Damage Ratio Research Articles

Multi-attribute-based procedure for seismic loss scenario in a historical area

AbstractSeismic events have shown to be exceedingly damaging to structures over time, with serious social and economic consequences. As a result, large-scale seismic risk assessments are essential for reducing the potential damage from future earthquakes. Therefore, the proposed study attempts to examine the vulnerability and risk of unreinforced masonry buildings (URM) placed in aggregate conditions in a historical area of the city centre of Lisbon. To this purpose, a comprehensive exposure model was developed combining satellite remote sensing, GIS software, and census data. Subsequently, seismic hazard was evaluated in the area, considering both Peak Ground Acceleration (PGA) and macro-seismic intensity for different return periods (i.e. 2-50-100-475-975-2500-5000 years). Vulnerability was assessed by introducing a novel approach to earthquake risk assessment using Multi-Criteria Decision-Making methodologies. Specifically, the method employs the Analytic Hierarchy Process (AHP) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) computational methods to evaluate parameter weights and vulnerability index. Damage scenarios, fragility curves and mean damage ratios curves were provided to offer an overview of the vulnerability of the assets exposed to risk. Finally, the expected consequences were evaluated in terms of direct economic losses showing an economic loss of 595 M€ for a 475-years return period, while 1108 M€ for 5000-years. This study significantly enhances seismic analysis for urban areas by introducing a Multi-Criteria Approach. This method simplifies vulnerability assessment, ensuring ease of application and reproducibility. Its insights offer valuable support for disaster risk management decisions, facilitating the implementation of resilience and risk-reduction strategies.

Rapid Urban-Scale Building Collapse Assessment Based on Nonlinear Dynamic Analysis and Earthquake Observations

Rapid damage assessment after an earthquake is crucial for allocating and prioritizing emergency actions. Building damage due to an earthquake depends on the seismic hazard and the building’s strength. While it is now possible to promptly access acceleration data as seismic input through online strong motion networks in urban areas, good models are necessary to evaluate the damage in different zones of the affected area. This study aims to present a rapid method for such an urban-scale building collapse evaluation by conducting a nonlinear dynamic analysis of modeled buildings. Based on the Nagato and Kawase model, this study estimates the yield shear strength of 3-story steel buildings, 3-story reinforced concrete buildings, and 1-story masonry buildings in Sarpol-e-Zahab City after the 2017 Mw7.3 earthquake. The damage ratio is calculated through nonlinear dynamic analyses using estimated records from the main earthquake shock in different city zones. The research found that the seismic yield shear strength of steel and reinforced concrete buildings might be weaker than that of the Iranian seismic code’s standard value. Conversely, masonry-building resistance is stronger than the guidelines assumed. The constructed numerical models can be used for the rapid building damage assessment immediately after a damaging earthquake.

Corrosion failure analysis of interfacial bond performance in circular seawater sea-sand concrete encased weathering steel structures

This paper investigated the bond-slip behavior of circular seawater sea-sand concrete encased weathering steel (CSSCEWS) structures after chloride-induced corrosion. Electrochemical corrosion tests and push-out tests were conducted on fifteen designed CSSCEWS specimens. The results revealed that the corrosion ratio and steel section type distinctly influenced the interfacial bond performance. Both the ultimate and residual bond strengths decreased with the increase of the corrosion ratio, and the decline rate slowed down gradually. Compared to the uncorroded specimens, the average damage ratio of the ultimate strength of the specimens with a corrosion ratio of 8% is 25.9%, while the average damage ratio of the residual strength is 49.1%. The bond toughness continuously decreased with prolonged corrosion, while the bond stiffness and energy dissipation index first increased and then decreased. Additionally, formulas for calculating the corroded bond strengths of CSSCEWS specimens were proposed. Considering the strength damage due to corrosion and the stiffness damage due to slip, a three-stage bond-slip constitutive model was proposed. Finally, this model was applied to the nonlinear spring elements in finite element modeling to effectively simulate the interfacial bond behavior during the loading of corroded CSSCEWS specimens.

Pavement damage characteristics in the permafrost regions based on UAV images and airborne LiDAR data

The rapid degradation of “Xing'an-Baikal permafrost” in Northeast China has led to various road engineering problems. Efficient inspection and control of pavement quality are critical for maintaining the structural integrity of roads and driving safety in cold regions. Taking the Jagdaqi-Walagan section (JWS) of the Jagdaqi-Mo'he Highway as the object, based on field investigation, unmanned aerial vehicle images and airborne LiDAR data, combined with geographical information system, this study analyzed the pavement damage characteristics in mid- to high-latitude permafrost regions, including quantification of damage ratio, extraction of pavement cracks, and evaluation of pavement roughness and driving quality. The results showed that the average pavement damage ratio was 8.80 %, significantly higher in isolated permafrost regions. A higher damage rate in the Jagdaqi-Mo'he direction than the opposite, with a more concentrated cracking distribution. The worst pavement roughness and most severe pavement bumping at repetitive repair locations. This study provides an effective method for investigating pavement damages and analyzing their mechanisms, and explores the application potential of visible light images combined with LiDAR data in frozen soil engineering. The results provide a scientific basis for assessing current highway conditions, enabling scientific maintenance, and evaluating the risk of engineering damages.

Damage ratio strength criterion for asphalt mixtures and its application in rutting prediction

The current damage ratio strength theory is employed to predict the multiaxial strength of asphalt mixtures at various temperatures. Based on the dimensionless triaxial strength of asphalt mixtures, the values of six empirical parameters are recommended to establish the corresponding dimensionless strength criterion. The multiaxial strength data of diverse asphalt mixtures, including OGFC-13, AC-13, AC-20, AC-25, SMA-13, and SUP12.5 at different temperatures, are employed to validate the proposed criterion, which is then compared with other criteria. The results indicate that the suggested dimensionless strength criterion with uniform parameter values can accurately predict the true triaxial, confining triaxial, and biaxial strength values of asphalt mixtures across various temperatures. Furthermore, the proposed criterion is employed to elucidate the mechanical mechanism of rutting, offering a valuable insight for predicting flow rutting of pavement under loads.

Analysis of Peri-Implantitis Photothermal Therapy Effect According to Laser Irradiation Location and Angle: A Numerical Approach.

In recent years, dental implants have become increasingly popular around the world. However, if the implant is not properly managed, inflammation may occur, and the implant itself may need to be removed. Peri-implantitis is a common inflammation that occurs in dental implants, and various laser treatments have recently been studied to eliminate it. In this study, the situation of removing peri-implantitis using photothermal therapy, one of the various laser treatments, was analyzed theoretically and numerically. The temperature distribution in the tissue for various laser irradiation locations, angles, and power was calculated based on heat transfer theory, and the degree of thermal damage to tissue was analyzed using the Arrhenius damage integral. In addition, the thermally damaged region ratio of inflamed and normal tissue was analyzed using the Arrhenius thermal damage ratio and normal tissue Arrhenius thermal damage ratio to confirm the trend of treatment results for each treatment condition. The results of the study showed that if only the thermal damage to the inflamed tissue is considered, the laser should be angled vertically, and the laser should be applied to the center of the inflamed tissue rather than close to the implant. However, if the thermal damage to the surrounding normal tissue is also considered, it was found that the laser should be applied at 1.0 mm from the right end of the inflamed tissue for maximum effect. This will allow for more accurate clinical treatment of peri-implantitis in the future.

Phase-Change Stamp with Highly Switchable Adhesion and Stiffness for Damage-Free Multiscale Transfer Printing.

Transfer printing is a technology widely used in the production of flexible electronics and vertically stacked devices, which involves the transfer of predefined electronic components from a rigid donor substrate to a receiver substrate with a stamp, potentially avoiding the limitations associated with lithographic processes. However, the stamps typically used in transfer printing have several limitations related to unwanted organic solvents, substantial loading, film damage, and inadequate adhesion switching ratios. This study introduces a thermally responsive phase-change stamp for efficient and damage-free transfer printing inspired by the adhesion properties observed during water freezing and ice melting. The stamp employs phase-change composites and simple fabrication protocols, providing robust initial adhesion strength and switchability. The underlying mechanism of switchable adhesion is investigated through experimental and numerical studies. Notably, the stamp eliminates the need for extra preload by spontaneously interlocking with the ink through in situ melting and crystallization. This minimizes ink damage and wrinkle formation during pickup while maintaining strong initial adhesion. During printing, the stamp exhibits a sufficiently weak adhesion state for reliable and consistent release, enabling multiscale, conformal, and damage-free transfer printing, ranging from nano- to wafer-scale. The fabrication of nanoscale short-channel transistors, epidermal electrodes, and human-machine interfaces highlights the potential of this technique in various emerging applications of nanoelectronics, nano optoelectronics, and soft bioelectronics.

Development of an Optimization-Based Budget Allocation Model for Seismic Strengthening Based on Seismic Risk Assessment

This study presents a technology used for the prediction of economic losses to facilities in a given area during an earthquake, thereby enabling the efficient application of performance-based maintenance and seismic strengthening. We also propose an algorithm for the establishment of a reinforcement plan that minimizes earthquake-induced economic losses within a constrained budget. The algorithm incorporates fragility functions from prior research and utilizes an optimization technique for budget allocation, leveraging the target damage ratio concept and constrained optimization. Based on the fragility curve, the probability of occurrence for each damage state for a specific PGA value and the damage rate for each damage state are calculated. From these values, the expected damage ratio (EDR) is estimated. An optimization-based budget allocation algorithm is developed to find the elements that would result in the lowest damage rate for a limited cost. To validate the applicability of the model, we created a hypothetical city with a 30 km × 30 km area containing bridges, embankments, and buildings. The estimated pre- and post-reinforcement damage was assessed in two earthquake scenarios, allowing us to test the effectiveness of the optimization-based budget allocation model in reducing damage. These results suggest that the proposed model offers a viable strategy for efficient seismic strengthening within budgetary constraints.

Experimental Investigation on the Damage Evolution of Thermally Treated Granodiorite Subjected to Rapid Cooling with Liquid Nitrogen

In many thermal geotechnical applications, liquid nitrogen (LN2) utilization leads to damage and cracks in the host rock. This phenomenon and associated microcracking are a hot topic that must be thoroughly researched. A series of physical and mechanical experiments were conducted on Egyptian granodiorite samples to investigate the effects of liquid nitrogen cooling on the preheated rock. Before quenching in LN2, the granodiorite was gradually heated to 600 °C for two hours. Microscopical evolution was linked to macroscopic properties like porosity, mass, volume, density, P-wave velocity, uniaxial compressive strength, and elastic modulus. According to the experiment results, the thermal damage, crack density, porosity, and density reduction ratio increased gradually to 300 °C before severely degrading beyond this temperature. The uniaxial compressive strength declined marginally to 200 °C, then increased to 300 °C before monotonically decreasing as the temperature rose. On the other hand, at 200 °C, the elastic modulus and P-wave velocity started to decline significantly. Thus, 200 and 300 °C were noted in this study as two mutation temperatures in the evolution of granodiorite mechanical and physical properties, after which all parameters deteriorated. Moreover, LN2 cooling causes more remarkable physical and mechanical modifications at the same target temperature than air cooling. Through a deeper comprehension of how rocks behave in high-temperature conditions, this research seeks to avoid and limit future geological risks while promoting sustainability and understanding the processes underlying rock failure.

Fatigue Damage in Asphalt Pavement Based on Axle Load Spectrum and Seasonal Temperature

In asphalt pavement structure design, traffic axle loads and pavement layer temperatures are crucial factors affecting fatigue damage calculations. To investigate the differences in fatigue damage calculations caused by different characterizations of traffic axle loads and temperature, fatigue damage calculations were conducted under equivalent standard axle loads (ESALs), axle load spectra (ALS), constant temperatures, and seasonal temperature variations using the field data from an expressway in Shandong Province, China under seven calculation plans. The results indicated: (1) the annual traffic composition is dominated by vehicle Type 9, with a proportion of about 43% in all the vehicle types, and its load level is also high, with a proportion about of 80% in the heavy load interval at all axle types; (2) The ESALs method underestimates the actual fatigue damage incurred in asphalt pavement by 6.04 times, with an accumulated damage of 2.34 × 10−9 (ESALs), 1.69 × 10−8 (ALS), respectively; (3) The fatigue damage results from a single month with consistent temperature showed similar trends, with an accumulated damage of 1.50 × 10−5, 9.07 × 10−5, respectively; (4) The cumulative fatigue damage calculated using the ALS method across the four seasons, respectively, is 6.51, 5.88, 6.42, and 4.60 times that of the fatigue damage calculated using the ESALs method. Although the ratio of fatigue damage between the two characterizations of traffic axle loads remains consistent, which is 6.04, the fatigue damage calculation that accounts for temperature variations can reveal seasonal trends in fatigue damage development. Based on the axle load spectra and considering temperature variations, fatigue damage calculation will be more closely related to the actual service state of asphalt pavement. These research findings provide insights for estimating asphalt pavement fatigue damage to some extent.

Lesion characteristics are associated with bowel, bladder, and overall independence following cervical spinal cord injury

Context/Objective There is a growing global interest in quantifying spinal cord lesions and spared neural tissue using magnetic resonance imaging (MRI) in individuals with spinal cord injury (SCI). The primary objective of this study was to assess the relationships between spinal cord lesion characteristics assessed on MRI and bowel, bladder, and overall independence following SCI. Design Retrospective, exploratory study. Participants 93 individuals with cervical SCI who were enrolled in a local United States Model Systems SCI database from 2010 to 2017. Methods Clinical and MRI data were obtained for potential participants, and MRIs of eligible participants were analyzed. Explanatory variables, captured on MRIs, included intramedullary lesion length (IMLL), midsagittal ventral tissue bridge width (VTBW), midsagittal dorsal tissue bridge width (DTBW), and axial damage ratio (ADR). Outcome Measures Bowel and bladder management scale of the Functional Independence Measure (FIM) and FIM total motor score. Results When accounting for all four variables, only ADR was significantly associated with bowel independence (OR = 0.970, 95% CI: 0.942–0.997, P = 0.030), and both ADR and IMLL were strongly associated with bladder independence (OR = 0.967, 95% CI: 0.936–0.999, P = 0.046 and OR = 0.948, 95% CI: 0.919–0.978, P = 0.0007, respectively). 32% of the variation in overall independence scores were explained by all four predictive variables, but only ADR was significantly associated with overall independence after accounting for all other predictive variables (β = −0.469, 95% CI: −0.719, −0.218, P = 0.0004). Conclusions Our results suggest that the MRI-measured extent of spinal cord lesion may be predictive of bowel, bladder, and overall independence following cervical SCI.

Machine learning-driven real-time identification of large-space building fires and forecast of temperature development

In firefighting, real-time knowledge of fire dynamics is crucial yet often unavailable. The building geometry and measured gas temperatures are integrated to ascertain fire states and predict temperature evolution, utilizing a machine learning framework that combines long short-term memory networks and transfer learning. The model is pre-trained on datasets with 1000 samples from parametric fire models and 200 from field simulations, enabling real-time predictions with on-site data. Numerical simulations in portal frame buildings demonstrate over 95% accuracy in identifying fire states and 90% in predicting gas temperatures. A method using correlation coefficients and standard deviations effectively detects damaged thermocouples with over 96% accuracy, given a damage ratio below 30%. Validation in two real fire scenarios showed more than 92% accuracy in locating fires and over 89% in forecasting gas temperatures 20 min ahead, which costs 2.14 s and 1.83 s, respectively. The machine learning framework also exhibits robustness to changes in ventilation conditions by making temperature predictions using reliability theory. The proposed framework provides clear information about the state and development of the fire to firefighters and is useful for promoting smart firefighting.

ESTIMATION OF EARTHQUAKE INSURANCE PREMIUM BY CONSIDERING EARTHQUAKE PROBABILITY AND THE DAMAGE RATIO OF BUILDINGS IN BANDA ACEH AND SIBOLGA CITY

Indonesia is one of the countries prone to earthquakes with significant damage. An area that is frequently hit by earthquakes is Sumatra Island. Several cities, such as Banda Aceh City and Sibolga City on Sumatra Island, quite often experience tremors. For this reason, mitigation efforts are needed through earthquake insurance in managing disaster risk in earthquake-prone areas such as Banda Aceh City and Sibolga City so that it can reduce the impact caused by earthquake disasters. This research aims to determine the probability of an earthquake occurring in Banda Aceh City and Sibolga City using the Probabilistic Seismic Hazard Analysis (PSHA) method. Apart from that, this research also aims to determine the value of the building damage ratio and the estimated value of pure earthquake insurance premiums in Banda Aceh City and Sibolga City. The analysis results show that the estimated pure premium value for residential commercial and industrial building types with less than nine floors in Banda Aceh City is around 2.96 and 21.03 times greater than that of Sibolga City. Meanwhile, the estimated pure premium value for commercial and industrial building types with more than nine floors in Banda Aceh City is more minor, around 6.42 times, compared to Sibolga City.

Application of a new method for probabilistic fatigue analysis from strain measurements on bridges

Increasing loads, ageing of materials as well as environmental change make the issue of fatigue damage critical on bridges, especially in the case of old steel or iron structures. The assessment of the fatigue loads on specific elements of these assets can be carried out from on-field strain measurements with the application of classical methods involving rainflow cycle counting and the use of Palmgren-Miner's rule. However, such a fatigue assessment suffers of significant uncertainties about the real fatigue damage ratio and the consecutive residual fatigue life. A new probabilistic method for the fatigue assessment is proposed, as the result of a joint research by OSMOS Group and the Ecole des Ponts. The theoretical background of the method is described, involving a probabilistic formulation of Miner's rule and the use of a Weibull-Basquin model to describe the health of structural elements. Real field case studies are presented, on two historical iron truss road bridges in France, with a dataset of more than 18 months of continuous strain measurements used for the fitting of the probabilistic model of fatigue loads. The incidence of the quantity of data and of the number of sensors used for the analysis is discussed, along with the conclusive results concerning the probabilistic description of the residual fatigue life.

Computational Modeling of Tool-Rock Frictional Contact With Anisotropic Damage

The mechanism of frictional contact is investigated between a blunt tool and quasi-brittle rocks with anisotropic damage. A recently developed anisotropic elasto-plastic-damage model is further validated using experimental results under monotonic and cyclic loadings for rocks and concrete. A finite element model of tool-rock frictional contact is validated by analytical results in the two asymptotic regimes of an elastoplastic rock. The mesh sensitivity is reduced using a fracture energy-based method for anisotropic damage. The tool-rock frictional contact is predominantly controlled by three dimensionless parameters: η\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\eta$$\\end{document}, ξ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\xi$$\\end{document}, and ζ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\zeta$$\\end{document}, which characterize elastoplasticity, brittleness, and anisotropic damage, respectively. The newly introduced damage coefficient ζ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\zeta$$\\end{document} controls the ratio of damage in different directions. As the elastoplastic parameter η\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\eta$$\\end{document} increases with more plastic deformation, the dimensionless average contact stress Π~\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\widetilde{\\Pi }}$$\\end{document} increases and then slightly varies before stabilizing. As the brittleness number ξ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\xi$$\\end{document} increases in a more brittle mode, the contact stress Π~\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\widetilde{\\Pi }}$$\\end{document} generally decreases. When the damage coefficient ζ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\zeta$$\\end{document} decreases from isotropic to anisotropic damage, the contact stress Π~\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\widetilde{\\Pi }}$$\\end{document} generally increases. The magnitudes of the average contact stress in numerical modeling are closer to experimental results when considering anisotropic damage.

TD3-BC-PPO: Twin delayed DDPG-based and behavior cloning-enhanced proximal policy optimization for dynamic optimization affine formation

This article addresses the dynamic optimal design problem of the affine formation for adversarial multi-agent systems in real-time confrontation environments. To maximize the win rate and maximize the battle damage ratio, a novel deep reinforcement learning (DRL) algorithm named TD3-BC-PPO is designed to adaptively control the shape transformation of affine formation, including translation, rotation, and scaling. Specifically, Twin Delayed Deep Deterministic Policy Gradient (TD3) is introduced to enhance the exploratory aspect of the strategy and efficiently leverage the crucial sparse win–loss rewards. Behavior cloning (BC) is used for strategy replication and model migration. Proximal policy optimization (PPO) is utilized for stabilizing policy updates, conducting a secondary optimization of the strategy through dense damage-related rewards. To validate the effectiveness and robustness of the proposed algorithm, extensive simulation experiments are conducted. Comparative analyses are performed against several baselines, encompassing a diverse range of formation confrontation situations. These situations involve various initial formation structures, differing attack angles, unequal combat quantity and expanded confrontation space dimensions. Simulation results show that the proposed TD3-BC-PPO algorithm can engender an impressive surge of at least 5.4% in the win rate and an incremental ascent of at least 0.274 in the battle damage ratio of the affine formation for adversarial multi-agent systems in complex real-time confrontation scenarios.

A lightweight detection method of pavement potholes based on binocular stereo vision and deep learning

The identification of pavement defects is crucial and must be done efficiently, accurately, and cost-effectively. A commercial-grade sports camera and mobile vehicle work together to detect pavement potholes in a lightweight manner. A dataset of 6,186 images with a resolution of 1500 by 1500 pixels has been constructed based on vehicle-mounted tilted images. Object detection and image segmentation are performed using a single-model MASK R-CNN, and the principle of binocular stereo vision is employed to reconstruct the three-dimensional (3D) structures of potholes. A novel methodology is introduced to calculate the 3D feature parameters of potholes, enabling the precise determination of the pavement pothole damage ratio. An average accuracy of 98% for detection and 94% for segmentation is achieved with the Mask R-CNN model. The proposed algorithms achieve an average DR calculation accuracy of 82%, facilitating precise identification of surface irregularities. The paper presents an intelligent approach for detecting pavement potholes.

Mechanised Removal of Cocoa Beans from the Pod and Strategies to Optimize the Technique: A Review

Confronted with problems associated with removing cocoa beans, methods, technologies and equipment have been developed and applied over the years. This paper comprehensively reviews the most effective method and technology to split cocoa pods and remove the beans. The working principle of the technique was explained with the cocoa pod opening mechanism, structures applicability and cost of the working method. The forces involved in opening cocoa pods are shearing, compressive, and impact depending on the machine type and the process used. The techniques applied in opening cocoa pods are grouped into traditional (manual) and improved (mechanised). The manual method of opening the cocoa pod is time-consuming and prone to accidents leading to injury to beans and farmers. The strength of the labour force available during harvest also affects the manual method. When cocoa beans are damaged, they deteriorate and are not appropriate for fermentation. The mechanised splitting has a high initial investment but very fast and reduced losses. Information gathered on cocoa pod mechanization shows that despite the countless efforts in developing various opening mechanisms. a high bean damage ratio and separation problems are still yet to be controlled. The current trends and techniques in cocoa pod opening mechanisms are also presented.

Numerical evaluation of impact resistance of reinforced concrete walls

Reinforced concrete(RC) structures are occasionally subjected to accidental impact during service, which can cause economic losses and casualties. Most previous research on the impact resistance of RC structures has focused on beams, columns, and slabs except walls. Thus, it is necessary to study the impact response and resistance performance of essential RC walls with high resistance requirements, such as critical shear walls, important structures, and vital protective structures of high-rise buildings in earthquake and mountainous areas under low-speed impact. This research verified the finite element model (FEM) through pendulum impact experiments on RC walls (with an impact mass of 2 tons) firstly, then proposed the damage assessment parameters of the RC wall, and analysed the impact response mechanism and resistance performance of RC walls with several reinforcement ratios under different impact loads. The research results indicate that the impact effect on the wall must consider the different value (D-value) between local and global deformation. The impact load significantly influences the peak impact force and the displacement of the RC wall. The mass affects the RC wall’s global residual deflection. At the same time, the velocity significantly influences local displacement, and correspondingly, the RC wall is more prone to local damage with high velocity. Thickness, the concrete fc, and the reinforcement ratio affect the impact resistance of the RC wall. The thicker wall can cause a shorter impact duration, and milder concrete damage, but the smaller rebar stress. The larger fc will bring greater rebar stress and milder concrete damage. A high reinforcement ratio will increase the impact force platform value and the RC wall’s concrete damaged ratio but will reduce the plastic strain of the rebars.

Behavior of Reinforced Lightweight Concrete Slab with Initial Cracks

The flexural behavior of lightweight concrete two-way slabs repaired or strengthened with externally bonded carbon fiber-reinforced polymer (CFRP) sheets is the subject of this study. The experiment included five reinforced lightweight concrete slab specimens with dimensions of 1000 mm in length, 1000 mm in width, and 120 mm in thickness. Tested one specimen without any strengthening and reinforced another specimen with a single layer of CFRP. The other specimens were repaired with a single layer of CFRP, applying damage ratios of 50%, 60%, or 70% of the ultimate load. Intentionally designed each slab to collapse under bending forces and maintained comparable dimensions. According to the experiment results, changing the degree of damage from 70% to 50% increases the ultimate load capacity by about 17.7%, and the ultimate deflection decreases by about 31.4%. CFRPs have the potential to fix structural damage under static stress testing conditions. However, it is essential to make sure that they stick well to surfaces that do not have suitable geometric properties or have been deformed. CFRP sheets effectively repaired the specimens, increasing the failure stress of the reinforced concrete slabs and preventing the spread of cracks.