• Journal of Korean Society of Steel Construction
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• v.27 no.2
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• pp.169-180
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• 2015

Recently, Seismic performance of the building built in the past is required to review, because the code for seismic design have been reinforced. In 2009, if the revised latest criteria of seismic design is applied, the majority the steel structure of the low-rise concentrically braced system is short of the seismic performance. Also, when the steel braces are subject to compressive load, which causes unstable behavior of the structure. In order to verify the compressive behavior of the reinforced braces, structural performance test was conducted with variables of slenderness ratio and the amount of reinforcement. Therefore, this study suggests restraining the bending buckling of slender H-shaped braces to resist compressive force. In order to verify the compressive behavior of the reinforced braces, structural performance test was conducted with variables of slenderness ratio and the amount of reinforcement.

• Journal of Korean Society of Steel Construction
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• v.27 no.2
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• pp.231-241
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• 2015

The direct strength method (DSM) has been adopted by the NAS (2004) and AS/NZS 4600 (2005) for the design of cold-formed steel members. The method can be successfully applied to the design of welded steel members. This paper reviews the development of the DSM for welded steel structural members. The design strength formulae for welded section columns and beams for the DSM are based on the test results performed on welded H-section, C-section, circular and rectangular hollow section columns, plate girders and stiffened plates. The comparison between the design strength of welded sections predicted by the DSM and that estimated by existing specifications is also provided. The comparison verifies that the DSM can properly predict the compressive, flexural and shear strength of welded section columns and beams with the interaction between local and overall buckling.

• Journal of Korean Society of Steel Construction
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• v.12 no.2 s.45
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• pp.151-165
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• 2000

Since vehicles become large and heavy and traffic volume is increased rapidly, many fatigue damages have been reported in bridge members. In order to prevent fatigue damages of bridge members and maintain safety it is essential to perform rational fatigue check. Only one vehicle is loaded on a bridge deck for the fatigue design. But in reality it is seldom that only one vehicle passes on a bridge deck. Usually more than two vehicles are passing on a bridge deck simultaneously. Therefore, it is necessary to consider the influence of simultaneous loading for a rational fatigue design. In this study, the influence of simultaneous loading is investigated by performing stress variation analysis due to vehicle load on the basis of linear superposition method and Monte-Carlo simulation of traffic flow, and then calculating the measure of fatigue damages.

• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.625-635
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• 1997

The base isolation technique and its benefits in reducing the transmitted earthquake energy into a structure have gained increasing recognition during the last two decades. Unfortunately, the current available design procedures, especially for base-isolated bridges, seem inadequate and too restrictive. As a result, practical design procedure still relies upon a series of deterministic time history analyses. In this study, the evaluation of the possibility of the normal mode method to predict the nonlinear seismic responses of base isolated bridges has been performed. The applicability has been examined through the numerical approach with isolator's elastic or plastic states of the base isolated bridges. Numerical results show that the 1st. mode period and the various responses are varied with the state but are conversed. And, the result show that the normal mode method is applicable to predict the seismic responses and to design the babe isolated bridge. Various analysis method to bridges with bilinearized hysteresis isolator and various pier heights are evalulated.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.683-690
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• 2008

When steel fabricators erect structural members in field, temporary tightening of fastener should be useful. However, if bolt holes are not aligned by production error or natural condition, additional effort andpain should be provided to align bolt holes. It lead to longer period than times of construction (a primarily day of construction) and more cost than originally cost. This problem will be overcomed by oversize or slotted holes. Early, AISC and Eurocode have included provision for design process such oversize or slotted holes. But, domestic design method is not refered about oversize and slotted holes. Meanwhile, domestic design method and construction environment are variance with Europe and the United States of America. Therefore, a suitable design method for oversize and slotted holes in domestic real condition is needed. In this study, we evaluated behavior of the joints and decided the friction coefficient on oversize and slotted holes of friction joints with high strength bolts.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.683-694
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• 2004

Advanced analysis and optimal design of semi-rigid space steel frames were presented. The advanced analysis can predict the combined nonlinear effects of connection, geometry, and material on the behavior and strength of semi-rigid frames. The Kishi-Chen power model was used to describe the nonlinear behavior of semi-rigid connections. Geometric nonlinearity was determined using stability functions. Material nonlinearity was determined using the Column Research Council (CRC) tangent modulus and the parabolic function. The direct search method proposed by Choi and Kim was used as optimization technique. One by one, the member with the largest unit value evaluated using the LRFD interaction equation were placed adjacent to a larger member selected from the database. The objective function was assumed to be the weight of steel frame, while the constraint functions were load-carrying capacities, deflections, inter-story drifts, and the ductility requirements. The member sizes determined using the proposed method were compared to those derived from the conventional LRFD method.

• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.611-620
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• 2003

Shear studs with a diameter of 19mm or 22mm are typically used in steel-concrete composite bridge. For the simplification of details in steel bridges, the convenience of removing concrete slab, and the efficient distribution of shear pockets for precast decks, large studs can be an excellent alternative. Through push-out tests on large stud shear connectors that transcend the limitation of current design codes, static behavior was investigated and comparisons with design equations performed. The shear stiffness of the connectors in elastic range and trilinear load-slip curves were proposed after shear tests on 25mm, 27mm, and 30mm studs. The ultimate slip capacity and ultimate strength of large studs were also evaluated, with the test results revealing conservative values for the design shear strength in Eurocode-4. For 30mm stud shear connectors, the welding quality and bearing capacity of concrete slab should be improved.

• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.661-672
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• 2003

The advanced analysis and optimal design of semi-rigid frame were presented. Advanced analysis can predict the combined nonlinear effects of connection, geometry, and material on the behavior and strength of semi-rigid frames. The Kishi-Chen power model was used to describe the nonlinear behavior of semi-rigid connections. Geometric nonlinearity was determined using stability functions. On the other hand, material nonlinearity was determined using the Column Research Council (CRC) tangent modulus and parabolic function. The direct search method proposed by Choi and Kim was used as optimization technique. The member with the largest unit value evaluated using the LRFD interaction equation was replaced one by one with an adjacent larger member selected from the database. The objective function was assumed as the weight of steel frame, with the constraint functions accounting for load-carrying capacities, deflections. inter-story drifts, and ductility requirement. Member sizes determined by the proposed method were compared with those derived using the conventional LRFD method.

• Journal of Korean Society of Steel Construction
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• v.24 no.2
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• pp.233-243
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• 2012

This study verifies the structural capacity of the composite PHC pile (Pretensioned spun high-strength concrete) consisting of a PHC pile and two CT structural steels. Four full-scale specimens are fabricated and the experimental tests were performed to investigate the flexural behaviors of the composite PHC piles. The composite PHC pile can enhance both the structural capacity and functional convenience, since the web of CT structural steel with holes in the web acts as a shear connector (referred to as the perfobond rib), which can connect concrete and steel. All specimens exhibited flexural failure and the ultimate strengths were larger than the anticipated design strength according to the design standard. Thus, the composite PHC pile can be applicable to wall structures with sufficient strength. In addition, it seems that the web of the CT structural steel with holes performs its role as shear connectors.

• Journal of Korean Society of Steel Construction
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• v.20 no.1
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• pp.9-20
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• 2008

It is important to increase the economy and efficiency of the diaphragm of the steel box girder bridge design. In this study, an experimental test is performed in a 4-span steel box girder bridge, which was under constructed according to the dead load of slab concrete and vehicle load. The test result is analyzed to verify the stress distribution of the diaphragm and the middle span. Next, stresses on the vertical stiffener are analyzed according to height. Stresses on the diaphragm with equal height are arranged respectively. Also, the stress distribution of the diaphragm and the middle span. Next, stress on the vertical stiffeners are analyzed according to height. Stresses on the diaphragm with equal height are arranged respectively. Also, the vertical stiffeners in the diaphragm was studied, and using the analyzed results, the proper length of the ratio of vehicle load with curing concrete to vehicle load with asphalt is calculated in each part of the steel box girder bridge. The results provide data that serve as basis for an economical and efficient design for the steel box girder bridge diaphragm.