Cross-sectional Properties Research Articles

Concrete spalling behavior and damage evaluation of concrete members with different cross-sectional properties under contact explosion

Concrete members such as columns, beams, slabs, and walls exhibit different damage modes under contact explosion due to their different cross-sectional properties, potentially posing distinct levels of threat to structural safety. Understanding the effect of cross-sectional properties on damage to concrete members is fundamental for accurately predicting blast response and rapidly assessing damage degrees of engineering structures. In this paper, FE models for concrete members under contact explosion were established and validated. Based on the FE models, parameter analyses were conducted to investigate the concrete spalling behavior of concrete members with varying cross-sectional thickness and width under contact explosions, and the stress wave propagation character was investigated to reveal the damage mechanics of concrete members and the effects of cross-sectional properties. It is found that, on the whole, the increase of both cross-sectional thickness and width reduces the concrete spalling damage on back surface, and the increase of cross-sectional width instead of thickness reduces the concrete spalling damage on side surfaces. Both the relation between spalling angle on the back surface and cross-sectional thickness and relation between spalling angle on the side surface and cross-sectional width are linear. Increasing the cross-sectional dimension restrains the concrete damage on the side surface more effectively compared to that on the back surface. According to the concrete spalling character, a damage index and a damage classification method were proposed, and based on the numerical results, a rapid damage evaluation approach was developed for concrete members with different cross-sectional properties under contact explosion.

Cross-sectional mechanical characteristics and sensitivity analysis of unbonded flexible risers under axial loads

Unbonded flexible risers exhibit complex structures. Different structural layers can withstand axial loads and exhibit different degrees of coupled deformation. Based on the different material properties and structural forms of each layer of an unbonded flexible riser, the structural layers are divided into three types: cylindrical, steel helical, and polymer helical layers. This study establishes a theoretical model of flexible risers under axial loads based on the law of conservation of energy and the geometry of deformation, and deduces theoretical expressions for the axial load and axial stiffness of flexible risers. MATLAB was used to compile calculation programs to calculate the cross-sectional mechanical properties of flexible risers under axial tensile and compressive loads and to compare the calculation results with the experimental results and the results of other researchers to verify the reliability of the theoretical derivation and calculation programs. By further calculating the cross-sectional force distribution of each structural layer of the flexible risers under axial tensile loads, it is clarified that the tensile armor layer is the main component that can withstand axial tensile loads. A sensitivity analysis of the helix angle and number of helical strips of the tensile armor layer on the tensile properties of flexible risers was conducted; the results show that the helix angle had a more obvious influence on the tensile properties of flexible risers. The results of this study can provide a reference for the structural design and optimization of flexible risers.

EFFECTS OF CIRCULAR HOLES DRILLED IN WOOD JOISTS

Holes are drilled in wood joists for routing pipes, wires or other components. This research investigated the effects of these holes on the shear and bending stresses in a wood joist. Strengths are calculated using the reduced section properties accounting for the holes. The question is whether the reduction in cross-section may account for any other stress concentration factors that may be present due to the discontinuity. It is also important to determine whether a stress concentration factor needs to be applied to wood joists with holes in them. A finite element model was created to determine the actual stresses in members with holes in their cross-sections. Holes of variable size and location were added to the members. Structural analyses were performed using standard procedures and found out that the stresses based on reduced cross-sectional properties were much less than that of the finite element model. Therefore, the calculation of stresses based on the reduced cross-sectional properties of a member does not adequately account for stress risers at the discontinuity. It was also found from the finite element model that the reduction in cross-section generates an increase in stress that is a fraction of the actual stress increase. It was suggested from this research to limit the location of a hole within a member’s cross-section to the middle third and to apply some stress concentration factors to account for the holes for both shear and bending stresses.

Hierarchical multi-scale analysis of the effect of varying fiber bundle geometric properties on the mechanical properties of 3D braided composites

A hierarchical multi-scale numerical model is developed to predict the effect of cross-sectional geometric properties on the mechanical response of three-dimensional (3D) braided composites. In this model, the effective properties are transferred from the fiber bundle scale to the mesoscale, and the finite element and analytical methods are used to predict the macroscopic mechanical properties. Damage evolution was evaluated, based on a continuous damage mechanics approach. A user-defined material subroutine (UMAT), in a nonlinear finite element analysis, has been developed to implement the proposed model and further determine the response and subsequent damage evolution in 3D braided composites subjected to quasi-static tension. The elastic properties of the composites are predicted using a hybrid multi-scale model. The agreement between the numerical simulations and the experimental results is good. It has been shown that the cross-sectional geometry of the fiber bundle properties has a significant influence on the tensile behavior of the composite, which is captured by the proposed multi-scale damage model. This research offers a theoretical analysis for selecting the optimized fiber bundle geometry for using in FE predictions of 3D braided composites.

Experiments and proposed model for residual stresses in hot-rolled wide flange shapes

This paper proposes a new residual stress model for hot-rolled wide flange steel cross sections. For this purpose, a dataset of 85 residual stress measurements is first assembled. The dataset is comprised of prior measurements available in the literature that are complemented by additional ones as part of the present study. A constrained optimization problem is then formulated by assuming parabolic residual stress distributions for both the flanges and the web of hot-rolled wide flange cross sections. The parameters of the developed residual stress model are inferred from the results of the optimization method and from rigorous statistical analyses. The results demonstrate that the cross-sectional area and the depth-to-width ratio strongly influence the residual stress distributions in the flanges and the web of a hot-rolled wide flange profile. The results suggest that there is no evidence that the yield strength of the material influences the developed residual stresses within a cross section. Contrary to available residual stress models in the literature that may be applicable for a limited range of cross-sectional geometries, the proposed model reduces the mean error between all available measurements and predictions by 60%–70%. The variance of the error is also reduced by a factor of two to four across all known cross-sectional properties.

Cortical bone distribution of the proximal phalanges in great apes: implications for reconstructing manual behaviours.

Primate fingers are typically in direct contact with the environment during both locomotion and manipulation, and aspects of external phalangeal morphology are known to reflect differences in hand use. Since bone is a living tissue that can adapt in response to loading through life, the internal bone architecture of the manual phalanges should also reflect differences in manual behaviours. Here, we use the R package Morphomap to analyse high-resolution microCT scans of hominid proximal phalanges of digits 2-5 to determine whether cortical bone structure reflects variation in manual behaviours between bipedal (Homo), knuckle-walking (Gorilla, Pan) and suspensory (Pongo) taxa. We test the hypothesis that relative cortical bone distribution patterns and cross-sectional geometric properties will differ both among extant great apes and across the four digits due to locomotor and postural differences. Results indicate that cortical bone structure reflects the varied hand postures employed by each taxon. The phalangeal cortices of Pongo are significantly thinner and have weaker cross-sectional properties relative to the African apes, yet thick cortical bone under their flexor sheath ridges corresponds with predicted loading during flexed finger grips. Knuckle-walking African apes have even thicker cortical bone under the flexor sheath ridges, as well as in the region proximal to the trochlea, but Pan also has thicker diaphyseal cortices than Gorilla. Humans display a distinct pattern of distodorsal thickening, as well as relatively thin cortices, which may reflect the lack of phalangeal curvature combined with frequent use of flexed fingered hand grips during manipulation. Within each taxon, digits 2-5 have a similar cortical distribution in Pongo, Gorilla and, unexpectedly, Homo, which suggest similar loading of all fingers during habitual locomotion or hand use. In Pan, however, cortical thickness differs between the fingers, potentially reflecting differential loading during knuckle-walking. Inter- and intra-generic variation in phalangeal cortical bone structure reflects differences in manual behaviours, offering a comparative framework for reconstructing hand use in fossil hominins.

Indications of musculoskeletal health in deceased male individuals with lower-limb amputations: comparison to non-amputee and diabetic controls

Individuals with lower-limb amputations, many of whom have type 2 diabetes, experience impaired musculoskeletal health. This study: (1) compared residual and intact limbs of diabetic and non-diabetic post-mortem individuals with amputation to identify structures vulnerable to injury, and (2) compared findings to diabetic and healthy control groups to differentiate influences of amputation and diabetes on musculoskeletal health. Postmortem CT scans of three groups, ten individuals each, were included: (1) individuals with transtibial or transfemoral amputations, half with diabetes (2) diabetic controls, and (3) healthy controls. Hip and knee joint spaces, cross-sectional thigh muscle and fat areas, and cross-sectional bone properties (e.g. area, thickness, geometry) were measured. Wilcoxon Signed-Rank and Kruskal–Wallis tests assessed statistical significance. Asymmetry percentages between limbs assessed clinical significance. Residual limbs of individuals with amputation, particularly those with diabetes, had significantly less thigh muscle area and thinner distal femoral cortical bone compared to intact limbs. Compared to control groups, individuals with amputation had significantly narrower joint spaces, less thigh muscle area bilaterally, and thinner proximal femoral cortical bone in the residual limb. Diabetic individuals with amputation had the most clinically significant asymmetry. Findings tended to align with those of living individuals. However, lack of available medical information and small sample sizes reduced the anticipated clinical utility. Larger sample sizes of living individuals are needed to assess generalizability of findings. Quantifying musculoskeletal properties and differentiating influences of amputation and diabetes could eventually help direct rehabilitation techniques.

Cross-sectional properties of rib geometry from an adult population.

Introduction: Human body models (HBMs) play a key role in improving modern vehicle safety systems to protect broad populations. However, their geometry is commonly derived from single individuals chosen to meet global anthropometric targets, thus their internal anatomy may not fully represent the HBM's target demographic. Past studies show sixth rib cross-sectional geometry differences between HBM ribs and population-derived ribs, and corrections to HBM ribs based on these data have improved HBM's abilities to predict rib fracture locations. Methods: We measure and report average and standard deviations (SDs) in rib cross-sectional geometric properties derived from live subject CT scans of 240 adults aged 18-90. Male and female results are given as functions of rib number and rib lengthwise position for ribs 2 through 11. Population means/SDs are reported for measures of rib total area, rib cortical bone area, and rib endosteal area, as well as inertial moment properties of these rib sections. These population corridors are compared between males and females, and against the baseline rib geometries defined in six current HBMs. Results: Total cross-sectional area results found average males ribs to be larger than those of females by between approximately 1-2 SDs depending on rib number and position, and larger in cortical bone cross-sectional area by between 0-1 SDs. Inertial moment ratios showed female ribs being between approximately 0-1 SDs more elongated than male ribs, dependent again on rib number and position. Rib cross-sectional areas from 5 of the 6 HBMs were found to be overly large along substantial portions of most ribs when compared to average population corridors. Similarly, rib aspect ratios in HBMs deviated from average population data by up to 3 SDs in regions towards sternal rib ends. Discussion: Overall, while most HBMs capture overall trends such as reductions in cross-section along shaft lengths, many also exhibit local variation that deviates from population trends. This study's results provide the first reference values for assessing the cross-sectional geometry of human ribs across a wide range of rib levels. Results also further provide clear guidelines to improve rib geometry definitions present in current HBMs in order to better represent their target demographic.

Socioeconomic and geospatial determinants of households’ food and non-food consumption dynamics within the West African Economic and Monetary Union

This article explores the cross-sectional properties of household's food and non-food consumption expenditures conceptualized as inter-dependent spatial random processes within the West African Economic and Monetary Union (WAEMU). To this end, the paper applies spatio-temporal econometric methods to data extracted from the first edition of the Harmonized Survey on Household Living Conditions (EHCVM, 2018/2019). The findings from the unconditional distribution of household economic wellbeing (measured by nominal per-capita food and non-food expenditures) using the inequality indicators of the Atkinson and Gini coefficients, suggest the presence of cross-sectional inequalities in household food and non-food wellness within WAEMU. However, food wellness inequality appeared lower than that of non-food wellness across the 8 countries. In addition, the economic security analysis, based on the indices of Watts, Sen, and Foster (aplha=1), highlight important spatial heterogeneity in household's vulnerability to poverty within-and-between WAEMU country members. Moreover, estimation of the semiparametric bivariate Gaussian copula model of food and non-food consumption expenditures, shows their significant dependence with household's demographic and geospatial characteristics, as well as the economic and health characteristics of the household head. Indeed, among other key findings, a gender based gradient in household's food and non-food wellness at respectively 3.6 and 4.4% is observed in favor of male headed households; along with an Urban/Rural divide in food and non-food wellness at 20.7% and 27.3%, respectively, in favor of urban households. Therefore, in line with goals 1, 2, 4, 5, 9 and 10 of the United Nations 2030 Agenda for sustainable development, the paper provides key insights for evidence based policy making within WAEMU.

Free form shape optimization of three dimensional beams using cross section analysis

We introduce an efficient method for shape optimization of three dimensional beams that is based on free-form design of the beam’s cross section. The cross section boundary of each beam segment is parameterized by a closed, unclamped B-spline curve, whose control points’ coordinates serve as design variables. The response of the beam is evaluated globally as a one-dimensional entity using 3D beam finite elements, while each cross section is modeled locally using cross section analysis following anisotropic beam theory. A fully consistent analytical sensitivity analysis is derived to account for the relation between the control points and the beam cross-sectional properties and design updates are performed using gradient-based optimization. The proposed method is applied to several test cases, aiming at minimization of compliance or maximization of the fundamental frequency. The numerical results and a comparison to other methods for beam optimization show that the method can generate highly competitive designs. A consistent quantitative comparison to high resolution continuum topology optimization shows that a performance which is only slightly inferior can be achieved, for only a small fraction of the computational effort.

Adapting in the Arctic II: Upper limb diaphyseal robusticity and habitual activity in Late Holocene hunter-gatherers from Alaska.

This study compares humeral diaphyseal robusticity and asymmetry between Late Holocene hunter-gatherers from Alaska with the goal of reconstructing habitual activity in relation to culture and environment. Ancestral remains from four geographic regions of Alaska were divided into five site groups defined by subsistence strategies and technology: Aleutian Islands, Coastal Bay, Far North Coastal, Inland/Riverine, and Tikeraq. Mid-distal humeral diaphyseal robusticity was quantified using cross-sectional geometric properties standardized by estimated body mass and bone length. Humeral strength and bilateral asymmetry were greatest in Aleutian Island males, moderate in Far North Coastal and Tikeraq males, and reduced in Inland/Riverine males. Left-biased directional asymmetry and reduced humeral strength were found in Coastal Bay males. Aleutian Island males had relatively mediolaterally strengthened humeri compared with other groups. Aleutian Island females had elevated humeral strength, while humeral asymmetry among females was moderate and did not vary between groups. Humeri were relatively round among Aleutian Island and Tikeraq females and anteroposteriorly (A-P) strengthened among Coastal Bay, Far North Coastal, and Inland/Riverine females. These results suggest elevated humeral strength and asymmetry in males that engaged in rowing and unimanual projectile hunting, while reduced humeral strength and asymmetry may reflect bow-and-arrow or ensnarement technologies. Left-biased humeral asymmetry may be associated with net-fishing. Humeral strength and asymmetry are consistent with select instances of unimanual projectile hunting in females, while differences in humeral A-P/mediolateral strength may reflect variation in butchery and processing of prey versus rowing and throwing behaviors.

A Novel Variable Stiffness Compliant Robotic Link Based on Discrete Variable Stiffness Units for Safe Human–Robot Interaction

AbstractVariable stiffness manipulators balance the trade-off between manipulation performance needing high stiffness and safe human–robot interaction desiring low stiffness. Variable stiffness links enable this flexible manipulation function during human–robot interaction. In this paper, we propose a novel variable stiffness link based on discrete variable stiffness units (DSUs). A DSU is a parallel guided beam that can adjust stiffness discretely by changing the cross-sectional area properties of the hollow beam segments. The variable stiffness link (Tri-DSU) consists of three tandem DSUs to achieve eight stiffness modes and a stiffness ratio of 31. To optimize the design, stiffness analysis of the DSU and Tri-DSU under various configurations and forces was performed by a derived linear analytical model which applies to small/intermediate deflections. The model is derived using the approach of serially connected beams and superposition combinations. 3D-Printed prototypes were built to verify the feature and performance of the Tri-DSU in comparison with the finite element analysis and analytical model results. It’s demonstrated that our model can accurately predict the stiffnesses of the DSU and Tri-DSU within a certain range of parameters. Impact tests were also conducted to validate the performance of the Tri-DSU. The developed method and analytical model are extendable to multiple DSUs with parameter configurations to achieve modularization and customization, and also provide a tool for the design of reconfigurable collaborative robot (cobot) manipulators.

Determination of the Modulus of Elasticity by Bending Tests of Specimens with Nonuniform Cross Section

BackgroundBending tests offer technical advantages when material testing is performed to determine the modulus of elasticity. In biomechanical studies, beam-like cortical bone specimens subjected to flexural loading are usually characterized by nonuniform cross-sectional properties along the beam axis and a comparatively large spatial variation of the local material properties.ObjectiveA suitable evaluation method for determining the average modulus of elasticity within the volume of beam-like specimens with nonuniform cross section was to be identified.MethodsA total of 138 samples of human pelvic cortical bone were extracted and tested under flexural loading. Different methods, all based on the linear-elastic flexural theory of beams, were applied to determine the average modulus of elasticity on the basis of measured deformations, and the results were compared. Some of these methods utilized the measured midspan deflection, and others used the elastic curve obtained by digital image correlation.ResultsThe results showed that it was not appropriate to determine the average modulus of elasticity from only the measured midspan deflection. The consideration of deflections at multiple points along the beam axis is recommended.ConclusionsAn evaluation method based on the fitting of the analytically determined elastic curve of the beam with its nonuniform cross-sectional properties to the measured deflections is considered the most appropriate method for determining the average modulus of elasticity of the specimen.

Numerical investigation on the shear behavior of slender reinforced concrete beams without shear reinforcement differed by various boundary and loading conditions

This paper presents a numerical investigation on the shear behaviour of reinforced concrete beams without shear reinforcement differed by two boundary conditions, i.e., cantilever and simply supported beam, and two loading configurations, i.e., one-point and uniformly distributed load. The finite element models are exactly constructed as specimens of an experimental program that investigates the effect of the bending moment on the shear response of members without shear reinforcement. Similar to the experimental observations, the finite element analyses show general differences in the shear resistance of members having the same cross-sectional properties but diverse M/V–combinations resulting from different support and loading conditions. For the same cross-sectional parameters, the shear resistance of the simply supported beam subjected to a uniformly distributed load is higher than that of cantilevers subjected to a concentrated load, and the shear resistance of the cantilevers subjected to a uniformly distributed load is higher than that of the simply supported beam. Through finite element analysis, more insight of this effect can be obtained by the investigations of the strain profile in the cross-section, the principal stress within the shear span, and the stress distribution at the longitudinal flexural reinforcement. Furthermore, the difference between the shear force at the critical shear crack formation and the maximum load-carrying capacity is distinguished by analyzing the governing load transfer mechanism. The validated FE models are used to investigate the influence of shear slenderness on the shear resistance of beams by various boundary and loading conditions. A comparison to the shear resistances predicted by design equations proposed in some codes of practice is also provided.

Research on dynamic characteristics of large deformation shearer cable based on absolute node coordinate formulation method.

The development of intelligent and unmanned coal mining has put forward higher requirements on the service life and dynamic reliability of shearer cables. However, it is difficult to comprehensively consider the complexity of hosting conditions of coal mining working face and the dynamic characteristics of cables in different towing systems in the design and development of cables. The cables are periodized by pitch and have the same cross-sectional structure and properties. Based on the homogenization theory and volume average principle, the cable was assumed to be an orthotropic elastomer, and the tensile experimental method and finite element method were combined to calibrate the cable equivalent mechanical parameters. Based on the Absolute Node Coordinate Formulation (ANCF) method, the rigid-flexible coupled virtual prototype co-simulation model of shearer cable towing system was constructed to obtain the kinetic and kinematic parameters of each node of the cable and study the dynamic gradual change characteristics of the cable in different working areas. This research method has an important theoretical significance and engineering application value for the acquisition of dynamic characteristic parameters of shearer cables and the optimal design and dynamic reliability of cables.

How the geometry and mechanics of bighorn sheep horns mitigate the effects of impact and reduce the head injury criterion

Male bighorn sheep (Ovis canadensis) participate in seasonal ramming bouts that can last for hours, yet they do not appear to suffer significant brain injury. Previous work has shown that the keratin-rich horn and boney horncore may play an important role in mitigating brain injury by reducing brain cavity accelerations through energy dissipating elastic mechanisms. However, the extent to which specific horn shapes (such as the tapered spiral of bighorn sheep) may reduce accelerations post-impact remains unclear. Thus, the goals of this work were to (a) quantify bighorn sheep horn shape, particularly the cross-sectional areal properties related to bending that largely dictate post-impact deformations, and (b) investigate the effects of different tapered horn shapes on reducing post-impact accelerations in an impact model with finite element analysis. Cross-sectional areal properties indicate bighorn sheep horns have a medial–lateral bending preference at the horn tip (p = 0.006), which is likely to dissipate energy through medial–lateral horn tip oscillations after impact. Finite element modeling showed bighorn sheep native horn geometry reduced the head injury criterion (HIC15) by 48% compared to horns with cross-sections rotated by 90° to have a cranial–caudal bending preference, and by 125% compared to a circular tapered spiral model. These results suggest that the tapered spiral horn shape of bighorn sheep is advantageous for dissipating energy through elastic mechanisms following an impact. These findings can be used to broadly inform the design of improved safety equipment and impact systems.

Local buckling behaviour of longitudinally stiffened stainless steel plate girders under combined bending and shear

This paper presents a comprehensive experimental and numerical investigation into the local buckling behaviour of longitudinally stiffened stainless steel plate girders under combined bending moment and shear force. Five plate girders configurated with longitudinal stiffeners with different geometrical proportions and vertical positions were fabricated from austenitic and duplex stainless steel plates. Initial geometric imperfections and material properties were measured, and all plate girders were tested to failure under a three-point loading configuration. The critical buckling strengths, ultimate capacities and failure modes were carefully analysed. Elaborate finite element (FE) models were developed and validated against the test results, and were then used to conduct parametric studies to generate further structural performance data over a wide range of cross-sectional properties, including various geometrical proportions and positions of longitudinal stiffeners, and loading combinations. The obtained test and FE results were utilised to assess the applicability of existing M–V interaction design methods in EN 1993-1-5 and that proposed by Jáger et al. for longitudinally stiffened plate girders. It was indicated that these two M–V interaction curves coupled with the design provisions in EN 1993-1-4 for determining the bending and shear endpoints, offer safe-sided predictions with a good level of consistency and accuracy, for longitudinally stiffened stainless steel plate girders under combined bending and shear. The reliability of these design approaches was further confirmed by statistical analysis.

Bending-shear interaction buckling of stainless steel plate girders: Numerical investigation and design method

A comprehensive numerical investigation of transversely stiffened stainless steel plate girders under combined bending and shear was carried out in this paper. By using the finite element (FE) software package ABAQUS, numerical models with incorporation of material nonlinearity, initial geometric imperfections and welding residual stresses were developed, and were used to replicate previously obtained test results. The validated numerical models were employed to perform parametric studies to generate structural data points for stainless steel plate girders over a broad range of cross-sectional properties, involving various combinations of bending moment and shear force. The summarised test and FE results were compared with the predicted strengths determined according to European code EN 1993-1-5 and proposals of Jáger et al., Chinese code GB 50017-2017, and American specification ANSI/AISC 370-21, highlighting that the applicability of existing design methods in predicting the ultimate resistances of stainless steel plate girders under combined bending moment and shear force was limited. By referring to the design methods in GB 50017-2017 and ANSI/AISC 370-21, two separate design recommendations were proposed, respectively. Further reliability analyses were performed to verify the applicability of the abovementioned design methods.

Finite Element Model Updating of RC Bridge Structure with Static Load Testing: A Case Study of Vietnamese ThiThac Bridge in Coastal and Marine Environment.

Diagnostic load testing refers to the use of the measured historical responses of the structure in the field data to better understand its dynamic and static structural behaviours. It is important and necessary to predict the health state, load capacity, and aging of the structure by updating the finite element (FE) model, which can give useful information to aid the design of retrofits and the maintenance of the existing bridge in the future. The paper presents an update of the full-scale FE model for the reinforced concrete (RC) bridge structure over the seawater river based on the experimental strains under the static load testing in which the representative FE model of the actual structure is determined from the optimisation procedures. The optimisation variables are applied, including the cross-sectional properties and concrete material calibrated through the genetic algorithm (GA) optimisation in the MATLAB software, which interfaces with the FE modelling in the scripting of the SOFISTIK TEDDY software automatically. The bending moments at the mid-span of the RC girders are determined in the FE modelling to compute stresses, which are compared with the measured stresses through optimisation scenarios with a percentage error of the objective function less than 10%. The measured data of concrete strains are recorded from reusable strain transducers installed on the mid-span girders for every bridge span, which are used to calibrate the bridge model in static load testing. The novelty of the solution is to implement innovative techniques using field data as an improved approach for calibrating automatically the analytical FE model parameters of all RC spans of the bridge until its static behaviours are very similar to those of the actual bridge. The final updated FE modelling is used to apply truck load configurations according to bridge design standards such as the AASHTO specifications, which can predict the load limits of the existing bridge structure more accurately and reliably. These proposed approaches can be applied to large bridges as well as complex structures with supporting FE analysis software and data processing software.

The behavior and determinants of illiquidity in the non-fungible tokens (NFTs) market

We provide the first study of time-varying and cross-sectional properties of liquidity in the nascent and rapidly growing non-fungible token (NFT) marketplace. Using transaction-level data, we document important weekday patterns in NFT liquidity. Despite the decentralized nature and infancy of the marketplace, we show the overall determinants of NFT liquidity have several parallels with highly developed financial markets. We then study how the arrival of new information impacts NFT marketplace liquidity. By reducing information frictions, NFT news increases NFT liquidity, especially when the media source tends to provide more specific or technical information about NFTs. Overall, our findings deepen our understanding of how liquidity impacts newly developed marketplaces.