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Exposed Column-Base with Multi-Rows of Anchor-Bolts under Bi-Axial Bending
Get PDFapplication/pdfAn anchor-bolt-yield-type exposed column base subjected to biaxial bending moment shows complicated restoring force characteristics due to increase of number of anchor-bolts resisting the bending moment. A wedge device proposed by the authors is applied to the exposed column base to simplify the restoring force characteristics and to improve slip phenomena. The non-slip-type exposed column base with multi-rows of anchor-bolts shows self-centering performance. An experimental study was carried out on both slip-type and non-slip-type exposed column bases to verify advantages of the non-slip-type over the slip-type.departmental bulletin pape
Models of Restoring Force Characteristics for Anchor-Bolt-Yield-Type Exposed Column-Base under Bi-Axial-Bending
Get PDFapplication/pdfAn experimental study of slip-type and non-slip-type exposed column bases subjected to cyclic bi-axial bending moment was made to investigate restoring force characteristics. Based on the test results the following conclusions were drawn: 1) Non-slip-type column bases showed non-slip-type multi-linear cyclic curves, linear from the origin at each loading cycle. 2) Slip-type column bases showed complicated slip-type cyclic curves, especially in 45-degrees cyclic loading because of plastic elongation of central-row of anchor-bolts. 3) Performance of energy absorption of non-slip-type column bases on cyclic loading tests was better than slip-type ones.departmental bulletin pape
Identification of Dynamic Characteristics of a Structure Based upon Evolutionary Spectrum Analysis
Get PDFapplication/pdfThis paper presents an identification algorithm of the dynamic characteristics, such as the natural frequency and the damping factor, of a structure deteriorating under natural environment. In this method, both an acceleration record x(t) of a seismic ground motion at the location of the structure and the structural displacement y(t) due to the ground motion are required. In addition, the respective non-stationary spectrum of x(t) and y(t) and the modulating function of x(t) found from evolutionary spectrum analysis are required. The applicability of the proposed method was shown according to the numerical analysis to a one-degree of freedom system. In the case of a multi-degree of freedom system, the dynamic properties of each mode can be obtained by making use of the modal analysis method. However, the identification of the natural modes of the system will be an important task in the future.departmental bulletin pape
Impression Colors as an Urban Image in Hiroshima
Get PDFapplication/pdfIn my course on “Urban Planning (the 1st semester, 2007)” for sophomores and “Landscape Engineering (the 2nd semester, 2007)” for seniors at our University, I gave such a lecture as the history of Kyoto and changes in the city. On this basis I then assigned the students to obtain and sample a color item typical of Hiroshima and write a report. This required both field work and the use of reference materials. Even students with little experience of writing reports were interested in the topic, and I gave a model to them and to them explained how they should carry out their investigation. After setting similar assignments for the pastsome years, I published a paper in “Research bulletin of the Hiroshima Institute of Tech, vol.42” based on statistical analyses of the reports submitted: “Impressive as an Urban Image in Kyoto”. Before the fifth group carried out their assignment I showed them the published papers, which included the names of students whose reports I cited, and nearly all the students voluntarily submitted several reports each. In choosing the present topic, I aimed to have the students sample Hiroshima’s color culture for themselves, become aware of the long history behind its flavors, and come in contact with traditions unique to Hiroshima. Of the 82 reports (96 colors) received, most of the students chose “red” from Miyajima, carp and a war. When they think of Hiroshima’s Red, every gradation of feeling from joy to grief and history gave the image of color from red to Orange. Also, I have compared vermilion-scarlet in Kyoto with red-crimson in Hiroshima. Color differs from city to city, because each city has a long and glorious histry and changs its appearance as well as image of color with surprising.departmental bulletin pape
A Study on High Effective Routing Method Using Node Loads in Ad-Hoc Networks
Get PDFapplication/pdfAn ad-hoc network technology is focused on realizing the ubiquitous network society. The network, however, has several problems because it is constructed with several independent wireless nodes which might be moved. A lot of routing protocols on such an unstable ad-hoc network have been studied. But most of protocols don’t take account of loads of their nodes in spite of its importance. We have proposed the more effective routing algorithm for the ad-hoc network using the node loads. The proposed method uses a CPU usage, a memory usage, and so on, as a definition of the node load, and also has the features of storing a multiple routes for a dynamic routing, transferring the node load information, and selecting the most effective route from the information. The simulation results show that the performance of the proposed method is better than the existing one in case that there are 50 % of high load nodes in the network.departmental bulletin pape
Basic study on Flood Behavior in River Confluence Region
Get PDFapplication/pdfIn recent year, the torrential rain, which is known as “guerrilla heavy rain”, occurred in many parts of Japan. The large-scale flood attacked us and caused serious damage. Coveying accurate information a disaster prevention to people is necessary for the reduction of serious damage. It is especially important to forecast where the disaster may be expected to happen. The rapid rising water level has the possibility of leading to the flood flow, and we must be accurately informed where it is happening. In this paper, the model experiment and the numerical simulation are carried out on the river confluence area. The calculation is executed by the finite volume method using the code of CFD2000. The vortex is only observed in the experiment, but the occurrence of the vortex and the upstream flow for upstream are seen in the calculation. The results of numerical simulations qualitatively show the experiment well, except some problems. It will be necessary to improve the model about problems in the future.departmental bulletin pape
Curing Prediction Solution of Warp Deformation for Viscoelastic Laminated Body with Chemical Reaction
Get PDFapplication/pdfEpoxy resin is usually used as an encapsulation of IC chips for electronic parts. As for the epoxy resin, a state changes from liquid to solid by the chemical reaction. Hereby, the residual stresses and the warp deformation occur in the electronic parts. In this report, the warp deformation for two laminated bodies consisting of epoxy resin and steel and epoxy resin and printed board, each of which is caused by chemical reaction and thermal load, was examined by the experiment and the theory. In other words, the theoretical contents are the thermo-viscoelastic analysis based on the linear viscoelasticity theory and a simple prediction solution about the laminated bodies consisting of the above-mentioned materials. As a result, it was clarified that the warp deformation for the laminated bodies generated by chemical reaction and thermal load could be predicted by using the combination of thermo-viscoelastic analysis and simple prediction solution which was derived from the bending theory of beam, and that the percentage of the warp deformation caused by chemical reaction was about 15 ～ 20% of the total warp deformation for the laminated bodies.departmental bulletin pape
Lateral Buckling Behavior of Build-Up Member Made of HSA700 High Strength Steel (part 1 Development of loading system)
Get PDFapplication/pdfA new building structure, which absorbs the severe earthguake input energy into a damper, is developed by Japanese steel companies. If we use the high strength steel member (HSA800 steel) as a main frame of a new building structure. We are able to prevent completely main frame under a severe earthquake from damage, and easily repair the building after the earthquake. We proposed the high strength build-up beam member made of two channels’ (HSA800 steel), fastened each other by friction bolts. The high strength build-up member has the following engineering subjects. : 1) Weak axial flexural rigidity of the member depends on friction bolt pitch. 2) Elastic buckling may occur in ordinary design dimension because applying stress of the member is twice higher than ordinary steel member. In this study, we performed three point week axial bending loading tests and four point strong axial bending loading tests to clarify the weak axial flexural rigidity and lateral buckling behavior of the presented high strength build-up beam member.departmental bulletin pape
A Study on Position Estimation Algorithm of Moving Objects with Active RFID Technology
Get PDFapplication/pdfIn order to realize the ubiquitous network society, many kinds of technologies are studied. The RFID technology is one of the important technologies to get the position information of moving objects such as human beings and robots. An active RFID technology is especially important for this field because of the communication distance of a few meters. The RFID tag position is calculated using its signal intensity, but the signal is not always stable because the signal is transferred with the radio wave and its intensity depends on the environment around it. We have studied the position estimation algorithm in order to reduce the dependencies from the environment. The particle filter has been introduced to estimate the position in our proposed algorithm. The accuracy of the position estimation by use of the proposed method is better than that of the existing methods.departmental bulletin pape
Rehabilitation technique of steel structure by means of wedge device
Get PDFapplication/pdfA wedge device consisting of a wedge, a counter-wedge and a spring, is proposed by the authors. The device is applied to earthquake-resistant elements to provide more effective energy absorption under seismic ground motion. New structural elements are also proposed: a non-slip-type column base, a non-compression brace, a self-centering beam-to-column connection and a non-compression knee-brace. An experimental study has been make on these structural elements subjected to cyclic loadings to clarify their earthquake-resistant performance and applicability to rehabilitation.departmental bulletin pape