The wind tunnel test examines the wind force using gable roof house models with Japanese roof tiles, which is not included in JIS C8955 as the design standard for photovoltaic panels. The test results show the maximum peak wind force for the panels on Japanese roof tiles in all wind directions is within that for the panels on flat surface roof in JIS C8955. On the other hand, the peak wind force on a panel on Japanese roof tiles is greater than that on the panel on flat surface roof in specific wind directions.
In 2016, a countermeasure against the Nankai trough long-period and long-duration ground motions (LPGMs) was announced. However, the response spectrum method (RSM), indicated by the Ministry of Construction notification Vol. 2009, is out of countermeasure. In the case of using RSM for the example waveform of LPGMs published in countermeasure, it tends to overestimate the velocity response of the seismic isolation interface. In this paper, we proposed the method of evaluating velocity response of the seismic isolation interface based on the periodic characteristics of the design response spectra for LPGMs.
The 2011 off the Pacific coast of Tohoku Earthquake caused extensive damage to many buildings by the tsunami, but no structural damage to seismically isolated buildings (SIBs) has been reported, and the safety of SIBs against tsunami is still unclear. In this study, hydraulic model experiments were conducted on SIBs to analyze the surge forces acting on SIBs and the pressure distribution on the superstructure. In addition, the response of the seismic isolation interface was analyzed to study the dynamic effects of the surge forces on SIBs.
In this study, the effect of optimization design for seismic brass damper using concept of Quality engineering and FEM analysis has been confirmed by experiment with small-scale specimen. This seismic damper consists of C2800 brass rod bent in U-shape and mounting piece with steel. The fact that the total energy absorption until fracture was significantly improved by increasing the elongation of the material and changing some specific geometry of the damper is consistent with the conclusion drawn by the optimal design, therefore the authors concluded that the proposed approach is effective for design of seismic damper.
In the previous study, authors proposed new flare-like structure for the purpose of improving buckling property of rubber bearing with small second shape factor. In this study, ultimate properties of high-damping rubber bearings with flare-like structure were predicted based on finite element analysis. Focusing on buckling, horizontal break and tensile break properties as important ultimate properties, finite element analysis was carried out for various shapes of flare-like structure including conventional structure. In addition, validity of the proposed theoretical equation in previous study was confirmed.
Since the response spectrum method (RSM), indicated by the Ministry of Construction notification Vol. 2009 (MCN), is out of the countermeasure against the Nankai trough long-period and long-duration ground motions (LPGMs) announced in 2016, we proposed a method for evaluating the influence of characteristic changes due to repeated deformation using RSM for LPGMs and seismically isolated buildings using lead rubber bearings. However, we identified potential areas for improvement in the effective damping calculation of RSM. In this paper, we propose an effective damping calculation method of RSM using effective ductility factor to improve the accuracy of the proposal method.
This paper performed a series of nonlinear response history analyses (NLRHAs) for double-layered domes supported by single-story substructures to investigate the effect of the roof span L of 60m to 150m, yielding story drift ratio θy, yielding base shear coefficient Cy of 0.3 to 0.6, post-yielding stiffness ratio p of 0.01 to 0.5 on the seismic force reduction factor Ds and ductility ratio μ. Furthermore, a simple force reduction factor evaluation method considering the resonance between the dome and substructure was proposed. Finally, static analyses with an equivalent seismic load with the proposed Ds were compared to the NLRHAs.
In this paper, prediction models of the nonlinear buckling load calculated by the geometric nonlinear analysis are constructed by supervised machine learning for lattice shells composed of steel pipes. Then, structural optimization was performed using the obtained prediction models. Specifically, shell shapes with high nonlinear buckling loads are generated in realistic computational time by solving optimization problems in which nonlinear buckling load calculations are replaced by the obtained prediction models. The effectiveness of the proposed method is verified through several numerical examples.
This study investigates the effect of tri-directional loading on the in-plane shear ultimate capacity of shear walls through loading tests and finite element analysis. The evaluation method considering tri-directional loading conditions for shear capacity of walls is modified and is applied to various sections including rectangular sections, and a low standard deviation of 0.04 or less is achieved for each test specimen shape, enabling high-precision evaluation. Results show an average safety factor of 1.28 using the Hirosawa mean equation with an out-of-plane deformation angle of 1.5%, based on past experimental databases.
In this paper, static loading tests using gravity were conducted to investigate the lateral force transfer mechanisms of a complex ceiling configuration with horizontal and sloped. The test results showed that it was necessary to use different structural models considering the axial stiffness of the suspension members and the bending stiffness of the ceiling plate. Based on numerical analysis, an appropriate structural model was proposed for each ceiling type by using the ratio of the bending stiffness of the ceiling plate to the sum of the vertical axial stiffness of the suspension.
This paper deals with a novel column-to-column bolted joint that is smaller than the conventional ones for applying to square hollow section. First, a cyclic loading test is conducted to clarify the structural performance of the column joint, e.g., stability under multiple repeated design loads and failure mode against excessive input, with varying pretension of bolts, axial force on the column, and the loading direction. Then, calculating methods of yield strength and maximum strength of the column joint are verified based on the test results, and the scope of application on the structural design of the column joint is proposed.
In the top-down construction method, an axial force under construction from steel column to concrete pile is transmitted by bond, stud connectors or bearing resistance at the end of the column.
Recently, the cross-section area of the pile has been smaller than before, and eccentricity of steel column tends to increase.
Focusing on bond resistance between steel column and concrete pile and shear resistance of stud connector, the axial strength of the concrete pile head embedded with steel column is evaluated by cover concrete thickness, eccentricity, and concrete compression strength as parameters.