Seismic evaluation of asymmetric wall systems using a modified three-dimensional capacity spectrum method

This paper proposes a modified three-dimensional capacity spectrum method to efficiently evaluate the seismic behavior of a building structure with asymmetric walls, where twisting is induced due to lateral loading. This method utilizes the demand surfaces and capacity curves that are created based on the inelastic earthquake response and seismic capacity of the asymmetric wall system, respectively. These two parameters are calculated from the displacement, torsional rotation angle and force coordinates of the structure under seismic loading. The seismic retrofit strategy of existing structures can be effectively determined by applying the proposed three-dimensional capacity spectrum method. In this procedure, a new performance point indicating the enhanced performance of the structure can be easily found by the modification of demand surfaces or capacity curves. The seismic evaluation and retrofitting strategies based on this approach are also discussed

Finite element modeling and experimental verification of lightweight steel floor vibration

Due to the lack of design standard and the difficulty of analysis, the floor vibration analysis of lightweight steel floors has received less attention than the analysis of typical floor structures. In this paper, the finite element model for lightweight steel floors is presented utilizing the rigid link and realistic support restraints. The rigid rink is used to solve the problem of difference in the centroid of beam, joist, and flooring material and to guarantee the same behavior of those members. Two different support restraints, all fixed restraint and mixture of fixed and released restraint, are used in the analysis. The finite element model is verified through the human impact loading test of the full-scale light-weight steel floors that have different joist condition and middle beam. The finite element analysis results indicate that the different joists having same moment of inertia yield similar natural frequencies, while the test results of full-scale floors show that the floor with the closed shaped joists yields higher natural frequency than the floor with open shaped joists. The test results also indicate that the finite element analysis using the mixture of fixed and released support restraint yields closer natural frequencies to those of actual floors

Development of an Efficient Steel Beam Section for Modular Construction Based on Six-Sigma

This study presents a systematic approach for the development of an efficient steel beam section for modular construction based on Six-Sigma. Although the Six-Sigma is frequently implemented in manufacturing and other service industries, it is a relatively new concept in the area of building design and construction. As a first step in this approach, market studies and surveys are conducted to obtain the opinions of potential customers. Then the opinions of customers are converted into quality characteristics for the steel beam using the quality function deployment methodology. A steel hollow flanged channel is chosen as the main modular beam shape, and the design concept is derived and developed by applying the Pugh matrix methodology. A pilot test was performed to validate the effectiveness of the developed beam section. The results indicated that the developed channel beam section showed excellent performance and retained high accuracy in fabrication, thus resulting in a significant reduction of steel consumption

Experimental and Numerical Study on the Characteristics of Motion and Load for a Floating Solar Power Farm under Regular Waves

Recently, the demand for floating solar power farms in lakes and coasts (rather than on land) has been increasing rapidly. It is important to develop a numerical analysis technique that considers environmental conditions to predict structural stability and accurate motion response while designing a floating solar power farm. In this study, we performed a comparison under conditions similar to those of the Inha University towing tank (IUTT) model test to verify the numerical analysis method. The results revealed that heave and pitch movements were dominant under head sea conditions. Relative behavior occurred because of the hinge connection of each unit, and complex motion characteristics appeared depending on the wave conditions. The numerical method was verified based on the motion response and load of the floating solar farm. The validity of the results was also confirmed