Keun Yeong Oh

Analysis Study on Axial Force in Bolted Connection under Fatigue Load

High-strength bolted connection is widely used for steel structure construction. Because high-strength bolted connection has simple constructability and structural qualification. Especially friction type with high-strength bolted connection has high stiffness and fatigue strength. At this time, initial clamping force is one of main factor to affect the strength and deformation behavior of connection. Therefore, the objective of this study is to investigate reduction of initial clamping force in high-strength bolted connection under fatigue load. And the parameter of this study is the size of the bolt and 3 types of initial clamping force. The analysis is used the finite element analysis program ANSYS Workbench.

An Experimental Evaluation of Structural Performance for High Strength Steel Stub Columns under Eccentric Loads

The researches on strength of members bending-compression were evaluated through experimental tests on eccentrically load of high-strength steel (HSA800). This test was performed on H-shaped steels of high strength steel (HSA800) to verify the P-M correlations of members subjected to combined forces according to axial load ratios. And this strength evaluation test was performed for various P-M combinations on adjusted eccentric distance. The results showed that all the specimens was satisfied with P-M correlations according to design criteria.

Structural Performance Evaluation of Built-Up Stub Steel Column with Various Steel Grades under Concentric Loading

The current local stability criteria (KBC2009, AISC2010) are enacted through theoretical and experimental studies of ordinary steels, but the mechanical properties of high strength steels are different from ordinary steels. The high strength steel in the applicability of design criteria should be needed to review because of increasing market demanding for high strength steel in the high-rise and long span buildings. In this study, stub columns of H-shaped and box section with various steel grades subjected to concentric loading were investigated, and these steels were checked to the applicability of current local stability criteria. The difference between the ordinary steel and high strength steel was compared. As a result of comparison with various steel grades, most specimens were satisfied with the design criteria, but some specimens with lower tensile strength were not reached the required strength. It is considered that the uncertainty of material was the higher when the tensile strength of material was the lower.

Effects of Different Bolted Connection Types on Seismic Performance of Column-Tree Steel Moment Connections

This paper experimentally presents the effects of different bolted connection types on the seismic performance of column-tree steel moment connections used in moment resisting frames. Two full scale test specimens were fabricated and tested: one specimen with slip critical bolted beam splices and the other one with bearing type bolted beam splices. The bearing type splice specimen was expected an improved deformation capacity by means of bolt slippage. The experimental results showed that the slip critical splice specimen successfully developed ductile behavior without brittle fracture until 5% story drift ratio, however for the bearing type splice specimen, the beam bottom flange fractured at 4.0% story drift ratio due to stress concentration around the weld access hole area. However the energy dissipation capacity of the bearing type splice specimen was better than that of the slip critical splice specimen until 4.0% story drift ratio.

The Damage Assessment of Steel Structures Using FDD Method

Mathematical model through system identification techniques is composed of the development of a variety of back Analysis solutions and signal processing technology reflecting physical damage of structures. This study was in progress divided into analysis and experimental research, and it was simulated by simplified model based on relevant theory of damage locations and damage estimates. Steel structure concerned by the vibration and impact load was researched in order to predict the dynamic behavior. The 3rd floor of one bay steel frame structure was used, because analysis of whole structure is inconvenient when analyzing and testing, and it is very hard to accurately predict actual behavior by complexity of model in case of three-dimensional structure. Natural frequency of the simulation was calculated as using ANSYS program, general-purpose finite element analysis program, and damage index was estimated through counting natural frequency when structural damage occurred in the test as using the FDD (Frequency-Domain Decomposition).

The Analytical Study for Seismic Performance of Coupled Steel Plate Shear Wall

In the last several decades, coupled shear wall have become recognized as efficient lateral load resisting systems for high-rise structures, increasingly. Coupled shear walls give considerable lateral stiffness and strength as well as providing an architecturally practical structural system. In this paper, in order to observe seismic performance of coupled steel plate shear wall, models of previous study was verified, and coupled shear wall with steel plate was carried out with various parametric analysis. Parametric analysis was performed with various width of bay. As a result, model that aspect ratio of steel plate was close to 1 was the most structurally safe.

The Prediction of Fatigue Damage Using Dynamic Characteristics for Steel Structures in 154kV Substation

Fatigue damage increases with applied load cycles in a cumulative manner. Cumulative fatigue damage analysis plays a key role in life prediction of structures subjected to field load histories. Steel structures of substations are subjected to a large number of repetitive loading of different magnitudes caused mainly by mechanical equipment such as gas insulated switchgear (GIS). In this paper, a method is presented to predict the fatigue damage of the steel structures of a 153kV substation using dynamic characteristics. Through the field measurements and the fatigue analysis, it was observed that the accumulated fatigue damage was very small after a year of operation and the amount of accumulated fatigue damage will be smaller than 0.2 until the end of the working life. The structural safety of the 153kV substation can be guaranteed by the normal inspection.

Nonlinear Finite Element Analysis of Diagonally Reinforced Coupling Beams with Head Bar Reinforcements

Coupling beams resist lateral loads efficiently is well known in coupled wall systems. In many cases, geometric limits result in coupling beams that are deep in relation to their clear span. Coupling beams with small depth-to-span ratio shall be reinforced with two intersecting groups of diagonally placed bars symmetrical along the mid-span. Its always hard to optimize construction projects. This paper used the finite element software (Abaqus) to analysis and simulate the nonlinear behavior of a new reinforcement called head bar and compared the results to the current standards.

Nonlinear Finite Element Analysis of U Shaped Steel Plate Reinforced Concrete Coupling Beams

Coupling beams have been used in high-rise shear wall buildings widely, which take great advantages of high stiffness, small lateral deformation and easy to satisfy with bearing capacity. Coupling beams exhibit different performance with deep beams, which always have small depth-to-span ratio. According to current standards coupling beams shall be reinforced with two intersecting groups of diagonally placed bars symmetrical along the midspan. Its always hard to optimize construction projects. This paper used the finite element software (Abaqus) to analysis and simulate the nonlinear behavior of steel composite reinforcement and compared the results to the current standards.