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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]

Buried circular corrugated steel arches (BCCSAs) are often adopted in underground engineering. However, the current design specifications cannot accurately estimate the BCCSA's load-bearing capacity due to the complicated interaction between the soil and the arch. This paper presents the strength design recommendations for deeply buried circular corrugated steel arches with various rise–span ratios under axial compression and under combined axial compression and bending moment respectively, with meeting a proposed width–thickness ratio limit of the BCCSA for local buckling prevention. At first, a finite element model (FEM) of sinusoidally corrugated steel plate (S-CSP) for analyzing its local plate buckling under axial compression (FEM-l) is established, and this FEM can eliminate other possible buckling modes except the local buckling mode by constraining the out-of-plane displacement at the crest and valley lines in S-CSPs. Through FEM-l, the local buckling behaviors of S-CSPs are studied and the width–thickness ratio limit of S-CSPs under axial compression for local buckling prevention is determined in terms of a design principle that local buckling of plate elements does not occur before fully sectional yielding. Then, a global arch-spring model of BCCSA is established for analyzing its elastic global buckling, with considering the interaction between the soil and arches by simplifying the radial restraint of soil as radial unidirectional springs around the arch. The normalized slenderness of BCCSA in the arch-spring model is obtained from its elastic global buckling load calculated by theoretical derivation with bidirectional spring assumption. Finally, the ultimate load-bearing capacity of BCCSAs is calculated by employing elastoplastic finite element models under axial compression and under combined axial compression and bending moment respectively. Based on extensive numerical results obtained in this study, the conservative strength design methods for BCCSAs are proposed in practical engineering applications. [Display omitted] • Local buckling prevention is implemented by proposed width–thickness ratio limit. • The soil radial restraint is equivalent to unidirectional radial springs. • Initial imperfection amplitude affects the load-bearing capacity of the arch much. • Axial compression stability coefficient under various rise–span ratios is proposed. • Load-bearing capacity is proposed for combined axial compression and bending. [ABSTRACT FROM AUTHOR]

This paper focuses on the investigation into global stability design of grid cylindrical-lattice shell (GCLS) under combined axial compression and moments. This study is an extension of previous researches carried out by the authours in the elastic buckling and axially load-bearing capacity of GCLSs (Zhu et al., 2021, 2022). Accordingly the elastic buckling load and global compression stability coefficient of GCLS loaded axially are employed. The finite element model adopted in this study has been validated by previous researches (Zhu et al., 2021, 2022; Guo et al., 2017). First the elastic buckling behaviours of GCLS under pure bending moments is explored by using eigenvalue buckling analysis. The obtained results demonstrate the effects of the bending moment direction, the beam-column stiffness ratio, the diameter-height ratio of GCLS, the number of columns, and the number of storeys of GCLS on the elastic buckling load of GCLS. Subsequently, the ultimate stability capacity of GCLS under pure bending moment are investigated numerically by using a large number of numerical examples in the common range of engineering applications. Accordingly, a design formula is established based on a relationship between the bending stability coefficient φ M and the compression normalized slenderness ratio λ N , namely the φ M - λ N curve for predicting pure bending-bearing stability capacity. Finally, the interaction design formula for predicting the stability capacity of GCLS under combined axial compression and moment is proposed conservatively by introducing axial compression stability coefficient and bending moment stability coefficient. This interaction design formula is further validated by employing a large number of the numerical examples and provides fundamentals for designing GCLSs in practice. [Display omitted] • Elastic buckling behavior of Grid Cylindrical-Lattice Shells (GCLSs) under combined axial compression and bending moment is investigated. • Stability curve φ M - λ N of GCLSs under bending moment is obtained by using numerical examples. • Stability capacity design of GCLS under combined axial compression and bending moment is proposed according to an interactive formula of N/N u ∼ M/M u. [ABSTRACT FROM AUTHOR]

This paper presents the stability behaviours and capacity design of the grid cylindrical-lattice shell (GCLS) which consists mainly of the multi-columns located circumferentially and the multi-story ring-beams uniformly distributed along the height. The GCLS under axial compression is investigated in the stability capacity by using a finite element model that has been validated by an experimental investigation carried previously out by the authors. A large number of numerical examples of GCLSs covering a common design range of engineering applications are analyzed numerically by employing the validated finite element (FE) model to investigate the ultimate load-carrying capacity, and accordingly a stability capacity design method regarding the compression stability coefficient φ N and the normalized slenderness ratio λ N is established. Based on a design criterion that the failure of the ring beams does not precede the multi-column instability, the strength design formula of the ring beam is proposed accordingly and validated by using FE numerical results. In summary, this paper supplies a complete design method for predicting the stability capacity of the GCLSs as well as strength check of the ring beams in the GCLSs under axial compression. This study lays a preliminary research foundation for subsequent research on the stability capacity design of GCLSs under a combined action of axial compression and bending moment. [Display omitted] • Load-carrying capacity of GCLSs under axial compression are investigated theoretically and numerically. • Stability curve φ N - λ N obtained by using numerical examples can be directly used in the design of the GCLSs. • The strength design formula of the ring beam is established based on the theoretical and numerical investigation. [ABSTRACT FROM AUTHOR]

In composite structures, the strength of different material can be fully taken advantage of due to the composite effect. In steel-encased concrete-infilled composite structures, steel plates are restrained unilaterally by infilled concrete. The contact buckling mode of steel plates differs from the bilateral buckling mode, and the buckling load is improved. Compared with flat-plates, corrugated-plates have greater out-of-plane stiffness and even larger buckling load restrained by a rigid medium and the shear connectors between them. This paper focuses on the compressive buckling behaviour of corrugated-plates in contact with a rigid medium, taking into consideration the influences of geometrical parameters and shear connector arrangement. First, through finite element (FE) analysis and theoretical derivation, we propose the bilateral and contact buckling loads of corrugated-plates. Then, based on the buckling analysis, the FE model considering material and geometrical nonlinearity is developed to investigate the load resistance of corrugated-plates and validated by existing experimental results. According to the numerical results, we propose the design formulas of the strength reduction factor of corrugated-plates and the upper limit of the normalized slenderness ratio for compact sections. The design formulas can further provide fundamental for the stability design of corrugated-plates under compression and bending moment. [ABSTRACT FROM AUTHOR]

• The local buckling of steel corrugated-plates is considered in the load-carrying capacity. • The moment capacity is evaluated based on the plastic stress distribution. • Simplified interaction equations with good accuracy are proposed. • The interaction curves of biaxial bending are almost exclusively related to the axial compression ratio. This paper studies the load-carrying capacity of concrete-infilled double steel corrugated-plate walls with T-section (T-CDSCWs) under axial compression and biaxial bending. T-CDSCWs are composed of flange and web walls and boundary elements. The T-section is mono-symmetric and exhibits different interaction curves of load-carrying capacity when subjected to axial load and different direction bending. Based on the finite element (FE) model established by the previous study, the local buckling of the steel corrugated-plates is considered in the load-carrying capacity. Subsequently, this paper investigates the behaviours of T-CDSCWs under axial compression and uniaxial bending, including stress distribution, load–displacement curves, and interaction curves. Based on the numerical results, the pure moment capacity is found to be evaluated by reducing the plastic moment capacity, and the interaction equations of N –positive M x , N –negative M x , and N – M y are proposed in the bilinear, linear, and parabolic form. For biaxial bending, the shape of the interaction curves is almost exclusively related to the axis compression ratio. Accordingly, this paper proposes the interaction equations of M x – M y subjected to certain axial compression. Moreover, the local buckling of steel corrugated-plates has no significant influence on the shape of the interaction curves no matter the bending direction. The global stability of T-CDSCWs is not involved in the study, and with the interaction equations obtained above, the global stability design of T-CDSCWs can be investigated by introducing the magnification factor of the bending moment caused by the secondary effect. [ABSTRACT FROM AUTHOR]

The concrete-infilled double steel corrugated-plate walls (CDSCWs) consist of two steel corrugated plates (SCPs), infilled concrete and two boundary elements. The two SCPs are connected by high-strength bolts and the spacing between the two SCPs is filled with concrete. The two vertical boundary elements are installed at both sides of CDSCWs. The sectional load-bearing performance of CDSCWs only under uniform compression has been investigated previously by the authors. But CDSCWs under a combination of compression and in-plane bending moment are applied in practice widely and commonly. Therefore, this paper presents the corresponding sectional load-capacity design method of CDSCWs under a combination of compression and in-plane bending moment. Firstly, an experimental investigation on sectional load-capacity of an I-shaped CDSCW specimen subjected to combined compression and in-plane bending moment is completed. The experimental results reveal a high axial load-bearing efficiency of the SCPs in the CDSCW specimen, and also validated the finite element (FE) model adopted in this study. Then, the FE numerical simulation is applied to systematically analyze the load-bearing performance of CDSCWs subjected to the combination of compression and in-plane bending moment. The coefficient φ sp is introduced to consider the local buckling of compressive zone and the weakening effect of tensile-compressive transition zone in SCPs. The coefficient β c is introduced to consider the weakening effect of tensile-compressive transition zone in concrete and the adverse cooperative effect among SCPs, concrete and boundary elements owing to their different ultimate strains at the ultimate state of CDSCWs. As a result, the N - M correlation curve for predicting the sectional load-bearing capacity of CDSCWs under both the uniform compression and in-plane bending moment is then established and also verified by the experimental results. • CDSCWs have favorable sectional load-bearing capacity. • FE analyses are used to study the load-bearing mechanism of CDSCWs under in-plane combined compression-bending loads. • The weakening effects of local buckling, tensile-compressive transition zone and cooperative performance are considered. • Cross-sectional load-capacity design formulae for CDSCWs are proposed. • An experiment of an I-shaped CDSCW specimen is conducted to investigate the cross-sectional capacity. [ABSTRACT FROM AUTHOR]