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Research Article
Experimental and Numerical Investigation of Buckling Behaviour in Q690 High-Strength Steel Tubes Under Combined Axial Compression and Bending Loads
Shek Rajib*
,
Lei Chen
Issue:
Volume 12, Issue 6, December 2024
Pages:
178-187
Received:
21 October 2024
Accepted:
9 November 2024
Published:
21 November 2024
Abstract: This paper investigates the buckling behavior of Q690 high-strength steel tubes under combined axial compression and bending loads through experimental testing and finite element analysis (FEA). A total of 27 full-scale specimens with varying slenderness ratios (λ) and diameter-to-thickness (D/t) ratios were tested to evaluate their load-bearing capacity, deformation characteristics, and failure modes. The experimental setup replicated real-world conditions, with constant axial loads applied alongside incremental bending moments until failure occurred. FEA models, developed using ABAQUS, incorporated geometric imperfections and material nonlinearities to simulate realistic structural behavior and predict critical buckling moments. The comparison between experimental and numerical results showed strong agreement, with deviations ranging from 5.6% to 7.9%, confirming the reliability of the simulations. The findings indicate that tubes with higher D/t ratios are more sensitive to imperfections, experiencing significant reductions in post-buckling moment capacity, while those with lower D/t ratios demonstrated greater resistance to buckling and maintained higher structural integrity. The transition between global and local buckling modes was effectively captured by both experimental and numerical approaches, validating the robustness of the models. This study emphasizes the importance of accounting for geometric imperfections and residual stresses in design practices to ensure the safety and reliability of high-strength steel structures under combined loading conditions. Additionally, the results underscore the effectiveness of advanced FEA tools in predicting structural behavior, providing valuable insights for improving design codes and practices. Future research is recommended to explore dynamic loading scenarios, such as wind or seismic effects, to further enhance the applicability of Q690 steel tubes in critical infrastructure projects.
Abstract: This paper investigates the buckling behavior of Q690 high-strength steel tubes under combined axial compression and bending loads through experimental testing and finite element analysis (FEA). A total of 27 full-scale specimens with varying slenderness ratios (λ) and diameter-to-thickness (D/t) ratios were tested to evaluate their load-bearing ca...
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Research Article
Seismic Risk Assessment for Sreemangal Town: Exploring the Use of Reliability-Based and RVS-FEMA 154 Methods for Building Safety in Bangladesh
Issue:
Volume 12, Issue 6, December 2024
Pages:
188-198
Received:
20 November 2024
Accepted:
4 December 2024
Published:
25 December 2024
DOI:
10.11648/j.ajce.20241206.12
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Abstract: In the present study, the vulnerability of the building stock of a small but important town (Srimangal Municipality under the Moulvibazar district of Bangladesh), located in the most earthquake-prone Sylhet region, was assessed. Besides, the applicability of two methods of vulnerability assessment (Reliability-Based Method and FEMA 154) for Bangladesh was also checked. 17.5% of the studied buildings were found vulnerable, and 65% of buildings were safe according to both methods. Most of the masonry buildings (85.71%) are at risk, as they are old and constructed before introducing Bangladesh National Building Code (BNBC) in 1993. For Bangladesh context, the Cut-Off Score of FEMA 154 was proposed as 1.5 instead of 2.0 in this study. The comparison between the two methods shows that the results obtained from the analysis were close enough to each other and both models gave reliable results. However, the lack of sophisticated damage data for the Reliability-Based Method could lead the results to be varied from the results obtained from another method. On the other hand, Basic Scores and Score Modifiers in FEMA set for developed countries might be calibrated for Bangladesh to decrease the result gaps. In conclusion, both methods were found suitable to use for vulnerability assessment of buildings in Bangladesh.
Abstract: In the present study, the vulnerability of the building stock of a small but important town (Srimangal Municipality under the Moulvibazar district of Bangladesh), located in the most earthquake-prone Sylhet region, was assessed. Besides, the applicability of two methods of vulnerability assessment (Reliability-Based Method and FEMA 154) for Banglad...
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Research Article
An Analysis of Influencing Factors for Vapour Transfer in Freezing Soils in High-filling Engineering
Zhanjun Huang,
Xiangdong Sun,
Zuoyue He*,
Dongjin Xu,
Hanhao Zhang
Issue:
Volume 12, Issue 6, December 2024
Pages:
199-210
Received:
2 December 2024
Accepted:
11 December 2024
Published:
25 December 2024
DOI:
10.11648/j.ajce.20241206.13
Downloads:
Views:
Abstract: Canopy effect has been paid more and more attention in high-filling engineering in cold and arid regions of China. Vapour transfer is considered as the main cause of canopy effect in freezing soil in the literature. However, the influencing factors of vapour transfer in freezing soils have not been systematically analyzed in the literature. Based on the coupled heat and mass transfer model proposed by the authors, the effects of hydraulic parameters and environmental factors on vapour transfer in freezing soils will be analyzed in this paper. The results show that the effects of the hydraulic parameters, such as the fitting parameters of the soil water characteristic curve (SWCC) and the saturated hydraulic conductivity, on the vapour transfer and the total water content are significant, even if the values of these parameters vary within a quite small range. The temperature gradient, the cooling rate, the water flux at the top and the sealing conditions at the bottom can also lead to an increment of the total volumetric water content. Therefore, these hydraulic parameters and environmental factors can all promote vapour transfer under suitable conditions. The effects of the terms related to vapour transfer in the governing equations on the total water volumetric content are also analyzed. In total, the water increment caused by vapour transfer is large, which can then cause frost damage in silt. The research results in this paper are helpful to understand the influence of factors for canopy effect and also have a great significance for guiding the design and maintenance of high-filling engineering.
Abstract: Canopy effect has been paid more and more attention in high-filling engineering in cold and arid regions of China. Vapour transfer is considered as the main cause of canopy effect in freezing soil in the literature. However, the influencing factors of vapour transfer in freezing soils have not been systematically analyzed in the literature. Based o...
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