International Journal of Steel Structures最新文献

In this study, efficient finite element modeling concept and application for a sub-assembly structure are presented to assess the progressive collapse resistance performance of a whole structure considering the three-dimensional effect of the slabs, the continuity of the adjacent spans, and the stress redistribution through the alternative path of the upper floors. Three modeling levels were considered based on the degree of lateral behavior simulation by considering the flexural rigidity of columns and girders outside the influenced range. Furthermore, the modeling methods for a sub-assembly structure were evaluated by comparing the load-displacement relationship, girder stress, and plastic hinge locations with those obtained from the simulation of the whole structure model. The results indicate that the sub-assembly structure modeling can significantly reduce time in modeling and analyzing large structures and yield reliable results for appraising progressive collapse resistance performance.

The force-transfer mechanism of a steel–concrete joint (SCJ) in a railway hybrid girder cable-stayed bridge was analysed using model tests and nonlinear finite element analysis (FEA), and the influence of the main design parameters on the load transmission performance was determined. The FEA results were in good agreement with the test results. The SCJ behaved linearly up to even under 2.0 times the design load, and the safety factors of the concrete and steel were not less than 2.02 and 2.55, respectively. The SCJ exhibited excellent deformation performance. Approximately 33.0% of the axial force was transferred from the steel girder to the concrete girder through the rear bearing plate (RBP), indicating that the RBP played an important role in force transfer. The force transmission efficiency of the steel cabin segment was approximately 2.0 times greater than that of the insert segment. The relative slip distribution along the bridge was saddle-shaped with large ends and a small middle. The uneven coefficients of the force shared by the PBL connectors and shear studs were 0.45–4.17 and 0.17–3.15, respectively. The deformation of the RBP was more complex than that of the front bearing plate (FBP), and the perforated plates, longitudinal prestressed tendons and webs strongly influenced the deformation distribution of the RBP. A parameter analysis revealed that the shorter the SCJ was, the greater the force transferred by the bearing plates and the greater the shear force shared by the shear connectors were. The greater the height of the steel cabin was, the greater the proportion of axial force transmitted by both the FBP and RBP was. Decreasing the stiffness of the PBL connectors and shear studs increased the relative slip considerably.

In offshore steel tubular structures corrosion caused by the environment can lead to perforations that compromise their integrity. However, there are still no well-established standards for assessing the reduction in structural capacity considering the damage dimensions. This article aims to investigate, both experimentally and numerically, the strength of tubular structures with oblong perforations under compressive loads, as well as to propose the use of regression to estimate the remaining load capacity. In the experimental analysis, four tubular members with varying length-to-diameter and diameter-to-thickness ratios are used, featuring oblong perforations oriented longitudinally and transversely. A finite element model is also developed using shell elements, and the experimental and numerical results are compared, with the four tested samples being replicated with identical geometry and stress–strain material curves. The numerical model results demonstrate remarkable agreement with the experimental findings, particularly regarding the maximum axial load capacity, validating its applicability to similar configurations. Based on the results, regression was employed to generate an optimized expression, minimizing the error between the predicted values and the numerical data. It is concluded that the size of the perforation in the transverse direction of the tubular element is critical to the loss of compressive strength, whereas the perforation length in the longitudinal direction contributes significantly less.

The production of stainless-steel systems has created a major impact on the advancement of technology and its application in various industries. The failure of stainless-steel machinery and structural components can be attributed to the important role played by mechanical and electrochemical properties. Thus, there is ample room for enhancement in these domains. The powder was compacted using cold compaction through single-action uniaxial pressing; applying a pressure of 600 MPa. Hydrogen sintering produced a refined pore structure, enhancing strength (222 MPa YS, 410 MPa UTS) but reducing ductility (13.9% elongation). Mixed-atmosphere sintering improved ductility (23.5% elongation) but lowered strength (188 MPa YS, 359 MPa UTS). It has been noted that the specimens sintered in a hydrogen sintering atmosphere exhibited a significant increase of 11 and 18% in the ultimate tensile strength and yield strength, respectively, compared to the specimens sintered in a mixed atmosphere. Fractography showed more ductile features in hydrogen-sintered specimens. Corrosion resistance was higher in mixed-atmosphere sintering, with a lower OCP ( − 399 mV). These results highlight the critical role of sintering conditions in material performance optimization.

This paper presents the results of an experimental fatigue behavior study, conducted on round standard specimens, which were machined from T-welded connections, which are extensively employed in the repair of offshore oil & gas structures. For the analysis, two different grinding/wet welding repair conditions were performed. Hence, the tested grinding depths conditions are 6 and 10 mm, which were subsequently filled with wet welding at three immersion water depths of 50, 70, and 100 m. The round specimens were subjected to high cycle fatigue tension tests, and the S–N curves were measured for air-repair an immersion repair condition. The results reveal a decrease of cycles number in the S–N data with water depth increment, compared with air repair condition. For the wet repair condition, the lowest stresses were obtained for the connections with a grinding depth of 10 mm and filled with wet welding at 50 m of water depth, however the stresses where higher to those obtained at repair air conditions. Nonetheless, for the case of a 6 mm grinding depth repaired with wet welding at 50 m of water depth, the stresses were similar to those at air repair conditions, therefore this last grinding-wet welding combined repair condition can effectively restore the original service life of T-shaped connections, damaged and repaired by the combination of grinding and wet welding. In contrast, for water depths of 70 and 100 m, significantly lower fatigue results were observed compared for both grinding and wet welding repair conditions.

The increasing adoption of lightweight, long-span pedestrian walkways has heightened concerns regarding vibration serviceability due to reduced natural frequencies and damping ratios. Traditional evaluation methods, such as root mean square (RMS) acceleration and maximum transient vibration value (MTVV), are widely used in design standards. However, significant discrepancies exist between threshold values specified in guidelines and real-world vibration experiences, leading to inconsistencies in serviceability assessments. This study proposes a probabilistic methodology that evaluates walkway vibrations based on in-situ measurements rather than predefined standard limits. By examining resonance-induced pedestrian discomfort, site-specific discomfort thresholds are established. A weighted MTVV (WMTVV) approach is introduced, integrating probabilistic modeling to enhance accuracy in real-world applications. To validate this framework, an experimental study was conducted on a 52-m span footbridge, incorporating long-term ambient vibration monitoring and controlled resonance experiments. The results reveal that existing vibration assessment methods often yield subjective and overly conservative or inadequate criteria. The study highlights the necessity of data-driven, probabilistic methodologies tailored to structure-specific conditions, thereby improving accuracy, reliability, and practical applicability in pedestrian walkway vibration evaluation.

The inclined façades of irregular tilted-midsection buildings, which midsections are intentionally designed to be inclined, generate eccentric loads on each floor. In addition, lateral loads, such as earthquakes, and self-weight induce overturning moments, causing lateral displacement in the inclined direction of the structure. To compensate for this structural instability and disperse the overturning moment, the lateral displacement needs to be controlled by applying multiple cores, or by adding a lateral force-resisting system, such as an outrigger system. In this study, the lateral force resistance performance of an irregularly shaped 60-story building with the midsection tilted by approximately 12.1° was investigated according to the change in core placement. The analysis modeling was classified into single–core and dual–core models, and consisted of six models where the core position was shifted horizontally along the tilted direction (X–axis). Eigenvalue and seismic response analyses were performed, and the structural characteristics were analyzed by comparison with the regular analysis model. The analysis results showed that as the core was placed in the inclined direction of the structure, the structural responses of the irregular tilted building under the load combination of vertical load seismic loads decreased. In addition, an analysis model with the best seismic resistance was evaluated for each core placement, and the location of the outrigger system that could effectively reduce the story drift ratio and maximum lateral displacement was investigated through static and time history analyses. This study can be used as a guideline for core placement and the number and location of outrigger systems installed in the planning and initial design stages of irregular tilted-midsection structures.

This study investigates the collapse mechanism of a half-through truss bridge, focusing on its structural reserves beyond the first failure under different damage conditions. Addressing the challenge of predicting collapse behavior in the presence of localized corrosion, a series of progressive collapse analyses were conducted using a three-dimensional finite element model. The findings reveal that the collapse mechanism is primarily governed by the instability of the upper chord system, even when the stress level is well below yielding. These results were validated using an equivalent two-dimensional upper chord system analytical solution. Furthermore, localized deterioration was shown to significantly reduce the bridge’s load-carrying capacity, potentially causing sudden catastrophic failure. The study provides a unique insight into the collapse mechanisms of corroded steel bridges, filling a critical gap not addressed in previous research. The key contributions include a comprehensive nonlinear analysis of progressive collapse, explicit modeling of localized corrosion effects, and the validation of findings using both 3D and 2D models.

This study aimed to elucidate the degradation mechanism of the mechanical properties of Q235B steel under the coupling action of axial tension and local cyclic corrosion. A custom stress corrosion testing apparatus was designed and fabricated for this purpose. Accelerated tests were conducted with varying corrosion durations (1, 3, and 5.5 days) and stress ratios (0.4, 0.6, and 0.8). The corroded steel plates underwent three-dimensional scanning and static ultimate tensile testing. The study revealed that steel plates with a corrosion rate exceeding 30% displayed characteristic necking, and their cross-sectional integrity was significantly diminished. There was a significant positive correlation between the corrosion rate of steel plates and stress ratios, and the mean cross-sectional loss rate in the corroded areas corresponded to the level of stress corrosion. Additionally, the decline in the nominal mechanical properties parameters (f_yⁿ, f_uⁿ) of the corroded steel plates was directly proportional to their corrosion rate. Two models predicting the corrosion-induced degradation of steel’s mechanical properties, incorporating stress ratio variables, were developed using multivariate linear regression analysis.

Trapezoidal corrugated web beams (CWB) have been the subject of extensive research. However, there is a noticeable gap in the literature concerning the determination of moment resistance in slender corrugated web beams with slender flanges (SCWSF). Previous studies, both experimental and numerical, have shown that the SCWSF bending resistance model outlined in EN1993-1-5 (Eurocode 3: Design of steel structures—Part 1-5: Plated structural elements, CEN, 2007) often leads to unsafe resistance predictions. This study investigates the moment capacity of SCWSF using a combination of theoretical, numerical, and experimental approaches. A numerical and analytical investigation is being conducted in the current part to analyze the moment resistance of SCWSF beams. Based on previous results from the experimental studies of SCWSF, a novel formulation has been developed to align with the failure modes and guidelines outlined in ANSI/AISC 360-16 (Specification for Structural Steel Buildings, Chicago, 2016) for the design of steel I sections to resist flexural strength. A new methodology has been developed to assess the moment resistance of SCWSF, considering factors such as flange slenderness, the ratio of flange width to beam height, and various loading conditions. This approach builds upon existing proposals for flat and corrugated web girders, incorporating numerical findings for further validation. The results suggest that all models demonstrate a conservative nature and lack accuracy across the full range of SCWSF beams. The recommended approach offers more accurate estimations compared to existing standards and proposed designs.