirements in current building codes, was subjected to two different scenarios of sudden edge-column removal under the accidental load combination established by the codes. The main aim of this study was to assess how the structural system can prevent collapse initiation after the removal of a single edge column at different locations. This building was later subjected to a larger initial failure with the aim of arresting collapse propagation as part of another piece of research and outside the scope of this specific study. The building was highly instrumented providing unique data at a building system level for the understanding of the development of alternative load paths after the column removals. This work is novel since existing tests of edge-column removal from precast systems correspond mostly to simplified beam-column-slab subassemblies where the interaction with the rest of the building is neglected. The results obtained from this work are particularly relevant towards understanding the role of tying systems used in precast concrete buildings under different accidental scenarios using typical load combinations defined in building codes. The structure was able to redistribute the loads after each column was removed due to a combination of Vierendeel and compressive arching and membrane actions, leading to very small deflections. The role of vertical, horizontal, and floor tying systems in providing continuity between prefabricated and hybrid members was analysed in view of the experimental results obtained. The response obtained differed significantly from design assumptions commonly adopted for tying systems that rely on tensile catenary action at large deflections. This research is timely considering the push to adopt prefabricated components in building construction driven by Net Zero targets while maximising robustness of buildings subjected to more extreme events exacerbated by climate change. • Two tests were carried out on a purposely built full-scale PC building structure. • Different edge columns were suddenly removed. • Alternative load paths were identified at low deformations. • The role of vertical, horizontal and floor tying systems was analysed. [ABSTRACT FROM AUTHOR]

Risks of bridge collapse were and continue to be real as evidenced by classical (e.g. Québec Bridge, Canada 1919; Seongsu Bridge, South Korea 1994) and recent (e.g. Skagit River Bridge, USA 2013; Francis Scott Key Bridge, USA 2024) episodes of catastrophic collapses. The causes of each collapse are diverse (e.g. natural disasters, changing conditions, design errors, intentional attacks). Still, the conclusions are always the same: deaths, injuries and large amounts of direct and indirect economic losses. In order to avoid these catastrophes, structural robustness and monitoring strategies can be used to analyse the bridge's vulnerability and anticipate any local-initial failure that can spread to the whole structure in the form of a progressive collapse. The objective of this work was to use an integrative threat-dependent and threat-independent approach to analyse the structural robustness of a never-before-studied U-shaped open cross-section steel truss railway bridge structure. Eight failure scenarios were considered and analysed through computational modelling. The extracted results make it possible: (i) to connect structural robustness analysis outputs with the definition of a new structural health monitoring strategy of the bridge; and (ii) to implement the conclusions in the real bridge with more than 100 sensors and a non-assisted alarm system for preventing progressive collapse. • Structural robustness analysis defines a new strategy for the structural health monitoring of steel truss bridges. • An integrative threat-dependent and threat-independent approach to analyse the structural robustness is used. • U-shaped open cross-section steel truss railway bridge structure is studied for the first time. • U-shaped cross-section bridge has more potential to experience problems than bridges with closed-box cross-section. • Implementation in a bridge with more than 100 sensors and a non-assisted alarm system for preventing progressive collapse. [ABSTRACT FROM AUTHOR]

Eduardo Torroja was a Spanish engineer and a famous figure in structural design. His vast production of technically demanding work includes thin reinforced concrete shells, daring structures that meet efficiency requirements through their thinness. One of his most remarkable works is the Frontón Recoletos, which is described in an extensive bibliography, enabling us to approach this milestone of structural engineering again with modern computational tools. Although thin shells have mainly been designed under the elasticity hypothesis, nonlinear analysis also deserves to be considered, since current computer processing speeds make this possible. The present work carries out a complete non-linear analysis of the roof of Torroja’s Fronton de Recoletos and can be considered as the continuation of the linear-elastic analysis previously carried out by Lozano-Galant and Paya-Zaforteza (2011). The key aspects of the investigation presented in this paper are the use of discrete reinforcement instead of the more common smeared approximation to modeling the roof reinforcement and the accurate definition of concrete through a robust constitutive equation, the Multi-crack model proposed by Jefferson (1999) for which FE software was used. The results have been checked against both the historical documentation in the Torroja Archive and the recent studies using linear models by Lozano-Galant and Paya-Zaforteza (2011). As it turns out, the relevance of geometric nonlinearities, material nonlinearities and stability behavior should not be neglected. [ABSTRACT FROM AUTHOR]

This paper describes a double experimental and analytical study of the fatigue behaviour of the Quisi and Ferrandet Bridges, twin 170 m long steel railway bridges constructed between 1913 and 1915 with typical Pratt truss structures and riveted connections. These bridges are part of the Spanish national railway network connecting the towns of Alicante and Denia, one of the key networks in the Valencia Region (Spain). The experimental laboratory investigation involved fatigue testing in one of the ICITECH laboratories at the Universitat Politècnica de València of: (i) a full-scale bridge span and (ii) an upper cross beam from the Ferrandet Bridge. During the tests, Linear Variable Displacement Transducers (LVDTs) and Strain Gauge (SG) sensors were used to capture the possible nucleation and propagation of fatigue cracks. Fatigue test carried out on the cross beam identified: (i) fatigue life of the critical detail, (ii) fatigue hot-spots along the cross beam and (iii) strain redistribution along the riveted element during crack growth. The experimental results from the full-scale bridge were adopted to calibrate an elastic numerical model of the whole structure, which was in turn used to estimate the Quisi Bridge's remaining fatigue life. The definition of the class of detail and remaining fatigue life were calculated by the S–N curves method, according to Eurocode 3, considering the available information on the bridges' loading histories. [Display omitted] • An integrated multi-field analytical method for prediction of the residual fatigue life of steel bridges is proposed. • Double fatigue lab investigation on: (i) upper cross beam; (ii) isostatic span. • S N curves method provided detail classes of 63 or 71 for the girder element.. • Strain gauges were able to track the redistribution of stresses as cracks grew. • The fatigue test of the isostatic span lasted 45 k cycles confirming that the bridge could operate safely for 27 years more. [ABSTRACT FROM AUTHOR]

• Two full-scale timbrel vaults have been constructed and tested. • The paper discusses the efficacy of TRM materials for the repairing of damaged timbrel vaults subjected to soil settlements. • TRM radial configurations restored the vaults continuity. • TRM radial configurations increased the vaults displacement capacity. This paper presents the experimental results obtained from tests on two masonry vaults reinforced by Textile Reinforced Mortar (TRM) materials subjected to monotonic and cyclic vertical settlements in one of their supports. Two full-scale square masonry timbrel vaults were built in one of ICITECH's laboratories at the Universitat Politecnica de Valencia (Valencia, Spain) using the traditional Catalan layered-construction technique, with various layers of clay tiles arranged in two perpendicular masonry textures joined by lime and cement mortar joints. Due to their peculiar geometric and mechanical features, i.e. their high slenderness ratio, low tensile strength and high material heterogeneity, these structures are especially prone to damage from high-risk events such as soil settlement or seismic excitation. To evaluate their response to vertical support displacements, both vaults were pre-damaged by either vertical monotonic or cyclic settlements. They were then strengthened by a radial TRM strengthening configuration and re-tested until failure. A complex network of traditional and optical sensors was used to monitor displacements, deformation and the development of the cracking mechanism under both settlement conditions. The results obtained show that TRM materials can be used to effectively repair severely damaged masonry timbrel vaults, helping to partially restore the initial elastic stiffness, as well as doubling the vaults' elastic phase and ultimate displacements. In addition, TRM materials did not alter the stiffness degradation trend, although they had a strong effect on peak reaction degradation and failure modes. This investigation represents a valuable and unique source of information about the efficacy of TRM materials to repair full-scale pre-damaged masonry timbrel vaults. [ABSTRACT FROM AUTHOR]

• A specific degradation analysis of elevated storage tanks is developed. • On-desk study, on-site survey, diagnostic approach and ranking are defined. • 32 case studies in Valencia are analysed. • Frequent damage and the related causes are identified. • Best maintenance and intervention strategies are proposed. Assessing the condition of existing structures, with a particular focus on analysing the degradation level, is a complex issue for those responsible for maintenance and monitoring. Elevated storage tanks (water towers) are particularly prone to suffering obsolescence and degradation. As many of these structures are no longer in use and in a poor state of conservation, researchers and local administrators need new tools to achieve a complete overview of the tank condition on a regional scale with limited resources. This paper presents a large-scale structural degradation analysis on the specific structural typology of storage tanks. Firstly, the tanks performances and degradation level are analysed by using a multicriteria approach useful to include both qualitative and quantitative data in the analysis. Secondly, 32 case studies in Valencia (Spain) are investigated to demonstrate the method's potential. Thirdly, the results of the degradation analysis were used to identify the most frequent damage, the related causes and the structures in the worst conditions. Finally, the best maintenance and intervention strategies to extend the tanks' remaining life and protect them from further damage are proposed. [ABSTRACT FROM AUTHOR]

• Load limiters (LL) to shoring systems in construction were investigated. • FE models were carried out of a RC building with and without LL. • Two local failure scenarios were investigated representing accidental events. • With LL, the residual damage was reduced due to the activation of more shores. • The risk of failure of the temporary structure was mitigated using LL. The risk of structural failure of buildings can be significant during construction. Temporary adjustable telescopic steel shores or props are commonly used in building construction. The failure of shores is sudden and therefore structural fuses as load limiters (LL) can be introduced to provide ductility in the temporary member for a specified limit failure load. Previous work by the authors showed that the design of shoring systems can be improved using LL for standard cases of imposed loads applied during construction. This paper extends this work to cases of accidental loading where the shoring system-permanent structure interaction is less known. The main principles of LLs are discussed and implemented in advanced numerical simulations of a real case RC building during construction by means of explicit nonlinear dynamic finite element analyses. Different local failure scenarios were investigated corresponding to cases observed in practice. The comparison of the numerical results obtained with and without LLs demonstrated for the first time the benefits of using LLs in terms of: (a) mitigating the risk of failure of the temporary structure; and (b) reducing permanent damage (cracking and short-term deflections in the slab) affecting the durability and functionality of the building. [ABSTRACT FROM AUTHOR]

• Experimental test of a full-scale timbrel masonry cross vault with vertical settlements. • Provides information about the displacement capacity of cross vaults subjected to soil expansion. • Discussion of the experimental results. • Evaluation of the crack patterns when downward settlements are applied. Masonry cross vaults are among the most attractive structures ever created by the human race. Although cross vaults have been the subject of various numerical and experimental studies, they are still in need of further investigation. In the research described here, carried out at the ICITECH laboratories of the Universitat Politècnica de València (Spain), a full-scale timbrel cross vault was constructed and tested under the vertical settlement of one of its supports. The geometry and construction technique of the vault resembled those in a church on the outskirts of Valencia, one of which had collapsed due to a soil settlement. The timbrel vault's behaviour was monitored by 23 sensors placed on its inner and outer surfaces and subsequently analysed from the results obtained in the tests. As expected, the vault experienced a fairly ductile response during the test, while peculiar crack patterns were observed in the form of bending cracks in the lateral arches, which were mostly found to follow the mortar joints in the upper surface of one of the diagonal elliptic arches. [ABSTRACT FROM AUTHOR]

• Bell swinging registered signals have been compared with these proposed by DIN4178 and some unsafe situations are detected. • By OMA analysis, damping ratio is evaluated under ambient and forced vibrations. • The use of genetic algorithms for the model updating presents a high dispersion of the results. • The optimum lateral confinement has been evaluated to update the FEM model. • A general methodology is proposed to analyze the damage generated by the swing of bells. Recent years have seen a growing interest toward implementation and testing of structural health monitoring techniques for cultural heritage structures, and many scientific papers report on the application of operational modal strategies as an effective knowledge-based tool for vulnerability reduction of masonry buildings. Focusing on historic masonry bell-towers, being such structures particularly prone to earthquake-induced damage, the most part of the studies discuss structural monitoring and vibration-based identification methods with the goal of their seismic protection. As a consequence, while there is great number of researches that investigate masonry towers behaviour under earthquake loads, only a few scientific papers discuss their structural response under service loads such as bell-loads. This issue is also of paramount importance, since in many real cases the bell-ringing has been stopped due to the dynamic interaction phenomena that are activate between the bells and the host structure. With the aim to contribute of improving the knowledge in this field, this paper focuses on a methodology for the study of the dynamic interaction between bells and slender masonry towers. The proposed methodology is divided into four phases: (i) Geometric and structural characterization of the tower and bells; (ii) Evaluation of the dynamic forces generated by the swinging bells; (iii) Experimental campaign to characterize the dynamic properties of the tower by means of operational modal analysis; (iv) Parametric finite element analysis. To illustrate the methodology, a real case of masonry bell-tower in which bell-ringing had to be stopped due to a history of strong vibrations is discussed. The paper includes a method of analysing the dynamic properties of masonry bell-towers, in which the dynamic interaction between the harmonic bell forces and the fundamental tower modes is analysed by means of a calibrated numerical model and the dynamic amplification factor. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Optical shape sensors consist of multiple single-core optical fibers. • Core position errors are due to errors in the manufacturing process. • In MCF, errors are in the range between a few hundred nanometers to one micrometer. • The effects of core position errors on the precision of shape sensors are analysed. Abstract Optical fiber sensors are now widely recognized as extremely reliable instruments to sense strain. Optical shape sensors consist of multiple single-core optical fibers or multicore optical fibers capable of sensing bending direction and curvature by comparing the longitudinal strain of different cores in an instrumented section and reconstructing the sensor shape. This paper describes a study on the effects of core position errors on the precision of optical shape sensors when measuring strain, bending direction and curvature, and identifies the role of measured curvature and core spacing (distance between section center and external cores), considering 7, 4, and 3-core fiber geometries, three of those most widely employed for sensing applications. The Monte Carlo technique was utilized to reproduce the measurement process. Forty-five simulations, including 3·106 trials, were carried out for each geometry with the aim of investigating the law of uncertainty propagation. The results of the analysis, applicable to both multiple single-core fibers and multicore optical sensors equipped with distributed or quasi-distributed strain-sensors, show the effects of core position uncertainty and will be useful for new sensor designs and user options by predicting the achievable performance of these devices. [ABSTRACT FROM AUTHOR]

Abstract Exposure to an aggressive marine atmosphere can seriously harm reinforced concrete (RC) structures and affects a building's service life. In particular, buildings close to the sea are at high risk of suffering damage, mainly due to the effects of chloride. The scientific and technical communities are interested in studying new parameters related to building degradation, including "exposure to aggressive environments" in order to predict a building's service life and schedule maintenance and monitoring systems. This paper proposes a marine exposure index aimed at quantifying potential risks and damage to RC building structures. The definition of the index includes three synergistically related techniques: i) the Analytic Hierarchy Processes to analyze the complexity of the problem and the parameters involved in marine exposure; ii) a state-of-the-art technique to evaluate the degree of building degradation; iii) an optimization calibration procedure by setting a Mathematical Programming problem. The resulting index can be extensively and fruitfully applied by researchers and practitioners in order to assess the building's exposure to an aggressive marine atmosphere. Architects and engineers could apply the proposed index in any phase of the building process, from the project to the maintenance and management phases. The effectiveness of the proposal was tested in a survey of 1816 buildings on the Valencia coast (Spain). Graphical abstract Unlabelled Image Highlights • Marine atmosphere can seriously harm reinforced concrete structures. • This paper proposes a new marine exposure index. • The definition of the index includes three synergistically related techniques. • The index can be used to assess a building's exposure to a marine atmosphere. • The index has been calibrated by surveying close to two thousand buildings. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Experimental test of a full scale masonry timbrel cross vault with cyclic settlements. • Provides significant information about the displacement capacity of cross vaults. • Discussion of the experimental results and the failure mechanism. • Evaluation of the crack patterns when upward/downward settlements are applied. Abstract Up-and-down cyclical displacement of supports-foundations, due for example to the presence of expansive soils, can affect the integrity of a structure and may even lead to its collapse. A recent study carried out at the ICITECH laboratories of the Universitat Politècnica de València analysed the effects of soil settlements on the behaviour of masonry cross vaults. One of the tests involved the construction and testing of a full-scale timbrel cross vault, one of whose supports was subjected to up-and-down vertical displacement cycles. The 4 × 4 m2 vault was composed of four 3.6 m diameter arches supporting a masonry web. Vertical displacements were applied to one of the supports by means of two synchronised mechanical jacks. The results of the tests provide valuable information to the scientific community, architects and engineers on the behaviour of timbrel cross vaults when one of their supports is subjected to cyclical movements. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • FBGs sensors are well established as highly sensitive strain-measuring devices. • MCF shape sensing technology has become a powerful and reliable instrument. • High accuracy in determining curvature and bending direction is crucial. • Measurement uncertainty of MCF sensors is analysed. Abstract This paper describes a study of the influence of strain measurement uncertainty on sensing curvature and bending direction, considering one of the most widely used fiber geometries for sensing applications (7-core Multicore Fiber) with different core spacings (distance between outer cores and fiber axis). The Monte Carlo method was proposed to simulate the real measurement process and 33 simulations with 106 iterations were performed to determine the laws of propagation of strain measurement uncertainty in calculating curvature and bending direction. The outcomes, which show the strong influence of strain uncertainty and core spacing on the precision of Multicore Fiber sensors, can be used to support the design of new sensors or new fiber geometry and to predict their achievable performance. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Patch repairs are widely used for local damage in RC columns. • 15 patch-repaired RC columns were tested at the ICITECH. • The paper analyses the effectiveness of patch repairs on RC columns. • Patch repair is compared with: all-four-sides and one-side repair. Abstract This paper describes an experimental study on patch-repaired reinforced concrete columns subjected to axial loads until failure. The behaviour of four series of columns repaired with Class R3 and R4 cement-based mortar was analysed both with and without a bonding agent. The results obtained were compared with control series of undamaged and damaged but unrepaired columns to determine the effectiveness of the repairs and the subsequent improvement in the behaviour of the columns. The results of this study were compared with those of previous work by the authors on the analysis of all-four-side repairs and one-side repairs. The conclusion reached was that patch repairs are highly effective as compared to the other techniques studied and that using Class R3 mortar achieves better results on damaged columns made with low-quality concrete. It was also concluded that applying a bonding agent does not improve the results, although this element was found to be necessary to prevent the premature detachment of the repair when there is a substantial difference between the stiffness of the column concrete and that of the mortar used in the repairs. [ABSTRACT FROM AUTHOR]

This paper describes and analyses the results of an experimental programme carried out at the Universitat Politècnica de València on 18 reinforced concrete (RC) columns, 12 of which had been repaired on one side with cement-based mortar before being subjected to axial loading until failure. The objective of the research was to determine the performance of the columns that had been repaired using different mortars, evaluate the influence of Class R3 and R4 mortar used and of the application of a binder or bonding agent. The results obtained were compared with those of the undamaged control columns and those of the unrepaired damaged columns to obtain values for the efficiency of the repairs and for the improvement in the load-bearing capacity of the columns. The results obtained indicate that the columns repaired with Class R3 mortar, with a lower elasticity modulus, function in better way than the Class R4 repaired ones. The presence or absence of a binder was not found to be a determining factor in improving the behaviour of the repaired elements. The chief novelty of the study lies in the fact that it is the first experimental study on RC columns totally repaired on one side only, using different types of mortar with and without the application of a binder. [ABSTRACT FROM AUTHOR]

• Analysis of bridge collapses offer opportunities to increase knowledge in bridge engineering. • A methodology to identify triggering events leading to progressive collapse on truss-type bridges. • Data collected from 25 case studies reported in the literature. • Identification of the most frequent initial constituted damages states or failures (ICDE) leading progressive collapse. • Actual consequences of collapsed bridges were compared to predictions from casualty models. Although truss-type bridge collapses usually have catastrophic consequences, their analysis present opportunities for improving different aspects in the field of bridge engineering, such as structural assessment, structural health monitoring, maintenance and conservation or even design strategies. As the world experiences more extreme events, efforts have been made to design more resilient bridges that can withstand local failures. Forensic techniques have contributed to understanding the causes and risk factors of bridge failures, and the creation of collapse databases has provided valuable insights for preventing such failures. However, these databases often focus on the hazards and do not provide information on initial damage and how it propagates, which is essential for improving the progressive collapse resistance of truss-type bridges. The main novelty of this paper is to present a methodology to identify triggering events leading to progressive collapse on truss-type bridges. It is the first time that a methodology includes a novel database which collects detailed information on initial damages and its propagation, as well as the consequences of the collapse. The methodology was implemented by collecting information from 25 case studies present in the literature. Results have allowed to identify most frequent initial constituted damages states or failures (ICDS) leading progressive collapse. In terms of consequences, results were thoroughly analysed and compared with predictions from different casualty models. The findings showed that the proposed methodology serves as an effective tool for identifying the triggering events of progressive collapse in truss-type bridges. [ABSTRACT FROM AUTHOR]

The grandstands of La Zarzuela Racecourse in Madrid designed by the engineer E. Torroja and the architects C. Arniches and M. Dominguez are one of the world’s most outstanding concrete constructions of the first half of the 20th century. This paper describes the design competition and the conceptual design process that led to their construction and carries out a critical assessment of the grandstands from the perspective of Structural Art. By doing so, the paper helps to develop the discipline of structural criticism, and points out lessons learned from their design and construction process which should not be forgotten at the present time, such as: (a) the importance of design competitions; (b) the fact that the pursuit of economy and efficiency can actually improve the quality and aesthetics of the design; (c) the importance of combining logical reasoning based on technical criteria with imagination to achieve excellence in structural design; and (d) the importance of estimating structural behavior by simple formulas and of learning from both existing structures and experimental models. [ABSTRACT FROM AUTHOR]

Strategic major infrastructure ageing requires structural health monitoring usage to avoid critical safety issues and disasters. Machine Learning can be a valuable tool to automate the process of analysing raw monitoring data. Usually, frequency domain damage-sensitive features are extracted with data pre-processing procedures; thus these features are used as input for classification or regression problems. This paper describes a method of locating damage in steel truss railway bridges through machine learning classification tools, enabling automatic analysis of raw strain sensors signals without any pre-processing or preliminary feature extraction. Data were generated by simulating different damage scenarios with a finite element software, and then were processed by two machine learning classification tools: (a) the K-nearest Neighbours was adopted with the Dynamic Time Warping algorithm metric to select the most informative features; (b) a model suitable for high-dimensional data analysis, known as the Convolutional Neural Network, was then trained to classify strain sensors time series. The results indicate that the method applied can detect damages with an accuracy of 93% and is suitable for structural health monitoring. [ABSTRACT FROM AUTHOR]