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This study presents enhancements made to traditional aluminum alloy gusset (AAG) joints, including the integration of a central stiffening (CS) system, an inter-panel stiffening (IS) system, and a peripheral stiffening (PS) system. Three sets of tests on a full-scale specimen are conducted to investigate the improved AAG joint's axial stiffness, in-plane and out-of-plane bending stiffness, as well as ultimate load-bearing capacity. Nonlinear refined finite element models (FEMs) are established and validated through experimental results. Theoretical mechanical models are developed by integrating experiments and FEMs. These models elucidate the contribution of the stiffening systems to the joint's mechanical performance. The CS system is proven to significantly assist in load transfer, particularly in out-of-plane bending conditions. The IS system enhances overall inter-panel integrity, especially during the plastic deformation phase under out-of-plane bending moments. The PS system improves joint stiffness by participating in load transmission under both axial load and in-plane bending moments. Compared to traditional AAG joints, the combined effects of the three stiffening systems enhance overall structural integrity, stiffness, and load-bearing capacity. This enables the full utilization of component material properties and provides excellent ductility before failure occurs. • A theoretical model of an improved aluminum alloy gusset joint was developed. • FEM and mechanical model alignment were achieved, validated by full-scale tests. • Three loading phases in directions confirmed joint enhancements in mechanical model. • Stiffening systems optimized load transfer, increasing joint stiffness and capacity. [ABSTRACT FROM AUTHOR]

Built-up radially battened columns (RBCs), comprising several identical circular steel tubes interconnected by multiple radial-shaped battens, represent an innovative column design that combines aesthetic appeal with exceptional load-bearing capacity. This makes them well-suited for architectural applications in large public buildings such as stations and airports. The axial compressive strength design methods for the built-up RBC have been extensively explored in the authors' prior studies. However, in real-world engineering applications, built-up RBCs may experience simultaneous axial compression and varying directional bending moments, particularly when considering potential eccentric compression or wind and earthquake loads in public buildings. Currently, strength design methods for this loading condition are still lacking. To address this deficiency, this paper primarily delves into the failure mechanism and strength design methods for built-up RBCs experiencing combined axial compression and arbitrary directional bending moments. Initially, the sectional strength of the built-up RBC is investigated by using a shell finite element model (FEM) for the built-up RBC. It is revealed that the compression-bending sectional strength of the built-up RBC exhibits significant differences with varying bending directions and tube numbers. Moreover, in some bending directions, the M - N sectional strength curve of the built-up RBC exhibits convexity. By integrating theoretically derived equations grounded in the principles of materials mechanics with FEM numerical calculations, concise and practical design equations are proposed for accurately predicting the sectional strength of the built-up RBC under combined axial compression and arbitrary directional bending moments. Subsequently, The buckling strength of the built-up RBC is studied using the FEM, considering initial geometrical imperfections consistent with first-order flexural buckling and accounting for geometric nonlinearity. It is noted that the bending direction of the built-up RBC may deviate during loading. Besides, the M - N buckling strength curve of the built-up RBC is not as convex as its M - N sectional strength curve. Based on calculations from numerous examples, practical design equations for predicting the buckling strength for the built-up RBC under axial compression and any directional bending moments are introduced. The key findings of this paper contribute to the compression-bending strength design of RBCs, enriching RBC design theory and promoting the widespread application of built-up RBCs in actual engineering projects. [Display omitted] • The M - N strength of RBCs varies with different bending directions and tube numbers. • The M - N sectional strength curve of the built-up RBC is convex. • The built-up RBC's bending direction may deviate during loading. • The M - N buckling strength curve of RBCs is less convex compared to its M - N sectional strength. • The M - N strength of RBCs can be predicted by a quadratic function. [ABSTRACT FROM AUTHOR]

The current Eurocode 3 rules for buckling of welded I-section members are based on the assumption of hot-rolled flanges. However, flame-cut flanges are widely used in practice and induce significantly different residual stress distributions, affecting the lateral-torsional buckling resistance. Experimental tests and finite element analyses considering residual stress distributions clearly highlighted the beneficial effect of flame-cut flanges compared with hot-rolled flanges on the lateral-torsional buckling resistance of welded I-beams. To complete these preliminary results, a large number of non-linear finite element analyses are performed considering welded beams made of hot-rolled or flame-cut flanges. The beams are composed of steel grades S275 and S355. Numerical results confirm the influence of the flange fabrication process on the buckling behaviour. Eurocode 3 rules are found to be overly conservative for welded beams made of flame-cut flanges. Consequently, proposals are made that are more suitable for estimates of the lateral-torsional buckling resistance of welded beams made of flame-cut flanges. The code rules are also very conservative for welded beams made of hot-rolled flanges with a medium-to-high slenderness. A design method is thus proposed to improve the prediction accuracy of the lateral-torsional buckling resistance of slender welded beams made of hot-rolled flanges. The novel design method from prEurocode 3 provides acceptable values of the buckling resistance for welded beams made of flame-cut flanges but is restricted to uniform doubly symmetric beams. An extension of its scope to mono-symmetric uniform beams as well as tapered beams is thus suggested. An enhanced imperfection factor is proposed, adapted to welded beams made of flame-cut flanges. • Design method to compute the LTB resistance of welded beams with flame-cut flanges using the Eurocode 3 buckling curves. • Design method to compute the LTB resistance of welded beams depending on their geometry, flange fabrication process and bending moment distribution. • Adaptation of the new verification format of prEN 1993–1-1 for lateral-torsional buckling to tapered and/or mono-symmetric beams. [ABSTRACT FROM AUTHOR]

Round-ended concrete-filled steel tubular (RECFST) columns are gaining increasing usage in bridge structures. During their service life, RECFST columns under eccentric compression may suffer from impact loading. This study conducted test and numerical investigations to assess the performance of RECFST columns under the coupled actions of compression, bending and lateral impact loads. Fourteen columns were fabricated and tested, considering the influences of axial-load ratio, bending moment and impact energy. The damage mode and the time histories of impact force and displacement were accessed and analyzed. The experimental findings revealed that the initial bending moment negatively affected the impact resistance of RECFSTs. In addition, finite element model was established in ABAQUS and calibrated against the test results. The calibrated model was then employed to conduct the failure mechanism analysis and parametric study. Finally, a single-degree-of-freedom (SDOF) analysis was conducted to predict the mid-height deflection of RECFST columns under combined action of compression, bending and lateral impact loads, by incorporating the influences of pre-axial load and initial bending moment. • Drop-hammer impact tests on RECFST columns with varying eccentric compression. • Coupling influence of compression, bending and lateral impact loads. • Prediction of mid-height deflection response using the SDOF method. [ABSTRACT FROM AUTHOR]

Thanks to the axial resisting contribution, inclined screw connections offer a mechanical advantage over connections with purely transversely loaded fasteners. However, the strong coupling between the axial and the transversal behaviour of the screw makes it challenging to predict the actual connection behaviour. Moreover, the presence of polyurethane interlayers for soundproofing or OSB interlayers of light-frame buildings between main members may increase the bending moment component interacting with the axial force in the screw, thus reducing the connection failure load. This paper experimentally assesses the behaviour of steel-to-timber connections, and a parametric finite element model of Winkler non-linear beam is presented and validated. Finally, a simplified analytical model for capacity prediction is presented. The results of the approach currently provided by the Eurocode 5, of an additive model and the proposed analytical model, are then compared with the results of 500 finite element analysis. • Timber-to-steel connections with soundproofing and OSB interlayers are tested. • Interlayers reduce slip modulus more than strength. • Non-linear beam on foundation model is suitable for screws connections. • Bending moment interacts with axial force reducing the connection capacity. • An elementary capacity model is validated on 500 finite elements analysis results. [ABSTRACT FROM AUTHOR]

Non-uniform elements, such as non-prismatic and those made from composite materials, are commonly used in structures. This is because the variation in their internal forces makes uniform elements less effective to withstand the external loads. This paper presents the formulation of the Green's Functions Stiffness Method (GFSM) for the static analysis of non-uniform Euler–Bernoulli frames subjected to arbitrary external loads and bending moments. The GFSM is a mesh reduction method that combines the strengths of the Stiffness Method (SM) and the Finite Element Method (FEM) with those of Green's functions, resulting in an analytic method for obtaining closed-form solutions of reticular structures. As a particular case, the GFSM is closely related to the Transcendental Finite Element Method (TFEM), which allows to obtain closed-form solutions from an implementation of the latter by only making changes at the post-processing stage. Two examples are provided with the analysis of a beam and a plane frame. Additionally, two appendices are included with the particularization of the GFSM for some specific non-uniform elements, and general stepped elements. • Closed-form solution of non-uniform Euler–Bernoulli frames. • New numerical method closely related to the Finite Element Method. • Decomposition of the structural response as a homogeneous and a fixed one. • The fixed response is obtained using Green's functions of fixed elements. • Closed-form solutions for arbitrary external forces and bending moments. [ABSTRACT FROM AUTHOR]

• The ultimate strength of a tubular structure subjected to a bending moment is analysed. • Three specimens are designed for the experimental test. • The moment-curvature and the stress-strain relationship of the tested specimens are studied. • The tested specimens are also evaluated based on the finite element method. • The results of the finite element analysis and the experiments are compared and discussed. The objective of the present work is to analyse the ultimate strength of a tubular structure subjected to a bending moment. The tubular monopile structures are experimentally tested as well as the nonlinear finite element analysis is performed. Three specimens are designed for the experimental test by taking into consideration the typical ranges of the monopile support structures used in offshore wind turbines. The moment-curvature and the stress-strain relationship of the tested specimens are studied. The tested specimens are also evaluated numerically based on the finite element method employing a nonlinear FE analysis. The finite element analysis accounts for the nonlinearities associated with the geometry and material. The geometrical imperfections are introduced to the structure together with the initial stress arisen in the process of fabrication. The results obtained from the finite element analysis and the experimental tests are compared to each other and discussed. [ABSTRACT FROM AUTHOR]

Highlights • Effects of axial force and bending moment on the burst pressure of corroded pipelines are studied. • Burst pressure is significantly reduced under compressive axial force and closing bending moment. • Developed failure loci considering axial forces, bending moments and internal pressures. • The failure loci are found to depends on corrosion depths and load combinations. • The failure loci can be used for burst pressures assessment with known axial force and bending moment. Abstract The remaining strength of corroded pipeline is generally assessed considering the internal pressure only. However, pipelines are often subjected to axial forces and bending moments due to external loadings, which may significantly reduce the burst pressure of the pipeline. This paper presents a study using finite element analysis on the effects of axial forces and bending moments to the burst pressures of corroded pipelines. It is revealed that the compressive axial force and the closing bending moment, causing compression in the corroded area, affect the burst pressure most significantly. Considering the axial compression and closing bending moment, failure loci of combined bending moments and internal pressures are developed for different axial forces. The developed failure loci can be used for assessing the burst pressure of corroded pipelines subjected to axial forces and bending moments. [ABSTRACT FROM AUTHOR]

Highlights • Pounding and soil support significantly affects the response of skewed bridges. • Pounding shifts predominant responses to high frequency region. • Having soil support shifts responses to the lower frequency region. • Combining individual effects may differ from considering factors simultaneously. • Omitting effects of any factor can cause underestimation of skewed bridge response. Abstract Some of the factors that are known to significantly affect the seismic response of bridges include bridge pounding and the influence of the supporting soil. For skewed bridges, the skew angle is another crucial factor. Although some studies on this topic have been done, most have been numerical. Experimental work has been scarce. Furthermore, none has considered the factors simultaneously. This study aims to bridge this gap in knowledge by conducting shake table experiments on a straight, 30°, and 45° bridge considering bridge-abutment pounding and soil support, separately and simultaneously. In most cases, the effects of pounding and soil support simultaneously can be seen as a combination of the effects of each factor separately. However, with a 45° skew angle, when pounding and supporting soil were considered separately, the bending moments near the base of the piers were increased compared to the idealised fixed base case without considering pounding. When both factors were considered simultaneously, the opposite was observed. In addition, in the transverse direction, the relative displacement of the girder would always be significantly underestimated if the assumption of fixed base and no pounding was adopted. [ABSTRACT FROM AUTHOR]

• Impact resistance of RC beam with and without UHPC strengthening was studied. • More ductile failure mode was obtained with UHPC jacketing. • Impact location affects the strengthening effects of UHPC jacket. • Refined FE modelling supplements the data collected from high-speed camera. To enhance the impact resistance of built reinforced concrete (RC) members, the effectiveness of using ultra-high performance concrete (UHPC) for strengthening RC structures was investigated in this study. The mechanical properties of UHPC were evaluated by the uniaxial compression, tension and flexural bending tests. Drop weights with hemispherical and wedge-shaped indenter were adopted to impact the beam specimens with and without UHPC strengthening. A total of six beams, including three control RC beams and three UHPC jacketed RC (RC-UHPC) beams, were tested. The beams were prestressed in the axial direction with a 200 kN force. The test results revealed that the UHPC jackets improved the structural impact resistance. With an impact mass of 411 kg and an impact velocity of 4.95 m/s, the maximum and residual deflection of the RC-UHPC specimen decreased by 15.3 % and 21.1 % as compared to the RC control specimen, and the failure mode shifted from diagonal shear failure to flexural failure. To further investigate the dynamic responses of the beams, a detailed finite element model was established and validated with the test results in terms of the impact force, structural deflection and damage profile. The dynamic shear force and bending moment distribution diagrams were numerically derived to examine the failure mechanism of the test specimens. Finally, a parametric study was conducted to evaluate the effect of different impact locations and UHPC jacket length on the impact resistance of strengthened RC beams. [ABSTRACT FROM AUTHOR]

Fiber-based section analysis methods are widely used to model and predict the fundamental axial force-bending moment-curvature ( P - M - ϕ ) behavior and the strength interaction ( P - M ) of concrete-filled steel tube (CFT) members. The accuracy of these predictions is governed by the uniaxial effective stress-strain relationships assumed for the steel tube and concrete infill of the CFT section. Prior research has developed these effective stress-strain relationships for compact CFT members. This paper presents the development and verification of effective stress-strain relationships for the steel tube and concrete infill of noncompact and slender CFT members. These relationships are developed using results from comprehensive 3D finite element analyses of CFT members with a wide range of geometric and material parameters. The 3D finite element models, which were developed and benchmarked previously by the authors, accounted explicitly for the effects of steel yielding and tube local buckling, concrete cracking and compression inelasticity, and the transverse interaction leading to steel hoop stresses and concrete confinement. As a result, the developed effective stress-strain relationships also accounted (implicitly) for these complexities (yielding, local buckling, confinement, etc.) of behavior. These effective stress-strain relationships are implemented in a nonlinear fiber analysis (NFA) macro model, and used to predict the behavior of noncompact and slender CFT members in the experimental database. The conservatism of the predictions using the effective stress-strain relationships is evaluated. [ABSTRACT FROM AUTHOR]

• Finite difference method can predict pipe's response under the ground movement. • Equations of axial force and bending moment are derived involving inelasticity. • Finite difference method is of great accuracy for predicting inelastic behaviour. • This method can evaluate strain demands of pipes under a wide range of geohazards. Permanent ground displacement triggered by geohazards constitutes a major threat to the integrity of long-distance pipelines. In this study, a novel and simple method is proposed to evaluate inelastic pipes' behavior under ground movements considering soil-pipe interaction based on the finite difference method. The existing finite difference-based method previously proposed by the authors for strain analysis of buried pipelines subjected to ground movements excludes material nonlinearity in pipes, which limits its applicability in engineering practice. To remedy this situation, the method presented herein maintains the well-established concepts of the existing finite-difference-based method but also introduces the scheme to consider the inelastic material behavior of steel pipes. More specifically, the expressions of internal axial force and bending moment, required in the finite difference equations, are explicitly derived based on the actual stress distribution on the pipe cross-section. The proposed method is validated against the finite element method (one-dimensional beam model) in terms of the strain and deformation demands using two indicative case studies, referred to as symmetric and non-symmetric soil resistance conditions, respectively. The comparison between finite element analysis and the proposed method indicates good agreement. Additionally, the proposed method is compared with four existing analytical methods for pipes subjected to strike-slip fault displacement. The proposed method is a simple but general technique to analyze pipes' response under a wide range of geohazards, and thus can be potentially used as an alternative method for preliminary design, safety prescreening, and reliability-based assessment of pipes against geohazards. [ABSTRACT FROM AUTHOR]

• A numerical scheme is developed based on fibre element discretisation. • Application to predict the collapse strength of cylindrical shell under longitudinal bending. • Comparison with equivalent finite element analysis shows the rationality of the proposed method. • Comparison with design guidance demonstrates the conservatism of codified methods. Cylindrical shell is a fundamental building block of many engineering structures. They are usually designed to be the primary load-carrying components to withstand different combinations of environmental loads. This paper presents a fibre-based approach to modelling the progressive collapse of cylindrical shells under combined axial compression and bending moment. In this method, the progressive collapse behaviour of cylindrical shells is incrementally evaluated by accounting for the local response of each fibre element. This approach offers a computationally efficient and robust scheme to compute the ultimate strength of cylindrical shells. Moreover, it enables the modelling of load-shedding between the buckled and intact shell elements on the compressive side, and the yielding failure on the tensile side, which appears to be ignored in existing design codes. Analyses are performed on cylindrical shells with a wide range of design parameters. Validation using the finite element method demonstrates a reasonably well performance of the proposed fibre-based modelling technique. [ABSTRACT FROM AUTHOR]

A submerged floating tunnel (SFT) is a structure that has been proposed as an innovative solution for waterway crossings around the world. However, to this day, no SFT has been constructed yet. One of the main reasons is that there is an insufficient insight into the structural reliability of the SFT. Here, a method to assess the expected structural response of an SFT under traffic loads and a reliability assessment of the results is presented. To do this, traffic models and structural response and reliability are coupled. The methodology presented herein proposes an innovative way to combine copula-based models and structural models to obtain more a more realistic structural response of the SFT. The focus will be on one failure mechanism, leakage caused by bending failure of the SFT in the longitudinal direction. The method utilizes a copula-based model to characterize the traffic loads and simulate traffic loads on the SFT (axle weight, inter-axle distance, and inter-vehicle distance). Next, a structural model is used to assess the structural response and derive stresses. Using a probabilistic analysis, the design of the cross-section can be adapted so that it meets the requirements for leakage caused by bending moments. For the case study is demonstrated that for a buoyancy weight ratio (BWR) of 1.1 an optimal design can be achieved based on a probabilistic method. This methodology could be extended to other failure modes of an SFT or to other structures. • The structural response of Submerged Floating Tunnels due to traffic loads. • Application of copulas to define a representative load sequence. • Application of low level Finite Elements Method to calculate the structural response. • Design optimization by use of probabilistic tools. [ABSTRACT FROM AUTHOR]

• Plastic behavior of foam-filled sandwich beams with circular tube core under transverse loading is studied. • Analytical model for the plastic behavior of the foam-filled sandwich beam with circular tube core is developed. • Analytical results are in good agreement with numerical ones. • Load-carrying capacity of sandwich beams increase with increase of foam strength, face-sheet thickness, tube-wall thickness. Under transverse loading, the plastic behaviour of the foam-filled sandwich beam with circular tube core is researched by numerical and analytical ways in this paper. The yield condition of the foam-filled sandwich section with circular tube core is proposed firstly. Based on the yield condition, the analytical model for the plastic behaviour of the foam-filled sandwich beam with circular tube core under transverse loading is developed, in consideration of the interaction of stretching and bending moment and the strength effect. To make ensure the correctness of the analytical model, the finite element analysis is carried out, and the analytical results are in good agreement with numerical ones. On the basis, the influences of structural and material parameters about load-bearing ability and energy-absorbing ability of foam-filled sandwich beams with circular tube core are discussed by analytical solutions. The results show that, with the increase of foam strength, face-sheet thickness, tube-wall thickness and the width of punch, the load-bearing ability and energy-absorbing ability of the foam-filled sandwich beams with circular tube core increase. In addition, when the loading location is close to the clamped end, the load-bearing ability and energy-absorbing ability of the foam-filled sandwich beam with circular tube core increases significantly. [ABSTRACT FROM AUTHOR]

• Plastic clay can be modelled in drained conditions. • FEM-3D calculations are appropriate to reproduce on site recorded displacements. • SRM underestimates the props loads. As part of the Grand Paris Express project, Fort d'Issy-Vanves-Clamart (FIVC) is one of the 60 new metro stations involving a 32 m deep excavation in layered soils made of limestones and clays. The support system was subject to a comprehensive monitoring program to assess the behavior of the soil and the structure during the works [22]. It comprises wall displacements using inclinometers, bending moments using fiber optic, struts and beams loads using strain gauges and earth pressures at the soil/wall interface using pressure cells. The present paper presents the back analysis done using Finite Elements Models (FEM) in 2D and 3D and, the subgrade reaction method (SRM). The results depict a great consistency between FEM and SRM in terms of reproducing, at the same accuracy level, the wall displacements and bending moments. However, the earth pressure redistribution behind the wall and the props loads are significantly underestimated by SRM (40%) especially for deep excavations. Only FEM can reproduce the measurements since arching effect is allowed within the soil. The present back analysis provides adjustment to the input soil parameters in compliance with their variation range. The resulting set of parameters could be used for an optimization purpose in future designs of deep excavations in similar ground conditions. [ABSTRACT FROM AUTHOR]

• Evaluation of the initial stiffness of welded I-beam to RHS column connections loaded by in-plane bending moments though numerical models and the component method. • The finite element model was developed and validated with previous experimental tests. • The results of numerical parametric studies were compared with the equations of the component method existing in the literature. • Different formulations of the stiffness coefficient that represents the component "column face in bending" was evaluated and a revision of one formulation was proposed. This present paper evaluates the initial stiffness of welded I-beam to RHS column connections loaded by in-plane bending moments. Currently, there is a need to find mechanisms to satisfactorily determine the stiffness of these joints, due to the vast diversity of geometric characteristics. In this context, a numerical and theoretical study was carried out to obtain the initial stiffness through numerical finite element models and the component method. Thus, with a validated numerical model, 36 different connections were evaluated with column face failure and with variations in column thickness, beam flange width, and beam height. The initial stiffness results were obtained for the numerical models and compared with results calculated by the component method. The formulations available in the literature were considered, since the normative prescriptions still do not include formulations for tubular connections. The adopted springs model was described, composed of three components that correspond to the characteristic efforts of the connection: column face in bending, column lateral face in tension or compression and column lateral face in shear. The component "column face in bending" contributed mainly to the determination of the initial stiffness. In the current normative prescription, there are no equations for the stiffness coefficient of this component. Thus, three different formulations from the literature were evaluated. Finally, an adjustment was proposed to satisfactorily represent the evaluated component and the initial stiffness of the connections. [ABSTRACT FROM AUTHOR]

• Instrumentation program of the world's largest-span soil-steel structure. • Three-dimensional nonlinear FE modeling for all soil and structural elements. • The influence of steel mesh and circumferential concrete collar to buried steel structures. • Investigating the performance of soil-steel structures with beveled ends. Soil-steel structures (SSS) are increasingly used as a solution for roadway and waterway overpasses. The inlet and outlet of the buried steel structure may encounter different end treatments and bevelling slopes to accommodate different design aspects. Current design codes require precise numerical analysis of SSS considering soil-structure interaction to evaluate the stability of the steel structure and unbalanced surrounding backfill. The current study evaluates the performance of large-span SSS considering different end treatment conditions. The numerical modeling approach was validated by conducting three-dimensional nonlinear finite element model for the world's largest-span soil-steel structure and comparing the model predictions with field observations. The steel structure has a span of 32.40 m and was constructed using a corrugation profile of 237 mm depth and 500 mm pitch. The ends of the structure were strengthened by attaching 400 mm X 1090 mm circumferential reinforced concrete collars. The numerical analysis predicted the same deflection trends as the field measurements at different construction stages. Furthermore, the validated numerical approach was employed to evaluate the performance of bevel-ended SSS. The benefits of stiffening SSS by using circumferential concrete collars and steel mesh reinforcements buried in the surrounding soil are evaluated in terms of the stability of steel structure and surrounding soil. The results indicated significant longitudinal bending moment induced in the steel plates that were affected by the slope of the beveled ends. It was also found that the steel mesh reinforcement and concrete collars reduced the induced straining actions in the steel structure by 30–50%. The obtained results demonstrate the necessity of rigorous numerical simulation in controlling the design and cost of SSS. [ABSTRACT FROM AUTHOR]

• 1/5 scaled RC double-column RC bridge pier (DCBP) specimens are prepared. • Lateral consecutive impact test on bare and CFRP strengthened DCBPs is carried out. • Dynamic responses and damage evolution of bare and CFRP strengthened piers are analyzed. • CFRP strengthening effect on vehicular impact resistance of prototype bridge is evaluated. As-built reinforced concrete (RC) piers could be subjected to vehicular collisions in their whole service life, resulting in severe shear failure of piers and even catastrophic damage to entire bridges. Considering that the vehicular collision is the lateral consecutive impact process including bumper, engine and cargo impacts, the effectiveness of CFRP shear-strengthening of double-column RC bridge piers (DCBPs) to resist the lateral consecutive impact needs to deeply studied. Firstly, the reduce-scaled vehicle model lateral consecutive impact test is performed on a bare pier, a CFRP shear-strengthened slight-damaged pier and a CFRP shear-strengthened intact pier in DCBP specimens. The influence of CFRP strengthening on the damage evolution, failure mode and transient dynamic responses and energy dissipation are examined. Then, numerical simulations of the present impact tests are conducted to validate the adopted finite element analyses (FEA) approach. Furthermore, based on the validated FEA approach, a local refined finite element (FE) model of a prototype simply-supported two-span double-column RC bridge is established, and six numerical simulations of typical light, medium and heavy trucks colliding with the entire bridge with/without CFRP strengthened pier are performed. Based on the simulated results, the effectiveness of CFRP strengthening on the dynamic shear demand, dynamic bending moment and deformation of the impacted pier, as well as the damage/failure and collapse of the entire bridge are further evaluated and discussed. It is found that: (i) compared with brittle shear failure of the bare pier, the strengthened slight-damaged and intact piers both have the excellent lateral consecutive impact resistance with exhibiting shear-flexural and ductile flexural failure modes, respectively; (ii) suppression of the shear damage evolution is beneficial to both strengthened slight-damaged and intact piers to have the higher damage and defamation tolerance to dissipate more impact energy; (iii) the strengthened intact piers in the prototype bridge model can withstand the higher dynamic shear demand and dynamic bending moment but experience the less deformation and damage; (iv) since the deformation and damage of strengthened intact pier in the prototype bridge model under actual vehicular collision are significantly reduced, the vehicular impact resistance and collapse resistance of entire bridge can be improved. [ABSTRACT FROM AUTHOR]

• Geometry of hexagonal hypar umbrellas, allowing for parabolic bisectors, described. • Bisectors disrupt flow of internal forces and impede structural performance. • Performance of 6-leaved umbrellas with r/A > 0.015 m−1 not sensitive to warping. • Hexagonal hypar umbrellas more efficient than square and triangular variants. Félix Candela was a celebrated builder of thin concrete hyperbolic paraboloidal (hypar) shells with a lasting legacy on the rationalist architectural movement of the 20th century. The iconic 4-edged square hypar umbrella became one of Candela most defining works due to its structural efficiency, economical constructability, and striking elegance. Yet, Candela's propensity for geometric experimentation led to the development of hexagonal 6-edged umbrellas capable of supporting parabolic discontinuities bisecting each tympan into two separate leaves for projects such as the Villahermosa Cathedral. Despite their artistic appearance, the structural performance of such topologies has never been subjected to rigorous analysis. In response, this paper presents a parametric investigation into the behaviour of 6-edged umbrellas, with and without parabolic bisectors, based on the proposed Villahermosa Cathedral. Finite element modelling revealed that hexagonal umbrellas exhibit markedly reduced deflections and stresses relative to equivalent square and triangular geometries, which are inversely related to the rise-to-area ratio. Unlike square umbrellas, critical bending moments are not sensitive to the edge rise for hexagonal 6-leaved variants with a constant projected area. However, 12-leaved hexagonal umbrellas adopting parabolic discontinuities suffer from disruptions in the flow of internal forces which ultimately yield a less efficient design. [ABSTRACT FROM AUTHOR]

• Buckling of elliptic cylinders with varied slenderness and eccentricity is studied. • Fast performance overviews are attained for FRP components through shell analyses. • Lamination parameters are used to express the stiffness properties in compact form. • The utilized methods provide design bases for optimizing FRP structural components. Structural members made of fiber-reinforced polymers (FRP) attract increasing attention in the development of novel architectural systems that challenge the standard design methodologies. Cylindrical surfaces constitute one of the typical geometric sets obtained with the FRP component fabrication. This paper explores the influences of two geometric parameters on the buckling performance of elliptical cylinders: inverse slenderness (ratio of minimum diameter to height) and eccentricity (ratio of radii along semi-axes). The overall stiffness properties are defined using lamination parameters. This analysis method eliminates the dependency of optimal solutions on the initial assumptions regarding the laminate configuration, which needs to be explicitly described in multi-layer modeling. Finite element analyses are utilized to compute buckling loads of the cylinders under axial compression force and bi-axial bending moments. The optimal lamination parameters and buckling stresses are determined for various parameters, and the lamination parameters corresponding to the optimal and simple [±45°] angle-ply design points are presented in the lamination parameter plane via Miki's diagram. The results reveal the level of performance that can be achieved by a specific geometry and provide guidelines for the optimal design of elliptical laminated cylinders against buckling. [ABSTRACT FROM AUTHOR]

For free-form structures with a single layer envelope, the node is subjected to axial load, as well as moment. The purpose of this paper is to develop and evaluate a new hollow spherical connector, termed the FREE (Flexible, Resilient, Efficient, Economic) node, for single layer free-form spatial envelopes. Reducing material and efficient shape are important points in the space structure node. Therefore, hollow spherical node sections with different holes were proposed and finite element analysis was performed, to determine the prototype among these parameters. The parameters are the size and shape of the hollow sphere. Bending experiments were also performed, to evaluate the structural capacities of the proposed node; and the corresponding test results were compared with finite element analysis. As a result, it may be said the proposed FREE node satisfied the required capacities. [ABSTRACT FROM AUTHOR]

A novel type of SPDs with bent web panels (BSPDs) is developed, in which the end plate of the BSPD is connected to the web of the composite beam. In this configuration, the bending moment resulting from the SPDs can be minimized, thereby reducing the damage to the concrete slab. In this study, twelve specimens were designed and tested under quasi-static hysteretic loading to investigate the influence of web thickness, constrained flange, out-of-plane buckling restraint, and BSPD length ratio on the mechanical properties of BSPDs. Furthermore, the failure modes and hysteretic force–displacement curves of BSPDs made of low-yield-point steel are obtained through the tests. Based on the results, the effects of design parameters on stiffness, shear strength, deformation capacity, overstrength factor, and energy dissipation capacity of BSPDs were analyzed. The excellent mechanical properties of the low-yield-point steel enabled the BSPD to yield in lower strength and dissipate energy at a larger deformation. Moreover, introducing the constrained flange and reducing the BSPD length ratio can further improve the seismic performance of the BSPD. Finally, finite element models were established to simulate the cyclic behavior of BSPDs. [Display omitted] • A novel type of Shear Panel Dampers with bent web (BSPDs)are proposed to alleviate the damage of the concrete slab. • The seismic performance of the BSPDs are verified with experiments. • Key parameters on the BSPDs performance are analyzed based on the experiment results. • The proposed shear strength formula in the code is modified based on the experiment results. • Finite element models are established to simulate the complex mechanical properties of the BSPDs. Shear panel dampers (SPDs) are widely used in eccentrically braced composite frames (EBCFs) to effectively increase their stiffness and strength and dissipate input energy through plastic deformation in seismic conditions. However, these vertically installed SPDs could also impose an additional bending moment and axial forces on the composite beam in the frame, thus damaging the concrete slab of the frame. The SPDs used in this study were bent in the middle and connected to the web of the composite beam in the frame to overcome the drawbacks of traditional SPDs. Therefore, the resulted bending moment and axial force by the SPDs can be minimized, thus controlling the damage to the concrete slab. In this study, the cyclic behavior of the bent SPDs (BSPDs) made of low-yield-point steel is experimentally studied. Twelve specimens were designed and tested under quasi-static hysteretic loading to investigate the influence of web thickness, constrained flange, out-of-plane buckling restraint, and BSPD length ratio on the mechanical properties of BSPDs. Furthermore, the failure modes and hysteretic force–displacement curves of BSPDs made of low-yield-point steel are obtained through the tests. Finally, finite element models were established to simulate the cyclic behavior of BSPDs and analyze the key factors affecting the mechanical properties of BSPDs. [ABSTRACT FROM AUTHOR]

T-stubs are generally used to represent the tension zone of bolted moment resisting connections. The bolts are considered at present as components loaded only in tension. This paper investigates the influence of the bolt bending on the behavior of the T-stubs. A 3D finite element model was first developed and validated by comparison with experimental results found in the literature. The numerical model was then used to analyse the behavior of various T-stubs regarding mainly the values of the axial tensile forces and the bending moments in the bolts. The results show the influence of the bolt bending moment on the failure mode of some T-stubs. The numerical model was also used to evaluate the accuracy of the analytical interaction formula determining the resistance of isolated bolts subjected to bending moment and axial tensile force. Finally, an analytical model is proposed to evaluate the bending moments and the axial tensile forces in the bolts considered as T-stub components. The comparisons with the numerical model results show that the analytical model represents well the behavior of T-stubs considering the bending moments in the bolts. [ABSTRACT FROM AUTHOR]

• Tests and numerical analysis of specimens with large width-thickness ratios. • Elastic-plastic local buckling and its effects on hysteretic behaviour of beam-columns. • Design formula for bearing capacity of Q690 high strength beam-columns. To evaluate local buckling and its effect on the hysteretic performance of high-strength Q690 thin-walled H-section beam-columns, cyclic testing was carried out on four H-section columns composed of plates with a nominal yield strength of 690 MPa. Based on China's standard for the design of steel structures (GB 50010-2017), the four H-section columns are categorized as S4 and S5 sections, and the axial load ratio of the columns is 0.2 and 0.35. After the test, the failure mode, second-order effect of bending moment, hysteresis curve, bearing capacity, backbone curve, energy dissipation, ductility and stiffness degradation of the specimens were investigated. The failure mode of the specimens is elastic–plastic local buckling of the column bottom flange and web. The ductility coefficient of the specimens is 2.08–3.04, and they have certain specific deformation and energy dissipation capacities. Following this, a finite element model was established to simulate the hysteretic performance of the Q690 thin-walled H-section beam-columns. The failure mode and hysteresis curve obtained by the finite element simulation corresponded well with the tests. Based on this agreement, a parametric study was carried out to investigate the influence of the flange width-thickness ratio, web width-thickness ratio, and axial load ratio on the local buckling and hysteretic performance of H-section beam-columns. The variation trend of the backbone curve and the bearing capacity were further investigated by the finite element parametric analysis. Finally, a prediction formula for the beam-column bearing capacity was proposed based on the finite element results. The comparison with the test results shows that the proposed formula has sufficient accuracy and can be used in engineering design. [ABSTRACT FROM AUTHOR]

• Validation of a finite element, for moment-axial-shear interaction of RC frames is presented. • Nonlinear force-based finite element formulation is used. • The Disturbed Stress Field Model is used as the constitutive relationship. • Load-deformation responses and failure modes of RC elements are accurately predicted. This paper focuses on a novel finite element formulation which can predict the bending moment-shear force-axial force interaction of reinforced concrete frames and walls, and validate it against 170 experiments available in literature. This distributed plasticity element is established on force-based finite element method, where the relationship between element nodal forces and section forces are exactly known. Hence, element discretization is nonessential when modelling frames using this formulation, reducing the number of degrees of freedom in the numerical model compared to displacement-based formulations. The computations are carried out at four hierarchical levels, namely structure, element, section and fibre. There are two nested iterative procedures at the structure level and the section level. In the existing formulation, these iterative procedures are computationally demanding due to use of initial stiffness matrices. Furthermore, it uses Modified Compression Field Theory at the fibre level, which has inherent drawbacks compared to its more evolved version, the Disturbed stress Field Model. The current study refines the iterative procedures at structure and section levels to fully operate with tangent stiffness matrices to improve the speed of convergence. In addition, the Modified Compression Field Theory is replaced with the Disturbed stress Field Model at the fibre level to compute fibre resisting force for a given fibre deformation, accounting for both averaged behaviour and local crack slip. The novel element is validated by comparing the predicted results with experimental results of 170 tests found in the literature. It is shown that the novel element predicts the load carrying capacity well with an average experimental-to-predicted load carrying capacity ratio of 0.99 and a coefficient of variation of 12.8%. Furthermore, the element can be used to discuss the different failure mechanisms of reinforced concrete frame elements. [ABSTRACT FROM AUTHOR]

Highlights: [•] We constructed two and three dimensional finite element models (FEM) to find the SCF. [•] We used FEM to obtain the SCF in T–butt welded connections under bending loading. [•] We made a grinding along the weld toe in the three-dimensional model. [•] SCF dependent of the internal angle at the weld toe. [Copyright &y& Elsevier]

• Analytical methods for load capacities of laterally restrained slabs are proposed. • Effects of boundary conditions and slab depth variation are considered. • Proposed methods are validated by finite element analysis and tests. • Effects of design parameters on the compressive membrane action are revealed. The lateral restraint eccentricity and rotational restraint stiffness significantly influence the compressive membrane action (CMA) in reinforced concrete slabs. However, these two factors have rarely been studied and no analytical model considering them has been established. In addition, most analytical methods for evaluation of CMA were derived for slabs with constant thickness, even though slabs with variable depth are quite common in practice. Therefore, this paper develops analytical methods to predict the load capacities of laterally restrained slabs considering the effects of lateral restraint eccentricity, rotational restraint stiffness, and slab depth variation. Based on the compatibility conditions and equilibrium of forces, the axial forces and bending moments can be derived by solving equations as long as the deflection at the load application point is provided. Then the corresponding load can be determined and the load capacity of the slab can be obtained by iterative calculations. The proposed methods are then validated by comparing to finite element analysis and four groups of test results, in which the effects of lateral restraint eccentricity, rotational restraint stiffness, and slab depth variation are explicitly reflected. Finally, comprehensive parametric analyses are conducted by using the proposed models. The interaction effects of the design parameters on the CMA are revealed for slabs with strong and weak rotational restraints, respectively. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this paper is to analyse the ultimate strength of ageing ship structures based on experimental and numerical assessments. Three experimental ultimate strength tests have been carried out on box girders under vertical bending moment and several effects have been detected due to corrosion. Extensive nonlinear finite element analyses have been performed to compare the numerical and experimental results. The ultimate bending moment of corroded box girders has been compared with existing formulas. A relationship to calculate the equivalent tangent modulus as a function of the total reduction of the cross-sectional area due to corrosion degradation has been proposed. A new stress–strain relationship has been developed, taking into account the residual stresses and the corrosion effect, which may be directly used as a master stress–strain curve for a non-linear finite element analysis. [Copyright &y& Elsevier]

Abstract: This work investigates the capability of two different fiber beam–column finite elements in simulating the dynamic response of a shear wall tested on a shaking table. The two elements account for the axial force-bending moment interaction in a comparable way. The first element can be considered as representative of a class of elements widely available to design engineers for nonlinear (either static or dynamic) analyses. The second element is more refined (and complex) and is specifically derived to reproduce the shear–flexure interaction. The specimen under study is one of the two 5-story, 1/3rd-scale, reinforced concrete (R/C) shear walls, which was subjected to a sequence of accelerograms during the CAMUS I program. The wall was designed according to the French code PS92 and is representative of large lightly reinforced walls, as defined in the Eurocode 8 standard. The measured response is used to assess the benefits and limitations of all the proposed structural models and the adopted finite element formulations; the relevant effects of shear in the response of the specimen are addressed and discussed. Important recommendations on the use of fiber beam–column elements for studying existing R/C structures, which do not comply with the flexure dominated paradigm of walls in the most recent code specifications, are provided. [Copyright &y& Elsevier]

Abstract: A new damage index for plane steel frames under earthquake ground motion is proposed. This index is defined at a section of a steel member and takes into account the interaction between the axial force N and bending moment M acting there. This interaction is defined by two curves in the N–M plane. The first curve is the limit between elastic and inelastic material behavior, where damage is zero, while the second one is the limit between inelastic behavior and complete failure, where damage is equal to one. The damage index is defined by assuming a linear variation of damage between the two abovementioned curves. Thus, for a given N–M combination at a member section, obtained with the aid of a two dimensional finite element program, one easily defines the damage index of that section. Material nonlinearities are taken into account by a stress–strain bilinear model including cyclic strength and stiffness degradation in the framework of lumped plasticity (plastic hinge model), while geometrical nonlinearities are modeled by including large deflection effects. The increase of damage related to strength reduction due to low-cycle fatigue is also taken into account. Several illustrative examples serve to demonstrate the use of the proposed damage index and to compare it with other well known damage indices. [Copyright &y& Elsevier]

Abstract: The purpose of this research is to examine the behaviour of elliptical concrete-filled steel tubular stub columns under a combination of axial force and bending moment. Most of the research carried out to date involving concrete-filled steel sections has focussed on circular and rectangular tubes, with each shape exhibiting distinct behaviour. The degree of concrete confinement provided by the hollow section wall has been studied under pure compression but remains ambiguous for combined compressive and bending loads, with no current design provision for this loading combination. To explore the structural behaviour, laboratory tests were carried out using eight stub columns of two different tube wall thicknesses and applying axial compression under various eccentricities. Moment-rotation relationships were produced for each specimen to establish the influence of cross-section dimension and axis of bending on overall response. Full 3D finite element models were developed, comparing the effect of different material constitutive models, until good agreement was found. Finally, analytical interaction curves were generated assuming plastic behaviour and compared with the experimental and finite element results. Ground work provided from these tests paves the way for the development of future design guidelines on the member level. [Copyright &y& Elsevier]

Abstract: Steel caging is an effective, economical, easily applied and widely used method of strengthening RC columns. Based on the results of two experimental studies, this paper proposes the finite element modelling of RC columns strengthened by a steel cage under axial loads and bending moments. The FE models were used to obtain the N-M diagrams of experimental cases in which a study was made of the improved resistance of RC columns strengthened with this type of strengthening technique. The paper also includes a comparison of different methods of connecting the cage around the beam–column joint and a parametric study to observe the influence of diverse parameters on the behaviour of the strengthened column, including: angle dimensions, number of strips, the yield stress of the steel used in the strengthening, the dimensions of the capitals at both ends of the column, concrete strength and the characteristics of the reinforcement used in the columns. Finally, the results of the various tests (experimental and numerical) described in the paper are used to be compared with three design proposals and the goodness of fit of each one is analysed. [Copyright &y& Elsevier]

Abstract: The aim of this work is the efficient numerical simulation of the bending behaviour of fibre reinforced cementitious matrix (FRCM) beams. For the production of the FRCM specimens, a high-strength cementitious matrix with hooked-end steel fibres is used. Two types of FRCM beams are considered. The first type has no conventional steel reinforcement, while the second one includes longitudinal and transverse reinforcement steel bars. For comparison reasons, conventional reinforced concrete (RC) beams are also studied. The beams are tested under static and cyclic loading. The response of the tested beams is simulated by means of effective two-dimensional finite element models, in which the contribution of the FRCM is taken into account by means of two different layers of finite elements. The first one represents the cementitious matrix while the second one accounts for the contribution of the steel fibres in a homogenized manner. The presented models are able to follow the nonlinearities that appear in the corresponding physical models. The validity of the proposed methodology is established by comparing the numerical results with the corresponding experimental results. [Copyright &y& Elsevier]

Abstract: An extension of Mohr’s analogy to bending of shear-deformable beams with eigenstrain-type actuation, such as a piezoelectric actuation, is presented first. Various refined shear-deformable beam theories are included by means of a theory-dependent parameter. The one-dimensional version of Reissner’s sixth-order plate theory is exemplarily addressed. The Bernoulli–Euler theory of beams rigid in shear, as well as the shear-deformable theory of Timoshenko, are included as special cases. Afterwards, the extended Mohr analogy is applied to the bending of smart beams with piezoelectric patch actuators. The following special problem of static shape control is solved: Seek a placement of single patch actuators, such that the displacement and the cross-sectional rotation vanish at some pre-selected locations of the beam, despite the beam is loaded by external forces. Using Mohr’s analogy, it is shown that the auxiliary loading of the adjoint beam must form a self-equilibrated system of loading in order to achieve the latter goal. The high potential of the proposed actuator placement is demonstrated for the case of a cantilever beam with a single force acting at the tip. Placements of single actuators are represented such that the tip displacement and the tip cross-sectional rotation vanish. The outcomes of shear-deformable theories are compared to the Bernoulli–Euler theory and to a Finite Element computation using piezoelectrically coupled elements. [Copyright &y& Elsevier]

Abstract: In structural engineering practice, composed plate structures are normally calculated as orthotropic plates in bending, applying either thin plate theory (Kirchhoff) or thick plate theory (Mindlin/Reissner), without accounting for the eccentricity of neutral planes in different directions. In reality this eccentricity causes a different force distribution, in which not just bending moments, twisting moments and transverse shear forces occur, but membrane forces as well. As a consequence, a coupled type of stretching–bending-shear orthotropy occurs. The present article presents a method to determine the required smoothed cross-section rigidities as an input in FEM software, which offers functionality for analysis of this type of orthotropy. To compute rigidity properties it is sufficient to have on hand a FEM program for 2D analyses. It is, however, likely that some enhancements have to be added to existing FEM software. Examples are included to show the reliability of the method and consequences in plate results. [Copyright &y& Elsevier]

Abstract: This paper presents the effect of inclination on the static behaviors of inclined variable-arc-length (VAL) beams. An updated Lagrangian formulation of the VAL beams has been developed via the variational approach. The first variation of the total potential energy is evaluated to establish the system of nonlinear finite element equations. These equations are then solved by using the iterative process to obtain static configurations. The second variation of the total potential energy is performed to determine the tangent stiffness matrix of the VAL beams. The critical values of uniform self-weight of the inclined VAL beams are obtained by equating the determinant of the tangent stiffness to zero. The critical uniform self-weights obtained from the finite element method are validated by those derived from the shooting method. The effects of inclination on the deflection, bending moment diagram, and axial force diagram at critical state are investigated herein. [Copyright &y& Elsevier]

Abstract: The response of a 120 m-tall guyed mast to three-dimensional seismic excitation is analyzed using the finite-element program ABAQUS. The Northridge earthquake and an amplified El Centro earthquake are applied. The mast is pinned at its base, and guy cables are attached at four equally spaced points along its height. The dynamic tension in the guys is modeled by a nonlinear function based on tests, and periods of slackness in the guys during motion of the system lead to snap tension loads and affect the response. The mast is represented by three-dimensional beam elements. Displacements, bending moments, and base shears are computed for the mast, along with guy tensions. The effects of guy stiffness and pre-tension, mast weight, and directionality of the ground motion are investigated. [Copyright &y& Elsevier]

• The model of double-ring joint was established under different loading conditions. • The calculation formulas of the semi-rigid properties were derived. • The formulas were verified by experimental and finite element analysis results. • The hysteretic behaviors under cyclic load were analyzed by ABAQUS. Taking double-ring joint as research object, the mechanical performances under pure bending, bending-shear and eccentric loading conditions of the joints were studied in this paper. Double-ring joints with different structural parameters were analyzed using finite element analysis and theoretical derivation methods and combined with experimental results. The following conclusions were obtained: 1) under the pure bending condition, the spring model of the double-ring joint was established, and the theoretical calculation formulas of the ultimate bearing capacity and initial rotational stiffness were derived; 2) under the bending-shear condition, the accuracy of finite element analysis models was verified by comparing the numerical with experimental results. The mechanical properties of double-ring joints under the bending-shear condition were similar to those under the pure bending condition; 3) based on the full-section plasticity criterion, the relationship between ultimate bending moment ratio η 0 N and axial force eccentricity δ was derived. With the exponential function for nonlinear fitting, the relationship between initial rotational stiffness ratio ξ 0 N and axial force eccentricity δ was derived. [ABSTRACT FROM AUTHOR]

• Impact of horizontal SOF on reliability of diaphragm wall is significant. • Stiffness modelled by random field considerably affects wall deflections variability. • Impact of number of realizations on the accuracy of results is investigated. The main goal of this article is to perform a probabilistic analysis on a cantilever diaphragm wall constructed in sandy subsoil characterized by spatially variable strength and stiffness parameters. Three quantitates are considered, namely, the deflection of the wall, the settlements behind the wall and the maximum bending moment along the wall. To enable high accuracy of the evaluation of these quantities, a hardening soil model with a small strain overlay is used. To account for soil spatial variability, the friction angle of the sand is modelled using an anisotropic random field with specified vertical and horizontal scales of fluctuation (SOFs). All computations of the considered boundary value problem are carried out by means of the random finite element method (RFEM). The influence of both the vertical and horizontal SOFs on the probabilistic distributions of all the considered quantities is investigated. Reliability analyses are carried out based on the obtained distributions. Additionally, the effect of the number of realizations in the simulation process is analysed. It is shown that in the case of a diaphragm wall, the value of the horizontal SOF can substantially affect the probability of both excessive deformations as well as high bending moment values. It is also shown that additional modelling of soil stiffness moduli by a random field may induce small but noticeable changes in the probability of exceeding the conditions of the serviceability limit state. [ABSTRACT FROM AUTHOR]

• The failure mechanism of reinforced concrete sewage tank was discussed. • FE calculations of the reinforced concrete sewage tank were performed. • Concrete was modeled with a coupled elasto-plastic-damage model. • Different arrangements of flexural reinforcement were tested. • Strain localization was sensitive to flexural reinforcement arrangement. The paper discusses a failure mechanism of reinforced concrete (RC) sewage tank in a wall corner that failed during a filling test through excessive horizontal displacements of walls under opening bending moment. To explain the reasons for failure, comprehensive finite element (FE) calculations of the RC sewage tank were carried out under plane strain conditions. Concrete was modeled with a coupled elasto-plastic-damage constitutive model. The model was enriched in a softening regime by a characteristic length of micro-structure to provide the mesh objective results. FE analyses were performed for different arrangements of flexural reinforcement in the corner. The focus was on the evolution of strain localization and corner strength. Reasons for the tank failure were discussed. The FE results showed a high sensitivity of both the load bearing capacity of the tank wall corner and strain localization to flexural reinforcement arrangement. In addition, two laboratory experiments on RC corners subjected to opening bending moments were numerically analyzed under plane stress conditions. [ABSTRACT FROM AUTHOR]

• The axes of arch-shaped pylons used in high-speed railway bridges were optimised. • Fixed point iteration and force-balance and finite element analysis were used. • Optimisation was performed under different conditions. • Bending moments and normal stresses were significantly reduced. • Deflections and displacements were also significantly reduced. In order to obtain reasonable arch-shaped pylon axes for high-speed railway cable-stayed bridges, an iterative optimisation method based on force-balance analysis, a fixed point iterative method for nonlinear equations, and finite element analysis was proposed. The developed method was used to optimise the axes of the arch-shaped pylons of two high-speed railway arch-shaped pylon cable-stayed bridges. The results showed that the arch-shaped pylon axis of a cable-stayed bridge with main spans of 2 × 80 m converged after seven iterations. The absolute maximum bending moments under the service load of the optimised arch-shaped pylons were reduced by 53.15–83.53%, and the maximum and minimum stresses under the service load were reduced by 79.81–106.80% and 52.63–66.74%, respectively. Under a double-line ZK-live load, the maximum upward and minimum downward deflections of the optimised arch-shaped pylons were reduced by 21.30–25.0% and 12.4–21.6%, respectively, which resulted in increased stiffness of the bridge. The optimised axes obtained after inputting different initial axes to the proposed method were identical, and the obtained axis was adopted as the final arch-shaped pylon axis design for the actual bridge. For the second arch-shaped pylon cable-stayed bridge, which had main spans of 2 × 90 m, the absolute maximum bending moments of the optimised arch-shaped pylons were reduced by 77.05–92.08%, and the maximum and minimum stresses under the service load decreased by 117.82–173.91% and 39.00–41.38%, respectively. The results obtained illustrate the suitability of the proposed arch-shaped pylon axis optimisation method and demonstrate its reliability. [ABSTRACT FROM AUTHOR]

• New joint for connecting aluminum rectangular hollow section members is proposed. • Six different full-scale ARH joints are tested under an out-of-plane bending moment. • The M-Φ curves, stress variation, and failure modes of the ARH joint are obtained. • A bilinear model is proposed to summarize the M-Φ curves of the joint. • The influence of different factors on mechanical behavior of ARH joints is analyzed. A new joint system for connecting aluminum alloy rectangular hollow section (ARH) members is proposed to overcome the problem of connecting rectangular tubes using the traditional Temcor joint. The structural performance of the ARH joint system under an out-of-plane bending moment is studied experimentally. The moment-rotation (M-Φ) curves, stress variation, and failure modes of the ARH joint obtained from the tests are discussed. A bilinear model is proposed to summarize the M-Φ curves of the joint. The influence of the key parameters, gusset thickness and bolt quantity on the mechanical behavior of the ARH joint is analyzed. Subsequently, finite element analysis is conducted to investigate the moment rotational behavior of the ARH joint. The comparison between the experimental and numerical results proves that the proposed finite element model is accurate enough and can be used to study the moment resistance behavior of the ARH joint system. The results show that the proposed ARH joint, for connecting rectangular hollow section members, can be considered as a semi-rigid connection. This study provides a reference for the practical application of the ARH joint in reticulated structures made of aluminum rectangular members. [ABSTRACT FROM AUTHOR]

• H-beam welded hollow sphere developed buckling failure subjected to eccentric compression. • The design formula of H-beam welded hollow sphere subjected to eccentric compression was proposed. • The test results verified the rationality of the proposed formula. • The bearing capacity of joints is greatly affected by ribbing, H-beam height, flange width, and hollow sphere size. • The axial force–bending moment relationship curve of the joint is independent of its geometric size. An H-beam welded hollow spherical joint is a new kind of spatial grid structure. In this study, the eccentric-loaded behavior of H-beam welded hollow spherical joints was studied, and the influential law of material strength, joint size, and stiffening rib on its mechanical properties was analyzed through experimental research and numerical simulation. Parametric analyses were conducted to study the eccentric-loaded behavior of H-beam welded hollow spherical joints subjected to pure bending or the combined action of axial force and bending moment using a finite element model verified through experiments. The calculation formula of the bending bearing capacity of the joints and the axial force-bending moment curve were also obtained. Finally, the design rule for eccentric compression was proposed and verified through test results. [ABSTRACT FROM AUTHOR]

• Finite element limit analysis of slabs with construction joints are presented. • New formulations for the torsional capacity of slabs with vertical construction joints. • The yield surfaces of slab with different vertical construction joint are shown. Reinforced concrete slabs constructed of precast elements and in situ concrete are commonly used for short-span road bridges. The construction joints between the concrete cast at different stages reduce the torsional capacity and thus the load-carrying capacity of the slab. However, the present formulations for the torsional capacity, based on limit analysis, only consider monolithically cast slabs. In this paper, the load-carrying capacity of reinforced concrete slab bridges with construction joints are investigated using limit analysis of perfect plastic materials based on the lower bound theorem. New formulations for the torsional capacity of slabs with vertical construction joints and partial construction joints are presented. The load-carrying capacity of slabs is calculated using finite element limit analysis based on the lower bound theorem. For the analysis, a complete yield criteria for the bending moments and torsional moments are setup applying a layer model. The size of the layers is calculated from the moment capacities and the derived torsional capacities. Examples of limit analysis of slabs with and without construction joints are compared, which demonstrate the reduction due to the construction joints. [ABSTRACT FROM AUTHOR]

• A new metallic damper with bolted and replaceable steel strip fuses was proposed. • The steel strips can be easily adjusted or replaced after damper failure without affecting the connecting parts. • The primary configuration design of steel strip was provided through theoretical derivation. • The seismic performance of proposed fuse strips was evaluated with cyclic tests and numerical simulations. • The steel strips exerted satisfied energy dissipation ability with pump hysteretic loops. In this study, a high efficiency metallic damper with replaceable steel strips and the adjustable construction is proposed for framed structures. The proposed damper uses bolted steel strips as the energy dissipation fuses, which can be adjusted or replaced after failure without affecting the connecting part. The steel strips participate in the load bearing and energy dissipation through an in-plane bending mechanism. In addition, to exert the load bearing and achieve the potential plasticity fully, the steel strips are desired to yield simultaneously and dissipate energy throughout the entire section. In this paper, the primary configuration design method was provided through a theoretical derivation. Further, the nonlinear performance of the proposed fuse strips was evaluated through a series of quasi-static cyclic tests. The influence of the configuration dimensions was investigated through the experimental study and corresponding finite element analyses. The results indicate that the strips successfully exert their potential energy dissipation with pump hysteresis loops. The fuse strips can better participate in the energy dissipation through bending-dominated working mode, and the bending moment strength of the steel strip is mainly controlled based on the width of the central region. The configuration of the transition region greatly affects the failure mode, the plasticity distribution, and the deformation capability. Based on the test data and the numerical simulation investigations, some primary design guidance for the fuse steel strips is suggested. [ABSTRACT FROM AUTHOR]

• Performance of bolted-flange connections under tension, moment and shearing. • Static tension, moment and shearing tests and FEA on bolted-flange connections. • Effect of flange thickness, bolt edge distance, flange edge width and bolt hole size. • Stiffness and strength of connections, bolt tension and contact force were obtained. • Yield bearing capacity obtained from proposed formulas agreed well with test and FEA. In this study, the square steel tube column is connected by bolted flange instead of traditional welding. For multi-rise structure, tension, bending moment, and shear force may act on the connection under vertical and horizontal loads. To investigate the mechanical behavior of flange connections, full-scale model tests and finite element analyses of 10 bolted-flange joints were carried out. The mechanical properties of the specimens and the influence of the flange thickness, flange size, and bolt hole diameter under a tension–bend–shear combination were obtained. The size of the bolt hole and flange has little effect on the load-carrying capacity of the connection. With the increase of the thickness of flange, the flexural rigidity and load-carrying capacity of the connection increase obviously, and the yield mechanism of the specimen changes from flange yield to bolt yield. The influence of the axial tension ratio on the bolt tension was investigated by the experiment-verified finite element models. The axial tension ratio is the value that the axial force of column divided by the cross-sectional area and the material design strength of the column. Increasing the axial tension ratio may increase the bolt tension, which has a harmful effect on the bolts at the tension side of the flange. Using yield line theory, formulas for calculating the static load-bearing capacity resisting the bending moment, shear and tension were deduced and verified by comparing with the result of experiment and finite element analysis. [ABSTRACT FROM AUTHOR]

• The bending moment in tensile bolt attached to T-stub should be considered in design. • Three key factors were suggested and discussed for the bolt stress calculations. • New T-stub connector model and calculation method were proposed. A T-stub is a component comprising a T-section with two bolts attached to its flange. It can be used to analyze the mechanical behavior of high-strength bolts in tension. In this study, the mechanical behavior of bolts was assessed via six static tests and 17 finite element analysis models. The effects of the thickness of the flange, the length of the inner and outer flange, and the diameter of the bolt were studied. With the exception of outer flange length, the parameters significantly affected the bolt bending moment, yielding load, and T-stub failure mode. Both the tests and the finite element analyses indicated that when the bolts yielded, the bending stress could reach 13% to 45% of the total tensile stress in the samples. It is not advisable to design bolts without considering the effect of the bending moment. A stable bending moment distribution relationship was also found between the bolt and the outer flange. The bending moment of the joint, the bending moment ratio of the bolt to the joint, and the distance from the contact force center to the bolt center are also discussed. Lastly, a new T-stub connector model and calculation method were proposed and proven to be reliable. This method is based on the theory of moment distribution and does not require the prying force to be calculated. [ABSTRACT FROM AUTHOR]