International Journal of Steel Structures最新文献

To enhance the structural connectivity of prefabricated steel frame systems and augment their construction efficiency, this study introduces an innovative prefabricated joint design tailored for square steel columns and H-beams characterized by varying beam heights. This study includes both static loading tests and seismic tests performed on full-scale joints featuring two different beam heights. This investigation involved a comprehensive analysis of the static and seismic performance of the joints, employing various performance metrics such as ultimate load capacities, ultimate rotation angles, hysteresis curves, skeleton curves, stiffness degradation curves, and ductility coefficients, in alignment with established structural codes and standards. The results indicate that the plasticity of the H-beam is fully developed, exhibiting a relative slip phenomenon. Additionally, the joints demonstrate commendable rotational capacity, with hysteresis curves consistently manifesting an inverse S-shape and exhibiting noteworthy stiffness degradation. Furthermore, the comparison with the unimproved joint shows that the novel joint, in addition to being easy to construct, has better ductility and energy dissipation capacity. The results of the study will provide a technical reference for further optimization and application of prefabricated beam-column joints.

Abstract

High-strength bolt attachment parts of steel bridges are prone to corrosion at an early stage, and blast nozzles and power tools cannot be inserted due to the structural shape during repairs, and there are many cases where rust remains partially. To solve such a problem, the Cold Spray technology, which uses a powder that mixes zinc and alumina, exhibits corrosion resistance by depositing a film even if rust remains. In this paper, first the anticorrosion mechanism on the residual rust was examined by focusing on the permeation prevention of the corrosion factor of the Cold Spray anticorrosion film and the adhesion of the residual rust boundary. Findings indicate that the Cold Spray anticorrosion film exhibits a porosity approximately one-tenth that of films engendered via the thermal spraying method, thereby constituting a denser film with heightened environmental barrier attributes. The firm adherence of the Cold Spray anticorrosion film to the residual rust interface is explained by differences in hardness between Cold Spray, residual rust, and zinc. Furthermore, the physical characteristics of zinc undergo modifications influenced by the temperature environment during construction, imparting a plasticity to zinc on uneven rust surfaces.

Concrete-filled steel tubes (CFSTs) are widely used in engineering structures due to their excellent mechanical properties and economic benefits. This study focused on the construction of artificial neural network (ANN) models with high prediction capabilities and prediction accuracies that could predict the axial compression load capacities of short CFST columns using machine learning methods. A database was created by searching literature published over the past 40 years regarding circular-CFST bearing-capacity testing. Three ANN models with different input parameters were developed, and used the Whale Optimization Algorithm to optimize the network weights and thresholds, the core idea of which comes from the humpback whale's special bubble net attack method. Then, the predictions of the proposed machine learning models were also compared with the theoretical values produced by the formulas proposed in existing codes. The results show that the ANN models had higher accuracies and a wider application range than the existing code models. Based on the Garson's algorithm, we perform parameter sensitivity analysis on the network model to enhance the interpretability of the neural network model. Finally, a graphical user tool is built to make the strength of CFST can be predicted quickly.

Shear deflection is a key factor to take into consideration since members with smaller web areas are more vulnerable to shear. As a result, this work focuses on using theoretical, experimental, and analytical methods to undertake a parametric analysis to determine the shear deflection of an open web steel beam under non-uniform bending. The ABAQUS software package was used to analyse a total of sixty nonlinear finite element models, and part of the model’s behaviour was tested experimentally. The flange and web slenderness ratios that distinguish the finite element models were noted using a codal comparison. In addition to the overall behaviour, the shear deflection of various member components was calculated and compared to the shear deflection equation provided by Das and Basole and, Timoshenko and Gere. The findings indicated that load versus deflection plots could be produced analytically and experimentally, proving a good link between the two. The current work presents an appropriate adjustment factor for the theoretical shear deflection equation to compute the precise shear deflection behaviour of an open web steel beam. The accuracy of the proposed formulation is proven by an R-squared (R²) value of 0.999. Additionally, the maximum shear deflection limit for the simply supported open web steel beam under non-uniform bending was calculated as part of this study, along with the impact of the span-to-depth ratio on shear deflection. The investigation comes to the further conclusion that the parametric variation significantly affects the shear deflection.

Abstract

In the context of steel composite wall (SC wall) standards, this study explores the relaxed provisions outlined in AISC N690 (2018), particularly concerning commonly used materials in general building construction, such as faceplate thickness, concrete strength, shear connector spacing, and steel tie spacing. These provisions were then applied to assess the viability of a “relaxed steel composite wall” as a seismic force-resisting system suitable for mid- and low-rise structures. Experimental investigations were conducted to achieve these objectives. A dedicated SC wall specimen was constructed, and various variables were examined, including the presence or absence of shear connectors, shear connector spacing, steel tie spacing, and faceplate types. The results were analyzed to assess fracture behavior, the relationship between shear force (V) and transverse displacement (Δ), shear stiffness variations, maximum in-plane shear strength, displacement ductility ratio (μ), and energy dissipation characteristics. Moreover, their displacement ductility ratios remained below 10, and they exhibited substantial energy dissipation capabilities. These findings suggest that the application of “relaxed SC walls” as seismic force-resisting systems is feasible for mid-, low-, and high-rise structures.

Recently, a great amount of research has been carried out to resolve a growing need for durable and resilient highway bridge construction/reconstruction systems in many countries. As a part of such studies, prefabricated composite girders with innovative precast deck-to-girder continuous connections have been proposed that facilitate construction by eliminating interference during on-site processes. This study aims to figure out the effects on the flexural performance of the prefabricated composite girders along with the non-interference deployment of the precast deck-to-girder interface connections. In this study, two test specimens of the prefabricated composite girder were designed. Ultimate bending tests were conducted to experimentally evaluate the behavior of shear interfaces and flexural performances of the test specimen girders. It was revealed from this study that the intersection of the lap connection between the transverse deck reinforcement and the shear connectors will have a significant effect on the flexural performance of the prefabricated composite girder. The flexural performance of the prefabricated composite girder with intersected connection type is ensured while the non-intersected connection type influences the flexural performance more seriously than the intersected connection type. The AASHTO LRFD specifications appears applicable to the existing intersected connection details. Further, a series of parametric studies based on the verified finite element model were performed to examine the influence of various dominant factors on the flexural moment strength of the prefabricated composite girder. From the results of parametric studies, conclusions were drawn. The results of this study could be used for future research to establish a procedure for evaluating the bending resistance capacity of prefabricated composite girders based on structural ductility through rotating capacity.

To investigate the development mechanism of sectional plastic stress and biaxial bending moments of H-section steel members prior to local buckling subjected to monotonic and cyclic loading, extensive parametric analysis models were established in ABAQUS. These models explicitly accounted for different axial force ratios, plate width-thickness ratios under different loading angles, verifying the applicability against existing experimental data. Based on the results of finite element analysis, the effects of various factors on the development of normal stresses in the cross-section were thoroughly investigated. A semi-empirical semi-theoretical calculation model was established to address biaxial loading in H-section steel members, considering bidirectional displacement, the form of normal stress distribution, and the relationship between the biaxial bending moments. By comparing the model with finite element results, it was observed that the model effectively predicted the progression of biaxial bending moments development subjected to biaxial loading in H-section steel members. This model provides a more convenient design approach for considering the partial plastic development of the cross-section in bidirectional flexural design.

The vibration responses of pedestrian bridges are mainly caused by two transmission routes of ground and airflow under vehicle excitation. In order to clarify the action mechanism and influence degree of ground excitation and airflow excitation on pedestrian bridges, based on stochastic theory and flow field analysis method, the calculation models of vehicle-induced ground excitation and airflow excitation considering the influence of vehicle length, vehicle width and bridge deck width are established respectively. Considering the effects of vehicle speed, road grade, and vehicle mass, the vibration response of a continuous steel box girder pedestrian bridge under the two transmission routes was analyzed in this study. The laws of vibration acceleration and stress were summarized, and the accuracy of the finite element model and the laws were verified by field-measured data. Results show that road grade and vehicle mass are the main factors causing the vibrations of pedestrian bridges under vehicle excitation. Vehicle speed has a great influence on structural vibration under airflow excitation. The vibration response is the largest at mid-span along the pedestrian bridge-length direction. When the vehicle speed is less than about 60 km/h, the influence of the airflow excitation on the structure may not be considered. On this basis, the comfort level of the pedestrian bridge was evaluated using the British Standards Institution. The given evaluation criteria of the pedestrian bridge complement the design regulations of the pedestrian bridge.

Abstract

Steel sheet piles are known for their straightforward assembly and construction, making them a popular choice that is often repurposed for other building projects once disassembled. Regarding the re-use of these steel sheet piles, understanding their behavior during penetration into the soil becomes pivotal. This study focuses on assessing the potential reusability of steel sheet piles as they penetrate into the soil. A laboratory-scale experiment involving the insertion of a steel sheet pile into a sand-filled tank was conducted. The experimental variables were the relative density of the soil, length of the steel sheet pile, and penetration method. The behavior of the sheet pile was analyzed, including the force-insertion length relationship and the strain of deformation occurring locally in the sheet pile. The results indicated that higher relative soil densities led to increased strain within the sheet pile. The strain values remained within the elastic range during the experiment. Notably, when interpenetrating the steel pile with a coupling mating joint test specimen, the strain showed an inverted mountain-shaped distribution within the interlock.

A filled thin-walled tube is an excellent energy absorption device, and its performance is closely related to the filled core material. In this paper, a porous metal-high performance concrete interpenetrating phase composites (PMCIPC) filling core material is proposed, which takes porous nickel as the matrix and high-performance concrete as the reinforcing element, trying to improve the energy absorption of thin-walled tube. Axial quasi-static compression tests were carried out on empty tube, PMCIPC and filled tube. Based on the experimental results, the effects of wall thickness and aspect ratio on the deformation and energy absorption performance of the filled tube were studied by numerical simulation. The results show that the larger wall thickness increases the energy absorption of the empty tube and the filled tube. The PMCIPC filling further improves the energy absorption capacity, and for the empty tubes with smaller wall thickness, the PMCIPC significantly increases the crushing force efficiency. When the aspect ratio (L/D) is 3.7, the deformation mode of the filled tube is Euler instability, and the performance begins to decrease sharply. Finally, a theoretical model is established to predict the mean crushing force of the filled tubes. The model results are in good agreement with the experimental results. This study provides effective guidance for the design of thin-walled structures with high energy absorption efficiency.