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Exploring fire resistance of high strength steel end-plate connections is one of the key technical bases for fire resistance design and fire safety assessment of high strength steel structures. Numerical simulation and parameter analyses of high strength Q690 steel flush end-plates will contribute to a reasonable design of high strength flush end-plate connections. In this paper, a finite element model of high strength steel flush end-plate connection considering thermal creep effect was established and validated by experimental results. The thermal creep finite element model can simulate accurately heat performance, failure modes and deformations of high strength flush end-plate connections at elevated temperatures. The increase of axial compression ratio has little effect on rotation, deflection, failure time, critical temperature, and critical rotation with elevated temperatures. The increase of bending moment ratio has little effect on the development trend of rotation and deflection. Proper increase of thickness of the end-plate can improve failure time and critical rotation, and the increase range is within 7% and 36% respectively. Proper increase of diameter of bolt can improve failure time, critical temperature, and critical rotation to a certain extent, and the increase range is within 10%, 6% and 27% respectively. Proper increases of thickness of the end-plate and diameter of bolt will improve the fire resistance of flush end-plate connection. [ABSTRACT FROM AUTHOR]

The evidence of soil nonuniformity has been reported in several site investigation reports and is well-confirmed for any soil in general. However, studies related to the spatial soil variability of offshore ground are somewhat limited, and current design practices for monopile foundations also overlook the uncertainty of the offshore ground. This paper presents the probabilistic evaluation of the serviceability limit state of monopile foundations considering the spatial variability of offshore ground. The nonuniformity of the ground is modeled utilizing the site-specific undrained shear strength (su) as a stochastic variable, using a spatially correlated Gaussian random field. A hardening soil constitutive model is utilized in 3D finite element analysis of offshore ground, with a focus on parameter calibration. The reliability of the serviceability limit state is assessed based on the allowable load on the pile head. The stochastic behavior of the maximum bending moment and maximum shear force along the depth of the monopile is also investigated. Besides, the paper also highlights the importance of incorporating ground nonuniformity during the design process of a monopile foundation. [ABSTRACT FROM AUTHOR]

In order to investigate the dynamic response of a deep‐water long‐span cable‐stayed bridge under the combined action of earthquakes and waves, this paper establishes a model of a certain deep‐water long‐span cable‐stayed bridge based on the finite element method. According to the corresponding theoretical models, the equivalent added mass caused by internal and external water during earthquake actions and wave forces were calculated. A comparative analysis of the dynamic responses under only earthquake actions, only wave actions, and the combined actions of earthquakes and waves were conducted. The results indicate that the presence of water increases the dynamic response of the structure under earthquake actions, with the maximum increase in structural shear force reaching 71.57%. Under lateral earthquake actions, the impact of hydrodynamic forces on the dynamic response of the structure increases with the depth of water, reaching its maximum increase at a water depth of 40 m. Under longitudinal earthquake actions, the impact of hydrodynamic forces on the dynamic response of the main tower also shows a trend of increasing with the depth of water. However, for the auxiliary piers, their shear force and bending moment show a trend of first increasing and then decreasing. As the water depth increases from 29 to 40 m, the impact rates of their shear force and bending moment decrease by 35.12% and 11.71%, respectively. The increase in wave height will cause an increase in the dynamic response of the structure, but it will not change the period of the response time‐history curve. Furthermore, the increase in wavelength not only causes an increase in the dynamic response of the structure but also leads to an increase in the period of the response time‐history curve. Compared to the solitary action of earthquakes, the increase in the amplitude of the internal force response of the main tower and auxiliary piers under the combined action is about 10%–12%, indicating that the impact of wave action on the dynamic response of the structure cannot be ignored, but earthquake action still dominates. [ABSTRACT FROM AUTHOR]

The collapsible tubular mast (CTM) can be compactly folded for transport and deployed in orbit to serve as a key structural element. Once deployed, the CTM is vulnerable to buckling under axial load and bending moments, compromising its load-bearing capacity. The intricate relationship between the CTM's cross-section and its buckling behavior poses a significant challenge for designers. This is due to the ultra-thin nature of the CTM, which gives rise to highly localized buckling modes rather than global ones. To overcome this challenge, we developed surrogate models using a neural network (NN) trained with data from finite element analysis (FEA). These NN-based surrogate models provide high computational accuracy in predicting nonlinear buckling loads under axial force and bending moments around the two principal axes of the CTM's cross-section, achieving R 2 values of 0.9906 , 0.9987 , and 0.9628 , respectively. These models also significantly improve computational efficiency, reducing prediction time to a fraction of a second compared to several minutes with FEA. Furthermore, the NN-based surrogate models enable the usage of the non-dominated sorting genetic algorithm (NSGA-II) for multi-objective optimization (MOO) of the CTMs. These models can be integrated in the NSGA-II algorithm to evaluate the objective function of existing and new individuals until a set of 1000 non-dominated solutions, i.e., cross-sectional configurations optimizing buckling performance, is identified. The proposed approach enables the design of ultra-thin CTMs with optimized stability and structural integrity by promoting design decisions based on the quantitative information provided by the NN-based surrogate models. [ABSTRACT FROM AUTHOR]

The present design guidelines for rigid-faced (RF) geosynthetic reinforced soil (GRS) walls recommend a minimum toe embedment depth as a geometric requirement. The toe condition effect is ignored in these designs. Development of tools for serviceability design and refinement of present design methods require a complete understanding of the toe condition's role. Finite element analysis of RF-GRS walls is carried out in this study for different toe conditions, such as fixed, rotating and frictional toe, representing different construction methods. The analysis of fixed toe conditions shows 3–5 times lesser deformations and 10–20 times lesser loads in bottom reinforcements compared to other toe conditions. Reduced reinforcement stiffness at the bottom of the wall for a fixed toe condition has a negligible effect on deformations. The fascia experiences high bending moments at the bottom of the wall with fixed toe conditions. Frictional toe condition mobilizes both sliding and rotation modes of wall deformations. It also shows toe force increasing by 5–20% for embedment depth increase by 6 times. The results for rotating toe with restrained sliding show higher top displacements than other toe conditions. The use of stiffer reinforcements at the wall top reduces such rotations. Possible design concepts to impart toe fixity in the field are also discussed. [ABSTRACT FROM AUTHOR]

Compared to conventional support methods, the close-fitting pile–wall integration technique features a minimized construction spacing between the retaining pile and the basement retaining wall. This approach leverages the pile stiffness to minimize the wall thickness and enhance underground space utilization. However, it currently lacks significant discussions and measured data about the interaction laws between the pile and the wall. The model test and finite element method (FEM) are employed to study the deformation and internal force interaction laws of two typical close-fitting pile–wall integrated structures, and a comparison with conventional design is conducted. Furthermore, this study separately investigates the impact of sensitivity factors, specifically the pile–wall stiffness ratio and floor plate stiffness, on both structures during the basement construction and serviceability stages. The test results can closely match the numerical simulation. The study results reveal that the wall impacts the bending moment of the pile to some extent. The internal force in the wall is significantly influenced by the lateral deformation of the pile and the floor plate. Compared to conventional designs, this structure significantly reduces the bending moment of the wall, particularly in the composite structure. Additionally, the analysis of sensitivity factors reveals their considerable influence on the pile–wall interaction. [ABSTRACT FROM AUTHOR]

This study investigates the seismic behavior of long-span prestressed concrete box-girder bridges subjected to long-duration (LD) ground motions and spectrally equivalent near-fault (NF) and far-fault (FF) short-duration ground motions. For this purpose, the Kömürhan and Gülburnu Highway Bridges built with the balanced cantilever method using prestressed concrete box-girder were selected. This paper consists of two main sections. First, ambient vibration tests were conducted to identify the modal parameters of the bridges and calibrate the finite element models. Second, using three ground motion sets consisting of 42 acceleration records applied to the orthogonal and vertical directions of the bridges, the structural responses were evaluated and compared. In order to determine the type of ground motion that is critical for this type of bridge, these sets consist of 14 long-duration ground motions, 14 spectrally equivalent near-fault short-duration ground records, and 14 spectrally equivalent far-fault short-duration records. The comparison parameters considered for this study were displacements and internal forces in the piers and decks. The results strive to highlight the extent to which the duration and characteristics of the ground motion sets affect the structural behavior. Results indicate that the mean deck displacements of selected bridges obtained from FF short-duration records were nearly 10.70% and 7.44% less than those obtained from the LD and NF short-duration ground motions. These trends were also observed in the bridge piers. Moreover, increases of up to 17.54% and 26.65% in the mean shear forces of the piers under LD and NF short-duration ground motions were observed compared to those determined from the FF short-duration counterparts. Similar trends were observed in the bending moment values. It was also observed that far-fault short-duration records may have substantial consequences on such structures. [ABSTRACT FROM AUTHOR]

This paper presents a multibody model of the post-derailment dynamics of a railway vehicle and its impact with a derailment containment wall (DCW) built aside the line and demonstrates the use of the model in the context of the structural sizing of devices intended to mitigate derailment effects. With respect to existing multibody models of railway vehicle dynamics, the innovative features of this model are a new contact model capable to provide a plausible prediction of the derailment process despite a simple and computationally efficient formulation, and the model of the interaction between the derailed vehicle and the impacted derailment containment structure, the latter being described by a Finite Element Model. Results from the model are compared to an established multibody software for a non-derailment case, and then a comparison is performed with a measurement from a derailment experiment published in the scientific literature, finding in both cases satisfactory agreement. The model is then applied to analyse a derailment scenario caused by the sudden failure of an axle for a locomotive vehicle travelling at 300 km/h in a HS curve, deriving the peak values of the impact force and bending moment at the base of the derailment containment wall. [ABSTRACT FROM AUTHOR]

Recent experimental evidence has shown that wood–steel–wood dowel-type connections exhibit a semi-rigid behaviour even after 90 min of fire exposure. Because a semi-rigid behaviour influences the bending moment distribution among structural members, considering the moment–rotation relationships within frame analyses in which structural members are modelled as beam elements can enable a realistic fire response analysis that is significantly simpler than the three-dimensional finite element method. This study proposes an analytical methodology that accounts for the thermo-mechanical behaviour of timber and dowels, enabling the simulation of the non-linear moment–rotation relationships under fire conditions. The proposed analytical model divides dowels into a series of elements on an elastoplastic foundation and performs a direct stiffness method in a time-incremental procedure using an element stiffness matrix derived from beam-on-elastic-foundation theory. This study also presents the results of load-carrying tests on timber frames with dowel-type connections performed under ambient and fire conditions. The analytical results were consistent with the fire test results. Additionally, the analyses were also performed under three conditions in which the dowels were rigid, linear elastic, and elastoplastic bodies. These three results converged to the same value after 65 min of heating, which suggests that the ultimate states of beams with dowel-type connections exposed to fire can be modelled by assuming that dowels are rigid bodies. [ABSTRACT FROM AUTHOR]

Hydrothermal co-liquefaction (HTCL) is the prominent process for producing bio-products with a higher conversion rate. It is performed at high temperatures and pressure in the presence of water. Earlier, it was mostly conducted in batch reactors, but it has major limitations including operating volume, back mixing, and tedious process for high productivity. With that, the present investigation is performed on designing the screw shaft for the high-pressure HTCL process. The dimensional factors including flight length, pitch, helix angle, and depth were considered to design the optimal screw shaft. Likewise, principal stresses, shear stress, bending stress, bending moment, and total deformation were regarded as inevitable response variables to analyze the internal strength of the shaft. In this regard, the Taguchi approach provides the L9 (34) orthogonal array as an experimental design. Then, the numerical results from the transient structural analysis were analyzed with the assistance of statistical methods such as Grey Relational Grade (GRG), Grey Fuzzy Reasoning Grade, Analysis of Variance (ANOVA), and Taguchi method to find the most influential dimensions for minimizing the response variable. Consequently, the results from both GRG and Taguchi optimization were compared, and selected the most optimum parameters. [ABSTRACT FROM AUTHOR]

As basic structural components of the ship hull, stiffened plates suffer both thrust and shear loads while ships sail in rough sea environments. In order to guide the scaled model design effectively, the similarity law is investigated in this paper. The parameters that determine the nonlinear behaviour of the stiffened plate under compression and shear loading are defined and the nonlinear similarity method is improved. This method is applied to design a scaled model under combined bending and torsional moment, and the collapse test is conducted to research the collapse characteristics. The collapse behaviour of actual ship structures under combined loads predicted by the model test is compared with that obtained by the nonlinear finite element analysis. The good agreement represents the capability of the newly improved nonlinear similarity law. The present research provides a proper way to investigate the collapse characteristics of actual ship structures through a model test. [ABSTRACT FROM AUTHOR]

In this study, OBC joint is improved by incorporating one web, two flanges, and two additional bolts, putting forward a novel semi-rigid joint referred to as IBC joint. Finite element models of both OBC and IBC joints are established and the former is validated based on previous research. Subsequently, a total of 84 numerical models is utilized to investigate and compare the mechanical behaviors of OBC and IBC joints, taking into account different thicknesses of side plate and flange as wll as various loading conditions. The numerical results indicate that: (I) in comparison to OBC joints, the IBC joints exhibit significant enhancements in strong axis bending performance and axial tensile performance, including average enhancement ratios of 48%, 67%, 44%, and 19% in initial strong axis bending stiffness, ultimate strong axis bending moment, initial tensile stiffness and ultimate tension, respectively; (II) compared to OBC joints, the IBC joints demonstrate reduced capacity in axial torsional resistance and axial compressive performance, with mean decline ratios of 54%, 39%, 14%, and 7% in initial torsional stiffness, ultimate torque, initial compressive stiffness and ultimate compression, respectively; (III) OBC joints have better weak axis bending performance compared to IBC joints, but this gap decreases remarkably with increasing thicknesses of side plate and flange; (IV) the initial out-of-plane shear stiffness and ultimate out-of-plane shear of the IBC joint exhibit average enhancement of approximately 20% and 10%, respectively, when compared to those of the OBC joint; (V) regarding in-plane shear performance, the initial stiffness of IBC joints exceeds that of OBC joints by an average ratio of 61%, while IBC joints with flange thickness over 10 mm demonstrate significant improvement in ultimate capacity; (VI) The mechanical performance of OBC and IBC joints shows varying degrees of improvement with an increase in the thicknesses of side plate and flange. [ABSTRACT FROM AUTHOR]

Axial forces are generated in the plates of ADAS-yielding dampers when subjected to lateral loading due to their boundary conditions. This on one hand can lead to an increase in strain level of the plates and accelerate the damage process, while on the other hand, the interaction of the bending moment with the tensile axial force leads to increasing strength, which is undesirable in the performance of ductile members. In this paper, a modified ADAS device (MADAS) is introduced to prevent undesirable interaction of axial forces, and its cyclic behavior is evaluated both experimentally and numerically. To this end, in the first step, two test specimens with different number of connection pins were prepared and subjected to cyclic loading in a rigid frame. Experimental and numerical results have shown that due to the removal of the constraint in the vertical direction, the level of forces produced by the damper is almost constant and the X-shaped plates have been able to tolerate significant number of cycles before crack initiation. Afterwards, the cyclic performance of ADAS and MADAS dampers was numerically compared individually and also when placed in the frame. Furthermore, in the frame equipped with ADAS damper, the increase in the level of forces produced by the damper led to the buckling of the braces, while the level of generated forces was totally in the expected range in the frame equipped with MADAS damper. [ABSTRACT FROM AUTHOR]

In this paper, the numerical study of the ultimate bearing capacity (UBC) of two closely spaced strip footings on granular soil is investigated using the finite element method (FEM) and upper bound limit analysis (UBLA). Although the UBC of two adjacent footings has previously been studied in other experimental and numerical research, in all the previously reported studies, the footings were not allowed to rotate and move horizontally freely. Due to the deformation of the soil medium, two closely spaced footings are subjected to horizontal movements and tilting, even under central vertical loads. When the two adjacent footings are not permitted to rotate and move in the horizontal directions, the unwanted bending moment and horizontal force act on the footings. Indeed, the UBC of two closely spaced rough footings is evaluated under incorrect constraints in earlier research. In the present research, the UBC of two adjacent rough footings is evaluated with and without these incorrect constraints. The key finding of this study is that constraining the horizontal and rotational movement of the foundation artificially increases the UBC, which does not reflect field conditions. When foundations are permitted to rotate and move horizontally, there is no increase in UBC; however, there is an increased risk of differential settlement and structural instability. [ABSTRACT FROM AUTHOR]

Based on the theory of zero bending moment under constant load, various optimization methods exist for the top beam of large-span continuous rigid frame bridges. These include achieving zero bending moment at the root of the cantilever beam, at the control stage section, and through the zero deflection method. This study aims to explore the methods and effects of optimizing roof beam design using the constant load zero bending moment method and the "three group bundle method". Using finite element modeling, the total number and eccentricity of prestressed tendons required for each suspended pouring block are determined. Additionally, the "three group beam matching method" is employed to adjust the steel beam, adhering to the design concept of "large cantilever beam matching and small cantilever beam matching", to achieve a reasonable configuration of the top plate beam. Through specific engineering examples, the results demonstrate that utilizing the constant load zero moment method and the "three group bundle method" can significantly enhance the structural performance and economy of large-span continuous rigid frame bridges. Moreover, it offers practical operability, providing an important reference basis for similar project designs. [ABSTRACT FROM AUTHOR]

Continuous rigid-framed bridges with super-high piers (CRFB-HP) have been widely applied in mountain areas. However, their seismic performance is still urgently to be clarified. In this study, the refined finite element model (FEM) of a CRFB-HP was constructed and verified according to the shaking table test results of its scaled model. On this basis, systematic elastic-plastic time history analysis of the CRFB-HP was conducted to investigate the influence of parameters on their seismic performance, including main bridge span, pier height and number of tie beams. The results show that CRFB-HP have the characteristic of long vibration periods and are more sensitive to long-period ground motions. Along the longitudinal and transverse directions, the peak pier top displacement and pier bottom bending moment of CRFB-HP are both relatively large under NLPL (+20~+70%) and NFPT (TP ≈ T1, +50~+120%) excitations. For the same span, the peak pier top displacement increases with the pier height increasing, while the peak pier bottom bending moment decreases with the pier height increasingFor the same pier height, the peak pier top displacement and peak pier bottom bending moment both increase with the span length increasing. Moreover, the pier height change has a greater effect on the pier top displacement than that of the span change. CRFB-HP show obvious high-order response participation (HRP) under different ground motions. The NFPT (TP ≈ T1), ground motions can significantly increase HRP. Moreover, compared with cast-in-place CRFB-HP, the HRP of a fabricated super-high pier is greater (+20~+30%). The peak pier top displacement and pier bottom bending moment both decrease with the increase in the number of tie beams. The reasonable arrangement of tie beams can improve the lateral seismic performance of CRFB-HP. However, compared to the cast-in-place CRFB-HP, the peak pier top displacement is larger, and the peak pier bottom bending moment is smaller, for the fabricated CRFB-HP. [ABSTRACT FROM AUTHOR]

Monopile foundations are extensively utilized in the rapidly expanding offshore wind power industry, and the stability of these foundations has become a crucial factor for ensuring the safety of offshore wind power projects. Such foundations are subjected to a myriad of complex environmental loads during their operational lifespan. Whilst current research predominantly concentrates on the effects of wind, wave, and current loads on monopile stability in extreme environments, it is imperative to consider the potential influence of unexpected submarine landslide loads. In this study, we provide a comprehensive overview of wind, wave, current, and submarine landslide loads on monopile foundations in extreme environments. Subsequently, we establish a finite element model for analyzing the stability of monopiles under complex lateral loads, and validate the accuracy of the model by comparing it with the previous numerical findings. A case study is performed with reference to the Xiangshui Wind Farm project to analyze the effects of varying submarine landslide densities, velocities, impact heights, and seabed sediment strengths on pile head horizontal displacement, pile rotation at the mudline, and maximum bending moment. The findings indicate that the increase in submarine landslide density, velocity, and impact height leads to an increase in horizontal displacement at the pile head, pile rotation at the mudline, and maximum bending moments, and a horizontal failure mode is observed in seabed sediments. Furthermore, under the same load conditions, a decrease in seabed sediment strength and internal friction angle triggers instability in monopiles, with a noteworthy transition from horizontal failure to deep-seated seabed sediment failure. Finally, we propose a criterion for monopile instability under diverse loading conditions. [ABSTRACT FROM AUTHOR]

In this paper, a new beam Euler–Bernoulli finite element for the transverse static bending analysis of cracked slender strip tapered footings on an elastic two-parameter soil is presented. Standard Hermitian cubic interpolation functions are selected to derive the closed-form expressions of complete stiffness matrix and the load vector. The efficiency of the proposed finite element is verified on an example with several width tapering variations of a simple cracked footing with the results of governing differential equation. Another novelty of this study is improved bending moment functions with included discontinuity conditions at the crack location. These functions now accurately describe the bending moments in the vicinity of the crack of the finite element. [ABSTRACT FROM AUTHOR]

The monopile-friction wheel hybrid foundation withstands various loads in the marine environment, such as the vertical load (V) transmitted from the superstructure, horizontal loads (H) caused by wind or wave, torsional loads (T) caused by rotating structures. In this article, 1 g model tests are used to investigate the behavior of the monopile-friction wheel hybrid foundation under independent horizontal load (H) or torsional load (T), and combined loads (H-T) in sand soil, respectively. The failure envelopes of H-T loading plane are obtained from the measured load-displacement data with the simplified calculation equations presented as well. Finally, we also discuss quantitatively the influences of the pre-vertical loads, foundation geometry and loading eccentricity on the bearing capacity of the hybrid foundation via the three-dimensional finite element method. The results indicate that the displacement response of the hybrid foundation under independent loading is significantly different from that subjected to combined loads (H-T). The torsional bearing capacity of the hybrid foundation can be significantly improved by 6.6-33.34% under pre-horizontal load. The horizontal bearing capacity of the hybrid foundation decreases sharply after the pre-torsional load reaches a certain value, which decreases by about 20%. The presence of a friction wheel improves the torsional/bending moment distribution of pile shaft. [ABSTRACT FROM AUTHOR]

Designing tunnels in urban areas necessitates an accurate estimation of their construction effects on adjacent structures. This study explores tunnelling impacts beneath raft foundations, focusing on settlement and bending moment variations due to different tunnel depths and soil densities. A verification model validated tunnel modelling with field data, employing a 2D finite element model to assess raft foundation performance above tunnels. It also examines the influence of tunnel depth, soil consistency, and spacing of two tunnels. Key results show raft settlement increasing by over 250% when tunnels are directly below at a 7.5 m depth, regardless of soil density. Soil cover thickness above the tunnel significantly affects the raft's bending moment, with an increase of up to 400% and 300% for 5 m and 7.5 m cover depths, respectively. Final tunnel construction stage settlements varied with soil density. The study also reveals that increasing the spacing between closely spaced tunnels beyond 1.2 diameters reduces both raft settlements and bending moments. These findings emphasize the importance of careful tunnel placement and soil cover management to minimize negative impacts on raft foundations. [ABSTRACT FROM AUTHOR]

The present study focusses on optimising a single supported excavation pit to achieve a more economical design using finite element analyses. Two methods for automating the derivation of the excavation pit's necessary embedment depth are presented, which involve either embedment depth reduction using additional calculation phases or adapting the entire model with renewed discretisation. The bending moments as well as the earth pressure distribution along the wall show good agreement, indicating that both methods are suitable for application. Subsequently, the feasibility of using optimisation algorithms (Particle Swarm Optimisation and Differential Evolution) for dimensioning the single supported excavation pit regarding stress analysis of the wall is investigated. Therefore, the embedment depth and the position of the strut are varied for five different sheet pile walls and three different strut profiles. The results demonstrate that both algorithms perform well, particularly with a higher number of calculation steps. After varying iteration steps and population size, the Differential Evolution approach shows better performance compared to Particle Swarm Optimisation by means of finding the optimal solution after a lower number of computational steps. [ABSTRACT FROM AUTHOR]

Branching structures are gaining popularity in the field of advanced structures and building design; they offer high performance in terms of strength and lightweight design, along with the flexibility and precision enabled by modern processing technologies like Additive Manufacturing. This paper provides a concise overview of a geometric design procedure for a novel ribbed class of structures which was previously developed by the authors as a biomimetic optimal Micro-architected dome. Hereinafter, linear lattice models are suggested to carry out structural calculations using the finite element method (FEM). The objective is to examine discretization thresholding and strain energy convergence criteria. Results show that convergence is reached for numbers of elements per leg, ranging from 2 to 6, depending on the geometrical configuration of the dome being studied. The strain energy balance also exposes the influence of each internal force on the total mechanical response of the structure, pinpointing bending moment and axial force as the main decisive factors. As a perspective, the study will focus on limit state design calculations and Analysis of how the local geometry influences the overall stability and strength of this new design. [ABSTRACT FROM AUTHOR]

Standard structural assessments of ship hulls include the evaluation of the elastic structural response. Elastic analysis neglects extreme and unpredicted loadings, which can produce catastrophic outcomes, such as the loss of the ship's ultimate strength. Moreover, hull elements are considered unaffected by age-related degradation. Therefore, this study models and quantifies the effect of corrosion-induced structural degradation on the ultimate strength of a high-tensile-steel (HTS) cargo ship using progressive collapse and nonlinear finite element methods. Uniform and pitting corrosion are modeled through selected scenarios, which hull elements might encounter during exploitation, producing a total of 148 calculation models. The findings show that corrosion-induced degradation can significantly decrease the ultimate strength of the hull (up to 30% for the most severe scenarios assessed). Furthermore, ultimate strength decreases almost proportionally to the amount of wastage considered. It was found that stiffener corrosion has a significant effect on the total ultimate strength. This study's aim is to emphasize the vast importance of including ultimate strength along with ageing effects in industry-standard structural assessments of large HTS ship structures, designed to last for several decades whilst exposed to excessive and unpredicted bending moments. [ABSTRACT FROM AUTHOR]

The aviation industry is currently developing rapidly. The Avionics rack is one of the most important parts of an aircraft which functions to place various electronic devices to support the aircraft during flight. As explained in CASR 25 point 25.561, of course, the avionics rack itself is specially designed so that the rack structure can withstand various flight conditions, one of which is when the aircraft experiences an emergency landing. Emergency landings that are generally experienced by aircraft will experience a G-Force of 9G forward, 6G downward, 3G upward, 3G sideward, and 1.5G rearward. This research aims to measure how strong the structure and materials used are to support the devices stored on the avionics rack. Through the Finite Element Analysis method using software, hand calculations in calculating the Margin of Safety, as well as shear force analysis and bending moment diagrams, results can be obtained that the analysis carried out on the identified structure is declared safe if something crucial occurs such as an emergency landing. [ABSTRACT FROM AUTHOR]

The present study investigates the flexural failure properties of a hybrid laminate beam subjected to three-point bending. A symmetrically laminated hybrid beam is constructed using high-strain and inexpensive glass fibre on the top layers and low-strain and expensive carbon fiber on the middle layers. Classical lamination plate theory is used to find the stress and strain distribution that occurs due to the bending moment on the compressive side. The theoretical failure limits of the laminated hybrid beam are analyzed considering the targeted span-to-depth ratios, volume fractions of the fibers and hybrid ratios using the Tsai-Wu failure criterion and Matlab codes. Using the graph of failure index versus hybrid ratios, the minimum thickness of carbon fiber needed for the delay of failure and cost efficiency of the laminated hybrid beam is identified by applying the linear interpolation method. The numerical results indicate that the failure index increases with the increasing loading span and decreases when the volume fraction of fiber increases. In particular, the placement of glass fiber on the top layer of the laminated hybrid beam might have contributed to obtaining higher strains and curvatures before the catastrophic failure properties of carbon fiber. The flexural stiffness of the laminates is found to increase when the hybrid ratio increases. Overall, it is noted that the theoretical analysis is one method that is less time-consuming and cost-effective than other alternative approaches, such as finite element methods and experimental tests to estimate the minimum thickness of high-stiffness and the expensive material needed to maintain the strength and stiffness of the hybrid composite structures over long periods. [ABSTRACT FROM AUTHOR]

Compared with circular, arched, and pipe-arched soil–steel structures, box-type soil–steel structures (BTSSSs) have the advantages of high cross-section utilization and low cover depth. However, the degree of influence of the crown and haunch radii on the mechanical performance of BTSSSs is still unclear. Therefore, two full-scale BTSSS models with a span of 6.6 m and a rise of 3.7 m but with different crown and haunch radii were established, and the mechanical properties during backfilling and under live load were tested. Afterward, 2D finite element models (FEMs) were established using the ABAQUS 2020 software and verified using the test data. The influence of cross-section geometric parameters on mechanical performance was analyzed by using the FEM, and a more accurate formula for calculating the bending moment during backfilling was proposed. The results show that the BTSSS with a smaller crown radius has a stronger soil–steel interaction, which promotes more uniform stress on the structure and makes the structure have smaller relative deformations, bending moments, and earth pressure. The span and arch height greatly influence the bending moment and deformation of the structure. Based on the CHBDC, the crown and haunch radii were included in the revised calculation formula. [ABSTRACT FROM AUTHOR]

A new type of UHPC‐NC (normal concrete) structure in the negative moment zone was proposed to improve the bearing capacity of the connection structure in the negative moment zone of prefabricated prestressed concrete (PC) beam bridges. First, the distribution characteristics of the crack, cracking load, ultimate moment, and ductility coefficient of the new structure were obtained by the 1:4 scale model tests. The feasibility of the connection structure is verified. Then, the value ranges of critical structural parameters affecting the bearing capacity of the connection structure based on the plane section assumption analysis, including the reasonable thickness of the UHPC layer, the reinforcement ratio of the longitudinal tensile reinforcement, and the diameter of the reinforcement, are obtained. At the same time, based on the verification of the finite element model, the influence of crucial research parameters on the bending capacity of the connection structure is obtained by using the finite element method. Finally, a theoretical method for the bending moment capacity of the connection structure of the UHPC‐NC structure is proposed, considering the high ductility characteristics of UHPC materials. The average relative error between the calculation results and the finite element method is within 7.2%, which verifies the reliability of the calculation method in this paper and provides a reference for its design and engineering application. [ABSTRACT FROM AUTHOR]

The hydrocarbon transportation industry uses extensive pipeline networks subject to complex loading conditions. The finite element analysis (FEA) has proven to be effective in simulating the deformation behavior in these pipelines, which assists in the assessment of their integrity and risks. In this work, a model developed using finite elements is proposed to analyze the behavior of API 5L Gr B carbon steel pipes, subject to internal pressure and lateral loads. The model is validated through uniaxial tensile and four-point bending tests. In addition, parametric analysis is carried out considering variables such as diameter, lateral load, and distance between supports. The objective is to identify which one of these variables has the most influence in the unit strain. The results indicate that the unit strain obtained from the numerical model agrees with the experimental tests. Furthermore, it is concluded that the diameter is the influential parameter. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effect of the ring plate on the mechanical performance of X-type tube-gusset joints. The failure modes, ultimate strengths, and failure mechanisms of X-joints with ring plates were investigated through experiments and finite element analyses. The results indicated that the ring plate and the chord within the effective range of the ring plate constituted the primary bearing structure of the X-joint. Increases in the ring plate thickness and width increased the ultimate strength of the X-joint. By considering the forces of the braces as a superposition of the bending moment and the force acting on the gusset of the X-joint, a simplified calculation method for the ultimate strength of X-joints was established. The derivation process was validated and refined through experiments and finite element analyses. Finally, a safe and reliable formula was derived for evaluating the ultimate strength of X-joints. [ABSTRACT FROM AUTHOR]

In reinforced concrete flat slab buildings, the transference of unbalanced moments in the slab–column connections usually results from the asymmetry of spans, vertical loads, and horizontal forces from the wind. The punching strength of the slab–column connections can limit the load-carrying capacity of the structure in these cases, leading to structural collapse. The design code provisions are still based on empirical or semi-empirical equations; as the punching shear failure mechanisms are complex, and the ultimate strength is affected by several parameters. In this context, this paper presents the results of the computational investigation of the mechanical behaviour of flat slabs subjected to balanced and unbalanced moments using numerical Finite Element models. The numerical models were calibrated and accurately reproduced the behaviour and the punching resistance for concentric and eccentric loading. Furthermore, a parametric study was conducted to evaluate the mechanical behaviour of flat slabs under different load eccentricities, confirming that the increase in the unbalanced moment negatively impacts the load-carrying capacity of the slab–column connection. Furthermore, it was observed that all computational results obtained from models with unbalanced bending moments were higher than those estimated by the design codes. [ABSTRACT FROM AUTHOR]

Distortion deformation usually imposes a potential threat to bridge safety. In order to comprehensively understand the distortion effect on thin-walled ultra-high performance concrete (UHPC) box girders, an innovative approach encompassing the governing distortion differential equation is introduced in this study based on the general definition of distortion angle within the cross-section plane. The analytical results obtained from the proposed method are in accordance with those obtained from the energy method, and exhibit favorable agreement with experimental findings documented in the existing literature. Furthermore, a finite element model is developed on the ANSYS 2021 R1 software platform with the employment of a Shell 63 element. Numerical outcomes are also in good agreement with the experimental data, affirming the validity and reliability of the findings. In addition, parameter analysis results indicate that the distortion angle remains approximately constant at a location approximately 1/10 of the span from the mid-span cross-section of the box girder, regardless of changes in the span-to-depth ratio. Increasing the web thickness yields a notable reduction in the distortion effects, and decreasing the wall thickness can effectively mitigate the distortion-induced transverse bending moment. Compared with normal-strength concrete box girders, UHPC box girders can reduce the distortion angle within the span range, which is beneficial for maintaining the overall stability of the box girders. The outcomes obtained from this study yield engineers an enhanced understanding of distortion effect on the UHPC girder performance. [ABSTRACT FROM AUTHOR]

Excavation in Sabkha soils, found in coastal regions of Saudi Arabia, presents complex challenges in construction due to their unique geotechnical characteristics. These soils are known for their high compressibility, collapsibility, and variable sediment deposition, rendition them unsuitable for excavation without adequate support systems. As urbanization and industrial activities continue to expand into these areas, the demand for effective excavation support systems becomes gradually critical. This study investigates the feasibility of employing Deep Soil Mixing (DSM) as an excavation support system in Sabkha soils. Utilizing finite element analysis through PLAXIS 3D software, the behaviour of DSM walls in Sabkha soil under various conditions is rigorously simulated. The findings of this research establish that DSM walls can serve as an efficient excavation support system in Sabkha soils, provided that crucial factors, particularly excavation depth, are considered during the design phase. The study demonstrates that properly designed DSM walls, in combination with appropriate anchoring methods, can substantially reduce horizontal displacement and bending moments, ensuring the stability of excavations in Sabkha soils. The research highlights the need for further investigations into the cost-effectiveness of DSM walls in comparison to other excavation support options to evaluate the economic feasibility of using DSM in Sabkha soil applications. [ABSTRACT FROM AUTHOR]

Two distinct approaches are available for scrutinizing the impact of diverse loads and the full-load capacity, modal characteristics, and fatigue life of an electric motorcycle frame. The initial method entails affixing stress sensors directly to the frame, whereas the second method leverages finite element method (FEM) software to conduct simulations. In this particular study, the simulation approach was adopted, and in this paper, the feasibility of establishing an analytical system for assessing an electric motorcycle frame was determined through the utilization of FEM software tools such as Visual Basic (VB) and ANSYS Parametric Design Language (APDL). Through the use of simulation analysis, we aimed to explore potential structural defects and provide directions for potential modifications, ultimately obtaining an electric motorcycle frame design that complies with regulations and exhibits improved performance. We first utilized computer-aided design software to create the motorcycle frame and generate a geometric model. Following this, FEM analyses were conducted to evaluate a prototype of the innovative electric motorcycle frame design. These analyses encompassed modes of force transmission in left and right bending moments, front and rear torques, and the results of postcollision deformation of the electric motorcycle frame. These analyses were carried out under specific conditions stipulated by the Vehicle Testing Center, covering a range of load conditions with various degrees of deformation and strength. This allowed us to assess whether the frame structure complies with regulatory standards. [ABSTRACT FROM AUTHOR]

During pipeline construction and operation, the occurrence of surface dents presents a critical concern, primarily arising from factors such as pipeline installation and geological forces exerted upon the pipeline, particularly in the form of rock protrusion. These dents pose a significant threat to the pipeline's safe functionality and have the potential to diminish its load-bearing capacity. Presently, China's oil and gas pipelines predominantly employ X80 high-grade steel. It is noteworthy that prior research into the ultimate load capacity of dented pipelines has largely centered on medium and low-grade steels. The implications of these findings for the suitability of the X80 pipeline remain inconclusive. Consequently, it is imperative to undertake a comprehensive investigation into the load-bearing capacity of high-grade steel pipelines with dent defects. In addition to internal pressure, variations in the pipeline's transported medium, ambient temperature fluctuations, soil displacement, and other factors introduce additional loading effects, including bending moments and axial loads. These supplementary loads introduce latent hazards to the pipeline's operational safety. Hence, this research endeavors to investigate the ultimate load-bearing capacity of X80-grade dented pipelines under the influence of typical loading conditions and to identify pertinent factors that affect this capacity. Finite element analysis (FEA) is deployed to study the behavior of the dented pipelines under typical loads. Failure criterion for ascertaining the ultimate load is proposed and verified by the comparison to test results. Furthermore, the impact of varying dent sizes on the ultimate load capacity of X80-grade dented pipelines is examined. These findings serve as a robust foundation for the safety assessment of dented pipelines, ensuring the sustained safe operation of these vital infrastructures. [ABSTRACT FROM AUTHOR]

In this paper, we present an investigation of the performance of reinforced concrete (RC) columns under combined bending loads and various axial forces using a finite element method (FEM) model developed with the ABAQUS finite element program, verified with actual experimental values. In the experimental study, we applied combined bending loads and various axial forces to four RC members. Two RC members were subjected to vertical cyclic loads using displacement control with 0% axial force, while the other two were tested with vertical cyclic loads, one with 10% axial force, and the other with 20% axial force. The axial force load was applied using a specially designed setup. The experimental results of the RC members include observations of final failure mode, ductility, and axial load–bending moment interaction curves (P–M correlation curves). The experimental study confirmed that as the axial force increased, cracks in the RC columns concentrated at the center of the column. The yield strength increased by 55% when the axial force ratio was 10%, and 106% when the axial force ratio was 20%. The maximum strength increased by 28% with a 10% axial force ratio, and 50% with a 20% axial force ratio. However, ductility tended to decrease as the axial force increased, reducing by 26% with a 10% axial force ratio and 60% with a 20% axial force ratio. The analytical study produced results consistent with the experimental research, showing similar numerical trends. Finally, when comparing theoretical values, experimental results, and analytical results using P–M correlation curves, we found that the experimental value has a safety rate of 18% compared to the theoretical value. The experimental and theoretical result values were similar. Therefore, it has been demonstrated experimentally and analytically that the current design has a safety value of about 18% for the performance of the actual structure. [ABSTRACT FROM AUTHOR]

In this paper, a closed form solution is proposed on bending of uniformly loaded rectangular plates with adjacent edges clamped and the two others simply supported (CCSS). Deflection surface can be expressed by a double sine series referred to as Navier solution. Numerical results of deflection, bending moments agree with existing solutions including solutions of finite element model (FEM). [ABSTRACT FROM AUTHOR]

In shear wall-frame systems, the foundation rotation that may occur under the shear walls changes the displacements and interstory drift ratios and changes the internal force distribution. This study investigates the effect of foundation rotations under shear walls on internal force distribution in shear-frame systems. The originality of the study lies in considering parabolic loads and dynamic analysis (first mode), in addition to static uniform or triangular distributed loads, when determining the shear wall moment contribution ratio under the influence of foundation rotation. The shear wall contribution ratio, a key parameter in many earthquake codes, is defined as the ratio of the sum of bending moments taken by the shear walls at the base to the overturning moment. It plays a crucial role in determining the building's behavior. Depending on this ratio, the load-reduction coefficient is changed. This study investigates the effect of foundation rotation on the moment distribution at the base for three different static load cases and the first mode in the dynamic analysis. The multi-story building is modeled as an equivalent sandwich beam. The moment contribution ratio (MCR) was calculated with the help of analytical solutions of the differential equations written for three different load cases in static conditions, and graphs were created for practical use directly calculating the MCR. In the methodology of the study, the initial step involves the calculation of the equivalent sandwich beam stiffness parameters and the foundational rotational spring. Subsequent to these calculations, the MCR values can be directly obtained with the help of graphs. This approach facilitates the rapid and practical determination of the MCR and can be used in the preliminary sizing phase to eliminate possible errors in the data entry of software that performs detailed analysis. In addition, in the presented study, it has been shown that taking a single mode into account is sufficient when calculating MCR values in dynamic analysis. [ABSTRACT FROM AUTHOR]

Bridges often improve the visual appeal of urban landscapes by incorporating curve elements to create iconic forms. However, it is noteworthy that curved bridges have unique mechanical properties under loads compared to straight bridges. This study analyzes a spatial three-curved steel box girder bridge based on an actual engineering case with a complex configuration. Initially, the finite element software Midas/Civil 2021 is utilized to establish a beam element model and a plate element model to examine the structural responses under dead loads in detail. Then, two different temperature gradient distribution models are employed for the temperature effect analysis. The backpropagation neural network (BPNN) optimized by the WOA algorithm is trained as a surrogate model for finite element models based on the results of temperature stress simulation. The results reveal that the bending–torsion coupling effect in the second span of the spatial three-curved steel box girder bridge is pronounced, with the maximum torque reaching 40% of the bending moment. The uneven distribution of cross-section stress is particularly significant at the vertices, where the shear lag coefficient exceeds 3. Under the action of temperature gradients, the bridge displays a warped stress state; the stress results obtained from the exponential model exhibit a 21% increase compared to BS-5400. Optimization of the weights by the WOA algorithm results in a significant improvement in prediction accuracy, and the convergence speed is improved by 30%. The coefficient of determination (R2) for predicting temperature stress can reach as high as 0.99. [ABSTRACT FROM AUTHOR]

In search of sustainable development this study gives the vision of evolutionary growth in construction industry. As said by Buckminster Fuller "You never change things by fighting the reality. To change something, build a new model that makes the existing model obsolete. "The dream of having a house is a challenging task for low and moderate-income earners in developing countries. Low-cost housing techniques can be adapted to achieve an environmentally friendly and innovative construction to overcome the problem. The materials like Bamboo and Polypropylene band (PP) have been considered as sustainable building materials for the replacement of steel in this present research. Bamboo is a construction material that has been used for a long period for rural housing techniques. Many researchers have determined that bamboo has high tensile strength properties and is also easily available. It is possible to lower the cost of the construction by using bamboo as the main reinforcement. Polypropylene (PP) band, which is rarely used as a building material in India which is strong has heat resistance, and is lighter in weight. The main objective of this study includes that, strength parameters such as flexural strength, compressive strength of the reinforced concrete beam can be achieved by using bamboo as the main reinforcement and Polypropylene band as vertical stirrup that can reduce the cost by 85% and also helps to achieve lightweight structure. The establishment of stable analytical model proves to be cost effective by reducing the number of test specimens for experimental work. This research targets to compare experimental investigations with FEA approach. The Finite Element Analysis (FEA) is carried out using ABAQUS for model geometry to observe experimental study. MATLAB application has been used to validate the structural behaviour through parametric studies like shear force and bending moment diagram using 3-point loading beam. [ABSTRACT FROM AUTHOR]

The study aims to develop a simplified strength assessment method for the preliminary structural design of a semi-submersible floating offshore wind turbine platform. The method includes load cases with extreme wave load effects and a load case dominated by wind load. The extreme load effects due to waves are achieved using the design waves. Seven characteristic responses of the semi-submersible platform due to waves are chosen. The design waves for the extreme characteristic responses are all from extreme wave conditions where the significant wave heights are close to the one for a return period of 100 years. The extreme load effects dominated by wind loads are approximated using the modified environmental contour method. The load effects are the tower base shear force and bending moment. The two load effects are correlated, and a linear equation can approximate the relationship between their extreme values. The finite element analysis results show that the frame design of the bottom of the outer column is essential for structural strength. The wave load can also result in significant stress in the area close to the tower base. [ABSTRACT FROM AUTHOR]

The paper highlights the results of determining the strength of the brake pad of a freight wagon under uneven loading in operation. The main reasons for the uneven loading on the pad have been found. A mathematical tool for determining the strength of the pad unevenly loaded has been proposed. In the study, the pad is considered to be a rod system loaded with concentrated forces and bending moments. Sensors have been used in order to detect the load state of the brake pads. These sensors have been defined in the simulation software, and they have been placed on the working surface of the pad in the area of its interaction with the wheel. The operation of these sensors was simulated in the simulation software package. The results of the calculation have shown that the stresses in the pad are about 21.1 MPa; thus, they exceed the permissible values by 29%. Therefore, considering the uneven loading of the pad in operation, the strength of the pad is not ensured. To test the obtained results, the strength of the pad was determined using the finite element method. The Coulomb criterion was used for the calculation. It was found that the maximum stresses in the pad were about 19 MPa. These stresses were 21% higher than permissible values and occurred in the back of the pad. The study has proven that the uneven loading on the brake pad in operation can cause their destruction during braking. This may also cause traffic accidents with freight trains during their movement. The results of this study will contribute to the theoretical developments and recommendations aimed at improving the brake system of a freight wagon and rail traffic safety. It is considered that the tensometric sensors will be applied in future experimental tests for comparison and verification of the achieved results from the simulation computations. [ABSTRACT FROM AUTHOR]

Typical concentrically braced frames (CBFs), such as cross-braced (X-braced) frames, are commonly used to provide resistance against lateral loads. These systems are prone to buckling under compression, resulting in instability before reaching the yield strength. In other words, this bracing system exhibits an asymmetric behavior in tension and compression that undermines its energy dissipation capacity during excitation and leads to substantial damage to the structural and non-structural members. In an attempt to improve these shortcomings, this study introduces the novel quasi-X-braced frames. The stiffness and stability of the quasi-X-braced steel moment frames were evaluated by novel analytical and numerical methods. Drawing on strain energy concepts and Castigliano's theorem, this study presents an accurate analytical formulation for the lateral elastic stiffness of two-dimensional single-span and one-story quasi-X-braced steel moment frames (QXB-MFs). In this regard, all effective parameters, including the axial and shear loads and bending moments of all members, were taken into account. The proposed relation was validated with results from different cases using OpenSees. The error between the elastic stiffness results of the developed relation and the finite element numerical analysis was found to be negligible. Also, the seismic performance of QXB-MF systems was investigated according to the FEMA P695 methodology for near-field and far-field ground motion records compared with the intermediate moment frame. The results showed that using quasi-X braces in the intermediate moment frame improves the seismic performance of this system. [ABSTRACT FROM AUTHOR]

The need for smooth, gapless mechanisms that offer superior aerodynamic performance has been the prime mover for a wide range of studies on the morphing concepts from the early years of the twenty-first century. In light of the importance of novel analytic means for inspecting such structures, this article describes a comprehensive dynamic model for the flexural vibration of a special type of morphing structure known as fish bone active camber (FishBAC). In view of the shortcomings of previous models, the developed procedure considers the variable thickness of the central spine of FishBAC as well as the possibility of arbitrary truncations in its numerous partitions to offer more accurate results. A general idea is first proposed based on the assumptions of classical plate theory for such partitioned structures. The equations are derived using the energy method and the assumption of artificial springs to satisfy the continuity of shear force and bending moment along the connecting lines between partitions. A robust Rayleigh-Ritz method along with a set of fast-converging admissible functions is presented to solve the governing equations of motion. Combined with the power of Mathematica and validated by other analytic models and finite element codes, this technique can be used to deal with a plethora of similar systems while paving the path for the dynamic analysis of FishBAC built around various airfoils. [ABSTRACT FROM AUTHOR]

Present work deals with the design and finite element analysis (FEA) of a three-wheeled foldable electric vehicle. The vehicle is intended for use of inhouse purposes. The design phase includes evaluation of stress and deflection using classical approach. Use of shear force and bending moment diagram for calculating stresses and deflections are shown. Section properties of individual members of the vehicle structure are also calculated. The theoretical values of stresses and deflection fall within the acceptable limits of yield stresses of the material. FEA of the vehicle has been carried out using Ansys software. Values of stress and deflection from FEA are in close correlation with those available in literature. From model analysis, six different modes of vibrations and corresponding frequencies are evaluated. Crash analysis of the vehicle is also carried for three types of impacts viz., front, rear and side. The velocity considered for analysis is 25kmph. Ergonomics aspect of the vehicle is also assessed. From the RULA and REBA analysis the ergonomic aspect of the vehicle is found to be in acceptable limits. [ABSTRACT FROM AUTHOR]

Pile-soil interaction is one of the most critical factors in evaluating foundations' static and seismic responses. During an earthquake, piles can become subject to stress caused by the surrounding soil and structure movement. To design a suitable seismic pile foundation, in addition to considering the effect of the structure on the pile (inertial interaction), the impact of the soil that applies to the pile (kinematic interaction) must be considered. Therefore, dynamic analysis of piles simultaneously exposed to both vertical and horizontal loads is one of the most essential subjects in geotechnical engineering. The present study evaluated various approaches proposed in the literature to determine the inertial and kinematic loads applied to the pile. Also, based on the results of the centrifuge test, the best method that could correctly predict the combined effect of these two loads on the pile response was presented. The results indicated that precise determination of the maximum lateral force exerted on the pile-soil-superstructure system plays a crucial role in the reliability of the theoretical methods employed to calculate the maximum bending moment of the pile. Also, if the appropriate theoretical approach is used, the accuracy can be similar to the 3D finite element analysis results. [ABSTRACT FROM AUTHOR]

The current design provisions for corrugated steel culverts in North America consider thrust at the springline to be the critical mechanism and location, respectively, when checking capacity. However, experiments have shown that, at shallow cover depths under vehicle loading, the response of these culverts involves both bending moments and thrust forces, and the critical location in terms of capacity is not at the springline. To address this, 3D finite element modeling of the culvert was undertaken using orthotropic shell elements for the corrugated steel structure and continuum elements for a discrete volume of the surrounding soil. The results of an extensive parametric study are used to develop equations for the critical thrust and bending moment under three different vehicle loading configurations. The proposed equations are then compared to the current design code equations in terms of how well they capture the behavior of the finite element model results. The proposed equations are then used to estimate the response of physical experiments conducted in the laboratory and the field and compared to the responses from distributed strain measurements. The equations were found to provide better estimates of thrust and allow the bending moments, which are currently not considered in North American design codes, to be estimated accurately. Limitations of the proposed equations are also discussed. [ABSTRACT FROM AUTHOR]

The steel-constructed buildings in Indonesia are on the rise, indicating a growing preference for their durability and versatility in construction projects. This led to the general application of Round Hollow Structural Section (Round HSS) as column and beam elements. Therefore, this study aimed to conduct parametric analysis of the effect of Diameter-to-Thickness Ratio (D t-1) on the three-point and four-point flexural analysis of Round HSS beam using MSC Marc/Mentat software. Nonlinear materials and geometries were employed, along with the application of contact analysis, with contacted and contacting bodies. Moreover, the load and boundary condition were set to be similar to the experiment. The results showed that a greater D t-1 led to the possibility of withholding a smaller load and causing smaller displacement in Group A with fixed diameter and different thickness values. Meanwhile, in Group B with fixed thickness but different diameters, a greater D t-1 led to the potential of restraining more load and experiencing smaller displacement. All specimens from both groups were observed to have failed due to a combination of global and local buckling at the right location under the load applied. AISC bending moment calculated was found to be greater than the values obtained from the finite element analysis for all sections under three-point loads. It was also discovered in the four-point flexural analysis that the bending moment of noncompact section was greater than for AISC while those for the compact section were lower. Furthermore, shear strength (Vn) calculated was observed to be greater than shear force from finite element analysis (Pmax/2). [ABSTRACT FROM AUTHOR]

In response to the problem of significant post-construction settlement that may occur in a motor racing circuit (MRC), two representative composite foundation testing areas, PHC pile (pre-tensioned spun high-strength concrete pile) and CFG pile (cement fly ash gravel pile), were selected for field tests to obtain the deformation law of pile–soil. Then, finite element numerical simulation was used to carry out back analysis on the geological mechanical parameters of the testing areas. The results showed that the error of soil settlement between the piles in the PHC pile and CFG pile testing areas were 8.2% and 9.6%, respectively, with good inversion precision. The obtained geological mechanical parameters can be used to predict the settlement of the rest of the MRC. On this basis, a finite element numerical model was constructed to analyze the bearing and deformation characteristics of the foundation of the MRC under five types of working conditions that may cause significant post-construction settlement. It showed that the settlement of the embankment was large in the middle and small on both sides after the consolidation of the embankment. The maximum settlement was about 27.0 mm, and the maximum longitudinal uneven settlement ratio of the embankment was 1.3/4000. The axial force of piles in the PHC pile and CFG pile composite foundations increased first and then decreased with depth. The maximum bending moment was located at the foot of slopes or at the boundary of strata, which was relatively small in the middle of the embankment. The deformation of the embankment and the bearing capacity of the piles could meet engineering requirements. This study has certain guiding significance for the design and construction of similar pile-net composite foundations. [ABSTRACT FROM AUTHOR]