• Computers and Concrete
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• v.33 no.1
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• pp.41-53
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• 2024

Under constant and cyclic axial compression, square composite short columns reinforced with Self Compacting Concrete (SCC) added with scrap rubber infilled inside steel tubes and with different types of concrete were cast and tested. The test is carried out to find the effectiveness of utilizing an aggregate manufactured from industrial waste and to address the problems associated with the need for alternative reinforcements along with waste management. The main testing parameters are the type of concrete, the effect of fiber inclusion, and the significance of rubber-infilled steel tubes. The failure modes of the columns and axial load-displacement curves of the steel tube-reinforced columns were all thoroughly investigated. According to the test results, all specimens failed due to compression failure with a longitudinal crack along the loading axis. The fiber-reinforced column specimens demonstrated improved ductility and energy absorption. In comparison to the normal-weight concrete columns, the lightweight concrete columns significantly improved the axial load-carrying capacity. The addition of basalt fiber to the columns significantly increased the yield stress and ultimate stress to 9.21%. The corresponding displacement at yield load and ultimate load was reduced to 10.36% and 28.79%, respectively. The precision of volumetric information regarding the obtained crack quantification, aggregates, and the fiber in concrete is studied in detail through image processing using MATLAB environment.

• Steel and Composite Structures
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• v.51 no.3
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• pp.243-260
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• 2024

Thirteen self-compacting recycled concrete filled aluminium tubular (SCRCFAT) columns were tested under concentric compression loads. The effects of the replacement ratio of the recycled concrete aggregate (RCA) and steel fibre (SF) reinforcement on the structural performance of the SCRCFAT columns were studied. A control specimen (C000) was cast with normal concrete without SF to be reference for comparison. Twelve columns were cast using RCA, six columns were cast using concrete incorporating 2% SF while the rest of columns were cast without SF. Failure mode, ductility, ultimate load capacity, axial deformation, ultimate strains, stress-strain response, and stiffness of the SCRCFAT columns were studied. The results showed that, the peak load of tested SCRCFAT columns incorporating 5-100 % RCA without SF reduced by 2.33-11.28 % compared to that of C000. Conversely, the peak load of tested SCRCFAT columns incorporating 5-100% RCA in addition to 2% SF increased by 21.1-40.25%, compared to C000. Consequently, the ultimate axial deformation (Δ) of column C100 (RCA=100% and SF 0%) increased by about 118.9 % compared to C000. The addition of 2% SF to the concrete mix decreased the axial deformation of SCRCFAT columns compared to those cast with 0% SF. Moreover, the stiffness of the columns cast without SF decreased as the RCA % increased. In contrast, the columns stiffness cast with 2% SF increased by 26.28-89.7 % over that of C000. Finally, a theoretical model was proposed to predict the ultimate loads tested SCRCFAT columns and the obtained theoretical results agreed well with the experimental results.

• Steel and Composite Structures
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• v.39 no.4
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• pp.471-491
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• 2021

In this study, we estimate the ultimate load of rectangular concrete-filled steel tubes (CFST) by developing a novel hybrid predictive model (ANN-BCMO) which is a combination of balancing composite motion optimization (BCMO) - a very new optimization technique and artificial neural network (ANN). For this aim, an experimental database consisting of 422 datasets is used for the development and validation of the ANN-BCMO model. Variables in the database are related with the geometrical characteristics of the structural members, and the mechanical properties of the constituent materials (steel and concrete). Validation of the hybrid ANN-BCMO model is carried out by applying standard statistical criteria such as root mean square error (RMSE), coefficient of determination (R²), and mean absolute error (MAE). In addition, the selection of appropriate values for parameters of the hybrid ANN-BCMO is conducted and its robustness is evaluated and compared with the conventional ANN techniques. The results reveal that the new hybrid ANN-BCMO model is a promising tool for prediction of the ultimate load of rectangular CFST, and prove the effective role of BCMO as a powerful algorithm in optimizing and improving the capability of the ANN predictor.

• Korean Journal of Materials Research
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• v.34 no.2
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• pp.72-78
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• 2024

The lightweight and high strength characteristics of aluminum alloy materials make them have promising prospects in the field of construction engineering. This paper primarily focuses on aluminum alloy materials. Aluminum alloy was combined with concrete, wood and carbon fiber reinforced plastic (CFRP) cloth to create a composite column. The axial compression test was then conducted to understand the mechanical properties of different composite structures. It was found that the pure aluminum tube exhibited poor performance in the axial compression test, with an ultimate load of only 302.56 kN. However, the performance of the various composite columns showed varying degrees of improvement. With the increase of the load, the displacement and strain of each specimen rapidly increased, and after reaching the ultimate load, both load and strain gradually decreased. In comparison, the aluminum alloy-concrete composite column performed better than the aluminum alloy-wood composite column, while the aluminum alloy-wood-CFRP cloth composite column demonstrated superior performance. These results highlight excellent performance potential for aluminum alloy-wood-CFRP composite columns in practical applications.

• Journal of Korean Society of Steel Construction
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• v.15 no.1
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• pp.9-15
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• 2003

As building structures become higher and longer-spanned these days, welding fabrication may become more and more difficult as the thickness of the plate increases. The use of high-strength steel is one of the solutions to reduce membrane thickness. Using high-strength steel would reduce the size of the column, which is under high axial load. Performance tests of high-strength box-type and H-shaped welded columns subjected to the combined bending and axial compressive load were carried out with variable axial load and slenderness ratio. Beam-column test results showed that the ultimate strength satisfied both ASD and LRFD codes

• Steel and Composite Structures
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• v.33 no.3
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• pp.375-388
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• 2019

This paper aims to investigate the axial load behavior and stability strength of square tubed steel-reinforced concrete (TSRC) columns. Unlike concrete filled steel tubular (CFST) column, the outer steel tube of a TSRC column is mainly used to provide confinement to the core concrete. Ten specimens were tested under axial compression, and the main test variables included length-to-width ratio (L/B) of the specimens, width-to-thickness ratio (B/t) of the steel tubes, and with or without stud shear connectors on the steel sections. The failure mode, ultimate strength and load-tube stress response of each specimen were summarized and analyzed. The test results indicated that the axial load carried by square tube due to friction and bond of the interface increased with the increase of L/B ratio, while the confinement effect of tube was just the opposite. Parametric studies were performed through ABAQUS based on the test results, and the feasibility of current design codes has also been examined. Finally, a method for calculating the ultimate strength of this composite column was proposed, in which the slenderness effect on the tube confinement was considered.

• Steel and Composite Structures
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• v.27 no.6
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• pp.747-759
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• 2018

This study proposed a new type of concrete column that was confined with both steel angles and spiral hoops, named angle-steel and spiral confined concrete (ASCC) column. A total of 22 ASCC stub columns were tested under axial compression to investigate their behavior. For a comparison, three angle-steel reinforced concrete (ARC) stub columns were also tested. The test results indicated that ASCC column had a superior mechanical performance. The strength, ductility and energy absorption were considerably increased due to the improvement of confinement from spiral hoops. The confinement behavior and failure mechanism of ASCC column were investigated by the analysis of failure mode, load-deformation curve and section-strain distribution. Parametric studies were carried out to examine the influences of different parameters on the axial compression behavior of ASCC columns. A calculation approach was developed to predict the ultimate load carrying capacity of ASCC columns under axial compression. It was validated that the predicted results were in well agreement with the experimental results.

• Steel and Composite Structures
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• v.35 no.5
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• pp.611-625
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• 2020

Experimental investigation and finite element analysis of corroded cold-formed steel (CFS) columns are presented. 11 tensile coupon specimens and 6 stub columns of corroded CFS that had a channel section of C160x60x20 were subjected to monotonic tensile tests and axial compression tests, respectively. The degradation laws of the mechanical properties of the tensile coupon specimens and stub columns were analysed. An appropriate finite element model for the corroded CFS columns was proposed and the influence of local corrosion on the stability performance of the columns was studied by finite element analysis. Finally, the axial capacity of the experimental results was compared with the predictions obtained from the existing design specifications. The results indicated that with an increasing average thickness loss ratio, the ultimate strength, elastic modulus and yield strength decreased for the tensile coupon specimens. Local buckling deformation was not noticeable until the load reached about 90% of the ultimate load for the non-corroded columns, while local buckling deformation was observed when the load was only 40% of the ultimate load for the corroded columns. The maximum reduction of the ultimate load and critical buckling load was 57% and 81.7%, respectively, compared to those values for the non-corroded columns. The ultimate load of the columns with web thickness reduced by 2 mm was 53% lower than that of the non-corroded columns, which indicates that web corrosion most significantly affects the bearing capacity of the columns with localized corrosion. The results predicted using the design specifications of MOHURD were more accurate than those predicted using the design specifications of AISI.

• Steel and Composite Structures
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• v.26 no.5
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• pp.583-594
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• 2018

Although a lot of experimental and analytical investigations have been carried out for steel bridge piers made of SS400 and SM490, the formulas available for SS400 and SM490 are not suitable for evaluating ultimate load and deformation capacities of steel bridge piers made of high strength steel (HSS) SM570. The effect of various parameters is investigated in this paper, including plate width-to-thickness ratio, column slenderness ratio and axial compression force ratio, on the ultimate load and deformation capacities of steel bridge box piers made of SM570 steel subjected to cyclic loading. The elasto-plastic behavior of the steel bridge piers under cyclic loads is simulated through plastic large deformation finite element analysis, in which a modified two-surface model (M2SM) including cyclic hardening is employed to trace the material nonlinearity. An extensive parametric study is conducted to study the influences of structural parameters on the ultimate load and deformation capacities. Based on these analytical investigations, new formulas for predicting ultimate load and deformation capacities of steel bridge piers made of SM570 are proposed. This study extends the ultimate load and deformation capacities evaluation of steel bridge piers from SS400, SM490 steels to SM570 steel, and provides some useful suggestions.

• Proceedings of KOSOMES biannual meeting
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• 2005.05a
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• pp.147-154
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• 2005

The ship plating is generally subjected to combined in-plane load and lateral pressure loads. In-plane loads include axial load and edge shear, which are mainly induced by overall hull girder bending and torsion of the vessel. Lateral pressure is due to water pressure and cargo. These load components are not always applied simultaneously, but more than one can normally exist and interact Hence, for more rational and safe design of ship structures, it is of crucial importance to better understand the interaction relationship of the buckling and ultimate strength for ship plating under combined loads. Actual ship plates are subjected to relatively small water pressure except for the impact load due to slamming and panting etc. The present paper describes an accurate and fast procedure for analyzing the elastic-plastic large deflection behavior up to the ultimate limit state of ship plates under combined loads. In this paper, the ultimate strength characteristics of plates under axial compressive loads and lateral pressure loads are investigated through ANSYS elastic-plastic large deflection finite element analysis with varying lateral pressure load level.