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Understanding that good decision-making is paramount for the success of an organization and recognizing that strategic decision-making inside museums is a topic that has been over-passed by researchers, this paper intends to contribute to the relevance of the subject through the implementation of an innovative tool. Decision-making in museums is normally focused on the intuition, subjectivity, and experience of the curator, who brings all his knowledge to the exhibition programming. However, museums’ management and environment are constantly changing, thus the application of this tool would aim to make decisions in a more democratic, transparent, inclusive, and accurate manner. Besides, it will be easier to understand how distinct subjects can work together, demonstrating successful results to improve the decision-making process when programming and measuring temporary exhibition seasons in museums. This paper describes the design and implementation of the Multi-Attribute Utility Theory (MAUT) for the Museu Nacional d'Art de Catalunya (MNAC). It also analyzes and evaluates the decision-making process when scheduling exhibitions for a season., Peer Reviewed, Postprint (author's final draft)

The traffic scenarios that may cause extreme load effects are of great importance to the safety assessment of bridge structures. The traditional simulation method of traffic flow cannot depict the distribution pattern of vehicles on the bridge deck when the maximum effect is induced. In this paper, a probabilistic Gaussian mixture model (GMM) for heavy vehicle scenarios on the bridge deck under free-flow condition is proposed for long-span bridges based on collected Weigh in Motion (WIM) data. The scenarios of extreme response under free-flow occur more frequently than congestion scenarios and are of similar value and relevance in the daily management and safety assessment of long-span bridges. A non-stationary Poisson process is utilized to simulate the uneven occurrence of heavy vehicles in different lanes, and it is assumed that they are located within the artificially defined cells on the bridge deck. Then, Nataf transformation is employed to consider the correlation of gross vehicle weights (GVWs) within close range in the same lane. The numerical study is carried out on a long-span cable-stayed bridge to investigate the effects of correlation in GVWs and stationarity of vehicle distribution location on the structural responses. The load responses calculated by the proposed model and Monte Carlo method for different effects are compared with the values derived from code model. The results show that with the increase of the correlation level of the neighboring GVWs, the simulated responses are more prone to get extreme values, which means an increasing probability of the most unfavorable spatial distribution of on-bridge vehicles. The same results are also found under the non-stationary simulation state for vehicle location. The non-stationary Poisson process provides an efficient, highly feasible method, which is also in the safe side, for simulating the vehicle spatial distribution for specific effects., The support from the National Natural Science Foundation of China (Grant number 51878495), the Academician Project Foundation of CCCC (Grant numbers: YSZX-01-2020-01-B), the National Key R&D Program of China (Grant number 2018YFB1600100) and the Shanghai Sailing Program (Grant number: 21YF1449300) is gratefully acknowledged. The opinions and conclusions presented in this article are those of the authors and do not necessarily reflect the views of the sponsoring organizations., Peer Reviewed, Postprint (author's final draft)

Conventional reinforced concrete for building partition walls has proven numerous advantages (in terms for instance of acoustic performance and robustness) with respect to other existing alternatives. However, its use leads to high material consumption and environmental footprint together with time-consuming processes for placing steel reinforcement. To reduce time-consuming processes and carbon footprint, the replacement of ordinary steel reinforcement by structural macrofibers is envisioned as a suitable solution due to: (1) the acceptance of fiber reinforced concrete (FRC) for structural applications in various guidelines (as Annex L of FprEN 1992-1-1:2023, draft for future Eurocode 2) and (2) the fact that the amounts of fibers necessary to reach the required mechanical performance of the FRC for crack control are expected to be economically competitive. Additionally, within the spectra of types of macrofibers capable of efficiently reinforce concrete, macrosynthetic fibers (MSFs) were considered in this research due to their benefits in terms of durability performance and reduced environmental impact (potential to use cements with lower clinker content and reduced thickness of elements). Aiming at confirming both the constructability, casting procedure and structural performance of macrosynthetic fiber reinforced concrete (MSFRC) partition walls, these walls were constructed in a real building in Switzerland. In this article, the design process is presented as well as the associated MSFRC material and structural experimental programmes, conducted both in laboratory and on-site. In addition, several FEM-modeling considerations as well as quality control and construction aspects observed during the implementation process are raised. Finally, for reference purposes, a first approach to the economic and environmental impact (CO2eq-based) of such MSFRC walls is presented., Peer Reviewed, Postprint (published version)

This paper summarises current research findings related to the behaviour and simulation of a relatively new type of structural component: recycled aggregate concrete-filled steel tube columns (RACFST). The first part of the paper presents a review of the latest experimental campaigns on RACFST columns subjected to a variety of loading conditions. For each of loading condition, highlight observations about the behaviour of RACFST columns are presented. The second part of the paper provides a summary of numerical modelling approaches developed for simulating the structural behaviour of RACFST columns. Special attention is paid to the selection and calibration of material models for recycled aggregate concrete. Finally, directions for future investigations in this area are outlined and discussed. The review will benefit researchers and professionals seeking to gain an in-depth understanding of the behaviour of RACFST columns, and fills a gap in existing literature regarding a number of practical issues related to the numerical modelling of these components., Peer Reviewed, Postprint (published version)

Mid-rise reinforced concrete buildings are projected to continue being the predominant typology for urban development. Thus, reducing the carbon footprint of such buildings is critical for achieving a sustainable built environment. Reducing the amount of concrete and steel in a building through structural and mix design optimization is identified as a primary resource efficiency strategy. This paper is among the first to present evidence of the decarbonization potential of these dematerialization strategies on a building level. The study combines structural design choices such as slab system design, steel reinforcement optimization and span width with materials-based strategies, such as low binder concrete and low-carbon binders. For each scenario, material quantities are calculated following design prescriptions by EN1992–1–1 while state-of-the art life cycle inventory data are adopted to calculate the carbon footprint. Results show that shifting towards more efficient structural systems (i.e., waffle slab system) could save up to 20% of the carbon footprint on the building level compared to more traditional systems, such as slab on beams and flat slabs. In addition, reducing the spans from 7.5 to 5 m can save up to 20% more. Finally, the use of low-clinker cement in low-binder concrete can save another 50% in terms of CO2 impact per built-up area. Realistically, results of the case study concluded that implementing these three strategies could reduce the typical 232 kg CO2e/m2 value of the carbon footprint of structural elements of a mid-rise building up to only 58 kg CO2e/m2, i.e., a four-fold reduction., Peer Reviewed, Postprint (published version)

The moisture content within the concrete pore network significantly influences the mechanical, thermal, and durability characteristics of concrete structures. This paper introduces a novel fully embedded wireless temperature and relative humidity sensor connected to an automatic acquisition system designed for continuous concrete monitoring. Relative humidity measurements from this new sensor are compared with those obtained by a commercial system based on the borehole method at different depths (2.5 and 4.0 cm) and exposure conditions (oven drying and humid chamber). The results allow for proving that both systems provide consistent internal relative humidity measurements aligned with the exposure conditions and highlight the capability of fully embedded wireless sensors as a practical and reliable alternative to the conventional borehole method. Additionally, the continuous monitoring of the wireless cast-in sensor exhibits reliability during unintended temperature fluctuations, emphasizing the effectiveness of permanently installed sensors in promptly detecting unintended curing variations in real time. The continuous real-time information provided combined with the practicality of these sensors might assist construction managers to improve the quality control of the concrete curing process and shrinkage behavior, and ensure the integrity of concrete surface finishing., Support from the INNOSUP Horizon 2020 Metabuilding 1st GROW/HARVEST CALL through the research project MONSEC is greatly acknowledged (Agreement Number: 370)., Postprint (published version)

With the rapid development of society and the economy, significant infrastructure, such as roads, buildings, high-speed railways, and bridges, have been built all over the world. However, the increase in operating time and environmental loads have destabilized the structures, resulting in slow structural damage. Such damage, if not detected in time, can threaten normal structural operations, or even cause significant hazards. Therefore, the operational safety of urban infrastructures, as an important practical issue, has attracted increasing attention from multi-disciplinary fields, such as public security, earth obser- vation, civil engineering, and so on., Postprint (published version)

The paper analyses the degradation process of commercial ultramarine blue pigments in cementitious materials. For this purpose, two commercial pigments (with and without a protective coating) in different solutions and cement pastes are studied incrementally. The results show that pigment degradation occurs due to an ion exchange phenomenon; during hydration high ion contents are released, calcium and potassium being the most aggressive for the pigment. Calcium distorts the unit cell; between the sodium of the pigment and the potassium in the medium a cation exchange phenomenon takes place. Both processes lead to the diffusion of sulphate and sulphide ions from the pigment to the medium causing loss of colour and the formation of ettringite., Peer Reviewed, Postprint (published version)

In civil engineering and architectural applications, Micro Electro-Mechanical System (MEMS) accelerometer-based inclinometers are widely used due to their costeffectiveness. However, a major challenge associated with these devices is their long-term durability and reliability. Typically, commercial inclinometers are employed to calibrate low-cost solutions over time, which ultimately increases monitoring costs and significantly reduces their economic advantages. To address this limitation, this paper presents a novel approach based on Artificial Intelligence (AI) to evaluate the long-term performance of the low-cost inclinometer called LARA (Low-Cost Adaptable Reliable Anglemeter). This AI-driven tool utilizes a Multilayer Perceptron to predict the inclination of a monitored steel structure under real environmental conditions. By comparing the predicted results with actual on-site measurements, potential inaccuracies in the low-cost inclinometer can be automatically detected, indicating the need for recalibration. The effectiveness and applicability of the proposed tool are demonstrated through a study conducted on a real steel frame located in Spain. This study demonstrates how the AI-based approach can enhance the assessment of the low-cost inclinometer’s performance and its suitability for long-term monitoring of real structures., The authors are indebted to the projects PID2021-126405OB-C31 and PID2021-126405OBC32 funded by FEDER funds—A Way to Make Europe and Spanish Ministry of Economy and Competitiveness MICIN/AEI/10.13039/501100011033/, and National Natural Science Foundation of China (52278313)., Postprint (published version)

The vertical jacking method has been widely used in water intake and drainage segmental tunnels. The construction method of standpipes by lifting could mainly be divided into upward shield method, vertical jacking method and vertical pipe jacking method. Comparing with the other two methods, the vertical jacking method has the advantage that its equipment is simpler. However, the vertical jacking force intensity is uncertain because it depends on many factors. The higher the pipe diameter, the higher the normal stresses, being the critical moment the starting of the jacking process. Based on numerical simulations, this paper intends to research on the structural behaviour of this method on large section standpipes and analyze the factors that controls the jacking process. The research results show: 1. The deformation of the main tunnel is a combination of two effects: the longitudinal sinking and the vertical ovalization. 2. The circumferential compressive stresses in the bottom segments of the main tunnel are greatly reduced due to the vertical force of the jack. 3. The shear of the transverse joint between two rings mainly appear in the joint between the opening ring and the contiguous one. 4. The thickness of the segment has little effect on the mechanical response of the structure for typical segment depth. 5. With the decrease of the opening area, the internal force of the open ring structure decreases, while the internal force of the contiguous rings decreases or remains basically unchanged., Postprint (published version)

Structural health monitoring (SHM) applications are gaining increasing attention because they enable the early detection and characterization of damage during a prevention phase. Furthermore, SHM can also provide useful information associated with the condition and performance of a structure over time. SHM applications require a network of sensors to measure various structural parameters. However, the high cost of the required sensors is considered to be a limitation for their implementation in structures with limited monitoring budget. This paper presents an alternative low-cost solution to decrease the high cost of instrumentation. LARA (Low-Cost Adaptable Reliable Accelerometer) is a novel low-cost triaxial accelerometer based on Arduino and Raspberry Pi technologies. This system has a sampling frequency of 333 Hz and a noise density of 51µg/vHz. This work presents an experimental campaign for the Operational Modal Analysis (OMA) of a footbridge using two types of sensors: a low-cost prototype LARA and a commercial one (HI-INC), in order to evaluate the reliability of the data acquired by LA-RA and to validate it as a low-cost accelerometer for SHM purposes., Postprint (published version)

Steel fiber-reinforced concrete (SFRC) has proven to be a suitable structural material for constructing elevated flat slabs, and several existing office and residential buildings, in which SFRC was used for these components, highlighted the positive outcomes from both technical and sustainability perspectives. However, research on the influence of fiber orientation on the flexural performance of SFRC slabs is relatively scarce despite the fact that a number of studies revealed that the use of constitutive models derived from three-point bending tests on notched beams leads to overestimations of the bearing capacity of statically indeterminate slabs. In this context, this study aims at presenting an extensive experimental program that consisted of testing three SFRC slabs (3.0¿×¿3.0¿×¿0.1¿m3) subjected to point load under a statically indeterminate test configuration. The testing procedure was followed by the extraction of 88 cores in order to analyze both fiber distribution and orientation by means of a non-destructive inductive method. The results indicate that lower orientation numbers were observed in cylinders drilled from the slabs in comparison with those observed in the 150¿×¿150¿×¿600¿mm3 notched reference beams tested to characterize the pre- and post-cracking flexural performance of the SFRC produced. Based on these results, a straightforward design-oriented approach to compute an orientation factor was proposed and considered to develop the constitutive law used to simulate the structural response of SFRC slabs by means of nonlinear finite element model. The numerical simulation results showed a good agreement with the experimental response, this evidencing that the orientation factor may permit to account for the differences caused by geometric and statistical scale-induced factors between both the beams used for the SFRC flexural properties characterization and slabs produced with the same SFRC., This study was financially supported by the Spanish Ministry of Science and Innovation under the scope of project CREEF (PID2019-108978RB-C32/AEI/10.13039/501100011033)., Postprint (published version)

The development of low-cost structural and environmental sensors has revolutionized monitoring practices across numerous fields, enabling cost-effective solutions for infrastructure and building health assessment. However, a critical challenge associated with these sensors is their long-term durability and reliability. Surprisingly, despite the significant interest in these low-cost devices, the literature does not present any solutions for ensuring their long-term performance. To address this gap, this study proposes an innovative artificial intelligence-based approach for evaluating the long-term performance of low-cost inclinometers using a low-cost adaptable reliable anglemeter. This method automatically compares the inclinations of actual onsite measurements with predicted values under real environmental conditions. Over time, if the discrepancies between both measurements surpass a predefined statistical threshold, it may signal potential inaccuracies in the low-cost inclinometer, thereby suggesting the need for recalibration or presence of structural anomalies. The effectiveness and applicability of the proposed tool were demonstrated through a long-term study conducted on a real steel frame in Spain., This work was supported by the projects PID2021-126405OB-C31 and PID2021-126405OB-C32 funded by FEDER funds through the program “A Way to Make Europe” and by the Spanish Ministry of Economy and Competitiveness MICIN/AEI/10.13039/501100011033/. It also received support from the National Natural Science Foundation of China (Grant No. 52278313)., Peer Reviewed, Postprint (author's final draft)

The present research aims to assess the reliability of Ultrasonic Tomography (UT) of void detection in post-tensioning ducts due to inappropriate execution of grouting. The methodology is based on the construction of the Probability of Detection (PoD) curves for this specific non-destructive technique, by relating the probability of success to identify a specified ungrouted region. The PoD curves are built on data collected during a testing campaign in the laboratory, under fully known grouting conditions. Six walls containing prestressing strands and bars in metallic and plastic ducts with simulated voids of different sizes were designed and executed. Both water-filled (infiltration) and empty voids (ungrouted region) were simulated. The classical frequentist and Bayesian approaches are used to derive the PoD curves. Since the available experimental data are limited, the Bayesian approach provides more reliable data and is, thus, proposed as the best alternative. It is finally concluded that the minimum size of the voids in metallic ducts that UT can detect with 95% confidence and 90% probability, is around 30 cm and this value will be used in future inspection campaigns in posttensioned bridges., Peer Reviewed, Postprint (published version)

Although it has been shown that using recycled concrete aggregate in new structural concrete is economical and sustainable, the use of this material for such applications is still not widespread. One of the reasons is that manufacturers, designers, engineers, owners, and other market players are not familiar with specifying and utilizing this material—although standards are starting to incorporate provisions for recycled aggregate concrete, successful, practical example projects are needed. The current paper describes the results of a partnership between universities and a precast concrete manufacturer of hollow core slabs. Seven hollow core slabs with volumetric replacement ratios of natural aggregate with recycled aggregate from 0% to 60% were tested to failure in both bending and shear, and then undamaged portions of the slabs were subjected to punching shear until failure. The results showed only mild differences in strength, with different replacement percentages of recycled aggregate under the various loading scenarios. Numerical simulations performed in Abaqus demonstrated the feasibility of analyzing recycled aggregate concrete structural elements and provided important insights into their behavior., Peer Reviewed, Postprint (published version)

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Structure and Infrastructure Engineering on 2024, available online at: http://www.tandfonline.com/10.1080/15732479.2024.2350035., Keyed dry joints are commonly utilised in segmental bridges for shear stress transmission. The aim of this study is to explore the shear behaviour and capacity of large shear key dry joints. The considered parameters included key base height, key number and concrete strength. The key base heights were found to have a significant impact on the failure mode and shear carrying capacity. When the key base height is increased by 100%, the shear carrying capacity of the joint is increased by 156%. Digital image correlation (DIC) and distributed fibre optic sensing (DFOS) technologies revealed the characteristics of load transfer in the large shear key, validated the principle of inclined strut column and observed the changing angle of inclined column with the increase in shear key size. Moreover, due to the shear transfer at the large key teeth, there is a trend of separation in the lower contact surfaces of the joint. Based on these findings, an improved calculation method for the shear strength of large key dry joints was established. The calculation results show more accurate predictions for large key dry joints than available calculation methods developed for smaller keyed dry joints., Peer Reviewed, Postprint (author's final draft)

A new method is proposed to convert ordinal ranking of a number of criteria and an additional piece of information into numerical weights. A literature review of methods for assigning cardinal weights based on ordinal ranking is performed, as well as an analysis of their behaviour. The new method, called ‘constant weight ratio’ (CWR), enables better adjustment to the decision-maker’s preferences than purely ordinal ranking methods. It also solves the problem of the excessive decrease in the weight of the most important criterion (or criteria) when the total number of criteria is large and the weight of the most important criterion (or criteria) must be high. It is achieved via three simple steps and flexible input data. The additional piece of information may be: (i) the relative importance of the criteria, i.e., the weight ratio, (ii) the total weight of the most important set of criteria, or (iii) the weight of the most important criterion. The proposed method is applied to two case studies in the cultural sector to illustrate that the resulting weights are equivalent to other methods requiring more input data from the decision maker., Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature, Peer Reviewed, Postprint (published version)

Modular construction can become sustainable by making all aspects of the design and construction process more effective during all phases. This paper aims to develop and use a sustainability assessment model for modular residential buildings in two case studies. This research uses the Integrated Value Model for Sustainable Assessment (MIVES), which is a multi-criteria decision-making model for sustainability assessment. This model considers all aspects of sustainability, environmental, economic and social, and helps stakeholders make decisions. Few previous studies have assessed all these aspects in full and MIVES make this assessment possible. For assessment purposes, two modular buildings have been chosen, namely “Ten Degrees Croydon” as the tallest high-rise modular residential building in the world and “Apex House” as the second tallest modular building in the world, both in London. These residential towers were assessed using MIVES, demonstrating a very satisfactory sustainability index in all the above aspects., The authors would like to acknowledge and thank the Department of Civil and Environmental Engineering at Universitat Politècnica de Catalunya. Part of this research was funded by the Ministerio de Ciencia e Innovación through the grant PCI2022-132948. The 4th author of this paper want to acknowledge the financial support provided by the Spanish Ministry of Science and Innovation under the scope of project CREEF (PID2019-108978RB-C32/AEI/10.13039/501100011033)., Peer Reviewed, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Postprint (published version)

The addition of fibres to concrete is an effective solution for enhancing its post-cracking tensile strength (fctR). Currently, this property is characterized through high-cost and time-consuming experimental tests since no reliable analytical methods exist to predict this mechanical property. This study provides two neural networks for predicting the fctR obtained from flexural beam tests for crack mouth opening displacements of 0.50 mm (fR1) and 2.50 mm (fR3). Network architectures are obtained with an optimization process that involved training 1568 Multi-Layer Perceptron configurations under Monte Carlo cross-validation over 50 iterations, with a total of 78,400 trainings for each fR,i. The resulting models were evaluated using performance metrics including Coefficient of Determination (R2), Correlation Coefficient (CC), Mean Absolute Error (MAE), Root Mean Square Error (RMSE) and Scatter index (SI). High predictive accuracies were achieved for both fR1 (R2 = 0.87, CC = 0.93, MAE = 0.64 MPa, RMSE = 0.90 MPa, SI = 19.2%) and fR3 (R2 = 0.85, CC = 0.92, MAE = 0.73 MPa, RMSE = 0.95 MPa, SI = 19.8%). Furthermore, the analysis of their global and local interpretability through the game-theory-based SHAP explanation method confirms their consistency with established understandings of fibre-reinforced concrete (FRC) behaviour. Moreover, numerical expressions are proposed as an alternative to traditional testing methods, offering a tool to predict the flexural post-cracking tensile strength for pre-design and quality control purposes of FRC structures. These approaches are deemed essential for advancing FRC technology marking a significant advancement in addressing the design limitations and widespread application challenges associated with the material., This work was supported by the Catalan agency AGAUR through its research group support program (2021 SGR 00341) and by the Spanish Ministry of Science and Innovation under the scope of project CREEF (PID2019-108978RB-C32/AEI/10.13039/ 501100011033)., Peer Reviewed, Postprint (author's final draft)

The development of low-cost structural and environmental sensors has sparked a transformation across numerous fields, offering cost-effective solutions for monitoring infrastructures and buildings. However, the affordability of these solutions often comes at the expense of accuracy. To enhance precision, the LARA (Low-cost Adaptable Reliable Anglemeter) system averaged the measurements of a set of five different accelerometers working as inclinometers. However, it is worth noting that LARA’s sensitivity still falls considerably short of that achieved by other high-accuracy commercial solutions. There are no works presented in the literature to enhance the accuracy, precision, and resolution of low-cost inclinometers using artificial intelligence (AI) tools for measuring structural deformation. To fill these gaps, artificial intelligence (AI) techniques are used to elevate the precision of the LARA system working as an inclinometer. The proposed AI-driven tool uses Multilayer Perceptron (MLP) to glean insight from high-accuracy devices’ responses. The efficacy and practicality of the proposed tools are substantiated through the structural and environmental monitoring of a real steel frame located in Cuenca, Spain., This research was funded by FEDER, grant number PID2021-126405OB-C31 and PID2021-126405OB-C32—A Way to Make Europe and Spanish Ministry of Economy and Competitiveness MICIN/AEI/10.13039/501100011033/, National Natural Science Foundation of China (52278313), and a grant provided by the Polytechnic University of Catalonia with a reference of ALECTORS-2023., Peer Reviewed, Postprint (published version)

The final authenticated version is available online at https://doi.org/10.1007/s11709-024-1055-5., Researchers are paying increasing attention to the development of low-cost and microcontroller-based accelerometers, in order to make structural health monitoring feasible for conventional bridges with limited monitoring budget. Parallel with the low-cost sensor development, the use of the embedded accelerometers of smartphones for eigenfrequency analysis of bridges is becoming popular in the civil engineering literature. This paper, for the first time in the literature, studies these two promising technologies by comparing the noise density and eigenfrequency analysis of a self-developed, validated and calibrated low-cost Internet of things based accelerometer LARA (low cost adaptable reliable accelerometer) with those of a state of the art smartphone (iPhone XR). The eigenfrequency analysis of a footbridge in San Sebastian, Spain, showed that the embedded accelerometer of the iPhone XR can measure the natural frequencies of the under study bridge., The paper is supported by the projects PID2021-126405OB-C31, funded by FEDER funds—A Way to Make Europe and Spanish Ministry of Economy and Competitiveness MICIN/AEI/10.13039/501100011033/, the National Natural Science Foundation of China (Grant Nos. 52278313 and 52411540031), the Project to Attract Foreign Experts (No. G2023133018L), and the Top Discipline Plan of Shanghai Universities—Class I., Peer Reviewed, Postprint (author's final draft)

Utilizing recycled fibers as reinforcement in cement-based matrices is an effective means of promoting waste recycling and adopting a circular economy approach in the construction industry. Within this framework, the recycling and potential reutilization of textile residues can improve the pre- and post-cracking performance of cement-based matrices intended for building components with up to intermediate structural responsibilities (i.e., panels and cladding elements for buildings). This research is focused on the mechanical and durability -through forced aging of dry-wet and freeze-thaw cycles- experimental characterization of laminated fabric-reinforced cementitious matrices (FRCMs) containing 4 and 6 nonwoven fabric layers obtained from end-of-life fire-protecting t-shirts. For this purpose, both direct and flexural tensile tests were conducted to characterize the mechanical performance of the composite. The tests on the 6-fabric layers produced panels with Portland Cement (PC) matrix, after 28-day of curing, led to average values of the maximum tensile strength of 3.7¿MPa with associated toughness index superior to 25¿kJ/m2, and mean modulus of rupture of 11.6¿MPa with a fracture energy index of 4.3¿kJ/m2. After dry-wet accelerated aging, the post-cracking performance of the developed composites decreased (on average, 40% in toughness and 11% in strength) due to fiber embrittlement. To better understand the performance of aged composites, shredded fibers recovered from protective clothing (mainly consisting of meta-aramid fibers) were immersed in the binary matrix. Accordingly, the mechanical properties of the fibers after 5 and 10 cycles of dry-wet aging were studied. Based on the results, replacing partially PC by silica fume (between 30% and 50%) was seen as a sustainable alternative to improve the performance of the aged fibers by more than 10%., The authors express their gratitude to the Agencia Estatal de Investigación, Spanish Ministry of Economy, Industry, and Competitiveness (Government of Spain) for the financial support received under the scope of the project RECYBUILDMAT (PID2019-108067RB-I00/AEI/10.13039/501100011033). Also, they acknowledge the funding of the research group TECTEX (2021 SGR 01056) from the Department de Recerca i Universitats de la Generalitat de Catalunya. The first author acknowledges the Banco Santander for the Research Scholarships (Postdoc-UPC 2022 Grant)., Peer Reviewed, Postprint (published version)

The project case of Qiwu Bridge using link slab action between simply supported composite spans is introduced. The 60¿m-span girder of Qiwu Bridge is the longest and heaviest among the composite girders erected by bridge-erecting machine in China. Qiwu Bridge consists of a series of 3 simply supported spans built with composite girders and connected at the pier supports by a link slab. This solution has both advantages of (1) smooth driving condition and enhancement of durability by removing expansion joints and (2) clear structural behavior as simply supported spans. A finite element model was established to simulate and predict the mechanical response of this semi-continuous solution. Numerical results showed that the removal of the shear connection around the link slab decreased the stress level but also caused a stress mutation. Qiwu Bridge was also monitored by vibrating wire strain gages to follow its actual structural response. From preliminary monitoring data and numerical results, it can be concluded that the proposed construction method and the static scheme is safe for the 60-span composite girder with a large safety margin. Further experimental results will be obtained during the service stage of the bridge to validate the in-service performance of the proposed steel-concrete composite bridge with link slab., The first author acknowledges the support provided by the China Scholarship Council (No. 202106260050). The third author acknowledges the support provided by the Spanish Ministry of Science and Innovation through the research project PID2021-126405OB-C31 and AGAUR for support to consolidated research groups., Peer Reviewed, Postprint (author's final draft)

This study aims at investigating the effect of incorporating different quantities of polypropylene fibres recovered during concrete recycling or embedded in recycled aggregates on the mechanical properties of new polypropylene fibre-reinforced concrete (PPFRC). Both recovered fibre (at replacement ratios of 0 %, 10 %, 30 % and 100 %) and recycled coarse aggregate (0 %, 100 %) were used in new concrete. Polypropylene fibre contents of 3 and 9 kg/m3 (0.33 % and 1.0 % by volume, respectively) were chosen for all concretes. The properties of recovered and virgin fibres were tested to determine the effect of recycling on fibre properties. The compressive strength, elastic modulus and stress–strain behaviour in compression were tested and a constitutive model was developed to fit the stress–strain behaviour of the PPFRC with mixed recovered and virgin fibres. The residual tensile strength was also tested for concretes with recovered fibres and fibres embedded in recycled aggregate. The results show that mixing of recovered and virgin fibres is feasible without significant effect on mechanical properties of concrete. At the same time, inclusion of recycled coarse aggregate from PPFRC recycling contributes to residual tensile strength through the presence of fibres embedded in the aggregate., Peer Reviewed, Postprint (published version)

The high-performance demands on industrial floors, both in terms of larger slab dimensions and increased durability under harsh operating conditions, have led to the growing use of expansive admixtures. These generate a controlled expansive reaction within the concrete and compensate the early-age shrinkage. Despite their increasing use, calculation methods that permit to consider the expansive agents during the pavement design phase with a certain level of reliability are still unexistent. This study presents a straightforward cross-sectional model to assess both the stress-strain state and joint-opening of concrete pavements with volumetric stability admixtures by considering the slab dimensions, concrete composition, exposure conditions, and base friction characteristics. For that, a novel experimental device is designed and implemented in this work to characterize the dimensional variations associated with expansive agents since casting. A Type-G commercial volumetric stability admixture is considered as the expansive admixture. A full-scale validation of the proposed model is performed on a jointless concrete panel constructed by RCR Industrial Flooring in Spain. This validation proves the feasibility of the combined approach of laboratory calibration of the expansive addition and the cross-sectional model presented to accurately estimate both the slab deformations and joint opening developed over the 77-day test period., This research project has been supported by RCR Industrial Flooring. Thanks are extended to Juan Carlos Martín, Agustín Escámez, and Christophe Cortinovis for their assistance and collaboration throughout the course of this study. Finally, support from AGAUR through the research project EB-Pav (2021 PROD 00071) is greatly acknowledged., Postprint (published version)

The Annex L of FprEN 1992-1-1:2023 (EC-2) provides provisions for the design of Steel Fibre Reinforced Concrete (SFRC) structures. This Annex is supported by a comprehensive background document (BD) that gathers the main outcomes of the research carried out on SFRC during the last thirty years. This paper aims to cover the sections of Annex L and supplement those with scientific literature, to help readers reach a deeper understating of the fundamentals and specific details of the proposed formulations and rules., Peer Reviewed, Postprint (published version)

Digital fabrication with concrete (DFC) is fast becoming an attractive alternative for components (i.e., façades, urban furniture) and structural typologies (i.e., short-span footbridges, columns, floor systems) for which complex geometries derived from particular aesthetical criteria and/or construction time constrictions are governing parameters. Additionally, some authors claim that this process allows improving the sustainability of structures, as less material is necessary compared to traditional concrete solutions, thus reducing greenhouse gas emissions linked to material consumption. Nonetheless, the environmental implications of DFC are still under scrutiny and remain objectively unquantified. In this study, a sustainability assessment model to allow decision-makers to evaluate and compare concrete footbridge alternatives—from the sustainability perspective—including those constructed by means of 3D printed concrete (3DPC) techniques, is presented. The proposed approach is based on the MIVES method. For this purpose, the most representative criteria and indicators of sustainability identified are measured and weighted-aggregated in a decision-making tree. The sustainability index (SI) of each alternative is the outcome derived from the application of the model, and the SI was used as reference for evaluating the alternatives. The sustainability of 3D-printed footbridges is quantified and compared to other concrete-based solutions: traditional reinforced cast-in-place and precast concrete, as traditional solutions, and ultra-high performance precast concrete and textile-reinforced concrete, as innovative alternatives. The results of the analysis lead to conclude that 3D-printed footbridges have positive impacts on environmental and social indicators, but economic indicators still need to be improved to attain a competitive solution. The approach proposed herein to assess the sustainability of footbridges can be extended to other cases and stakeholders' prefer, The authors want to acknowledge ACCIONA, S.A. for the economic funds and information provided. This study was also financially supported by the Spanish Ministry of Sci-ence and Innovation under the scope of project CREEF (PID2019-108978RB-C32/AEI/10.13039/501100011033). A. Monserrat was supported by the Ministerio de Uni-versidades (Spain) with the Recovery, Transformation and Resilience Plan (RD 289/2021 and order UNI/551/ 2021) of NextGenerationEU; Postdoctoral Margarita Salas Fellowship funded by Universitat Politècnica de València., Peer Reviewed, Postprint (published version)

One of the main challenges for bridge damage identification using monitoring data is to acquire sensitive damage features but insensitive to operational and environmental effects as well as noise. Specifically, the temperature as part of environmental variability can mask structural damages in bridges. Principal Component Analysis (PCA) has been applied here as a well-known and robust technique for removing environmental variability and obtain damage-sensitive indices. As a first aim, PCA is used considering only ambient vibrations and the natural frequencies are considered as damage indicators. As a second objective, PCA in conjunction with Hilbert Huang Transform (HHT) and Variational Mode Decomposition (VMD) are applied to eliminate the environmental influence in transient vibrations due to traffic. The combined methodology is applied to the case of a numerical benchmark by using the Instantaneous Phase Difference (IPD) as novel vibration damage feature in the case of non-stationary vibrations. The results show that the proposed strategy to use the non-stationary vibration due to traffic instead of ambient vibration seems a promising tool for damage identification and, therefore, its capabilities in real bridge applications are worth exploring further when experimental data from real bridges will become available., The authors thank Prof. Eleni Chatzi, ETH Zurich, for giving us the data as well as documentation from the numerical bridge utilized in the case study. To the Dirección de Investigación de la Universidad Peruana de Ciencias Aplicadas for the support provided for the realization of this research work through the UPC-EXPOST-2023-1 incentive., Peer Reviewed, Postprint (author's final draft)

Given the established incentive to produce more sustainable concrete, the application of alternative and environmentally preferential materials, such as limestone (LS) powder, as partial cement (OPC) replacement, can make a significant global contribution toward sustainability. This paper presents the sustainability aspect of this green concrete through its potential application in reinforced concrete slabs and columns. For that purpose, 26 experimentally verified, concrete mixtures with and without LS powder were evaluated using the multi-criteria decision analysis framework ECO2. The conducted analyses show the significant potential and competitiveness of concrete with reduced cement and high LS powder content and their potential application in all types of reinforced concrete structures. In the case of slabs, the best ECO2 score was obtained for concrete containing LS powder. In the second case, due to the nature of the structural performance requirements in columns, approximately equal sustainability potential of OPC and LS concretes was observed. © 2023 The Author(s)., Peer Reviewed, Postprint (published version)

The need for measurable data from physical assets to actively feed a living Digital Twin (DT) is paramount. The requirements and needs that the gathered data should fulfill in order to be practically implemented in the stream data pipeline are heterogeneous, some of them general and other case-specific. This article summarizes a set of identified challenges and requirements for a seamless infusion of well-established Structural Health Monitoring (SHM) systems within DT platforms, without the objective of solve all of them. This identification is performed based on a review of traditional SHM systems with a vast array of information sources as well as on the review of techniques for the systematic digitalization of existing assets. On the other hand, ten real demo cases belonging to Ashvin, an H2020 Research and Innovation project, are providing real world testing beds for an active development of SHM infused in DT systems. Multiple information sources are studied in those sites, which also enriches with more realism, the identification of requirements and challenges presented herein. These assets provide a perspective to researchers about practical implications of these needs., All authors acknowledge the funding of ASHVIN, “Assistants for Healthy, Safe, and Productive Virtual Construction Design, Operation & Maintenance using a Digital Twin” an H2020 project under agreement 958161., Peer Reviewed, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

The Eurocode 2 for the design of concrete structures (EN1992-1-1:2004) is undergoing a revision that will lead to the publication of the second generation of this code to be used across all CEN member countries. Therefore, the impact of the code will reach hundreds of millions of people. Importantly, the Eurocode 2-revision will incorporate many significant changes, amongst which is the introduction of design provisions for fibre reinforced concrete (FRC). In this regard, one of the most important aspects for ultimate limit state (ULS) design will be the consideration of the shear strength of FRC members without shear reinforcement. Such a failure mode is associated with a number of uncertainties, as well as with a potentially-brittle failure response. However, so far, the design models proposed in the Eurocode 2-revision have not been accompanied by a robust reliability-based calibration of the FRC partial factor ¿SF. Within this context, this paper presents the results of an investigation on the safety format and the partial factor ¿SF for FRC members without shear reinforcement currently provisioned in the draft for the new Eurocode 2 (prEN1992-1-1:2021). Firstly, a database of experimental results on FRC beams is used to determine the model error. On that basis, a probabilistic analysis is performed using the First Order Reliability Method (FORM) to determine adequate values of ¿SF for varying target reliability indices. The results of the study show how ¿SF values need to updated in order to reach reliability indices typically considered for ULS design. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG., Peer Reviewed, Postprint (published version)

Structural fibers represent an effective strategy for enhancing the post-cracking tensile strength (fctR) of concrete. Currently, the characterization of this property relies predominantly on experimental methods, introducing uncertainties during the design phase and impeding advancements in new fiber types or the optimization of existing ones. This paper introduces a multilayer perceptron neural network designed to predict the fctR of fiber-reinforced concrete (FRC) undergoing the Barcelona Test. The optimal architecture of the predictor is determined through the evaluation of 9216 configurations involving input dimensions and the number of hidden layers and neurons. Generalization performance is rigorously assessed using repeated random sub-sampling validation across 50 iterations. The finalized model demonstrates a high accuracy in predicting fctR for various cracking stages in FRC (R2 of 0.87, 0.86, and 0.83). A comprehensive parametric analysis is conducted to establish coherence between the model's predictions and the established understanding of FRC behavior. Furthermore, numerical expressions are presented as an alternative tool to traditional testing, offering predictions for the residual strength of the Barcelona Test. These predictions consider factors such as fiber dosage, concrete strength, specimen type, height, and fiber geometric characteristics, serving as valuable tools for pre-design and quality control purposes. Such approaches are essential for fostering advancements in FRC technology., T. Ikumi is supported by the Torres Quevedo programme PTQ2018-009877 sponsored by the Spanish Ministry of Science and Innovation. The authors also express their gratitude to the same Spanish Ministry for the financial support received under the scope of the project CREEF (PID2019-108978RB-C32) and to the Catalan agency AGAUR trough their research groups support program (2021 SGR 00341). Finally, P. Pujadas wishes to recognise the support from Serra Hunter programme., Postprint (published version)

The aim of this study was to assess the social impacts of microalgae-based systems for wastewater treatment and bioproducts recovery by using the Social Life Cycle Assessment (S-LCA) tool. In particular, two systems were analysed: 1) a system treating urban wastewater, and 2) another system treating wastewater from the food industry. Moreover, these alternatives were compared to 3) a system for bioproducts production from microalgae grown in a standard growth medium. The recovered bioproducts in all the systems considered were: natural pigments, biogas and digestate, which can be reused as biofertilizer. Results showed that the scenario using standard growth medium was the one showing the best results in all impacts and stakeholder categories (up to 24-fold lower impacts depending on the impact category). This was mainly due to: i) the simplicity of the system, which consequently improves health and safety for workers; ii) the absence of contaminants which consequently improves health and safety, acceptability and olfactory impact for both consumers and the local community; iii) the presence of well-established legislation, regulatory frameworks, and full-scale deployment, which benefit value chain actors and society. Overall, this study also identified several social factors hindering a transition towards a circular bioeconomy in the microalgae-based systems for the wastewater treatment and resource recovery sector., Authors acknowledge the AL4BIO project (RTI2018-099495-B-C21) (MCIU/AEI/FEDER, UE) and the CYAN2BIO project (PID2021-126564OB-C32). The authors are grateful to the Government of Catalonia (Consolidated Research Group 2017 SGR 1029). Marianna Garfí is grateful to the MINECO (RYC-2016-20059)., Peer Reviewed, Postprint (author's final draft)

A hybrid girder bridge adopts a steel segment at the mid-span of the main span of a continuous concrete girder bridge. The critical point of the hybrid solution is the transition zone, connecting the steel and concrete segments of the beam. Although many girder tests revealing the structural behavior of hybrid girders have been conducted by previous studies, few specimens took the full section of a steel–concrete joint due to the large size of prototype hybrid bridges. In this study, a static load test on a composite segment to bridge the joint between the concrete and steel parts of a hybrid bridge with full section was conducted. A finite element model replicating the tested specimen results was established through Abaqus, while parametric studies were also conducted. The test and numerical results revealed that the concrete filling in the composite solution prevented the steel flange from extensive buckling, which significantly improved the load-carrying capacity of the steel–concrete joint. Meanwhile, strengthening the interaction between the steel and concrete helps to prevent the interlayer slip and simultaneously contributes to a higher flexural stiffness. These results are an important basis for establishing a rational design scheme for the steel–concrete joint of hybrid girder bridges., This research was funded by Spanish Ministry of Science and Innovation (grant number PID2021-126405OB-C31), Shanghai Science and Technology Commission (grant number 20XD1432400) and Guangdong Yejian Construction Drawing Review Center Co., Ltd. (grant number GDYJ-RD-17)., Peer Reviewed, Postprint (published version)

Nodal rotations are produced by bending and shear effects and bending rotations can be easily calculated using Euler–Bernoulli’s stiffness matrix method. Nevertheless, shear rotations are traditionally neglected, as their effects are practically negligible in most structures. This assumption might lead to significant errors in the simulation of the rotations in some structures, as well as the wrong identification of the mechanical properties in inverse analysis. Despite its important role, no other works studying the calculation of shear rotations in deep beams were found in the literature. To fill this gap, after illustrating the errors of commercial software regarding calculating the rotations in deep beams, this study proposed a simple and intuitive method to calculate shear rotations in both isostatic and statically redundant beams. The new method calculates the shear rotation for all segments separately and introduces the result to the total rotation of the structure. This method can be applied to find the shear rotation in a redundant structure as well. A parametric study was carried out to calculate slenderness ratios to determine in what structural systems the shear rotations can be neglected. In addition, the errors in the inverse analysis of deep beams were parametrically studied to determine the role of shear rotation in different structural systems. Finally, to validate the application of the method in actual structures, a construction stage of a composite bridge was analyzed., The authors are indebted to the projects PID2021-126405OB-C31 and PID2021-126405OB-C32 funded by FEDER funds—A Way to Make Europe and Spanish Ministry of Economy and Competitiveness MICIN/AEI/10.13039/501100011033/, BIA2017-86811-C2-1-R and BIA2017-86811-C2-2-R funded by FEDER funds., Peer Reviewed, Postprint (published version)

Peer Reviewed, Postprint (published version)

As a means to improve sustainability in the construction sector, the 3D-printed concrete technologies (3DPCTs) are emerging as potential alternatives to traditional construction for reinforced concrete structural components. Traditional technologies are still used in most architecture and civil engineering applications, although D-shape technology for 3DPCTs (DS-3DPCT) has proven technically feasible for producing pilot structural elements such as footbridges. These pilots have been contextualized within research and industrial frameworks, in which relevant technical information is confidential and cost and environmental performance related conclusions are still to be validated and reported. Moreover, scarce research has been conducted on sustainability performance by DS-3DPCT, and that carried out is primarily incipient and focused on identifying governing indicators and some specific non-generalizable quantifications. Former studies ack dealing with sustainability by DS-3DPCT from a holistic and integrated perspective, which requires quantifying and coupling the three main economic, environmental and social pillars. This research project comprehensively develops a sustainability-oriented decision-making approach for assessing construction technologies for footbridges based on MIVES and Delphi method. The Castilla-La Mancha park DS-3DPCT footbridge constructed by ACCIONA S.A. in 2016 in Madrid was the representative case study to validate this approach applicability. The results quantify the case study as sustainable, with excellent values for greenhouse gas emissions reduction, generation of qualified jobs, benefits to brand, occupational risk prevention, and design flexibility. However, this DS-3DPCT requires more maturity in the technology to improve its economic values. This approach range of application might be extended to other structural typologies by introducing -when necessary-other relevant indicators and weights’ distributions., Peer Reviewed, Objectius de Desenvolupament Sostenible::8 - Treball Decent i Creixement Econòmic, Objectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables, Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura, Postprint (published version)

The use of fibre-reinforced concrete (FRC) in structural applications is increasing significantly as a result of (1) the acceptance of this composite into design guidelines and (2) the improvement in terms of sustainability performance that has been reported for cases where FRC has been used. In this context, fibre orientation and distribution are factors that govern the post-cracking response of the FRC. Researchers have already dealt with the analysis of both variables from an experimental and numerical perspective, and design-oriented recommendations were included in existing design guidelines (i.e., fib Model Code 2020). Nonetheless, there are still technical aspects to be answered within a research framework before the influence of these variables on the mechanical response of FRC could be covered with sufficient reliability. In this regard, this research is aimed at shedding light on the influence of the mould geometry and concrete pouring/vibration procedures on the fibre orientation and distribution variables as well as on the post-cracking performance of the FRC. An extensive experimental programme aimed at characterising these variables using novel testing techniques (i.e., an inductive non-destructive approach for quantifying fibre amount and orientation and the BCN test for assessing the pre- and post-cracking responses of the FRC) was carried out for this purpose. A relationship has been found between the shape of the formwork and the direction of pouring, along with the direction and distribution of the fibres, both of which proved to have an influence on the residual tensile strength of the concrete. However, it has been confirmed that the first crack resistance depends on the concrete matrix, with the addition of fibres having no relevant influence on that mechanical parameter. The results and conclusions derived from this experimental programme can be extended to FRCs and boundary conditions similar to those established herein., This research was funded by the Ministry of Economy and Competitiveness of Spain through the S2C project (2017-6013-3) and co-funded by the Cantabrian Government through the grant for the Industrial Doctoral Program (CVE-2020-8540)., Peer Reviewed, Postprint (published version)

Globally, corrosion is the costliest cause of the deterioration of metallic and concrete structures, leading to significant financial losses and unexpected loss of life. Therefore, corrosion monitoring is vital to the assessment of structures’ residual performance and for the identification of pathologies in early stages for the predictive maintenance of facilities. However, the high price tag on available corrosion monitoring systems leads to their exclusive use for structural health monitoring applications, especially for atmospheric corrosion detection in civil structures. In this paper a systematic literature review is provided on the state-of-the-art electrochemical methods and physical methods used so far for corrosion monitoring compatible with low-cost sensors and data acquisition devices for metallic and concrete structures. In addition, special attention is paid to the use of these devices for corrosion monitoring and detection for in situ applications in different industries. This analysis demonstrates the possible applications of low-cost sensors in the corrosion monitoring sector. In addition, this study provides scholars with preferred techniques and the most common microcontrollers, such as Arduino, to overcome the corrosion monitoring difficulties in the construction industry., The authors are indebted to the projects PID2021‐126405OB‐C31 and PID2021‐126405OB‐C32 funded by FEDER funds—A Way to Make Europe and Spanish Ministry of Economy and Com‐petitiveness MICIN/AEI/10.13039/501100011033/, project PID2019‐106555RB‐I00 and project IDEAS 2.14 from Ports 4.0. It should also be noted that funding for this research was provided for Seyed‐milad Komarizadehasl by the European Social Fund and the Spanish Agencia Estatal de Investi‐gación del Ministerio de Ciencia Innovación y Universidades, grant (PRE2018‐083238)., Peer Reviewed, Postprint (published version)

The study aims to investigate the feasibility of using recycled aggregate (RA) and recovered fibers (RFs) obtained from recycling polypropylene fiber-reinforced concrete (PPFRC) in new concrete production. The mechanical properties were compared between a parent PPFRC, polypropylene fiber-reinforced recycled aggregate concrete (PPRAC), and recovered polypropylene fiber concrete (Re-PPRFC). All concretes were designed to have the same compressive strength and slump. The parent concrete was produced with 3 and 9 kg/m3 of polypropylene fibers. After recycling, the RA and RF were collected, and new concretes with RA and RF, PPRAC and Re-PPRFC, respectively, were produced with the same fiber content as the parent concretes. Both the compressive and flexural tensile strength (pre- and post-cracking) were characterized and the stress–strain relations derived accordingly. The results obtained for the different concretes were compared, proving that the RA and RF obtained by PPFRC recycling can benefit the design-oriented properties (workability and mechanical performance) of new concretes., This study has received funding from the China Scholarship Council (CSC) grant number 202106930007 and MBCC Group. The APC was waived by the journal., Peer Reviewed, Postprint (published version)

The integration of multicriteria decision-making (MCDM) methods with building information modeling (BIM) provides robust support for decision-making when assessing the sustainability of construction projects. Among the MCDM methods, the Integrated Value Model for Sustainability Assessment (MIVES) has proven to provide a representative and meaningful quantification of sustainability in different areas of civil engineering. Although previous studies have integrated BIM and MIVES, none automated the sustainability assessment process as BIM was only used to define the measurements of the MIVES indicators. This study accordingly developed a new method coupling the MIVES and BIM methodologies to realize automatic sustainability assessment of bridges. The proposed technique was validated using a real viaduct to evaluate sustainability and conduct a sensitivity analysis identifying the indicators with the most influence on sustainability performance. Critically, this methodology is not limited to the sustainability assessment of bridges as it can be readily adapted to other types of infrastructure., The authors are indebted to the projects PID2021-126405OB-C31, and PID2021-126405OB-C32 funded by MICIN/AEI/10.13039/501100011033/ and FEDER funds A way to make Europe., Peer Reviewed, Postprint (published version)

Over the last few years, several policies and new technological solutions have targeted the construction sector with the aim of reducing the sector's impacts on the environment. Among the different technological advances proposed, the reuse of materials in construction has been reported as a promising solution for an increase in sustainability and circularity. In particular, a type of cities' undergrounds assets for which materials' reuse is being explored are trenches for protecting services (i.e., water and gas transport pipelines, and optic fibre and other telecommunications services). Nonetheless, the economic and environmental benefits and impact of this type of system is still insufficiently quantified. In this research study, the economic and environmental impacts of four scenarios of trenches were assessed by using Life Cycle Costing (LCC) and Life Cycle Assessment (LCA). The four alternatives analysed consisted of: (1) the classical solution; (2) the classical solution with the reuse of soil; (3) the control low-strength material, and (4) the eco-trench. The results allowed concluding that in the eco-trench system, for which all material is reused, the environmental and economic impacts could be reduced by more than 80% and 50%, respectively. A parametric study for which the dimensions of the trenches were varied, permitted to reinforce these results and to quantify the impact's change along with the width and depth of the trench. Overall, this study provides a comprehensive view of the high-impact potential of reusing material for the construction of trenches in cities. The outcomes allow also remarking that the eco-trench system could be an attractive and advantageous solution for urban infrastructure stakeholders, both from an economic and environmental perspective., Peer Reviewed, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.6 - Per a 2030, reduir l’impacte ambiental negatiu per capita de les ciutats, amb especial atenció a la qualitat de l’aire, així com a la gestió dels residus municipals i d’altre tipus, Postprint (published version)

Alkali-activated concrete mixed with waste dredged sand (DS) is a new type of green concrete. In addition to reducing resource consumption and CO2 emissions, this approach is also cost-effective. Therefore, the ongoing research on its application in real industrial production is of great importance. This study examined the impact of the steam curing system on the mechanical properties and microstructure of alkali-activated dredged-sand concrete (AADSC). Different alkali equivalents and DS contents were used to produce AADSCs, and such AADSCs were cured using different steam curing schemes. The results show that steam curing significantly improves the early strength and 28-day strength under low alkali equivalent. The curing promotes the 1-day strength at 3% alkali equivalent from 2.1 MPa to 27 MPa after steam curing, and the 28-day strength increase was 7.8%. It is also found that the rise in compressive strength does not have a direct correlation with the energy consumption of steam curing. Even though the energy consumed by steam curing at 40 °C was 67% more than that at 60 °C, the 1 d strength under 40 °C steam curing was 7.5% lower. However, low-temperature steam curing retains more room for concrete strength increase. These results indicate the importance of a reasonable steam curing regime for the strength of AADSC., Acknowledged financial supports include the National Key R&D Program of China (Grant No. 2021YFB2600200), the Fundamental Research Funds for the Central Universities (Grant No. B230205017), State Key Laboratory of High-Performance Civil Engineering Materials (Grant NO. 2019CEM002), and National Natural Science Foundation of China (Grant No. 51979090)., Peer Reviewed, Postprint (author's final draft)

Bridges are vital components of transport infrastructures, and therefore, it is of utmost importance that they operate safely and reliably. This paper proposes and tests a methodology for detecting and localizing damage in bridges under both traffic and environmental variability considering non-stationary vehicle-bridge interaction. In detail, the current study presents an approach to temperature removal in the case of forced vibrations in the bridge using principal component analysis, with detection and localization of damage using an unsupervised machine learning algorithm. Due to the difficulty in obtaining real data on undamaged and later damaged bridges that are simultaneously influenced by traffic and temperature changes, the proposed method is validated using a numerical bridge benchmark. The vertical acceleration response is derived from a time-history analysis with a moving load under different ambient temperatures. The results show how machine learning algorithms applied to bridge damage detection appear to be a promising technique to efficiently solve the problem’s complexity when both operational and environmental variability are included in the recorded data. However, the example application still shows some limitations, such as the use of a numerical bridge and not a real bridge due to the lack of vibration data under health and damage conditions, and with varying temperatures; the simple modeling of the vehicle as a moving load; and the crossing of only one vehicle present in the bridge. This will be considered in future studies., Peer Reviewed, Postprint (published version)

An increasing number of researchers are working on Structural Health Monitoring (SHM) applications. However, the high price of traditional commercial accelerometers is known to be one of the significant drawbacks of SHM methods. On the one hand, to apply SHM applications to structures with a lower budget dedicated for their health and safety assessments, development of low-cost sensors can be an answer. On the other hand, low-cost sensors are known to have lower accuracy and resolution compared with those of traditional commercial accelerometers. For the first time in the literature, this paper represents a methodology for improving the resolution and accuracy of low-cost, low-resolution accelerometers. To do so, this paper proposes averaging the outputs of several aligned synchronized low-cost accelerometers. The validity of the proposed methodology has been examined through a series of laboratory experiments. These experiments tested accelerometers made from one, two, three, four and five combined MPU9250 chipsets on a shaking table. Moreover, two commercial accelerometers (393A03 and 356B18) were used to validate the accuracy of the developed solutions., Postprint (published version)

This material may be downloaded for personal use only. Any other use requires prior permission of the American Society of Civil Engineers. This material may be found at https://ascelibrary.org/doi/abs/10.1061/JAEIED.AEENG-1559., Residential skyscrapers (RSs) are very relevant to all aspects of sustainable development as an integral component of urban development. The need for high-rise buildings was first identified in Chicago in the later part of the nineteenth century. Today, more and more skyscrapers are being built to accommodate occupants in the small available land plots in the world’s megacities. In this paper, following the review of previous studies, a series of effective indicators are prioritized so that a model for the investigation of the sustainability performance in RSs that is related to the three aspects of sustainability is presented. The RSs should be designed to respond to different requirements during their life cycle, which includes environmental, social, and economic aspects of sustainable development in the initial design that results in a higher quality of life in the RSs. The method used in this paper is a multicriteria decision-making (MCDM) method for sustainability assessment and the integrated value model for sustainable assessment (MIVES). Nine RSs as case studies have been evaluated in Dubai, United Arab Emirates (UAE). Based on the multicriteria model used in this paper, the analyzed RSs in Dubai, UAE, have a sustainability performance in the range of 0.29 < SI < 0.62, where SI is the sustainability index., Peer Reviewed, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Postprint (author's final draft)

A part of the retaining earth wall of the main line of the Catalonian railways (FGC), close to the station of Terrassa collapsed abruptly and without any previous warning. The collapse of this part of the wall provoked the disruption of the operation of trains for three days due to the difficulties in the debris removal. The re-construction of the wall lasted several months. After investigation, it became evident that the failure was due to the pit corrosion of the main reinforcement due to the leakage of a pipeline containing water with chlorides (drinking water network). From the results of the investigation, the main parameters related to the durability of the concrete in the wall were deduced. Once the failed section of the wall was refurbished, it was possible the inspection of the condition state of the reinforce-ment mainly in the rest of the wall (around 100 meters), removing extrados land. The assessment of the actual state and remaining service life of the rest of the retaining earth wall was carried out based on the different behaviour of each part, due to the different leakage in relation to the failed section. Based on this evidence, the residual service life of the rest of the wall was estimated as adequate during the remaining years of railway operation, The second author acknowledges the financial support provided by the Spanish Ministry of Science and Innovation through the research project PID2021-126405OB-C31 and AGAUR (Government of Catalonia) for the support to consolidated research groups., Postprint (published version)

Soil-cement is a building material that is considered low-cost and has a low environmental impact. Despite its benefits, performance optimisation studies are scarce compared to other materials such as concrete. The possibility of obtaining soil-cement with improved characteristics, such as flexural strength, would enable the increased use of this product in new applications in construction. The aim of this study is to produce high-performance soil-cement (HPSC) specimens and to evaluate and compare this new material with high-performance concrete (HPC) in terms of flexural strength. A total of 12 specimens were produced with a mixture of 23.5% (by mass) of cement with the application of 10 MPa of pressure for its compaction. The results show that, at 28 days, the specimens reached an average strength of 6.73 MPa and, at 240 days, 12.34 MPa. This means that the HPSC reached a flexural strength resistance equivalent to HPC without the need for mined materials, such as sand and gravel, or the additives adopted in some doses of HPC, such as superplasticisers. Therefore, when using local soil, HPSC can be considered an environmentally preferable alternative to HPC for many construction applications where flexural strength is a requirement., Peer Reviewed, Postprint (published version)

Dry joints with keys are often used in precast concrete segmental bridges (PCSBs) to transfer shear stresses. Large dry joints with keys can often provide greater shear bearing capacity, which can meet the needs of rapid construction and simple assembly. This study focuses on the shear response of super-sized dry joints with keys under direct shear. Various monitoring methods, including digital image correlation (DIC) and distributed optical fiber sensing (DFOS), were used to systematically study the stress process of large concrete keys. The results show that as the size of the key teeth increases, the shear bearing capacity and ultimate vertical displacement of the specimens also increase. DIC and DFOS techniques provide detailed information on key tooth failure, which is beneficial for subsequent stress analysis of shear keys., The authors acknowledge the support provided by the Spanish Ministry of Science and Innovation through the research project PID2021-126405OB-C31 and AGAUR (Government of Catalonia) for support to consolidated re-search groups, and CSC scholarship of China (202206710009)., Peer Reviewed, Postprint (published version)

Nowadays, low-cost sensors based on low-cost microcontrollers and microprocessors are gaining a lot of attention from researchers. This increasing interest is due to the fact that the implementation of low-cost solutions may make Structural Health Monitoring (SHM) applicable and affordable to structures with a low budget for their SHM. However, many of the present solutions do not have comparable accuracy and resolution with those of the traditional commercial accelerometers. Also, the noise density of these newly developed prototypes has not been checked through laboratory experiments. In fact, the characteristics of the designed and created accelerometer are simply copied from the datasheet of the chipset used to develop the solution. Moreover, the sampling frequency of the majority of the available low-cost solutions usually is lower than 100 Hz. This paper presents a consistent work with the development of a low-cost wireless accelerometer with a sampling frequency of 333 Hz and noise density of 51µg/vHz. This accelerometer's accuracy, noise density, and reliability are evaluated through a series of laboratory experiments. It is essential to mention that this accelerometer does not need any additional data acquisition equipment and is self-sufficient., Postprint (published version)