• Steel and Composite Structures
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• v.19 no.5
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• pp.1055-1075
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• 2015

In order to investigate the accuracy and applicability of steel equivalent constitutive model, the calculated results were compared with typical tests of steel frames under static and dynamic loading patterns firstly. Secondly, four widely used models for time history analysis of steel frames were compared to discuss the applicability and efficiency of different methods, including shell element model, multi-scale model, equivalent constitutive model (ECM) and traditional beam element model (especially bilinear model). Four-story steel frame models of above-mentioned finite element methods were established. The structural deformation, failure modes and the computational efficiency of different models were compared. Finally, the equivalent constitutive model was applied in seismic incremental dynamic analysis of a ten-floor steel frame and compared with the cyclic hardening model without considering damage and degradation. Meanwhile, the effects of damage and degradation on the seismic performance of steel frame were discussed in depth. The analysis results showed that: damages would lead to larger deformations. Therefore, when the calculated results of steel structures subjected to rare earthquake without considering damage were close to the collapse limit, the actual story drift of structure might already exceed the limit, leading to a certain security risk. ECM could simulate the damage and degradation behaviors of steel structures more accurately, and improve the calculation accuracy of traditional beam element model with acceptable computational efficiency.

• Journal of Korean Society of Steel Construction
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• v.16 no.1 s.68
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• pp.21-32
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• 2004

In this study, a continuous optimum design model with its application program for plane steel frame structures developed. In the model, the sequential unconstrained minimization technique (SUMT) transforming the nonlinear optimization problem with multidesign variables and constraints into an unconstrained minimization problem and the refined plastic hinge analysis method as one of the most effective second-order inelastic analysis methods for steel frame structures were implemented. The total weight of a steel frame structure was taken as the objective function, and the AISC-LRFD code requirements for the local and member buckling, flexural strength, shear strength, axial strength and size of the cross-sectional shapes of members were used for the derivation of constraint equations. To verify the appropriateness of the present model, the optimum designs of serveral plane steel frame structures subject to vertical and horizontal loads were conducted.

• Journal of the Earthquake Engineering Society of Korea
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• v.17 no.4
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• pp.171-180
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• 2013

The purpose of this study is to evaluate the effectiveness of the seismic retrofit performance for a reinforced concrete structure with steel damper. The nonlinear static analysis of the RC frame specimens with and without retrofit using the steel damper was conducted and the reliability of the analysis was verified by comparing the analysis and test results. Using this analysis model and method, additional nonlinear analysis was conducted considering varying stiffness and strength ratios between RC frame and steel damper and the failure mode of RC frame. As the result of the study, the total absorbed energy increased and the damage of RC frame was reduced as stiffness and strength ratios increased. The seismic retrofit performance, evaluated by means of the yield strength, increasing ratio of the absorbed energy and damage of the frame, increased linear proportionally with the increase of the strength ratio. In addition, the seismic retrofit performance was stable for stiffness ratios larger than 4~5. The energy absorption capacity of the frame governed by shear failure was better than that of the frame governed by flexure failure.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.235-242
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• 2001

Inelastic seismic response of steel moment frame structures, which are usually quite gravity load and subject to large displacement under severe earthquake, may be severly influenced by the structure P-Δ effects. The P-Δ effect may have an important impact on the dynamic behavior of the structure in the nonlinear seismic analysis. In multi degree of freedom systems P-Δ effects may significantly affect only a subset of stories or a single story alone. Therefore, a story drift amplification of structure is happened by P-Δeffects and such nonlinear dynamic behaviors are very difficult to evaluate in the structures. In this study, two systems having different design methods of steel moment frame structures are investigated to evaluate the P-Δ effects due to gravity load. The plastic hinge formations, maximum rotational ductility demands, and energy distribution will be compared and evaluated following whether the P-Δ effects are considered or not. And design methods are proposed for the prevention of the instability of structures which due to the P-Δ effects.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.10-11
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• 2013

Green Frame is a column-beam system formed by composite precast concrete column and beam connected with steel buried in both members. During the installation of Green columns, the columns of Green Frame, covering 3 floors per each piece and beams, the eccentricity can be observed due to the construction error and the weight of beam itself. Such eccentricity may have a little influence on a single frame, yet, it can develop critical issues to the installation of subsequent beams or beams on the upper floors in the context of a building as a whole that has multiple frames. These issues lead to delay in frame installation, decrease of productivity and increase of cost, etc. Therefore, this study presents a steel-joint connection method in order to solve the issues. The steel-joint connection method exists on slope plane and reinforcing plate in steel frame buried in composite PC members. Through this method, the issues can be resolved without requiring additional equipment or manpower.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.101-102
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• 2018

There is a risk that the damage caused by frequent earthquakes can lead to the risk of personal injury due to cracks in buildings and collapse of major structures. Although the seismic design of the new building is designed to be reinforced, the existing structure is not exposed to the risk of earthquake. Therefore, it is aimed to develop the steel frame type CFT composite method which can easily reinforce the CFT structural system with excellent seismic performance against the old non - seismic structure.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.14-15
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• 2018

Logistics facilities are characterized by wide spans and high flooring, most of which are constructed with PC (Precast Concrete) methods to meet a wide range of commercial and industrial needs. However, the PC structure is a pin joint design, and the construction cost is increased due to the restrictions caused by the installation process, and the construction period is lengthened. In order to solve the above problem, SMART Frame, which is a structural system similar to the steel frame structure, was developed by embedding a steel frame at both ends of the PC. The purpose of this study is to analyze the erection time reduction effect of steel connected precast concrete components (SMART frames) for long span and heavy loaded logistics buildings compared to existing PC frames. For this study, a logistics building constructed with pin joint PC components is selected as a case. The result is compared with the existing PC frame to confirm the erection time reduction effect.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1523-1526
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• 2007

This study introduces the testing results of the carbody. The load test was performed to evaluate the structural characteristic and stability of the stainless carbody. The carbody is made of stainless steel. The body structure consisted of side frame, under frame, roof frame, and end frame. Of these components, the side frame and under frame were the most important components considering the vehicle and passenger loads. Loading test were performed under the condition based on "Performance Test Standard for Electrical Multiple Unit". The test results showed that the body structure is safe and stable under the condition of designed load.

• Korean Journal of Construction Engineering and Management
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• v.8 no.3
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• pp.150-158
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• 2007

As higher and bigger buildings, steel structure is so for a basic building structure. Quality management of the steel frame work is started from pre plan phase. And classification and relation of works is very important in quality management. The purpose of this study is developing a quality management model for the better quality management in a steel frame work. This model consider a interrelationship of works and $input^{\circ}{\S}utput$ information, and based on the actual condition of current quality management.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.51-56
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• 2000

Demand for new nondestructive evaluations is growing to detect tensile crack growth behavior to predict long term performance of materials and structure in aggressive environments, especially when they are in non-visible area. Acoustic emission technique is well suited to these problems and has drawn a keen interests because of its dynamic detection ability, extreme sensitivity and location of growing defects. In this study, we analysed acoustic emission signals obtained in tensile test of high strength fire resistance steel for frame structure with time frequency analysis methods. The results obtained are summaries as follows ; In the T and TN specimen consisting of ferrite and pearlite grains, most of acoustic emission events were produced near yield point, mainly due to the dislocation activities during the deformation. However, B specimen under $600^{\circ}C$ - 10min had a two peak which was attribute to the presence of martensite phase. The first peak is before yield point the second is after yield point. The sources of second acoustic emission peak were the debonding of martensite-martensite interface and the micro-cracking of brittle martensite phase. In $600^{\circ}C$-30min to $700^{\circ}C$-60min specimens, many signals were observed from area before yield point and counts were decreased after yield point.