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In this study, a CFPBS (Cone-type Friction Pendulum Bearing System) was developed which controls the acceleration delivered to the structure to prevent damage and degradation of the critical communication equipment in case of an earthquake. The isolation performance of the CFPBS was evaluated by numerical analysis. The CFPBS was manufactured in the...
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... shaking table test was conducted in the order shown in Table 3, and the maximum values for each axial direction among the acceleration signals obtained from the acceleration sensor installed on the specimen and the input acceleration signal were compared with the results of numerical dynamic analysis of CFPBS. Figs. 15 and 16 present the PSD function of the CFPBS response acceleration signal during the vibration of an artificial seismic wave (Uni-axial test, PGA=0.25 g). The area of 0.5~10 Hz is believed to be the mode with a large contribution. The specific frequency of the CFPBS is concentrated around the low frequency area <4Hz because of the ...
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... [Hz] (c) 10Hz low pass filtered PSD function Fig. 15 Response signals of the none-patterned CFPBS at an artificial earthquake uni-axial test, PGA=0.24 g Table 4 shows that the CFPBS has weak seismic performance for small-sized earthquakes. On the other hand, for large-sized earthquakes, whose input seismic wave has a PGA over 0.3g, the CFPBS showed outstanding seismic performance with ...
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... acceleration data obtained from shaking table test in Table 4 was converted to the reduction rate μ r by Eq. (15). Fig. 25 compares the reduction rate obtained from numerical dynamic analysis and the design equation. The Kobe NS seismic wave beyond the allowed displacement was excluded. The none-patterned CFPBS showed better seismic control performance than the patterned CFPBS for earthquakes over 0.3 g, and was similar to the numerical dynamic analysis ...
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... and numerical dynamic analysis result of case of μ r was 0.05 Fig. 26 compares the maximum displacement response of CFPBS calculated from numerical analysis and the maximum displacement response measurement from the single-axis shaking table test. μ r was assumed to be 0.011 for the none-patterned CFPBS and 0.05 for the patterned CFPBS just like Fig. 25. The none-patterned CFPBS did not coincide with case of μ r was 0.011, and was similar to the case of 0.05. Regardless of the existence of the pattern, the response displacement of the CFPBS showed a similar tendency, μ r was 0.05, but was approximately 5mm greater. Fig. 27 compares the maximum displacement response of the CFPBS ...
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A CFPBS (Cone-type Friction Pendulum Bearing System) was developed to control the acceleration delivered to a structure to prevent the damage and degradation of critical communication equipment during earthquakes. This study evaluated the isolation performance of the CFPBS by numerical analysis. The CFPBS was manufactured in the shape of a cone dif...
Citations
... ByFig. 1 Aseismic device composed of 4 CFPBS's(Cone-type Friction Pendulum Bearing System) expressing Eq. (4) as a motion equation for force during time, ∆t, it can be expressed as Eq. (5) (Jeon et al. 2011), where μ r is the ratio of the ball radius to the cloud friction coefficient and θ is the slope angle of the CFPBS. The mass (m) can be found from the load to apply to the bearing, and μ r is an arbitrary value. ...
A CFPBS (Cone-type Friction Pendulum Bearing System) was developed to control the acceleration delivered to a structure to prevent the damage and degradation of critical communication equipment during earthquakes. This study evaluated the isolation performance of the CFPBS by numerical analysis. The CFPBS was manufactured in the shape of a cone differenced with the existing FPS (Friction Pendulum System), and a pattern was engraved on the friction surface. The natural frequencies of the CFPBS were evaluated from a free-vibration test with a seismic isolator system consisting of 4 CFPBS. To confirm the earthquake-resistant performance, a numerical analysis program was prepared using the equation of the CFPBS induced from the equations of motion. The equation reported by Tsai for the rolling-type seismic isolation bearings was proposed to design the equation of the CFPBS. Artificial seismic waves that satisfy the maximum earthquake scale of the Korean Building Code-Structural (KBC-2005) were created and verified to review the earthquake-resistant performance of the CFPBS by numerical analysis. The superstructural mass of the CFPBS and the skew angle of friction surface were considered for numerical analysis with El Centro NS, Kobe NS and artificial seismic waves. The CFPBS isolation performance evaluation was based on the numerical analysis results, and comparative analysis was performed between the results from numerical analysis and simplified theoretical equation under the same conditions. The validity of numerical analysis was verified from the shaking table test.
The research, development and use of seismic isolation systems have been increasing with the gradual development of structure safety assurance methods for earthquakes. The High Damping Rubber Bearing (HDRB), one type of seismic isolation system, is a Laminated Rubber Bearing using special High Damping Rubber. However, as its damping function is slightly lower than that of the Lead Rubber Bearing, a similar seismic isolation system, its utilization has not been high. However, the HDRB has a superior damping force to the Natural Rubber Bearing, which has similar materials and shapes, and the existing Lead Rubber Bearing has a maleficence problem in that it contains lead. Thus, studies on HDRBs that do not use lead have increased. In this study, a test targeting the HDRB was done to examine its various dependence properties, such as its compressive stress, frequency and repeated loading. To evaluate the HDRB`s seismic performance in response to several earthquake waves, the shaking table test was performed and the results analyzed. The test used the downscaled bridge model and the HDRB was divided into seismic and non-seismic isolation. Consequently, when the HDRB was applied, the damping effect was higher in the non-seismic case. However, its responses on weak foundations, such as in Mexico City, represented increased shapes. Thus, its seismic isolator.
The demand of natural gas is gradually increasing as a clean fuel in the world. Therefore, LNG storage tanks and related facilities of the importance of leading a community-based facility have emerged. The seismic design of LNG storage tank including seismic analysis have been developed steadily. But, the seismic analysis and design techniques for LNG storage tanks are lacking, in Korea. Consequently, it is necessary to develop an analysis model that LNG storage tanks in isolation system can describe the behavior. Further, LNG storage tank capable of ensuring safety and economy, it is necessary to develop design techniques. The studies have suggested seismic design procedures of LNG storage tanks with isolation system including triple-FPB and idealized complex hysteresis model of triple-FPB.
