This 21st century will be the age of the global environment and the realization of more sustainable development demands a paradigm shift in many fields technology development, social systems, and many others. Road traffic that is the major form of transportation must also advance in new directions through the introduction of new paradigms, not only to contribute to the mitigation of global environmental problems but to overcome many other challenges traffic accidents, traffic congestion, environmental protection, and soaring maintenance costs. This paper describes the moving magnetically levitated roads for motor vehicles as a new paradigm for road traffic, and has done a basic study of this new structure.
This paper presents histories, current status, and problems associated with steel fabrication in Japan, with particular emphasis on quality assurance of the products. Inspections employed in various phases of steel construction and qualifications required for engineers and technicians are overviewed, and problems to be resolved for assuring good quality to steel buildings are identified. The following observations and recommendations are notable: participation of industry inspectors for the authorization of fabricators; changes of design and construction procedures in view of reduction of the frequency and time of inspections currently stipulated; reevaluation of precision requirements in light of cost effectiveness; and standardization of welded connection design to avoid wrong designs.
Shear connector of headed stud is often employed in steel-concrete hybrid structure. In order to evaluate mechanical property of stud shear connectors, the conventional push-out test method specified in the Japanese Standard is employed. However, in this push-out test, the alternating load can not be applied to the stud. From this point of view, we devise specimen to which the alternating load can be applied easily and carried out a series of static and fatigue tests under pulsating and alternating load conditions. As a result, it can be seen that there is not any difference between fatigue strength characteristics under both load conditions.
A numerical study is carried out on the effect of stiffeners and the corresponding design method of hybrid steel plate girders. A hybrid steel plate girder is a steel girder whose flange plates are composed of high strength steel, and the web plate of low strength steel in order to decrease the material cost. In such a hybrid steel girder, just before the ultimate state, the top and bottom parts of the web plate have been yielded although the flange plates are still remain in the elastic region. Therefore, usual design method cannot be used for the hybrid steel girders. In this paper, numerical analysis is conducted on the strength and behaviour of hybrid steel girders, with especially highlighting the effect of longitudinal stiffeners and the load bearing stiffeners. According to the analysis, it is shown, for example, that the longitudinal stiffeners located lower than the usual position is slightly effective.
Authors conducted a sereis of studies on strength and behaviour of hybrid steel girders in order to obtain the backgound data which should be refered to establish the design method of hybrid steel girders numerically and experimentally. The current paper is aimed to represent the pricipal results of the experimental tests on hybrid steel girders. For the experimental tests, three test models were provided. The first and the second models were provided to investigate the fundamental behaviour and the effects of the longitudinal stiffener. In the third model, stiffening behaviours and effects of web plate by the transverse stiffeners at an intermediate support of continuous hybrid girder were examined. The first model was collapsed by the shear buckling of the web plate, and the second model is collapsed by the vertical buckling of the top flange. The third model shows the torsional buckling alike behaviour in the transverse stiffeners at an intermediate support.
This paper presents an analytical study on the width-to-thickness requirements for flanges and webs of steel beams subjected to cyclic loading. Limit values are derived numerically for the combination of flange and web thickness that ensure sufficient beam rotation capacity. Interaction between lateral-torsional and local buckling was examined, and local buckling induced by lateral-torsional buckling was found to be the major source of strength reduction when the web is relatively thick. Restraining effect of top flanges (due to the presence of floor slabs) was found to be conspicuous and more pronounced for thick webs.
The purpose of this paper is to discuss the performance evaluation of a shear wall damper with low yield strength steel by a dynamic response analysis. In order to indicate the performance to resist earth quakes, we performed a dynamic analysis of multi-story frames with the dampers, which were modelled by hysteresis models derived from a static loading test. The improvement of the frame performance by installing shear wall dampers is discussed being based on the criterion of the performance-based design method.
A nonlinear FEM is employed to analyze the ultimate behavior of steel octagonal-section columns composed of plate with various width-thickness ratios. From numerical results, equivalent averaged stress-strain relations for steel octagonal-section columns including the effect of local buckling are derived. The equivalent stress-strain relations for cyclic loading are also formulated. By introducing the equivalent stress-strain relations into a frame analysis, a numerical method, which is capable of analyzing ultimate behavior consideration of local buckling, is developed. Accuracy of the proposed method is shown through several numerical examples.
In the present paper the effects of differential earthquake motions at supports, which are assumed to be caused by wave passage and local site, on the seismic responses of a large-span reticular dome are checked in several cases. The calculated results show the seismic responses of the dome are reduced by the wave passage effect due to the loss of coherency. On the other hand, the seismic responses of the dome increase because of the additional wave transmission caused by the local site effect. The differential support motions do also influence the internal forces generated in the substructure and foundation as revealed based on the analysis. These obtained data provide the useful information for the design practice of large-span structures to consider the effects of spatial variability of support motions.