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The investigation of the behavior of reinforced concrete (RC) elements without shear reinforcement is a current focal point, driven by the incomplete consolidation of predictive formulas for shear strength in RC elements. Currently, the literature provides, indeed, a limited number of experimental and numerical studies on this subject. This paper seeks to advance the comprehension of the behavior and collapse mechanisms of RC beams not provided of shear reinforcement, as commonly employed in RC slabs of bridges. The paper commences with a critical review of several predictive formulas for the shear strength of RC elements lacking transverse reinforcement, as stipulated by various international codes. The objective is to identify the principal parameters involved in the formulations and discuss their roles also by means of sensitivity analysis. Following this, the results of nonlinear numerical analyses, based on a three-dimensional finite element (FE) model, are presented. The FE model was initially calibrated using experimental results from a benchmark beam lacking shear reinforcement, retrieved from the literature, which exhibited a brittle shear failure. Subsequently, several specimens were prepared for the numerical investigation, assuming multiple combinations of geometrical and mechanical parameters. For specimens experiencing shear failure, the strength was compared with that provided by code formulas, as well as using the strut-and-tie approach for the cases characterized by a reduced shear span-to-depth ratio. In general, these analytical tools significantly underestimated the numerical strength, underscoring the necessity for further insights based on experimental tests. The numerical outcomes have been, indeed, prodromal to design an experimental campaign. • Finite element modeling of a reinforced concrete beam without shear reinforcement. • Review of all major approaches in technical regulations worldwide. • Parametric analysis of the shear behavior of reinforced concrete beams without transverse reinforcement. • Assessment of the predictive capacity of technical regulations formulations. [ABSTRACT FROM AUTHOR]

This paper presents a reliability analysis of concrete masonry infill walls with an aim to examine the efficacy of the resistance factor specified in the infill design under seismic loading. A numerical model for masonry infilled reinforced concrete frames was developed and encoded in OpenSees for this study. The model was validated using experimental data. Two features were involved in this reliability study, including 1) that the effect of spatially varying masonry compressive strength f ′ m on the lateral resistance of masonry infills was considered using the Random Finite Element Method, and 2) that seismic load with different return periods was considered to provide a more complete treatment of a reliability analysis. The study selected six Canadian cities with varying levels of seismic intensity for this analysis. By calculating the probability of failure of infill frames subjected to earthquake loading at different locations, the paper showed that the current resistance factor of 0.6 in the infill design equation suggested by the Canadian masonry design standard is conservative. To achieve a reliability index of 3, this factor could be increased to 0.65 for all cities studied. For cities with low seismicity such as Toronto, the results suggest that an even higher resistance factor is justified. • A meso-model encoded in OpenSees to simulate the in-plane behaviour of masonry infilled RC frames. • A reliability-based study on masonry infilled RC frames using the Random Finite Element Method (RFEM). • Considered spatially varied masonry compressive strength and seismic loads with varying return periods. • Calibrate the resistance factor specified in CSA S304-14 for the design of masonry infills. [ABSTRACT FROM AUTHOR]

A gap in current design approaches demands explicitly introducing a capacity design approach when designing steel-concrete composite reduced web section (RWS) connections. This paper addresses this gap by presenting test-validated finite element models and parametric investigations, focusing on the presence and absence of composite action over the web opening, the diameter, and the end-distance of the web opening. Additionally, the first-ever comprehensive experimental and numerical database from the literature on bare steel and composite RWS connections is compiled and thoroughly analysed to develop the capacity design assessment for such connections. Both parametric investigations and the database highlight the significance of the capacity design ratio between the connected components in achieving a desirable ductile mechanism. This is crucial, as evidenced by the results: a 15 % increase in the connection's moment capacity led to an average 21 % difference in dissipated energy, favouring the web opening with a diameter of 50 d o over 80 d o , in RWS connections with the presence of composite action. The results show that proper consideration of the capacity design approach in designing RWS connections ensures a stable yield mechanism is developed, resulting in the redistribution of global action and capping deformation demands on non-ductile elements. This enhances connections' rotational capacity and ductility by forming the Vierendeel mechanism. Lastly, the paper presents a detailing recommendation for employing RWS connections in both existing and new structures for seismic purposes. • Demountable steel-concrete composite extended end-plate RWS specimens examined under cyclic loading. • High-fidelity modelling and parametric finite element investigation. • A complete up-to-date database on steel and composite RWS connections. • Current design approaches demand an explicit introduction of the capacity design approach for prequalified RWS connections. • Vierendeel mechanism enhances the rotational capacity and the ductility of RWS connections. [ABSTRACT FROM AUTHOR]

Bridge girders are subjected to repeated patch loading during incremental launching (i.e. travelling over supports). Plastic deformations are likely to occur in the girder already at the first patch loading. They influence the girder's structural response and bring about a decrease in the ultimate resistance at subsequent patch loadings. This problem is analysed in the present paper through the serviceability limit state (SLS) of incrementally launched bridge I-girders (ILBGs). The SLS of ILBGs is a current problem since only a few studies, with contrasting conclusions and certain limitations, have been recognised in the literature. Research is limited on plate girders without longitudinal stiffeners made of structural steel. Flat slide-type launching shoes are considered in this paper. The serviceability requirement (repeatable behaviour of ILBGs) and criterion (that effective membrane strains should remain in the elastic range) are adopted from the literature. So, the serviceability resistance is adopted as a load at the start of the effective membrane plastic strains in the girder. In order to propose a practical and simple SLS design procedure, the serviceability resistance is normalised against the ultimate resistance, so a serviceability correction factor (k sls) is defined. The paper presents a parametric numerical analysis of the factor (k sls). A finite element model previously developed and validated by the author is employed to simulate a nonlinear response of patch-loaded girders. The parametric study includes 599 girders. k sls is inversely proportional to the web thickness and directly proportional to the flange thickness and the yield strength of the steel material. The load length, web depth and flange width do not influence k sls. The influence of the spacing between transverse stiffeners on k sls is negligible. Finally, by regression analysis of the results of parametric study, an original and reliable serviceability correction factor is proposed as the main objective of the research. The range when the SLS of ILBGs should be checked is also defined. [Display omitted] • The serviceability correction factor (k sls) is the serviceability resistance normalised against the ultimate resistance. • A parametric numerical analysis of k sls is conducted. The numerical database contains 599 patch-loaded girders. • The load length, web depth and flange width do not influence k sls , while the influence of the spacing between transverse stiffeners is negligible. • k sls is inversely proportional to the web thickness and directly proportional to the flange thickness and steel grade. • A reliable, original and simple empirical expression for k sls is proposed. [ABSTRACT FROM AUTHOR]

This paper proposes a novel structural analysis approach, the neural networks-based spring element (NNSE) method, to synergize machine learning (ML) techniques with the line finite element method (LFEM) for the second-order analysis method of pile-supported structures. Traditional LFEM, widely used in upper structure design, showcases limitations in efficiently modeling complex Soil-Structure Interaction (SSI) along piles since it requires dense element mesh for accuracy. Conversely, ML offers a mesh-free alternative for analyzing single piles but struggles in simulating pile-supported structures as the training sample collection for large-scale problems might be unbearable. This paper addresses these challenges by proposing a new analysis framework to utilize the neural network (NN) model, which only describes structural responses of single piles, for the simulation of entire pile-supported structures. In the proposed method, the NN model is not directly used for structural analysis but employed to formulate a new spring element named the NNSE to model single piles in pile-supported structures. This NNSE can be seamlessly implemented within the existing LFEM framework to analyze pile-supported structures, eliminating the dense mesh requirement for single piles and thereby significantly improving the computational efficiency. Extensive examples are provided to verify the effectiveness of the proposed method, indicating its potential in promoting the second-order analysis method to the design of pile-supported structures. • A novel NNSE method is proposed for analyzing pile-supported structures. • NNSE efficiently captures nonlinear SSI using one element per pile. • This method surpasses existing solutions in both efficiency and accuracy. • NNSE provides a novel integration of FEM and ML for structural analysis. [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]

This paper presented an innovative uplift-restraining friction pendulum bearing (UR-FPB) to address the limitations of traditional FPBs, which are unable to withstand vertical tensile loads. The UR-FPB is composed of a friction set acting as the horizontal sliding module and an anti-uplift set acting as the vertical uplift-restraining module. Based on this configuration, the study derived the theoretical force-displacement relationships of the UR-FPB, established three solid finite element models in Abaqus, and proposed a hybrid modeling method based on OpenSees. Then the practical effectiveness of this bearing and the credibility of the theoretical analysis models and hybrid numerical models were validated. The theoretical and numerical results demonstrate that the frictional behavior of the UR-FPB in horizontal sliding is characterized by multi-stage hysteresis relationships. The numerical results on the sliding characteristics and the corresponding hysteresis relationships are highly consistent with the theoretical results. The UR-FPB has a large horizontal sliding capacity similar to that of traditional FPBs, while the design of the anti-uplift configuration does not reduce or limit this sliding capacity. Significantly, the study investigated the uplift-restraining behavior of the UR-FPB and its effect on the horizontal responses. The analysis results suggest that the UR-FPB has a good uplift-prevention capacity and this paper recommends that the design value of tensile capacity should not exceed the yield force in tension. Therefore, this novel uplift-restraining friction bearing has an expected effectiveness, which can simultaneously resist vertical tensile loads and function as a horizontal seismic isolator. The proposed hybrid modeling method may provide a useful reference to model the behavior of the UR-FPB in software used for response-history analysis. • The study develops an innovative uplift‐restraining friction pendulum bearing (UR-FPB). • Three solid finite element models of the UR-FPB are established. • A hybrid modeling method for the UR-FPB is proposed based on OpenSees. • Theoretical analysis models and hybrid numerical models are validated. • This bearing exhibits excellent three-dimensional mechanical behaviors. [ABSTRACT FROM AUTHOR]

This paper investigates comprehensively the resonance and cancellation conditions for the free vibration of elastically-supported (ES) beams subjected to successive moving loads. Focus is placed on application of the cancellation condition to minimize bridge vibrations, considering particularly the effect of elastic supports. In terms of the modal amplitude R of free vibration of the ES beam, both resonance and cancellation conditions are identified. This paper is featured by the fact that the cancellations are classified into two types as the external (load-related) and internal (structure-related) ones. Through the (internal) cancellation function, the criterion for selecting the optimal support stiffness ratio (SSR) is derived for the first time for suppressing the resonance of short to medium-span railway bridges. It depends solely on the bridge/vehicle length ratio L / d , and can be utilized to achieve near-perfect cancellation. The theoretical findings are validated by the finite element method (FEM) for various parameters. The results reveal that for beams with lengths in the ranges of (0.5 d , d ] and (1.5 d , 2 d ], an SSR closer to the lower bound of the acceptable range should be selected to achieve the best effect. And for beams with lengths in the range of (d , 1.5 d ], the SSR should be selected as close to the optimal value as possible. Besides, it was found that damping in the beam and supports contributes to further suppression of vibration for bridges designed with optimal SSR. • Derive new resonance and cancellation conditions for elastically supported beams. • Classify cancellations as external (load-related) and internal (structure-related) ones. • Optimal support stiffness ratio (SSR) for near-perfect cancellation of resonance. • Optimal SSR relies solely on the bridge/vehicle length ratio and is easy to use. • Verify the effectiveness of SSR criterion for various factors. [ABSTRACT FROM AUTHOR]

Currently, progressive collapse studies are mostly conducted based on an event-independent assumption. With studies employing an event-dependent premise mainly concerning explosion or fire events, the aftermath of impact loading is seldom reported. Meanwhile, interactions between reinforced concrete (RC) members and superstructures under impact loading need further evaluation. In this paper, finite element models of RC structures subjected to impact loading and progressive collapse are established and validated utilizing LS-DYNA. A valuing methodology of erosion parameters for the continuous surface cap model (CSCM) considering element size is proposed in this process. The influence of impact column removal (ICR) on the progressive collapse performance of RC frame structures is studied at sub-assemblage and structure levels. The parametric study indicates that the ICR process can be described by an impact loading stage and a gravity load stage. It is also found that structures experiencing ICR are exposed to a higher risk of progressive collapse, with the downward force exerted by the impacted columns being a significant contributing factor. Dynamic analyses demonstrate that the acceleration of the column removal point (CRP) can be used to validate and quantify the downward force. The hybrid force-displacement boundary conditions of frame columns give rise to the development of downward force. Recommendations for resisting progressive collapse considering ICR are proposed based on the analytical results of the paper. • A new threat-dependent perspective to progressive collapse research is elucidated, focusing on impact column removal (ICR). • Interactions between impacted columns and superstructures are illuminated, emphasising the influence of downward force. • The boundary conditions of frame columns suggest a new research roadmap for impact response of structural members. • The study on the effects of ICR indicates higher progressive collapse risk due to downward forces and initial damage. • Recommendations of resisting progressive collapse considering ICR are proposed. [ABSTRACT FROM AUTHOR]

In this paper, a novel equilibrium-based form-finding approach for a mega-latticed structure is presented based on vector-based 3D graphic statics and the Combinatorial Equilibrium Modelling (CEM). This approach can be effectively applied to the conceptual design phase of the structures with various design objectives under conservative loads. It allows us to adjust the design parameters in real time during the design phase and to obtain the resultant forms immediately. Based on a certain selection strategy, the forms have a better state of internal membrane forces compared to the original spherical structure. An ANSYS Parameter Design Language (APDL)-based automatic geometric modelling method for mega-latticed structures with various surface forms is developed. The proposed method solves the problem that the existing modelling methods are only available for spherical structures. It is highly applicable for modelling mega-latticed structures with spherical, cylindrical, and other heterogeneous surfaces. Furthermore, a complete design workflow that combines the proposed form-finding approach (for conceptual design), the automatic geometric modelling method (for transformation), and the finite element method (for deepening design and analysis), is discussed. This paper provides a reference for the design of mega-latticed structures and similar truss-based spatial structures. • A new equilibrium-based form-finding approach for a mega-latticed structure is proposed. • An automatic geometric modelling method for mega-latticed structures is improved. • A design workflow combining the form-finding approach and finite element method is discussed. • A case study is performed to verify the validity of the whole structural design process. [ABSTRACT FROM AUTHOR]

Hybrid reinforced concrete steel (RCS) frames consisting of reinforced concrete (RC) column and steel (S) are used frequently in practice for mid-to-high-rise buildings. RCS frames possess several advantages from structural, economical and construction view points compared to either traditional RC or steel frames. One of the key elements in RCS frames is the beam-to-column joint. This paper suggests a design method to evaluate the mechanical behaviour of a novel type of exterior RCS beam-column connection in which a steel profile totally encased into a RC column is used to connect the beam through the steelwork part of composite section. The proposed design model is developed considering experimental test results and finite element (FE) analyses. In the first part of the paper, an experimental investigation on the static behaviour of the hybrid joint is presented. Four full-scale specimens were tested under monotonic loading. The primary differences between the specimens are the concrete class and the anchorage length of the embedded steel profile in the RC column. The experimental results indicated that the overall behaviour of the specimens was significantly affected by the shear panel deformations of the embedded profile. Next, a finite element model was created. The FE model predictions compared favourably against experimental tests and confirmed the order of yielding/cracking of joint components. Finally a design method based on Eurocodes 2, 3 and 4 is proposed to determine the initial rotational stiffness and the bending resistance of the joint. • Experimental tests on hybrid steel beam to RC column joints with encased steel profile. • Limited impact of long encased steel profile on mechanical characteristics. • Order of yielding/cracking of components evaluated experimentally and by finite elements. • An Eurocode model for the initial rotational stiffness and bending resistance. [ABSTRACT FROM AUTHOR]

The most common and practical connection between CLT walls can be realized with inclined screws. This choice avoids the realization of more elaborated half-lap or spline joints. The failure mechanism of CLT-to-CLT screwed connections is highly ductile. However, the epistemic and aleatoric uncertainties associated with the capacity estimation of the connection might lead to an undesired overstrength, compromising the expected hierarchy between failure mechanisms. This paper presents the results of an extended experimental campaign to estimate the overstrength of CLT-to-CLT screwed connections. However, the overstrength directly obtained from the experimental tests could be underestimated. In the experimental campaign, the same wood and screw stock is used, which might not represent the actual scatter of the material properties and construction uncertainties of the as-built connection (e.g., the screw inclination). Therefore, this paper attempts to provide a model-driven assessment of the overstrength factor, assuming more realistic values for the parameter uncertainties. The authors propose a method for removing the contribution of epistemic uncertainty to the model-driven estimation of the overstrength based on experimental tests with two Montecarlo simulations. Following the proposed method, the paper compares the overstrength estimations from the experimental tests to the predictions of analytical and nonlinear finite element models. This study has proven that an overstrength factor between 1.8 and 2 can represent the actual uncertainties in as-built CLT-to-CLT screwed connections. • Overstrength assessment of CLT-to-CLT screwed connections. • Proposal of a novel formulation for overstrength. • Experimental tests on CLT-to-CLT screw connections. • Epistemic and aleatoric uncertainties in the overstrength estimate. • Uncertainty propagation in analytical and FE models. [ABSTRACT FROM AUTHOR]

This paper is concerned with the behaviour of square concrete-filled dual-stiffened steel tubular (CFDSST) slender columns with a concentrically-placed inner circular steel tube. Previous studies have illustrated that these columns have greater structural performance in terms of load-carrying capacity compared with conventional concrete-filled stiffened steel tubular (CFSST) columns. However, the behaviour of CFDSST slender columns filled with ultra-high strength concrete (UHSC) has not been investigated and current design codes do not include provisions for UHSC, although it is increasingly popular owing to demands for structures to be lighter and more sustainable. Accordingly, the current paper fills that gap in existing knowledge and explores the behaviour of CFDSST slender columns using finite element (FE) analysis. The available test results from previous studies were collated and are employed to validate the numerical model. The validated FE model is then employed to investigate the axial load versus deflection responses for a wide variety of UHS-CFDSST slender columns. The behaviour of both intermediate-length and long columns is assessed through parametric analyses. The results of these studies show that the strength of the concrete sandwiched between the two steel sections, the yield strength of outer steel tube, and the outer tube slenderness ratio have a significant effect on the axial resistance of UHS-CFDSST intermediate-length columns, while the capacity of long columns is most affected by the sandwiched concrete strength. The ultimate resistances are compared with different available design methods, and AISC 360–16 code is recommended for predicting the ultimate resistance of UHS-CFDSST slender columns with modifications proposed to account for the different components forming this innovative cross-section. • New research is presented on the behaviour of square concrete-filled dual-stiffened steel tubular (CFDSST) slender columns. • Ultra high strength concrete is employed for the infill, for the first time. • An advanced finite element model is developed and validated. • The behaviour of intermediate-length and long columns is assessed by parametric analyses and reliable design is proposed. • The results show the potential of these sections to offer innovative structural solution for heavily loaded scenarios. [ABSTRACT FROM AUTHOR]

• 15 tests of bolted joints between Fe-SMA and steel plates are carried out. • The reliability of reinforcing steel structures with bolted Fe-SMA is verified. • The key influencing parameters of the bolted joints are obtained. • Some design suggestions on bolted joints between Fe-SMA and steel plates are proposed. The new intelligent material Iron-based Shape Memory Alloy (Fe-SMA) brings novel solutions for the performance rehabilitation of existing steel structures. To fully utilize the potential of the Fe-SMA active prestressed reinforcement, the systematic study of reliable joint is significant. Therefore, the bolted joints between Fe-SMA and steel plates was experimentally studied in this paper, whose reliability and convenience in metal structures have been generally accepted. Firstly, a series of 15 mechanical performance tests of bolted joints between Fe-SMA and steel plates were carried out. The key influencing parameters of the bolted joints were obtained, and different failure modes were observed, which can provide experimental verification for further finite element modelling and theoretical study. Furthermore, the effects of end distance e , edge distance s , bolt diameter d , thickness of Fe-SMA plate t and bolt layout on the ultimate load-bearing capacity, initial stiffness and failure modes of the bolted joints between Fe-SMA and steel plates were discussed, and some specified design suggestions on bolted joints between Fe-SMA and steel plates were proposed. This paper mainly aims to provide the experimental basis and design recommendations for compilation of the relevant specifications, which is expected to advance the scientific application of Fe-SMA in the performance rehabilitation of steel structures. [ABSTRACT FROM AUTHOR]

Concrete-filled tubular flange (CFTF) girders offer superior torsional stiffness compared to traditional I-shaped plate girders, providing enhanced flexural performance. To accurately assess the flexural capacity of CFTF girders, both flexural tests and theoretical analyses were conducted on specimens with and without concrete decks. The experimental data were meticulously analyzed to understand the flexural mechanism, yielding sequence, interface slip, strain distribution, and confinement effect of CFTF girders. Subsequently, finite element models were then utilized to analyze the influence of cross-section dimensions and material optimization on the flexural behavior of CFTF girders. Comparative analyses with I-shaped girders were also performed to highlight the structural advantages of CFTF girders. The proposed flexural calculation formulas were validated against both experimental and analytical results, demonstrating a fitting accuracy between 95 % and 98 % for the yield moment and between 96 % and 98 % for the ultimate moment. The method proposed in this paper provides a reliable and accurate approach for evaluating the flexural capacity of CFTF girders, significantly contributing to the advancement of design and analysis practices in structural engineering. • The flexural tests and theoretical analyses on concrete-filled tubular flange (CFTF) girders were conducted. • The flexural mechanism, interface slip, strain distribution, and the confinement effect are analyzed. • Finite element models are utilized to analyze the influence of cross-section dimensions and material optimization. • A calculation method for the elastic and plastic flexural behavior of CFTF girders is proposed. [ABSTRACT FROM AUTHOR]

In this paper, scale model test and numerical analysis are conducted to investigate the stress distribution and crack development in the anchorage zone of a cable-stayed bridge with a cross-anchor structure. Initially, scale model test is performed on the tower-crossbeam connection zone to observe the stress distribution at key positions. Then, the anchorage zone is simulated using ABUQUS, considering the material's nonlinearity. The correctness of the finite element model is verified through model test. Finally, we analyze the stress and crack development under 2.7 times the design load. Results show that cracks are prone to occur on the concrete sidewalls. Cracks appear under 1.14 times the design load, and through cracks appear under 1.56 times the design load, initially in the upper-middle part of the anchorage zone. The stress distribution in the stirrups is the most complex among the rebar stresses. After local cracks and through cracks appear in the concrete, the stress in the stirrups increases rapidly. • Scale test of anchorage zone in cable-stayed bridge with cross-anchor structure. • The finite element model of cross-anchor structure verified by static test. • Concrete and rebar stress distribution under design load. • Analysis of concrete stress and cracks development under overload condition. [ABSTRACT FROM AUTHOR]

To address two main challenges (excessive mid-span deflections and numerous cracks in the main girder) in long-span prestressed concrete (PC) box-girder bridges, this paper proposes a long-span simply-supported UHPC box-girder bridge. In comparison to conventional PC box-girder bridges with three-dimensional prestress, the proposed UHPC box-girder consists only one-dimensional (longitudinal) prestress, and the thickness of the bottom/top plate and web of the UHPC box-girder are relatively thin and are strengthened with dense diaphragms and stiffening ribs. The 4th Beijiang River Bridge adopts this type of bridge with a span of 102 m, which is the longest span simply supported prestressed UHPC box-girder highway bridge in the world. Considering the fact that the thickness of the top plate of the UHPC box-girder is relatively thin (only 20 cm) and the transverse prestress is removed from the top plate, thus, under the direct action of wheel loads, the risk of bridge deck cracking may correspondingly increase. To investigate the mechanical behavior of the deck system of UHPC box-girder bridges, a 1:2 scaled experimental specimen associated with the field bridge is tested. The mechanical behavior of the new deck system is investigated and discussed. It is found that because the support strength of the stiffening rib is significantly weaker than that of the web, the UHPC deck slab should still be regarded as a two-way slab rather than a one-way slab in the elastic stage. In addition, although the test load location is unfavorable to the UHPC deck slab and the first crack appears on the UHPC deck slab, this deck system finally suffers from bending failure of the transverse rib. Furthermore, finite element analysis is carried out to study the mechanical behavior of this new deck system. Parametric analysis considers some factors including the reinforcement ratio in the transverse rib, the height of the transverse rib, and the space between transverse ribs. The results provide a good reference for design and optimization in the new deck system of UHPC box-girder bridges. • Proposing a long-span simply-supported prestressed UHPC box-girder bridge. • Stress mode of proposed bridge's deck system is analyzed under line-elastic condition. • The mechanical behavior of the new deck system of UHPC box-girder bridges have been experimentally conducted. • The corresponding structural responses are numerically investigated based on finite element analysis. [ABSTRACT FROM AUTHOR]

Based on the bending-active concept, this paper presents a self-shaping system with bunched carbon fiber-reinforced polymer (CFRP) rods to construct complex curved surfaces, establishing an overall design and construction process. Such component consists of a bunch of slender and easily bendable CFRP rods that are preformed and then bounded by connecting joints. Then, those components form free-form spatial structures. The proposed system offers several advantages: strong designability, low transportation cost, short construction period, polished appearance and low maintenance requirements during service. For component design, to determine the shape of such component, a two-stage mechanical analysis is proposed based on the large deformation theory and finite element analysis (FEA): a form-finding process to determine the deformed component shape through its cross-sections and boundary-load conditions; and a reverse form-finding process to obtain these above-mentioned parameters from a given component shape. The reliability of both methods is verified through in-plane bending tests. A design demonstration of a saddle-shaped curved spatial structure is performed using this method. Overall, the proposed system can guide the actual construction projects of complex curved surfaces with self-shaping bunched CFRP rods. • CFRP lattice components for constructing large-scale curved surface structures. • Large deformation theory & FEA for effective form-finding of elastic components. • Segmented solutions for efficient determination of components' sectional forms. • Bending tests on CFRP components validate effectiveness of form-finding methods. • Design demo of saddle-shaped structure validates design and construction process. [ABSTRACT FROM AUTHOR]

Accurate assessment of the damage to a structure is the key to structural health monitoring. Among them, one effective means to assess the real-time status of the structure is by establishing a finite element model (FEM) of the structure and updating it synchronously. Previous research mainly updates the FEM of the structure with a certain moment in time without considering the continuous changes of structural parameters over a longer time. In this paper, we propose a FEM updating method for steel truss structure based on knowledge-enhanced deep reinforcement learning, which introduces long short-term memory (LSTM) network based on a deep deterministic policy gradient (DDPG) algorithm and constructs a knowledge-enhanced noise function (NF) module based on parametric analysis. The NF-LSTM-DDPG algorithm can fit a continuous variation of structural parameters. The ablation experiments revealed that the LSTM network and the NF module facilitate the exploration and learning ability of the DDPG algorithm. The NF-LSTM-DDPG algorithm is used in an actual steel truss structure case, and the variation rules of the elastic modulus and support deviations obtained from the solution are consistent with the actual situation. The average relative error of the 34 strain measurement points after updating is 14.147 %, and the relative error is higher than 20 % in only 13 days out of 187 days of continuous monitoring. Five days were selected for the comparative study, and the experimental results show that the relative error of the NF-LSTM-DDPG algorithm is 13.206 %, which is higher than that of the particle swarm optimization algorithm and the simulated annealing algorithm. The change of elastic modulus updated based on the NF-LSTM-DDPG algorithm is more reasonable than other algorithms. • Reinforcement learning model can fit the continuous variation of structural parameters in the finite element model. • Improved deep deterministic policy gradient algorithm by introducing long short-term memory and noise function module. • Constructing knowledge-enhanced noise function modules based on parameter correlations. • The NF-LSTM-DDPG algorithm is better than the particle swarm optimization algorithm and simulated annealing algorithm in terms of accuracy and stability. [ABSTRACT FROM AUTHOR]

This paper presents laboratory tests, numerical simulations and web crippling design of high strength steel unlipped channel sections under interior-two-flange loading. An experimental programme comprising 10 test specimens (with six for grade S690 high strength steel and four for grade S960 high strength steel) was firstly implemented, and test results including failure modes, full load-deformation curves and ultimate loads were reported. Subsequently, finite element models were constructed and validated against the obtained test results, and then used to conduct supplementary parametric studies to widen the examined parameter ranges of high strength steel unlipped channel sections. Considering that relevant codified design rules are absent, the applicability of the design rules of EN 1993–1-3, EN 1993–1-5 and AISI S100 for normal strength steel unlipped channel sections to their high strength steel counterparts was evaluated against the obtained test and numerical results. It is shown that the resistance predictions from the codified design provisions were generally inaccurate and scattered. Hence, a modified AISI S100 design method and a slenderness-based design method were proposed and demonstrated to be accurate, consistent and reliable for the web crippling design of high strength steel unlipped channel sections under interior-two-flange loading. • Web crippling of high strength steel unlipped channel sections under ITF loading is studied. • A total of 10 web crippling tests and 150 finite element simulations are carried out. • The codified European and American design methods are found to be inaccurate. • An improved AISI S100 design method and a slenderness-based design method are proposed. [ABSTRACT FROM AUTHOR]

This paper presents experimental and numerical investigations into the global buckling behaviour and resistances of cold-formed austenitic stainless steel flat-oval hollow section beam-columns under combined compression and bending. A testing programme, including initial geometric imperfection measurements and ten beam-column tests about the cross-section major and minor principal axes, was firstly conducted. The key obtained test results, including failure loads, load–deformation histories and failure modes, were reported. Following the testing programme, a numerical modelling programme was performed, with finite element models developed to simulate the beam-column test results and then used to conduct parametric studies for generating additional numerical data. Then, the applicability of relevant codified design interaction curves to cold-formed austenitic stainless steel flat-oval hollow section beam-columns was evaluated based on the test and numerical data. The evaluation results revealed that the design interaction curve of the American specification resulted in an overall good level of design accuracy and consistency, while the design interaction curve of the European code led to slightly conservative resistance predictions, mainly due to the conservative bending end point. To address this shortcoming, a revised Eurocode design interaction curve with an improved bending end point was proposed and shown to provide more accurate resistance predictions for cold-formed austenitic stainless steel flat-oval hollow section beam-columns than the original Eurocode design interaction curve. • Ten beam-column tests on cold-formed austenitic stainless steel flat-oval hollow sections were performed. • The global buckling behaviour about the cross-section major and minor principal axes was investigated. • FE models were developed and validated against the test results and then used to conduct parametric studies. • The relevant codified design interaction curves were assessed. • A revised Eurocode design interaction curve was developed. [ABSTRACT FROM AUTHOR]

This paper presents experimental and numerical investigations into the post-fire local buckling behavior and residual resistances of S890 ultra-high strength steel (UHSS) circular hollow section (CHS) under combined compression and bending. The physical testing was firstly conducted and encompassed heating, soaking and cooling of specimens, as well as post-fire tensile coupon tests, measurements of initial local geometric imperfections and eccentrically loaded stub column tests. Then, finite element models were developed and validated with reference to the experimental observations and then adopted for parametric analyses to derive additional numerical data, considering various cross-section dimensions and loading combinations. As a result of the lack of design provisions for ultra-high strength steel structures after exposure to elevated temperatures, the applicability of the relevant ambient temperature design interactive curves given in the current European, American and Australian standards to post-fire S890 UHSS CHS under combined compression and bending was assessed, with post-fire material properties used. The assessment results showed that all design standards exhibited conservative and scattered predictions of residual resistances for S890 UHSS CHS under combined compression and bending at ambient temperature and after exposure to elevated temperatures. The American specification provided more precise predictions of residual failure loads for non-compact and slender (Class 3 and 4) sections than the Eurocode and Australian standard, due to the accurate compression and bending endpoints. In comparison to the American and Australian specifications, the Eurocode resulted in more precise results in predicting residual failure loads of compact (Class 1 and 2) sections, owing to the accurate compression and bending endpoints as well as the nonlinear design interaction curve. • Post-fire behavior of S890 UHSS CHS under combined compression and bending was investigated. • Eighteen post-fire eccentric compression tests were conducted. • FE models were developed and validated against test results and then used to perform parametric studies. • Design rules were assessed for their applicability to S890 UHSS CHS under combined compression and bending. [ABSTRACT FROM AUTHOR]

Laminated insulating glass units (IGUs), commonly used in modern buildings, are prone to shattering from explosive loads, causing significant damage and loss. Existing research on IGUs is constrained by a lack of experimental validation and comprehensive numerical analyses, as large-scale explosion tests are rarely reported due to safety and cost concerns. Furthermore, previous modeling efforts often oversimplify critical factors such as the supporting structure, component interactions, strain rate effects, hourglass energy, and failure criteria, leading to an inadequate representation of glass behavior under explosive loads. This paper addresses these gaps by conducting large-scale explosive test on glass system and utilizing sophisticated nonlinear dynamic analysis with LS-DYNA for simulation. The research considers the influence of the support system and incorporates detailed considerations of component interactions, constitutive relationships, and strain rate effects in the numerical simulations. The results confirm that the proposed model successfully replicates the crack patterns and damage observed in experimental test. Also, it accurately predicts the trajectory, quantity, and size distribution of glass fragments. The proposed modeling approach offers a more informed assessment of damage and improves the evaluation of glass safety in practical applications. • A full-scale explosive testing of laminated insulated glass units (IGUs) provides valuable data for simulation model development. • An advanced finite element model is provided for accurate assessments of glass blast resistance. • The Johnson-Holmquist 2 material model is validated for accurately simulating glass behavior under high-speed impacts. • Explosion-proof performance levels of insulating laminated glass are quantified under large explosion conditions as per related standards. [ABSTRACT FROM AUTHOR]

A new fire design method by Geometrically and Materially Nonlinear Analysis with Imperfections (GMNIA) and using strain limits is proposed for stainless steel columns in this paper. In the proposed design method, owing to their computational efficiency, beam finite elements are employed to carry out the GMNIA of stainless steel columns in fire whereby the material strength and stiffness deterioration at elevated temperatures, the spread of plasticity, global instability effects, indirect fire actions and thermal expansion are directly taken into account. Due to the inability of beam finite elements to consider local buckling effects, the use of strain limits determined based on a modified continuous strength method (CSM) is proposed to capture the deleterious influence of the local instability effects on the structural resistances of stainless steel columns in fire. The ultimate capacity of a stainless steel column in fire is determined by (i) the temperature level at which the CSM strain limit is attained or (ii) the critical temperature at which the column is no longer able to carry the applied initial room temperature loading, whichever occurs first. In this study, stainless steel square hollow section (SHS) and rectangular hollow section (RHS) columns with and without axial and/or rotational end-restraints are taken into consideration. The capacity predictions obtained using the proposed design method are extensively verified against the benchmark results from shell finite element modelling and also compared against the predictions from the European structural steel fire design standard EN 1993–1-2. • A new advanced fire design method for stainless steel SHS and RHS columns based on GMNIA with strain limits is proposed. • Extensive numerical parametric studies are carried out, considering 2268 stainless steel SHS and RHS columns in fire. • Accuracy, safety and reliability of the proposed fire design method for stainless steel SHS and RHS columns are verified. • The proposed fire design method leads to more accurate and reliable ultimate resistance predictions relative to EN 1993-1-2 provisions. • The proposed method leads to an advanced and streamlined fire design, directly providing the failure temperatures and failure modes. [ABSTRACT FROM AUTHOR]

To break through the three major technical bottlenecks of traditional long-span arch bridges, which are excessive self-weight, high cost and difficult construction, a new steel-ultra high performance concrete (UHPC) composite truss arch bridge scheme and a matching cyclic construction method were proposed. The main arch can be divided into several times for closure from the inside out. Special transverse connection devices need to be installed between the arch ribs constructed with successive closures by step. The devices can not only ensure the stability of the arch ribs constructed subsequently, but also do not cause serious stress superposition on the already closed arch ribs. Therefore, sliding connectors for the cyclic construction of new arch bridges and the corresponding simplified modeling method were proposed in this paper. Subsequently, the working mechanism was analyzed, and the design method was proposed. Finally, the feasibility of sliding connectors and the correctness of the corresponding design method were verified by the experiment. The results indicate that it is necessary to install a transverse sleeve structure in the sliding connector, which plays a key role in transverse adjustment. The design of key dimensions in sliding connectors is controlled by the maximum vertical and longitudinal displacements of the inner arch. The outer arch could slide freely under the premise of ensuring stability, and the mechanical superposition response of the inner arch was relatively small. For the inner arch, the vertical displacement at the crown only increased by 10.94 %, and the maximum compressive stress in the UHPC arch ribs only increased by 16.3 %. The sliding connector also has the potential for further optimization to achieve smaller stress superposition. • Sliding connectors for the cyclic construction of steel-UHPC composite truss arch bridges and the corresponding simplified modeling method were proposed. • For the sliding connector, the working mechanism was analyzed, and the design method was proposed. • The feasibility of sliding connectors and the correctness of the corresponding design method were verified by the experiment. • For the inner arch, the crown deflection only increased by 10.94 %, and the maximum compressive stress in the UHPC arch ribs only increased by 16.3 %. [ABSTRACT FROM AUTHOR]

Masonry building aggregates constitute a significant portion of Italian and Mediterranean countries built heritage. These structures originate from the progressive transformation and interconnection of originally isolated structural units over time. Masonry aggregate seismic performance is affected by significant uncertainty arising from the lack of knowledge of their complex structural arrangement, which is also reflected in the reliability of modeling assumption adopted for the analysis and the descending outcomes. This paper presents a numerical study investigating the seismic behavior of an elementary building aggregate made of three almost identical structural units. Different boundary conditions are explored in the analysis, extracting and comparing the responses of the individual structural units modeled both in aggregate and isolated and with rigid or flexible floors. Homogenized masonry approach is implemented for the building aggregate models with 2D layered inelastic shell elements. The structural models are realized with the STKO software platform for OpenSees, enabling parallel computing to analyze large scale models. Results will highlight the extent of the so-called "aggregate effect" for the elementary aggregate building and its potential benefits to the structural units, showing also that the behavior of structural units in aggregate strongly depends on their position and the polarity of the seismic forces. • The overall seismic response of masonry building aggregates is investigated by a refined finite element nonlinear model. • Homogenized modelling approach with 2D shell-layered finite elements is adopted for the masonry. • A three-story masonry building aggregate made of three elementary structural units is used as a case-study. • Structural units are analyzed as fully connected or isolated with rigid or flexible floors. • The extent of the so-called "aggregate effect" and its potential benefits to seismic safety are commented, [ABSTRACT FROM AUTHOR]

This paper presents experimental numerical investigations on the structural behaviour of cold-formed high strength steel irregular octagonal hollow section (OctHS) columns with both non-slender and slender cross-sections. An experimental programme, including material tests, measurements of initial global geometric imperfection, and pin-ended column tests, was first conducted. The key findings from the experimental programme are presented and discussed. Following the validation against the experimental results, the proposed finite element modelling methodology was established to replicate the test observations, and then was adopted to generate a boarder range of numerical results through parametric studies. The collected experimental and numerical data were used to evaluate the applicability of current structural steel design methods on the column buckling strength for irregular OctHS columns. Assessment results demonstrate that the design method adopted in Chinese code can provide accurate prediction, whilst modified design method adopted in Eurocode 3, considering the effect of steel grade on the column strength, has been proposed and shown to greatly enhance the prediction accuracy with improved consistency. The corresponding assessments on the design approaches adopted in American and Australian codes were also discussed. • Cold-formed steel irregular octagonal hollow section columns were fabricated through press-braking and subsequent welding. • Variations of material properties within the cross-section and initial global imperfection were measured and presented. • A total of 12 irregular octagonal hollow section long columns were tested. • FEM for irregular octagonal hollow section columns was developed and a total of 539 numerical models were generated. • The applicability of current design methods was assessed and modified against the experimental and numerical results. [ABSTRACT FROM AUTHOR]

The dynamic characteristics, particularly damping, play crucial roles in the design, monitoring, and vibration control of stay cables. The free vibration test, commonly used for damping identification of stay cables, demonstrates notable technical advantages in specific mode excitation and improving the signal-to-noise ratio. Nevertheless, challenges arise from uncertainties associated with ineluctable ambient vibration influences and noise contamination in measured responses. In recent years, there has been a growing interest in Bayesian modal identification methods due to their remarkable ability to quantify uncertainties. However, further advancements are needed in the time domain, particularly when addressing the relatively short duration of free vibration response data. This is essential to minimize the impact of background ambient vibration and enhance the accuracy of modal identification. This paper proposes a novel Bayesian modal identification approach specifically crafted to address free vibration data affected by ambient vibrations, aiming to achieve high-precision modal identification and effective uncertainty quantification from free vibration response of stay cables. Additionally, a speedup algorithm is used for determining the most probable values (MPVs) to enhance computational efficiency. The efficacy of the proposed approach is validated through simulated scenarios, encompassing both a single-degree-of-freedom structure and a finite element model of a stay cable. Furthermore, the effectiveness of the proposed method is validated through its application in a laboratory test involving a scale model of the stay cable, as well as in a field test of actual stay cables of Sutong Bridge. The results demonstrate that the proposed method achieves high accuracy in identifying modal damping ratios, and effectively quantifies uncertainties in the identification results. • A novel Bayesian approach for modal identification using free vibration data. • Addressing uncertainties linked to ambient vibrations and noise in responses. • High-precision modal identification and effective uncertainty quantification. • A fast computational algorithm determining the most probable values. • Successful validation using diverse simulated, experimental and field datasets. [ABSTRACT FROM AUTHOR]

This paper introduces novel analysis procedures for the structural assessment of masonry earth retaining structures subjected to traffic loading. Given their substantial presence, particularly in transportation networks of historical cities, and the challenges posed by ageing, deterioration, and exposure to loads beyond their original design considerations, this research highlights the necessity of accounting for potential load redistribution mechanisms during their assessment. This can prevent overly conservative interventions that may not be necessary and also contravene sustainability and heritage preservation principles. Four distinct analysis procedures – 2D monotonic, 3D monotonic, 3D static moving load and 3D dynamic moving load – are developed, each progressively more refined than its predecessor in capturing potential load redistribution mechanisms in masonry earth retaining structures. These mechanisms may develop due to the dynamic loading conditions of the vehicular passage, the 3D structural configuration of retaining structures, and non-linear material behaviour. By comparing the structural capacity evaluated using the four procedures, contributions from different sources of load redistribution can be separately quantified, aiding in the reduction of conservatism inherent in less refined assessment procedures. The application of the developed procedures and consequent quantification of load redistribution is demonstrated through a case study of an existing masonry retaining structure in Amsterdam, the Netherlands. • Analysis procedures for masonry earth retaining structures under traffic loading. • 2D monotonic, 3D monotonic, 3D static and 3D dynamic moving load procedures. • Load redistribution is due to dynamic loading and 3D structural configuration. • Demonstrated application to a case study in Amsterdam, the Netherlands. [ABSTRACT FROM AUTHOR]

Steel-concrete composite beams with shear studs providing composite action between the concrete slabs and steel beams are widely used in modern steel-framed building construction. Three-dimensional finite element modelling has been a viable option for investigating the fire behaviour of composite beams. Although many finite element models are available in the open literature, most of them are simplified models verified by limited test data. Meanwhile, early test data often did not have all the required information for finite element simulation, and some assumptions need to be made. But more detailed test data are now available in the open literature for steel-concrete composite beams, which can be used to develop a generalised finite element model. In addition, National Institute of Standards and Technology has proposed new stress-strain models for steels at elevated temperatures, which can be compared with the more widely adopted Eurocode 4 steel material models in simulating composite beams. Accordingly, this paper selected 22 specimens, including two reinforced concrete slabs, 12 composite beams with reinforced concrete slabs, two composite slabs with profiled steel sheeting, two steel-concrete composite push test specimens with profiled steel sheeting, and four composite beams with profiled steel sheeting, from nine references to verify the developed finite element model. The proposed finite element model can capture different failure modes of composite beams, such as steel yielding/local buckling, concrete cracking/crushing, debonding of profiled steel sheeting, and stud fracture, which is crucial to comprehend the composite beam behaviour at elevated temperatures. • A detailed FE model was developed for composite beams exposed to fire. • The constitutive models of steel and concrete materials at elevated temperature were considered. • Different types of failure modes of composite beams exposed to fire can be well predicted by the FE model. [ABSTRACT FROM AUTHOR]

The triangular strand wire rope exhibits superior performance and holds substantial potential over its round strand counterpart, which is brought by its unique and excellent structural design. However, the investigation of specialized strand components with such distinctive shapes remains limited, and the predominant challenge resides in modeling. This paper introduces a precise vector expression for the spatial trajectory of distinct steel wire types within the triangular strand wire rope structure. Moreover, a comprehensive suite of parametric modeling methodologies tailored for finite element analysis have been established, based on ABAQUS/CAE. The finite element model has been validated by experiments. Furthermore, a series of examples with various boundary conditions and parameters are intended to evaluate the factors affecting the accuracy of the FE model. Employing the established parametric modeling method, triangular strand wire ropes with a range of lay length were established, the differences in their mechanical properties under tensile load were compared, yielding insights that form the basis for proposed design considerations regarding lay length ratios. This model is apt for investigating the macroscopic mechanical response and local force characteristics of triangular strand wire ropes during typical service processes. Moreover, its versatility extends to the realm of other complex rope structures, promising to address the behavioral analysis of intricate strands and rope configurations. [Display omitted] • A new spatial structure expression for triangular strand wire rope was developed. • The mechanical characteristics of triangular strand wire rope were obtained. • The influence of lay length on the performance of the wire ropes was compared. • Optimum structural parameters for various wire rope can be designed by the FE model. [ABSTRACT FROM AUTHOR]

The connection system controls the behavior of the Cross-laminated timber (CLT) structures under horizontal loads. This paper introduced an innovative energy-dissipation angle bracket for CLT structures, which takes advantage of the soft-steel bracket and high-damping rubber to provide superior ductility and energy-dissipating capacity. Experimental tests under monotonic and reversed cyclic loading were performed to investigate the failure mechanism and mechanical properties of this energy-dissipation connector. After validating the detailed finite element models based on the test results, numerical parametric analysis was conducted to evaluate the influence of several parameters. The results show that the energy-dissipation angle bracket connector mainly exhibits three failure modes, including the rupture of dissipative ribs, local bearing failure of the base, and the debonding of the internal rubber. The ribs' rupture is the dominant failure mode, especially under cyclic loading, after which the connector can still work integrally because of the rubber that is tightly bonded to the steel skeleton. All the tested connectors show high ductility and great energy-dissipating capacity, as indicated by the ductility larger than 9.5 and the equivalent viscous damping ratio within 9 %− 26 %. According to the numerical parametric analysis, the load-carrying capacity of the energy-dissipation angle bracket is positively correlated with the steel skeleton's thickness and ultimate strength, and the adoption of the washer, while the rubber's height has little impact on the load-carrying capacity. The outcomes of this study provide valuable references for subsequent improvement and potential applications of the innovative angle bracket for CLT structures. • An innovative energy-dissipation angle bracket for CLT structures was proposed. • Failure mechanisms and mechanical properties were investigated by experimental tests. • 3D detailed finite element models were developed with validation of test results. • The influence of several parameters was evaluated by numerical parametric study. [ABSTRACT FROM AUTHOR]

The application of machine learning techniques based on Lamb waves for structural health monitoring of composite material damage has been widely adopted. However, this method often struggles to acquire sufficient labeled historical Lamb wave signals for training machine learning models. This issue can be addressed through the implementation of transfer learning. This paper proposes a data-driven transfer learning model for locating coordinates of damage areas in plate-like structures with complex geometric features such as rivets and grooves. Based on the differences in conditional distributions in various structural health monitoring scenarios, a Cross-Component Regression for Damage Localization Model (CRDM) is introduced for damage localization across components. Due to the limited availability of labeled target data, CRDM aims to preserve global properties of the target data-dominated conditional distribution, besides considering the predictive accuracy of individual samples. Therefore, a hybrid loss function is constructed by combining Mean Squared Error (MSE) and Conditional Embedding Operator Difference (CEOD). Subsequently, the target model is fine-tuned based on this loss function. Experimental validations are conducted on finite element models and real datasets, confirming the effectiveness of the CRDM model in damage localization for plate-like structures. • Lamb waves are employed to assess the damage in CFRP composite material plate structures. • The influence of external conditions on Lamb waves is taken into consideration. • Transfer learning based on regression problems is utilized to predict the damage location. • The model is fine-tuned from a mapping-based perspective. [ABSTRACT FROM AUTHOR]

After millions of years of natural evolution, bamboo stems have formed exquisite variable cross-section hollow multi-node structures that are lightweight, tough, and stable. Bamboo is difficult to break and damage from the roots under dynamic loads, providing an important reference for te biomimetic design of lightweight components. This paper investigates the structural characteristics and variation patterns of bamboo stems and subsequently proposes an imitation bamboo stem structure design strategy for engineering structural members, namely, imitation bamboo double-jointed columns (IDJC). We establish a macro scale finite element model to predict the mechanical properties and failure modes of the IDJC under cyclic bending loads, and validate the model using experimental and analytical methods. The simulation and experimental results show that compared with traditional double-jointed columns (DJC), the weight of the IDJC is reduced by 41.7 %. Under bending load, the compressive stress of each section is approximately equal, reducing stress concentration, and increasing bending resistance. The strength to weight ratio of IDJC is 1.96 times that of DJC, indicating lightweight and high-strength characteristics. The stiffness degradation, energy dissipation, and damping and vibration reduction performance of the IDJC were also evaluated. The results showed that compared with the DJC, the stiffness degradation rate of the IDJC decreased by 6.87 times, the energy dissipation rate increased by 1.07 times, and the damping and vibration reduction performance improved by 48.40 %, reflecting a high stability and robust vibration reduction performance. The results demonstrate the potential application of biomimetic structures for the development and design of resource-rich, low-carbon, and sustainable bamboo for bamboo engineering members with excellent performance and functionality. Biomimetic structures have great potential in replacing nonrenewable structural materials in the fields of civil engineering and transportation. ● Quantitative study on the characteristics and patterns of bamboo stem structure. ● A bamboo like structural component was prepared using the concept of biomimetics. ● The prepared structural components have excellent stability and damping performance [ABSTRACT FROM AUTHOR]

Achieving full integration of inspection and monitoring data with finite element models for structural condition assessment remains a persistent challenge in engineering. This paper introduces a novel approach aimed at enhancing structural analysis by amalgamating inspection and monitoring data with finite element models. On one hand, a hybrid substructure method was proposed. Initially, mathematical equations linking monitoring data with finite element mechanical information are established. Subsequently, a self-adaptive sparsity matching tracking algorithm is employed to attain highly accurate interface constraints for critical regions. Consequently, Finite element model updating was carried out in key areas based on monitoring data. On the other hand, an interacting analysis theory between substructures and the main structure is developed. This enables nonlinear analysis of substructures and equivalent linear elastic analysis of the main structure, ultimately achieving refined structural assessment. The feasibility of this analysis method is confirmed through experiments of concrete beam and steel arch bridge models. This approach enables a comprehensive integration of monitoring data with finite element models, facilitating detailed substructure analysis and refined overall structural assessment. • A new framework is proposed that combines targeted sensing data with finite element models. • Hybrid substructure modeling method integrating inspection and monitoring data. • An interacting analysis theory between substructures and the main structure is developed. • An adaptive sparsity matching tracking algorithm is proposed to get the high-precision key area interface constraint for substructures. [ABSTRACT FROM AUTHOR]

In order to promote the use of new sustainable steel fibers (SF) reinforced coal gangue aggregates (CGA) concrete, impact tests were performed in this paper. The impact resistance of steel fiber-reinforced coal gangue concrete was investigated using a self-developed drop-weight facility. The test variables were the CGA replacement rate (0 %, 50 %, and 100 %), the SF volume content (0 %, 0.75 %, and 1.5 %), and the drop height of the drop-weight (0.5 m and 1.0 m). Using 15 kg of hard steel as a drop-weight, the drop-weight impact test was performed on steel fiber-reinforced coal gangue concrete beams with a span of 300 mm; the damage pattern, impact reaction force-time, displacement-time relationships, and energy absorbed by steel fiber-reinforced coal gangue concrete beams were studied. The test shows that, compared with natural aggregate, CGA reduces concrete's static mechanical properties and impact resistance, and adding SF improves the static mechanical properties and impact resistance of coal gangue concrete. As the CGA replacement rate increased from 0 % to 50 % and 100 %, the reaction force of impact of the specimens decreased by 2.54 %− 6.06 % and 3.69 %− 12.33 %. The SF volume content was increased from 0 % to 0.75 % and 1.5 %, and the reaction force of impact of the specimens was increased by 23.05 %− 32.34 % and 72.27 %− 81.84 %, respectively. The impact resistance of steel fiber-reinforced concrete beams under impact loading was investigated numerically using a nonlinear explicit finite element model in LS-DYNA. The Finite Element results were validated with experimental results. Based on the validated finite element model, a parametric study was carried out to investigate the effects of coal gangue replacement rate, steel fiber volume content, and drop height of the drop weight on the behavior of the beams. This study might provide a basis for the future engineering project applications of steel fiber-reinforced coal gangue concrete under impact conditions. • New sustainable coal steel fibers reinforced gangue aggregates (CGA) concrete was investigated. • Impact resistance of this new type of concrete was studied. • Numerical modelling was made to this new type of structure. • Parametric analysis of SFCGC beams was carried out [ABSTRACT FROM AUTHOR]

This paper presents the results from two full-scale transversally stiffened plate girder's load tests in shear and bending. The plate girder's internal stiffener forces and shear buckling resistance are estimated using the web and stiffener measured strains. These results show that the reported axial compression and bending moment of the intermediate transverse stiffeners for the tested plate girder are 70% of the FprEN 1993–1-5: 2022 [1] design force. The two full-scale plate girders fail due to buckling shear. Nonlinear FEM analyses based on the test girder geometry, measured initial geometric imperfections, and the material properties from the tensile tests, show excellent agreement with the test results, with less than 5% on the maximum applied forces and related displacements. The principal membrane stresses path that triggers the failure of the web plate are investigated based on numerical results and compared with the test measurements. Contrary to the assumption of a rotated stress field model, the principal compression stress obtained in the experimental test was higher than shear buckling stress in the vicinity of the intermediate transverse stiffener. • Experimental shear behaviour of full-scale thin-walled plate girders in what concerns shear loading past ultimate loading. • Focus on intermediate transverse stiffener behaviour and shear load path. • Data acquisition techniques are resumed regarding measurements using optical extensometer and laser scanning. • Finite Element Model and Analysis were performed for the simulation of the experimental tests reported. • Obtained experimental and numerical outcomes are compared to current recommendations provided by EN1993-1-5. [ABSTRACT FROM AUTHOR]

Prefabrication assembly technology has been widely recognized due to its rapid construction, minimal environmental impact, and superior quality of precast components. The reliability and construction convenience of the connection joints of precast components are particularly important. In this paper, a novel Ultra High-Performance Concrete (UHPC)-filled concrete-filled steel tube (CFST) socket connection (UCSC) was proposed for the column-beam connection. To explore the shear behavior and shear load transfer mechanism of UCSC joints, four direct shear experiments were conducted in terms of different parameters (socket depth, presence of studs). Meanwhile, ABAQUS was used to perform a systematic parametric analysis (socket length, embedded length, outer diameter of CFST, thickness of steel tube). The results indicated that the shear performance of UCSC joints was significantly influenced by both the socket depth and the outer diameter of CFST. The proposed finite element model (FEM) can predict the load-displacement relationships of UCSC joints with a maximum peak load error of 2.3 %. Combining the experimental results and numerical results, a simplified calculation model was formulated to accurately estimate the shear bearing capacity of UCSC joints, and was verified by numerical and experimental results with a maximum error of 8.6 %. The research results have practical implications for the preliminary design of UCSC joints to avoid non-ideal failure mode. • Experimental studies were conducted to evaluate the shear performance of UCSC. • A FEM was established to predict the force-displacement curve and shear failure mode of UCSC. • A simplified calculation model was developed to predict the ultimate shear bear capacity of UCSC. [ABSTRACT FROM AUTHOR]

Concrete-filled corrugated steel tubular (CFCST) column is a novel type of steel-concrete composite column, comprising four corrugated steel plates, four square-section steel bars at the corners, and infilled concrete. The transversely placed corrugated steel plates can effectively prevent their premature local buckling, release the axial load, and provide lateral confinement effects on the infilled concrete. This paper investigated the axial compressive behavior of CFCST columns through experimental, numerical, and theoretical approaches. Experiments were conducted on 20 specimens, focusing on their axial load-resistant behavior. The specimens demonstrated excellent axial bearing capacity, ductility, and residual bearing capacity. Besides, the mechanical behavior of corrugated steel plates throughout the loading process was analyzed through the development of the horizontal and vertical strains. Furthermore, a finite element (FE) model was developed to simulate the axial compressive behavior of CFCST columns, which was validated against the experimental data. The FE model was used to analyze the compressive behavior of each part in CFCST columns, revealing that the infilled concrete and steel bars primarily bear the axial load, while the corrugated steel plates mainly provide lateral supports to the infilled concrete. Finally, a simplified method for calculating the critical width of corrugated steel plates and a formula for the axial bearing capacity of CFCST columns were proposed. It was indicated that the limiting width-to-thickness ratio of the corrugated steel plates was larger than that of the steel elements in conventional CFST columns. These formulas were demonstrated to be accurate enough and suitable for the engineering designs. • Axial compression tests involving 20 CFCST columns were performed. • Finite element models were developed and validated against test results. • The mechanical behavior of each part of the CFCST column was analyzed in detail. • A theoretical analysis was conducted to determine the critical width of the corrugated steel plate. • Theoretical formula of the axial bearing capacity of the CFCST columns was proposed. [ABSTRACT FROM AUTHOR]

This paper discussed the torsional performance of special-shaped concrete-filled steel tubes (SCFST) columns. A pseudo-static test research of nine specimens was carried out under pure torsion. The investigated factors include section shape, stiffening form, width-to-thickness ratio of column limbs and steel tube thickness. The failure modes, hysteresis curves, skeleton curves, energy dissipation capacity, and stress distribution were analyzed to investigate the torsional performance of specimens. The overall failure modes of different section forms are ductile damage. There are a number of 45°oblique buckling in the steel tube, and the steel plates at the top and bottom of the column are transversely torn. At the concave corner, the weld of multi-cell and the welded point of the tensile steel bar were cracked from the top to bottom. Besides, the concrete is mainly crossed by torsional oblique cracks. The hysteresis curves of the SCFST columns are plump shape without pinching phenomenon, representing good energy dissipation capacity. The effect of stiffened methods is the most significant for the torsional performance. The ductility and bearing capacity of multi-cell specimens are better than those of tensile-bar stiffened specimens. Based on the same torsion ratio of concrete and steel tube and ignoring the effect on the tensile bars, calculation methods for initial torsional stiffness and torsional bearing capacity were proposed. Comparison results show that the calculation method has good performance in terms of the accuracy and efficiency. • A pseudo-static test research of special-shaped concrete-filled steel tube specimens was carried out under pure torsion. • The finite element model for SCFSTs was developed and parametric analysis was conducted. • Calculation methods for initial torsional stiffness and torsional bearing capacity were proposed. [ABSTRACT FROM AUTHOR]

Being critical components in composite structures, the short-term structural behaviour of stud shear connectors has been extensively investigated. Despite this, there has been somewhat limited attention devoted to their time-dependent behaviour. In this paper, the results of four long-term push-out tests are reported: the test parameters including the loading age and stud diameter. The test results are shown to be simulated accurately by a finite element model established using ABAQUS, in which the long-term behaviour of the concrete is considered by implementing a stepwise approach. The numerical procedure is applied to conduct a parametric analysis, with the effects of different parameters, viz., the loading age, concrete material, external environment, stud size and reinforcement ratio being considered. Based on the numerical results, an analytical formulation is derived for the creep coefficients of composite members with different loading ages. Comparisons with FE model data shows that the derived equation has sufficient accuracy and can be applied for designing composite structures considering their long-term response. • Tests of stud connections under sustained loading; • Significant creep slip of the connection found during the tests; • Creep model of stud connection proposed for analysis of composite structures. [ABSTRACT FROM AUTHOR]

Although extensive experimental and numerical studies have been conducted on the axial performance of steel tube and sandwiched concrete jacketed CFST columns, contableurations with outer square tubes and inner circular CFST components are rarely found. This paper investigates the axial performance of square steel tube and sandwiched concrete jacketed circular CFST columns, examining the effects of outer steel ratio and sandwiched concrete strength on failure patterns, relative load-strain curves, and load-bearing capacity. The analysis of ultimate compressive capacity confirmed the effective confinement provided by the outer square steel tube. Based on the experimental results, a finite element model was established to further study the working mechanism of retrofitted columns. The load on components, distribution of longitudinal stress and transverse constraint stress on concrete revealed that the inner concrete experiences dual confinement effects from both inner and outer steel tubes, with the constraint of the outer square steel tube becoming significant only during the load dropping phase. Furthermore, a simple equation was proposed for predicting the axial compressive load-bearing capacity of retrofitted columns using superposition methods and design codes. Comparison results demonstrated good agreement between experimental and calculated values. • The axial performance of circular CFST columns strengthened with square steel tube and sandwiched concrete jackets was investigated. • The outer tube thickness had a greater impact on the compressive strength of retrofitted columns compared to the sandwiched concrete strength. • A finite element model was established to study the force mechanism of axially-loaded circular CFST columns strengthened with square STSCJ. • An equation was proposed to calculate the axial compressive capacity of retrofitted columns based on the superposition methods and design codes. [ABSTRACT FROM AUTHOR]

This paper studied the seismic behavior of a novel self-centering concrete-filled steel tubular column-steel beam (SCSTCSB) joint. The restoring force was provided by the post-tensioned tendons arranged in the CFST columns. Cyclic loading tests were performed on five 1/3 scaled specimens by varying the parameters of steel tendon type, concrete strength (f c), and axial compression ratio (n). The failure modes, hysteresis behavior, stiffness and strength degradation, energy dissipation, post-tensioned tendons response, residual deformation, and strain distribution were studied in detail. The finite element models were established to capture the stress distribution of the joints. In addition, parameter analysis was performed by expanding 17 finite element models. The results show that the ratio of residual deformation to beam rotation angle of the specimens ranged from 0.068 to 0.172. And the proposed joints demonstrated excellent self-centering ability. The self-centering (SC) performance of joints with ordinary steel tendons was better than that of joints with high-strength steel tendons. With the increase of n , the SC performance of the joints intensified at the lower ratio (n from 0.1 to 0.3) and weakened after n = 0.3. The flexural capacity of the joints improved with the increase of axial compression ratio (n), width-thickness ratio (D / t), diameter of steel tendons (d), and assembly part strength (f y,a). • The seismic behavior of self-centering CFST column-beam joints with PT tendons arranged in column was investigated under cyclic loading. • Ordinary steel tendons exhibited better results than high-strength steel tendons in self-centering (SC) performance. • With increase of axial compression ratio, the SC performance of joints intensified at the lower ratio (0.1-0.3) and weakened after n = 0.3. • The flexural capacity of the joints increased with increasing axial compression ratio, concrete strength, diameter of steel tendons and assembly part strength. [ABSTRACT FROM AUTHOR]

In this paper, experiments were carried out to analyze the behavior of the square columns reinforced longitudinally by GFRP bars along with different ratios of hooked end fibers under eccentric compressive loading. Eight short square columns with a cross-section dimension of 150x150mm and a height of 1200 mm, were fabricated to conduct the experimental program. A 150 mm enlargement in column-cross at both ends was considered to develop an eccentric axial load. The columns were tested under different load eccentricity ratios (0.26, 0.5, 1). Different tie spacings (50, 100, 120) mm. Different ratios of steel fibers 0 %, 0.5 %, and 1 % were incorporated into the concrete mix. It was observed that columns with steel fibers demonstrated good characteristics, including higher ultimate load, increased ultimate deflection, and enhanced ductility and toughness compared to the columns without steel fibers due to multiple cracking behaviors. The ductility of the columns reinforced with GFRP bars was enhanced by 46.8 %, and 68 % for steel fiber volume ratios of 0.5 % and 1 %, respectively. The energy absorption was increased by 42 % and 77 % for steel fibers ratios of 0.5 % and 1 %, respectively. When GFRP bars were used as longitudinal reinforcement, there was an improvement in the bond behavior between the concrete and the GFRP bars. All concrete columns reinforced by GFRP bars failed due to flexure-compression failure. There was no observed rupture of GFRP bars during the experimental test and the maximum strain did not reach 40 % of their ultimate strain capacity. Nonlinear Finite Element analysis was conducted to simulate the behavior of tested columns. The equations from previous studies and the codes were established to predict the nominal peak capacity of columns considering all parameters. In general, there was a reasonable level of agreement observed between the experimental data and the theoretical results determined for seventy-column specimens in the current study and from previous studies in the literature. • Performance of concrete columns reinforced with GFRP bars under an eccentric compressive loading. • Variable ratio of End – Hooked steel fibers were used. • Behavior was examined in experimental and analytical manners. • 4-Non-linear finite element analyses were achieved and compared with experimental results. • The nominal capacity of the columns was predicted. [ABSTRACT FROM AUTHOR]

Equipping cross-ties on the cables of cable-stayed bridges to form a cable network is regarded as an effective measure to suppress large cable vibrations and has been realized in practical engineering. However, most of the existing studies on the suspended cable (small sag) network have ignored the contributions of dynamic axial forces to transverse forces of the cables. More importantly, the dimension of the characteristic matrix is relatively large. Therefore, the current study introduces the transfer matrix method (TMM) to solve the in-plane free vibration problem of a two-cable network with dynamic axial forces of the cables considered simultaneously. Compared with the methodology utilized by the previous studies, the dimension of the resulting characteristic matrix is smaller and is independent of the number of cross-ties. Three cases, i.e., a two-cable network with two cross-ties, with three cross-ties and with four cross-ties, are explored in detail. Their frequencies and mode shapes are compared with those obtained by finite element model (FEM) to demonstrate the validity of the results in this paper. Meanwhile, the effects of dynamic axial forces on the first two frequencies and mode shapes are analyzed. The results show that the contributions of dynamic axial forces should be taken into account in transverse forces when calculating the first two frequencies of the cable network with flexible cross-ties. • A novel analytical method is proposed to solve the cable network system. • Dynamic axial forces are included to obtain more accurate results. • The dimension of the resulting characteristic matrix is small. • The dimension does not increase with the increase in the number of cross-ties. [ABSTRACT FROM AUTHOR]

The assumed mode method (AMM) is widely used for dynamical modeling but faces increasing challenges in developing low-dimensional and high-precision models of complex structures for investigations of nonlinear dynamical responses and active vibration control. This is mainly because the current complex structure has an increasing number of components, each of which needs to be discretized by multiple assumed modes in dynamical modeling, leading to increasing degrees of freedom for the system. To address this issue, this paper proposes a dimension-reduced method based on the assumed mode weighting method, referred to as Mode Weighting Method (MWM). The modeling process of a multi-beam structure is fully presented as an example to show the strategy of the MWM. During this process, the assumed mode (AM) model (the dynamic model derived in terms of a set of assumed modes) is developed first where the joints of the structure between its components are considered as artificial springs and each component is discretized by its vibration modes without constraints. The components of the eigenvector of the characteristic equation derived from the AM model are taken as the weighting coefficients to get the approximate analytical global modes of the structure by multiplying the corresponding assumed modes. Consequently, a nonlinear dynamic model with a few degree of freedom is obtained by discretizing the structure with the weighted modes. Moreover, a technique for simply obtaining the weighted mode (WM) models by directly processing the AM model through a transformation matrix is presented. To validate the proposed method, the simulations on the natural characteristics and the dynamical responses for both linear and nonlinear models, are performed respectively based on the WM and the finite element models, where both results are well matched each other. This work provides a new way of developing advanced dynamical modeling methods for structural dynamics design, optimization, and active vibration control. [Display omitted] • A Mode Weighting Method (MWM) for nonlinear dynamical modeling of complex structures. • A low-dimensional and high-precision dynamical model of a muti-beam structure. • Investigation of the dynamical characteristics of the muti-beam structure with nonlinear elastic supports. [ABSTRACT FROM AUTHOR]

Highlights • Development and validation of ABAQUS material models for steel headed studs and UHPC. • Experimentally-supported finite element simulations for model validation. • Assessment of in-plane torsion and direct shear interaction for an eccentrically loaded stud group. • Identification of failure mechanisms for stud diameter-to-base plate thickness ratios. Abstract A novel bridge repair method has been developed to strengthen steel bridge girders with section loss due to end corrosion. The repair comprises of welding headed shear studs to the non-corroded portion of the web plate and encasing them in ultra-high performance concrete (UHPC) to create an alternate bearing load path. The interaction between the headed studs and the UHPC panels is crucial in the force transfer. Therefore, a careful study is needed through high-fidelity finite element analysis to complement the experimental results. This paper presents the development of a model in Abaqus finite element software that enables capturing the behavior of studs embedded in UHPC. The model was validated using a series of experimental results from push-out tests with headed shear studs welded onto a thin web plate. Experimental results from push-out tests performed on stud diameters of 12, 16 and 19 mm and two levels of eccentric loadings were used to calibrate the modeling methodology. The model explicitly considers effects of material damage, contact between the studs and UHPC, and the precise geometry of the weld collar of studs. After validation, design parameters such as interaction of in-plane torsion and direct shear, and limits for web thickness-to-stud diameter ratio were studied to compliment the experimental data. The results are expected to inform engineers about the design of this novel repair method. In addition, this paper may enable future finite element studies on the performance of studs in UHPC. [ABSTRACT FROM AUTHOR]

Highlights • Beam finite element with eccentric, variable neutral axis. • Non-linear materials and material softening considered. • Computationally efficient finite element formulation. • Case studies considering large deflections and material nonlinearity considered. • Applicable to composite beams, bridge decks and other similar structures. Abstract This paper presents a beam finite element and analysis methodology for structures with neutral axes (NA) that are eccentric to the positions about which they are modelled, and that change position during the process of an analysis. This NA shift occurs due to non-linear material behaviour (softening, cracking, etc.). The proposed formulation is based upon a modified corotational approach. It has been developed specifically for structures subjected to severe fires, although it is also applicable to the non-linear analysis of structures such as wind towers and bridge decks where the position of the neutral axis in a beam section changes due to material nonlinearity. The analysis formulation results in lower computational effort relative to contemporary analysis methods employing shell or volume elements, while providing comparable results. Four case studies that include material nonlinearity, large deflections and geometric nonlinearity are included to validate the proposed formulation, and results are compared to shell element models analysed using Abaqus. The contributions of this paper are: (a) the application of standard Euler beam theory in a novel manner to allow for adjusted position of neutral axes in beams, (b) the presentation of simple case studies that can be used for validating finite element methods, but which incorporate material, geometric and cross-sectional non-linearity, and (c) illustrating the influence of cross-sectional discontinuity and how it may influence results when using beam elements. [ABSTRACT FROM AUTHOR]

Highlights • This paper proposes a clustering based tree seeds algorithm for damage identification. • Uncertain modelling errors and measurement noises are considered. • Benchmark studies are conducted to demonstrate the improvement of the approach. • Numerical and experimental verifications are conducted to demonstrate the performance. • The accuracy and robustness of the proposed approach are compared with existing methods. Abstract This paper proposes a novel structural damage identification approach by using the clustering based Tree Seeds Algorithm, termed as C-TSA, taking into account of both the finite element modeling errors and measurement noise. In order to make the standard TSA more powerful and robust, K-means cluster technique is introduced into the standard TSA before starting the seeds search, which is beneficial to enhance the algorithm's global optimization performance. The objective function based on the modal data is formulated for structural damage identification. Numerical studies on benchmark functions and a 61-bar truss structure are conducted to investigate the accuracy and robustness of the proposed approach. The finite element modelling errors and noises in the measurement data are considered. Experimental verifications on a laboratory steel frame structure model is conducted to further validate the accuracy of the proposed approach. The results from the numerical and experimental studies are compared with those obtained from several latest evolutionary algorithms. The identification results demonstrate that the proposed approach is more competitive and robust for structural damage identification even considering the modelling errors and measurement noises. [ABSTRACT FROM AUTHOR]