Corrosion of reinforcing steel in concrete structures, especially in chloride-rich environments, remains a leading cause of structural degradation and presents significant challenges for maintenance. Traditional steel corrosion inspection techniques, both direct and indirect, often fall short in terms of accuracy, efficiency, and cost-effectiveness. In this paper, an interpretable machine learning (ML)-aided framework is developed for predicting steel corrosion degree in concrete, which integrates multi-scale feature selection (MSFS), optimal algorithm determination, and SHapley Additive exPlanations (SHAP) techniques, addressing key limitations of conventional ML models, such as limited feature selection, poor generalization, and black-box opacity. The learning capability of the computational model is verified through extensive comparisons with multiple baseline algorithms. A digital example is presented to demonstrate the accuracy and efficiency of the developed framework. From the example, it is found that the MSFS method can identify key features of steel corrosion, such as crack width (w), geometric ratios (cb/d, cl/d, cb/cl), and concrete properties (fc, W/C). This ensures an optimal balance between accuracy and generalization, as validated by 5-fold cross-validation and independent dataset testing, with the optimal model achieving a test set R2 of 0.94 and a 33.6% reduction in RMSE compared to the default model. It is also found that the SHAP technique can further vindicate w and cb/d as the most influential factors governing internal corrosion. This paper pioneers the ML computational models for the prediction of structural deterioration, e.g., steel corrosion in concrete, which can replace traditional mathematical model-based prediction. These innovations represent a significant step toward the future of digital-driven structural performance prediction.
Engineering (General). Civil engineering (General), Building construction
Puppetry has been utilised as an effective mechanism to facilitate conversation and communicate complex topics across a variety of disciplines. To provoke discussions, our project aimed to utilise puppets as an effective and entertaining ‘bridge’ to increase the confidence of young people, enabling them to question and explore scientific endeavours, and to increase the confidence of engineers to communicate their work with young people. This proof-of-concept was anchored in the research of the Centre for Enzyme Innovation at the University of Portsmouth, UK, which focuses on developing low-carbon biotechnological solutions for recycling problem plastic waste in a circular economy. The science was effectively interpreted and discussed through co-designed puppetry workshops between engineers from the University of Portsmouth and young people from the community through engagement with community partners Artswork, The Makers Guild, the company Making Theatre Gaining Skills in Bognor Regis and secondary school students at the Admiral Lord Nelson School in Portsmouth. Through this approach, we demonstrated that 86 per cent of the young people gained a deeper understanding about what engineers do, and 79 per cent about how engineering improves our lives. The majority of engineers felt more confident and motivated in utilising arts-based techniques in their engagement practice following the project. Through this work, we demonstrated that puppetry can be used to bridge the gap between scientists/engineers and underserved communities, although this can be limited by the power dynamics that currently exist in society.
As China’s railway network expands, the complexity of tunnel engineering has increased, particularly for large cross section and small spacing tunnels. These tunnels exhibit significant excavation spans, multiple construction stages, and interdependent construction processes. However, the effects of different tunnel excavation methods on the deformation and stress distribution during the excavation process are still not clear. Therefore, based on a small spacing railway tunnel in Chongqing, this study employs monitoring, numerical simulation, and machine learning methods [gray wolf optimizer (GWO), particle swarm optimization (PSO), and genetic algorithm (GA)] to analyze tunnel deformation and stress. A method for automatic parameter optimization was proposed, which improved the accuracy of the machine learning prediction model (the error has decreased from 9.38% to 0.67%). The results indicate that the center cross diagram and double side drift methods reduce deformations and stress compared to the bench method (reduced by 55.03% and 54.36%, respectively). The GWO model demonstrates superior predictive performance for vault deformations and stress; the R2 of GWO was increased by 0.06 compared to that of PSO and by 0.047 compared to that of GA.
There has been a large increase in the number of days per year with numerous EF1-EF5 tornadoes. Given the significant damage incurred by tornadoes upon communities, community resilience analyses for tornado-stricken communities have been gaining momentum. As the community resilience analysis aims to guide how to lay out effective hazard mitigation strategies to decrease damage and improve recovery, a comprehensive and accurate approach is necessary. Agent-based modeling, an analysis approach in which different types of agents are created with their properties and behavior clearly defined to simulate the processes of those agents in an external environment, is the most comprehensive and accurate approach so far to conducting community resilience simulations and investigating the decision-making for mitigation and recovery under natural hazards. In this paper, agent-based models (ABMs) are created to simulate the recovery process of a virtual testbed based on the real-world community in Joplin City, MO. The tornado path associated with the real-world tornado event that occurred in May 2011 is adopted in the tornado hazard modeling for the Joplin testbed. In addition, agent-based models are created for another virtual community in the Midwest United States named Centerville using an assumed tornado scenario of the same EF-scale as that in Joplin. The effects of hazard mitigation strategies on the two communities are also explored. A comparison between the analysis results of these two testbeds can indicate the influence of the characteristics of a tornado-prone community on the resilience of the community as well as on the effects of hazard mitigation strategies. It is observed that a community's level of development significantly impacts the tornado resilience. In addition, the effects of a specific type of hazard mitigation strategy on the recovery process are contingent upon testbed characteristics.
Disasters and engineering, Cities. Urban geography
Engineering light-matter interactions using non-Hermiticity, particularly through spectral degeneracies known as exceptional points (EPs), is an emerging field with potential applications in areas such as cavity quantum electrodynamics, spectral filtering, sensing, and thermal imaging. However, tuning and stabilizing a system to a discrete EP in parameter space is a challenging task. Here, we circumvent this challenge by operating a waveguide-coupled resonator on a surface of EPs, known as an exceptional surface (ES). We achieve this by terminating only one end of the waveguide with a tuneable symmetric reflector to induce a nonreciprocal coupling between the frequency-degenerate clockwise and counterclockwise resonator modes. By operating the system at critical coupling on the ES, we demonstrate chiral and degenerate perfect absorption with squared-Lorentzian lineshape. We expect our approach to be useful for studying quantum processes at EPs and to serve as a bridge between non-Hermitian physics and other fields that rely on radiation engineering. Robust engineering of non-Hermitian light-matter coupling will be crucial for future optical device design. Here the authors present a photonic system that operates on an exceptional surface, demonstrating chiral and degenerate absorption with super-Lorentzian lineshape.
J. Valdoz, Benjamin C. Johnson, Dallin J. Jacobs
et al.
The extracellular matrix (ECM) has pleiotropic effects, ranging from cell adhesion to cell survival. In tissue engineering, the use of ECM and ECM-like scaffolds has separated the field into two distinct areas—scaffold-based and scaffold-free. Scaffold-free techniques are used in creating reproducible cell aggregates which have massive potential for high-throughput, reproducible drug screening and disease modeling. Though, the lack of ECM prevents certain cells from surviving and proliferating. Thus, tissue engineers use scaffolds to mimic the native ECM and produce organotypic models which show more reliability in disease modeling. However, scaffold-based techniques come at a trade-off of reproducibility and throughput. To bridge the tissue engineering dichotomy, we posit that finding novel ways to incorporate the ECM in scaffold-free cultures can synergize these two disparate techniques.
The bio-inspired honeycomb column thin-walled structure (BHTS) is inspired by the biological structure of beetle elytra and designed as a lightweight buffer interlayer to prevent damage to the reinforced concrete bridge pier (RCBP) under the overload impact from vehicle impact. According to the prototype structure of the pier, a batch of scale models with a scaling factor of 1:10 was produced. The BHTS buffer interlayer was installed on the reinforced concrete (RC) column specimen to carry out the steel ball impact test. Then, the modified numerical model was subjected to the low-energy input impact test of the steel ball without energy loss during the falling process at the equivalent height of 1.0–3.5 m, and the dynamic response characteristics of the RC column were analyzed. By comparing the impact force and impact duration, maximum displacement, and residual displacement in the impact model, the BHTS buffer interlayer’s protective effect on RC columns under lower energy lateral impact was evaluated. Later, a high-energy input lateral impact test of a steel ball falling at an equivalent height of 20.0 m was carried out. According to the material damage, dynamic response, and energy absorption characteristics in the impact model, the failure process of the RC columns was analyzed. The results showed that BHTS absorbed 82.33% of the impact kinetic energy and reduced 77.27% of the impact force, 86.51% of the inertia force, and 64.86% of the base shear force under the failure mode of a 20 m impact condition. It can transform the shear failure of the RC column into bending failure and play an effective protective role for the RC column. This study can provide useful references for collision prevention design in practical engineering.
Affected by dip angle and thickness of strata and the tunneling method, soft rock tunnel has obvious characteristics of large deformation, long deformation time and difficult support. Based on a case study of Gelong the deformation and failure mechanism of surrounding rock, stress characteristics of supporting structural and control method of large section highway tunnel passing through strong-medium weathered carbonaceous slate stratum are studied. This paper proposed construction method based on strengthening the longitudinal stiffness of supporting structure and increasing the integrity of surrounding rock, The results showed that the deformation of surrounding rock and the stress of supporting structure increased rapidly in the early stage of construction. The cumulative deformation of vault settlement and horizontal convergence reached 116.9 mm and 97.9 mm, respectively, accounting for 73.53% and 76.62% of the total deformation. The proportion of surrounding rock pressure shared by the primary support and the secondary lining was about 8.9:1.1. This shows that the initial support after comprehensive reinforcement has a strong supporting capacity, and effectively reduces the secondary lining pressure of the tunnel, which plays a vital role in the long-term service of the secondary lining.
Structural health monitoring (SHM) has been widely applied in the field of Mechanical and Civil Engineering in recent years. It is very hard to detect damage, however, using the measured data directly from the remote cloud platform of on-site structure, owing to changing environmental conditions. At the same time, outlier data from the remote cloud platform often occurs due to the harsh environmental conditions, interferences in the wireless medium, and the usage of low-quality sensors, which can greatly reduce the accuracy of structural health monitoring. In this paper, a novel temperature compensation method based on a long-short term memory (LSTM) network and the particle filter (PF) is proposed to separate the temperature effect from long-term structural health monitoring data. This method takes LSTMs as the state equation of PF, which solves the problem whereby PF cannot accurately derive the state equation for complex structures. A feedback model using the probability distribution generated by PF is developed to filter the observed value, thus measurement outliers can be successfully reduced. A numerical simulation and the measured deflection data from an SHM system are utilized to verify the proposed method. Results from the numerical simulation show that the LSTM-PF method can satisfactorily compensate for the temperature effect even when the nonlinear temperature effect is considered. Moreover, outputs from the SHM system of a large-scale suspension bridge indicate the temperature effect can be compensated and outliers can be appropriately reduced at the same time using the measured deflection data.
Traffic volume and vehicle loads are increasing with time during the bridge service life. Time-dependent reliability theory considers the time-varying effects of loads and resistance, which has been commonly adopted in recent engineering reliability research. The degradation of bridge resistance and increase of vehicle load and frequency varies with time, as described by a nonstationary stochastic model. The gamma stochastic process is adopted to describe the frequency function of vehicle load occurrence to promote the application of nonstationary processes in reliability studies, and time-dependent reliability analyzing approach is proposed for reinforced concrete bridges based on increasing load frequency. The time-dependent reliability equation is modified to account for the verifying effect of historical load information on time-varying resistance by including the coefficient of variation of bridge resistance as a time-associated variable. The above two methods are then used to perform a time-dependent reliability analysis on a prefabricated prestressed concrete bridge. The results show that the structural time-dependent reliability immunes the correlativity of frequency increment of vehicle loads; the time-dependent failure probabilities within 20 to 40 years range from those obtained by proof load tests with load intensities between 31.6% and 36.4% of the initial resistance, indicating higher precision of the modified equation. When the load frequency λ is less than ten times a year, the inspecting time interval is within 35 years, and the historical load intensity is less than 29.1% of the initial resistance, the approach based on load frequency function λ(t) is available. When the load frequency exceeds 36.4% of the bridge’s initial resistance, and the annual growth rate of frequency (γ) exceeds 150%. The RC bridge structure constructed in the marine environment has a higher failure probability within 20 years; thus, extra attention must be paid as corrosion resistance of reinforcements should be enhanced during its design and construction.
Lorenc Wojciech, Seidl Günter, Berthellemy Jacques
Composite dowels have opened new possibilities for engineers designing composite structures. The fundamental and most important characteristic of composite dowels is the shape of the cutting line. It is important to understand why only one particular shape of the cutting line is used in bridge engineering, while so many different shapes have been investigated by many researchers. The essential part of the process of developing composite dowels – the development of the shape of the cutting line – is presented in this paper. The influence of the steel web thickness is presented, and technological problems of steel fabrication are highlighted. The role of empirical experience from the first bridges, push-out tests, and finite element simulations is presented. Assumptions for numerical procedures are given. The distinction between the steel failure and concrete failure modes is introduced for composite dowels. The paper presents how the concept of “shape” was divided into “shape,” “ratio,” and finally “size,” and how, because of the fatigue problems in bridges, all the three factors have emerged to result in the form of shapes that can satisfy the requirements for bridges. Research leading to the invention of the first version of the clothoidal shape is presented.
Engineering geology. Rock mechanics. Soil mechanics. Underground construction
Size effect has always been the focus of rock mechanics as a bridge between laboratory test and engineering site. Previously, the research conditions and objects of the rock size effect have mostly focused on cylindrical rock samples with different height-to-diameter ratios (H/Ds) under uniaxial or conventional triaxial compression, while there has been little research on the rock size effect under true triaxial compression (TTC), especially rectangular rock samples with different sizes and the same length-to-width-to-height ratio. Based on this, the deformation, strength, and failure characteristics of Beishan (BS) granite and Baihetan (BHT) basalt with different sample sizes under TTC were studied by a comparative analysis method. The size effect of deformation and failure characteristics under TTC are not obvious, including stress-strain curves, Young’s modulus, peak strains, failure angles, and macrofailure mode. However, the damage stress (σcd) and peak strength (σp) have obvious size effect; that is, the smaller the sample size is, the higher the strength is. Additionally, the relationship among the peak strength, sample size, and intermediate principal stress (σ2) is power function. In addition, by comparing the peak strength increment caused by the sample size of the two types of rocks, the σp of the fine-grained BHT basalt is more sensitive to sample size than that of the coarse-grained BS granite. Finally, by analyzing the relationship between the size of the mineral grains or clusters in the two types of hard rocks and the complexity of crack propagation in the fracture surface under TTC, it is suggested that the minimum side length of rock samples should not be less than 10 times the maximum mineral clusters (such as feldspar phenocrysts in BHT basalt). In addition, the method of estimating elastic strain is established by analyzing the relationship between the size of the rock sample σ2 and the elastic strain under TTC.
After a cable-stayed bridge was opened to traffic in 2008, as of October 2017, various types of diseases have appeared in epoxy asphalt concrete pavement. However, as of now, the durability evaluation of steel bridge deck pavement is almost blank during the operation period. Therefore, the research team investigated and tested the service performance of epoxy asphalt concrete pavement on the cable-stayed bridge. The results showed that the intensity has attenuated to varying degrees at different positions of the heavy lane, and the most damaged area was the pavement of the uphill section. The crack resistance of the epoxy asphalt mixture was less affected by external conditions. In the composite beam, the bending strength of the mixture was significantly decreased where was under complex stress and threat of disease, and the deformation performance increased initially and then decreased. There was a bridge pavement that was under delamination and complex stress in the single layer beam, the low temperature performance of the lower layer of the pavement was inferior to that of the upper layer of the pavement. The epoxy asphalt mixture had good water stability. The fatigue life of epoxy asphalt mixture was more sensitive to the change of strain, and the change of modulus showed a gradual decay trend. It has been unable to meet the working environment under large strain conditions.
Materials of engineering and construction. Mechanics of materials
The behavior of FRCM (Fabric Reinforced Cementitious Mortar) confined clay brick masonry columns is analyzed in this paper. The results of an experimental investigation conducted on small-scale columns made by clay brick masonry confined with steel-FRCM (or Steel Reinforced Grout, SRG), PBO (poly-paraphenylene-benzo-bisoxazole) FRCM and basalt-FRCM, tested under monotonic compressive load, are described and discussed. Tests were conducted on thirteen prismatic columns; eleven columns (two unconfined and nine confined) were tested under concentric load while an eccentric load was applied on two confined columns. For each confinement system, the parameters investigated were the ‘confinement ratio’, the ‘load eccentricity’ and the ‘overlap configuration of the fiber fabrics’. FRCM confinement improved the structural response of masonry columns in terms of ultimate strength, ultimate strain and ductility. Some models from the literature were also examined to evaluate their applicability in predicting the axial capacity of confined columns.
Chemicals: Manufacture, use, etc., Textile bleaching, dyeing, printing, etc.
In this paper to increase the efficiency of direct displacement based design (DDBD) in designing structures equipped with viscous dampers (VDs), a method has been proposed to determine optimal distribution of VDs. The proposed method has been based on defining an optimization problem which minimizes the sum of damper coefficients to achieve the required equivalent viscous damper. To solve the optimization problem the distributed genetic algorithm (DGA) has been applied. To illustrate the method, three 2, 5 and 20 story steel frames equipped with linear VDs and designed using DDBD, have been considered and optimal placement of VDs has been determined. The controlled structures using uniform distribution (UD) and optimal distribution (OD) of VDs subjected to ten artificial earthquakes compatible with design spectrum and nonlinear time history analysis has been conducted. Results show that to achieve the same equivalent viscous damping for both uniform and optimal distributed VDs distribution, using OD has reduced significantly the sum of dampers coefficient (up to 30%) as well as the maximum damping force(up to 24%). Also evaluating the performance of controlled structures under different artificial records has shown that using OD has led to less control system cost while both distributions has similar performance.
With the rapid population growth, the need for elevators is being increased. The common type of elevator used in the building industry is a cable-lifted elevator which requires an elevator pit, machine room, and also counter-weight. Hydraulic elevators have been used for high loads and a few floors and do not require to machine room on the roof. Screw systems such as power screw used more for industrial lifters, due to its low speed, frictional losses, and heat production at higher speeds and also the possibility of buckling. Ball screw has soft motion, low sound and vibration, as well as very low frictional losses, which can have a higher speed than a power screw, and therefore may be applied for the elevator. For this purpose, the design of a ball screw-driven elevator for carrying of six people in three floors with a speed of 0.6 m/s has been considered. The conceptual design of the elevator and its components, selection of appropriate ball screw and nut, design of the straight bevel gear, and finally, the determination of the motor power and speed in both conditions with and without counter-weight have been presented. Comparison of these systems with the conventional traction system show that at the same speed, this method requires a motor with higher power in the case of no counter-weights, but if the speed is reduced to 0.45 m/s, a motor with less power is needed and among the other benefits such as the elimination of the pit, machine room, and the counter-weight, makes this method to be more preferable comparatively and easier to implement in the residential buildings. If the counter-weight is used, the power of the motor is reduced significantly and the system may be performed utilizing the existed single-phase current in home buildings using a proper inverter.