• Steel and Composite Structures
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• v.13 no.3
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• pp.295-308
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• 2012

This paper experimentally investigated the buckling capacity of built-up steel columns mainly, Cruciform Columns (CC) and Side-to-Side (SS) columns fabricated from two Universal Beam (UB) sections. A series of nine experimental tests comprised of three UB sections, three CC sections and three SS sections with different lengths were tested to failure to measure the ultimate axial capacity of each column section. The lengths used for each category of columns were 1.8, 2.0, and 2.2 m with slenderness ratios ranging from 39-105. The measured buckling loads of the tested specimens were compared with the predicted ultimate axial capacity using Eurocode 3, AISC LRFD, and BS 5959-1. It was observed that the failure modes of the specimens included flexural buckling, local buckling and flexural-torsional buckling. The results showed that the ultimate axial capacity of the tested cruciform and side-by-side columns were higher than the code predicted design values by up to 20%, with AISC LRFD design values being the least conservative and the Eurocode 3 design values being the most conservative. This study has concluded that cruciform column and side-to-side welded flange columns using universal beam sections are efficient built-up sections that have larger ultimate axial load capacity, larger stiffness with saving in the weight of steel used compared to its equivalent universal beam counterpart.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.298-303
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• 2016

Owing to the advantages of reduced weight and wind effect, the space-framed towers that consist of vertical and horizontal members of circular hollow tubular sections have been adopted widely for various purposes. It is critical to guarantee the strengths of tubular joints where vertical and horizontal members are connected structurally to make the entire space-framed system behave as a single tower structure. In this study, a strength evaluation was conducted for T-type tubular joints subjected to the concurrent action of compression and bending. Three of the available design codes, i.e., AISC, Eurocode 3, ISO 19902 were investigated and a design equation was suggested for an ultimate strength interaction between the axial force and bending moment based on nonlinear finite element analyses by selecting the slenderness ratios at the joints as major parameters.

• Journal of Korean Society of Steel Construction
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• v.17 no.4 s.77
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• pp.491-498
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• 2005

This study involves the development of a computer program to analyze the local buckling stresses for the flange and the web of I-beams under compression at elevated temperatures, and the optimization algorithm to analyze the optimum width-thickness ratios which does not occur their local buckling prior to yield failure. The high-temperature stress-strain relationships of steel used in this study were based on EC3 (Eurocode3) Part1.2 (2000b). In this study, the local buckling stresses and the optimum width-thichness ratios were analyzed considering the influences of the yield stress, local buckling coefficients and width-thickness ratios of the flange and the web. Design examples show the applicability of the computer program developed in this study.

• Journal of the Earthquake Engineering Society of Korea
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• v.26 no.1
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• pp.23-30
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• 2022

This study proposed a simplified finite element analysis procedure for designing the nonstructural masonry wall in the out-of-plane direction. The proposed method is a two-step elastic analysis procedure by bilinearizing the behavior of the masonry wall. The first step analysis was conducted with initial stiffness representing the behavior up to the effective-yield point, and the second step analysis was conducted with post-yield stiffness. In addition, the orthotropic material property of the masonry was considered in the FE analysis. The maximum load was estimated as the sum of the maximum loads in the first and second step analyses. The maximum load was converted into the moment coefficients and compared with those from the yield line method applied in Eurocode 6. The moment coefficients calculated through the proposed procedure showed a good match with those from the yield line method with less than 6% differences.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.545-553
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• 2023

Purpose: This study proposes a casing type of shear key to connect with floating breakwater modules composed of concrete and PE(Poly Ethylene), and evaluates the structural performance of the shear key. Method: According to Eurocode, extreme load tests of shear keys with several cross-sections were conducted. Result: The maximum shear resistance of the casing type is 1.5 times than those of the plain concrete type, and the use of the casing shear key leads to ductile behaviors after its peak shear resistance than the shear key made of reinforced concrete. Conclusion: The use of the proposed casing type of shear key will contributes to improve the safety of the shear connection between modular structures.

• Journal of Korean Society of Steel Construction
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• v.18 no.1
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• pp.113-122
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• 2006

The purpose of this paper is to evaluate the fire resistance of the TSC beam, a composite beam composed of a concrete beam enclosed by steel plates. Since a discrepancy was observed between the structural mechanisms of TSC and typical composite beams, the fire performances of the two beams are likewise believed to be partially dissimilar. In this experiment, small and medium-sized TSC beams were tested under given conditions in the laboratory, with/without one of the most widely used spray-on fire protections in Korea. Furthermore, based on the steel and concrete properties under elevated temperatures that were obtained from Eurocode, temperature development across the section was suggested, analyses. To determine the capacity of a modified plastic section, th e fire performance of the model was also examined.

• Steel and Composite Structures
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• v.21 no.3
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• pp.479-500
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• 2016

Seismic design criteria allow enhancing the structural ductility and controlling the damage distribution. Therefore, detailing rules and design requirements given by current seismic codes might be also beneficial to improve the structural robustness. In this paper a comprehensive parametric study devoted to quantifying the effectiveness of seismic detailing for steel Moment Resisting Frames (MRF) in limiting the progressive collapse under column loss scenarios is presented and discussed. The overall structural performance was analysed through nonlinear static and dynamic analyses. With this regard the following cases were examined: (i) MRF structures designed for wind actions according to Eurocode 1; (ii) MRF structures designed for seismic actions according to Eurocode 8. The investigated parameters were (i) the number of storeys; (ii) the interstorey height; (iii) the span length; (iv) the building plan layout; and (v) the column loss scenario. Results show that structures designed according to capacity design principles are less robust than wind designed ones, provided that the connections have the same capacity threshold in both cases. In addition, the numerical outcomes show that both the number of elements above the removed column and stiffness of beams are the key parameters in arresting progressive collapse.

• Earthquakes and Structures
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• v.19 no.6
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• pp.411-425
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• 2020

Unreinforced masonry (URM) walls present low shear strength and are prone to brittle failure when subjected to inplane seismic overloads. This paper discusses the shear strengthening of URM walls with Textile Reinforced Mortar (TRM) jackets. The available literature is thoroughly reviewed and an extended database is developed including available brick, concrete and stone URM walls retrofitted and subjected to shear tests to assess their strength. Further, the experimental results of the database are compared against the available shear strength design models from ACI 549.4R-13, CNR DT 215 2018, CNR DT 200 R1/2013, Eurocode 6 and Eurocode 8 guidelines as well as Triantafillou and Antonopoulos 2000, Triantafillou 1998, Triantafillou 2016. The performance of the available models is investigated and the prediction average absolute error (AAE) is as high as 40%. A new model is proposed that takes into account the additional contribution of the reinforcing mortar layer of the TRM jacket that is usually neglected. Further, the approach identifies the plethora of different block materials, joint mortars and TRM mortars and grids and introduces rational calibration of their variable contributions on the shear strength. The proposed model provides more accurate shear strength predictions than the existing models for all different types of the URM substrates, with a low AAE equal to 22.95%.

• Steel and Composite Structures
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• v.42 no.5
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• pp.633-647
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• 2022

This paper presents the results from reliability analyses of the current Eurocode 4 (EN 1994-1-1) and AISC 360-16 design models for predicting the resistance of headed stud shear connectors within profiled steel sheeting, when the ribs are oriented transverse to the supporting beam. For comparison purposes, the performance of the alternative "Luxembourg" and "Stuttgart" model were also considered. From an initial database of 611 push-out tests, 269 cases were included in the study, which ensured that the results were valid over a wide range of geometrical and material properties. It was found that the current EN 1994-1-1 design rules deliver a corrected partial safety factor γ_M^* of around 2.0, which is significantly higher than the target value 1.25. Moreover, 179 tests fell within the domain of the concrete-related failure design equation. Notwithstanding this, the EN 1994-1-1 equations provide satisfactory results for re-entrant profiled sheeting. The AISC 360-16 design equation for steel failure covers 263 of the tests in the database and delivers 𝛾_M^*≈2.0. Conversely, whilst the alternative "Stuttgart" model provides an improvement over the current codes, only a corrected partial safety factor of 𝛾_M^*=1.47 is achieved. Finally, the alternative "Luxembourg" design model was found to deliver the required target value, with a corrected partial safety factor 𝛾_M^* between 1.21 and 1.28. Given the fact that the Luxembourg design model is the only model that achieved the target values required by EN 1990, it is recommended as a potential candidate for inclusion within the second generation of Eurocodes.

• Journal of Korean Society of Steel Construction
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• v.10 no.2 s.35
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• pp.153-160
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• 1998

The sectional dimensions and initial crookedness of the RHS(rectangular hollow section, ${\boxe}-75{\times}75{\times}3.2,\;{\boxe}-100{\times}100{\times}4.2,\;{\boxe}-125{\times}125{\times}6.0$) were measured. The axial compressive strength tests for columns with slenderness $46{\sim}84$ were performed as well as stub tests and tensile tests. FEM analysis was also used. The measurement shows that the errors of sectional dimensions are negligible. For the column length corresponding to ${\lambda}=100$, the initial crookedness with the 2.5% probability estimated from the measured results is 1/490, 1/1121 1/1395 for each section respectively. The yield strengths obtained from tensile test are higher than the specified minimum value by more than 30%. The column test shows that the maximum axial resistances are almost same as, or a little higher than the FEM results and the specified strength curves of AISC Specification and Eurocode, when the maximum strengths from the stub tests are used as the yield strength of the steel. But the test results show much higher column strength than those specified in the Standard and Code, when the specified minimum yield strength of the steel is used.