• Journal of Korean Society of Steel Construction
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• v.24 no.3
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• pp.257-265
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• 2012

Current trends in steel construction include using tapered, non-compact sections to minimize the use of excess material as much as possible by choosing the cross-sections instead of the classical approach of using prismatic members. In addition, snug conditions, especially the end-plate type, have the advantage of incurring less construction costs and shorter assembly times as opposed to full pre-tensioned conditions. On the other hand, it is important to predict the collapse of the PEB system due to over-loading. Large-scale tests of tapered steel portal frames with non-compact sections were conducted. The primary test parameters included the bolt connection method and the loading condition (vertical and horizontal load). The test results on initial stiffness and load capacity were investigated. Furthermore, comparisons between the analytical and experimental data for load-displacement curves were initiated. In addition, we evaluated the applicability of a snug bolt for the PEB frame in the field.

• Journal of Korean Society of Steel Construction
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• v.10 no.2 s.35
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• pp.211-219
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• 1998

The objective of this study is to investigate the structural behavior of Concrete-Filled Tubular Column H-Beam End-Plate Connections with Penetrated HT-Bolts under monotonic load. Simple bending tests are carried out with 5 kinds of specimens including beam specimen. The parameters of these tests are the thickness (T=22, 26. 30mm) of End-plates and the diameter (M=20, 22mm) of bolts. From the tests, the increasing values of yielding strength and initial stiffness of each specimen were gained as the thickness of End-plates and diameter of bolts are increasing. And the application of Bjorhovde et al and Eurocode 3 classification method by non-dimensional moment-rotation curves to the connections showed that all of them are included in rigid region as far as initial stiffness is concerned and all of them are also rigid as far as ultimate strength.

• Steel and Composite Structures
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• v.34 no.1
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• pp.107-122
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• 2020

Moment resisting stub columns (MRSCs) have increasingly adopted in special moment-resisting frame (SMF) systems in steel building structures, especially in Asian countries. The MRSCs typically provide a lower deformation capacity compared to shear-panel stub columns, a limited post-yield stiffness, and severe strength degradation as adopting slender webs. A new MRSC design with cored configuration, consisting of a core-segment and two side-segments using different steel grades, has been proposed in the study to improve the demerits mentioned above. Several full-scale components of the cored MRSC were experimentally investigated focusing on the hysteretic performance of plastic hinges at the ends. The effects of the depths of the core-segment and the adopted reduced column section details on the hysteretic behavior of the components were examined. The measured hysteretic responses verified that the cored MRSC enabled to provide early yielding, great ductility and energy dissipation, enhanced post-yield stiffness and limited strength degradation due to local buckling of flanges. A parametric study upon the dimensions of the cored MRSC was then conducted using numerical discrete model validated by the measured responses. Finally, a set of model equations were established based on the results of the parametric analysis to accurately estimate strength backbone curves of the cored MRSCs under increasing-amplitude cyclic loadings.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.5
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• pp.709-718
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• 2010

This paper deals with two contents: first, distributions of plate slenderness ratios, stiffened plate slenderness ratios, and stiffener slenderness ratios, which include dimensions and material variables of stiffened plates, of stiffened plates of large-sized in-service vessels, and, second, comparison of compressive strengths. The investigated vessels consist of 59 tankers, 49 bulkers, 28 product carriers, 15 container carriers, and 12 multi-purpose vessels. The tankers are ranged from handymax class to VLCC and larger than Suezmax class. The sizes of the bulkers are 20K to 200K deadweight. The maximum size of containers is less than 5000TEU class. Two parameters for normal distributions of the slenderness ratios (mean and standard deviation) are suggested and probable ranges of the slenderness ratios are also graphically presented. The ultimate strengths of the stiffened plates are presented using the various simplified formulas and nonlinear FEAs. As well, average compressive strength curves, which are necessary for the estimation of the hull girder moment capacities, are proposed. It is proved that formulas for stiffened plates in CSR overestimate slightly in overall average strain range. Mode5 formula (plate buckling mode) in CSR show unreasonably conservative results with respect to the ultimate strengths rather than post-ultimate average compressive strengths.

• Steel and Composite Structures
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• v.30 no.5
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• pp.405-416
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• 2019

Profiled composite slab has been widely used in civil engineering due to its structural merits. The extension of this concept to the bearing wall forms the profiled composite wall, which consists of two external profiled steel plates and infill concrete. This paper investigates the structural behavior of this type of wall under axial compression. A series of compression tests on profiled composite walls consisting of varied types of profiled steel plate and edge confinement have been carried out. The test results are evaluated in terms of failure modes, load-axial displacement curves, strength index, ductility ratio, and load-strain response. It is found that the type of profiled steel plate has influence on the axial capacity and strength index, while edge confinement affects the failure mode and ductility. The test data are compared with the predictions by modern codes such as AISC 360, BS EN 1994-1-1, and CECS 159. It shows that BS EN 1994-1-1 and CECS 159 significantly overestimate the actual compressive capacity of profiled composite walls, while AISC 360 offers reasonable predictions. A method is then proposed, which takes into account the local buckling of profiled steel plates and the reduction in the concrete resistance due to profiling. The predictions show good correlation with the test results.

• Steel and Composite Structures
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• v.41 no.5
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• pp.681-695
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• 2021

Many existing transmission or communication towers designed several decades ago have undergone nonreversible performance degradation, making it hardly meet the additional requirements from upgrades in wind load design codes and extra services of electricity and communication. Therefore, a new-type non-destructive reinforcement method was proposed to reduce the on-site operation of drilling and welding for improving the quality and efficiency of reinforcement. Six built-up steel angle members were tested under compression to examine the reinforcement performance. Subsequently, the cyclic loading test was conducted on a pair of steel angle tower sub-structures to investigate the reinforcement effect, and a simplified prediction method was finally established for calculating the buckling bearing capacity of those new-type retrofitted built-up steel angles. The results indicates that: no apparent difference exists in the initial stiffness for the built-up specimens compared to the unreinforced steel angles; retrofitting the steel angles by single-bolt clamps can guarantee a relatively reasonable reinforcement effect and is suggested for the reduced additional weight and higher construction efficiency; for the substructure test, the latticed substructure retrofitted by the proposed reinforcement method significantly improves the lateral stiffness, the non-deformability and energy dissipation capacity; moreover, an apparent pinching behavior exists in the hysteretic loops, and there is no obvious yield plateau in the skeleton curves; finally, the accuracy validation result indicates that the proposed theoretical model achieves a reasonable agreement with the test results. Accordingly, this study can provide valuable references for the design and application of the non-destructive upgrading project of steel angle towers.

• Earthquakes and Structures
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• v.26 no.1
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• pp.77-86
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• 2024

To investigate the seismic performance of steel pipe-aeolian sand recycled concrete columns, this study designed and produced five specimens. Low-cycle repeated load tests were conducted while maintaining a constant axial compression ratio. The experiment aimed to examine the impact of different aeolian sand replacement rates on the seismic performance of these columns. The test results revealed that the mechanical failure modes of the steel pipe-recycled concrete column and the steel pipe-aeolian sand recycled concrete column were similar. Plastic hinges formed and developed at the column foot, and severe local buckling occurred at the bottom of the steel pipe. Interestingly, the bulging height of the damaged steel pipe was reduced for the specimen mixed with an appropriate amount of wind-deposited sand under the same lateral displacement. The hysteresis curves of all five specimens tested were relatively full, with no significant pinching phenomenon observed. Moreover, compared to steel tube-recycled concrete columns, the steel tube-aeolian sand recycled concrete columns exhibited improved seismic energy dissipation capacity and ductility. However, it was noted that as the aeolian sand replacement rate increased, the bearing capacity of the specimen increased first and then decreased. The seismic performance of the specimen was relatively optimal when the aeolian sand replacement rate was 30%. Upon analysis and comparison, the damage analysis model based on stiffness and energy consumption showed good agreement with the test results and proved suitable for evaluating the damage degree of steel pipe-wind-sand recycled concrete structures.