Interaction of Buckling Modes for Cellular Steel Beams Under Flexure

Rujuta A. Bhat,Laxmikant M. Gupta 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.1

Steel beams with web openings are extensively used in commercial structures because of their advantages in saving headroom and for providing a passage for utilities like air ducts, water pipes, etc. Design guidelines for such beams are provided by the EuroCode3 and by AISC design guide. The Indian Standard does not provide the design guides and thus an attempt has been made in this paper to utilize the approach for common beams given in IS800:2007 to obtain design bending strength for cellular beams. Finite element analysis has been carried out to obtain predicted values of bending strength of cellular beams. In order to validate the fi nite element model developed for this study, few examples of cellular beams were selected from literature and the results were compared. Ultimate load at failure, mid-span displacement and modes of failure were the parameters used to validate the developed model. Beam models with three grades of steel (E250, E350 and E450) and varying slenderness values covering section categories from plastic to semi-compact have been analyzed. It was found that while the specifi cations can conservatively predict the bending strength for E250 grade steel, they were found to be quite unconservative for higher grades and specially for the beams having semi-compact webs.

Shear Lag Effect in Welded Single Angle Tension Member

Jagdish R. Dhanuskar,Laxmikant M. Gupta 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.3

The typical failure of a welded single angle tension member is a gross section failure. The rupture strength of the single angle tension member is aff ected by the eff ect of shear lag. Full-scale tests on twenty-seven single angle specimens reported in this paper. Four diff erent angle sections with four diff erent section types were used in the test. The test parameter includes the steel’s grade, length of the connection, the eccentricity of the connection, and balanced and unbalanced weld arrangement. Twenty-three specimens failed by fracture of the gross section area, one failed in mixed mode (angle tear and the weld failure), and the remaining three failed in the weld. To interpret the experimental results, fi nite element analysis was performed on the specimen’s model. The fi nite element model well represents the welded single-angle tension member’s behaviour, and fi nite element results show exemplary test results. The ultimate strengths of the test specimens were also evaluated by using the current design standards (IS 800, AISC, CSA, AS 4100, and EC-3), the (1− x̅/L) rule, and Kulak and Wu’s equation. In general, IS 800 provides a good prediction of test results, AISC and AS 4100 provide a slightly conservative forecast; however, CSA and EC-3 provide a slightly un-conservative prediction. For a balanced weld arrangement, the specimen’s ultimate strength increased with an increase in connection length; however, an increase in connection length does not increase the specimen’s ultimate strength for an unbalanced weld arrangement. The angle specimen’s effi ciency decreased signifi cantly with an increase in eccentricity. The rupture strength predicted by assuming the ultimate strength of the connected leg and the strength contributed by the outstanding leg at the critical section shows a good prediction of the strength over the (1− x̅/L) rule.

Experimental investigation for failure analysis of steel beams with web openings

Samadhan G. Morkhade,Laxmikant M. Gupta 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.6

This paper presents an experimental study on the behaviour of steel beams with different types of web openings. Steel beams with web openings became progressively more accepted as a well-organized structural form in steel construction since their existence. Their complicated design and profiling method provides better flexibility in beam proportioning for strength, depth, size and location of holes. The objective of this study is to carry out the experiments on steel beams with different types of web openings and performed non-linear finite element (FE) analysis of the beams that were considered in the experimental study in order to determine their ultimate load capacity and failure modes for comparison. Ten full scale models of steel beam with web openings have been tested in the experimental investigation. The finite element method has been used to predict their entire response to increasing values of external loading until they lose their load carrying capacity. FE model of each specimen that is utilized in the experimental studies is carried out. These models are used to simulate the experimental work to verify test results and to investigate the nonlinear behaviour of failure modes such as local buckling, lateral torsional buckling, web-post buckling, shear buckling and Vierendeel bending of beams.

Experimental Investigation of Block Shear Failure in a Single Angle Tension Member

Jagdish R. Dhanuskar,Laxmikant M. Gupta 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.5

A limited test data are available for double-bolt line connection in a single angle tension member, which failed in block shear. To address this, twelve single angle tension members with a double bolt-line connection was reported in this paper, considering the block aspect ratio and connection length as the test parameters. All the tested specimens were failed in block shear. For the tested specimens, numerical analysis was performed, which shows good agreement with experimental results. Experimental outcomes were then compared with the current design provisions present in the IS 800, AISC, CSA, AIJ, EC 3, SBC, and with other existing proposed models. These standards and models show some discrepancies with regard to the experimental results. This discrepancy was due to the shear failure plane position as assumed in the design standards. Those shear planes were specifi ed in the standards as net and gross shear planes. However, the experimental and numerical investigation shows that between the gross shear plane and the net shear plane lies the actual shear failure plane. Based on this, the block shear mechanism was modifi ed and proposed a rational equation that provides a more exact prediction of block shear capacity than the current design standards and the other existing models. The proposed block shear equation shows the precise forecast for both single and double-bolt line connections used in a single angle tension member.

Rotation Capacity Prediction of Open Web Steel Beams Using Artificial Neural Networks

Ganesh S. Gawande,Laxmikant M. Gupta 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.4

Artificial neural networks (ANN) are artificial intelligence technologies used in various fields of science and engineering to represent fascinating human behaviours. Engineers frequently deal with incomplete and noisy data, which is one of the areas where neural network (NN) shine. Aim of this study is to use an ANN approach to determine the rotation capacity of open web steel beams. Using a single point load applied at the span's centre, a theoretical, experimental, and analytical study was conducted. Following the results of experimental and analytical comparisons, the ABAQUS software tool was used to assess a total of 88 nonlinear finite element models. Local slenderness ratios of several finite element models differentiate them. Different elements comprising geometrical and mechanical features of open web steel beams were delivered as input to NN models, including flange and web slenderness, depth and breadth of section, load span and angle section. Suggested formulation's accuracy is confirmed by arithmetical regression created using analytical nonlinear finite element modelling and behaviour of the open web steel beam derived analytically was tested experimentally. Based on research and statistical analysis, the current study found that ANN has a great potential for forecasting the rotation capacity of open web steel beams.

Classification of Open Web Steel Beam: An Analytical and Experimental Study

Ganesh S. Gawande,Laxmikant M. Gupta 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.6

The cross-section classification is an important topic in flexural steel member design since it tackles a cross-section's susceptibility to local buckling and specifies design resistance. As a result, work focuses on determining the classification limits for various classes of open web steel beams. A comprehensive investigation considering theoretical analysis, experimentation, and data analysis to assess the impact of a solitary point load applied at the beam's midpoint. Based on findings of the different studies, a total of eighty-eight nonlinear finite element models were examined using the ABAQUS software programme. The different finite element models are distinguished by their local slenderness ratios. Most of the steel design regulations consider the influence of the “individual plate rule”, “restricted load pattern rule”, and “monotonic rule” for cross section classification and neglect the effect of interactive behaviour. From the literature, it is found that classification should be done at the member level rather than at the cross-sectional level. To address this issue, open web steel beams were classified using the box section as a base. The classification limits for distinct classes of open web steel beams were derived at the member level, taking into account the interaction of different failure modes and local buckling modes. This suggestion is based on the effects of local and local-to-overall interaction buckling modes, which are not explicitly addressed by current design rules. Based on existing research and statistical assessment of test data, the current study provides suitable classification limits and rotation capacity formulations for open web steel beams.

Investigation on Shear Deflection Behaviour of Open Web Steel Beams: An Analytical and Experimental Study

Gawande Ganesh S.,Gupta Laxmikant M. 한국강구조학회 2024 International Journal of Steel Structures Vol.24 No.1

Shear defl ection 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 defl ection of an open web steel beam under non-uniform bending. The ABAQUS software package was used to analyse a total of sixty nonlinear fi nite element models, and part of the model’s behaviour was tested experimentally. The fl ange and web slenderness ratios that distinguish the fi nite element models were noted using a codal comparison. In addition to the overall behaviour, the shear defl ection of various member components was calculated and compared to the shear defl ection equation provided by Das and Basole and, Timoshenko and Gere. The fi ndings indicated that load versus defl ection 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 defl ection equation to compute the precise shear defl ection behaviour of an open web steel beam. The accuracy of the proposed formulation is proven by an R-squared (R 2 ) value of 0.999. Additionally, the maximum shear defl ection 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 defl ection. The investigation comes to the further conclusion that the parametric variation signifi cantly aff ects the shear defl ection.