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• Based on the test results, a refined finite element model was established for the push-out test of SSGCs. • Parametric analysis was carried out through the finite element model, and the factors affecting the static performance of the specimen were analyzed. • The stiffness of the SSGCs at the elastic stage was theoretically analyzed by using the thrust pile comprehensive stiffness method. A refined finite element (FE) model was established to simulate the push-out test of shear stud group connectors (SSGCs). The failure phenomena and interface shear-slip curves obtained by the FE model were compared with the test results and found to be in good agreement. The verified FE model was then used in a parametric analysis, considering the concrete strength, stud diameter, stud height, stud spacings (longitudinal and transverse), strength of grouting material, and number of shear studs in a SSGC. Based on the Winkler foundation model and the comprehensive stiffness principle of thrust piles, a theoretical calculation formula for the stiffness of SSGCs was obtained, considering the concrete material, stud diameter, and number of shear studs in a SSGC. The calculation formula was verified with the test results and fitted with the FE analysis results. [ABSTRACT FROM AUTHOR]

Concrete-filled steel tubular (CFST) columns are widely utilized in structures owing to their cost-effectiveness, high strength, ductility, and proven fire resistance. Despite these advantages, concerns persist regarding the performance of CFST columns with locally corroded steel tubes, impeding their widespread adoption in offshore structures. This research employs three-dimensional finite element (FE) simulations for circular CFST stub columns subjected to axial compression, validated against experimental data. Verification includes full load-displacement histories, ultimate axial strengths, and failure modes. The validated FE models are then employed to assess and compare the structural behavior of CFST columns with various shapes of localized corrosion, analyzing overall load-deformation curves, interaction stress-deformation responses, and composite actions. To acquire critical data for understanding stub column behavior, 81 specimens underwent non-linear finite element analysis, with local corrosion represented by artificial notches in steel tubes. Test parameters, such as notch orientations, lengths, depths, widths, and concrete compressive strength, are varied. Results elucidate the impacts of these parameters on different aspects of stub column responses with corroded steel tubes. Furthermore, the accuracy of existing design models in predicting the ultimate axial strengths of CFST columns with corroded steel tubes is assessed. Finally, through parametric analysis of test results, a practical model is proposed and verified for computing the peak resistance of a CFST stub column with a locally corroded steel tube. • Finite-element simulation model for circular CFST stub columns with locally corroded steel tubes is developed. • The influence of different shapes of localized corrosion on the performance of circular CFST stub columns is investigated. • The behavior of circular CFST stub columns with locally corroded steel tubes is parametrically studied. • The proposed finite-element simulation and design models provide accurate predictions. [ABSTRACT FROM AUTHOR]

Highlights • Full-scale angle-encased CFST members under axial tension are investigated experimentally and numerically. • Load-transfer mechanism between components is assessed. • Component interactions that help to achieve high tensile performance are evaluated. • Design method based on load-transfer mechanism and component interactions is proposed. Abstract Load-transfer mechanism of concrete-filled steel tubes (CFSTs) with encased built-up angles under concentric tension is assessed experimentally and numerically in this paper. Seven full-scale angle-encased CFST test specimens with the length of 4000 mm were tested. The test parameters were the diameter-to-thickness ratio (D / T), connecting type, and configuration of encased-angles. Finite element analyses (FEA) were performed to further investigate the tensile behaviour of the composite members. The load distribution, load-transfer mechanism, and interactions between components, i.e. the tube, inner concrete, and encased-angles, were extensively evaluated. All these components could synergistically work under axial tension, though the encased angles were disconnected from the endplates. The strength of the angles could be effectively used through the load-transfer from the concrete, owing to the interactions between each component. In addition, the connecting types exerted minor effects on the ultimate tensile strength despite the existence of an insufficient confining region within the connecting area. The tensile strength design method was proposed for the angle-encased CFST member, based on experimental and numerical analyses on the load-transfer mechanism and component interactions. The comparisons between the calculated predictions and the results from the tests and simulations demonstrated the proposed design method was accurate and reliable. [ABSTRACT FROM AUTHOR]

• Six steel–concrete composite adapter (SCCA) specimens and one reinforcement concrete adapter (RCA) specimen were tested under axial compression. • The superiority of SCCA over RCA was proved. • The effects of stud spacing, the thickness of stiffened plates, and the amount of bottom circumferential rebars on SCCA were reveal. • Finite element models were established and validated by the test results. • Parametric analysis was conducted and the prime sensitive parameters affecting the ultimate compressive capacity were presented. Adapter is one of the most important components in wind turbine hybrid towers. It allows the upper steel segments to connect reliably with the lower concrete segments and thus they can work well as a whole structure. However, traditional reinforced concrete adapters (RCAs), which have been commonly used in engineering practice, encounter many shortcomings such as complicated construction processes and strength/stiffness degradation after the concrete cracking. In this paper, a novel type of steel–concrete composite adapter (SCCA) was proposed. Experimental and numerical studies on its compressive behavior were conducted. Six SCCA specimens and one RCA specimen were tested under axial compression. The tested parameters include the stud spacing, the thickness of stiffened plates, and the amount of bottom circumferential rebars. By revealing the failure modes, load–displacement relations, ultimate strength, deformability, and strain relations of SCCA, the superiority of SCCA over RCA was proved. To extend the scope of the experiment and conduct parametric analyses, finite element models were established and validated with test results. Sensitive parameters related to the ultimate capacity of SCCA were investigated. Additionally, reasonable studs spacing which is beneficial for enhancing the ultimate capacity of SCCA was obtained. [ABSTRACT FROM AUTHOR]