A Simple Approach for Estimating the Fundamental Mode Shape of Layered Soil Profiles

2019 ◽  
Vol 13 (01) ◽  
pp. 1950003
Author(s):  
Haizhong Zhang ◽  
Yan-Gang Zhao
Keyword(s):  
Mode Shape ◽  
Fundamental Mode ◽  
Close Agreement ◽  
Site Response ◽  
Vertical Direction ◽  
Simple Approach ◽  
Layered Soil ◽  
Soil Profiles ◽  
Seismic Code ◽  
Response Parameter

The fundamental mode shape of layered soil profiles is a key site response parameter, it has been adopted into the Japanese seismic code to represent the shape of the soil displacement response along the vertical direction. In this study, a simple approach for estimating the fundamental mode shape of layered soil profiles is developed. The proposed approach can directly model the fundamental mode shape and can be conveniently implemented using arithmetic operations, thus making it suitable to be used by the engineers. The assessments of the proposed approach using a series of layered soil profiles demonstrate that it can produce results in close agreement with the actual results.

An Energy-Based Approach to the Generalized Optimal Locations of Viscous Dampers in Two-Way Asymmetrical Buildings

2014 ◽  
Vol 30 (2) ◽  
pp. 867-889 ◽  
Author(s):  
Jui-Liang Lin ◽  
Manh-Tien Bui ◽  
Keh-Chyuan Tsai
Keyword(s):  
Strain Energy ◽  
Ground Motions ◽  
Damping Ratio ◽  
Intrinsic Property ◽  
Simple Approach ◽  
Engineering Practice ◽  
Viscous Dampers ◽  
Response Parameter ◽  
Control Target ◽  
Target Performance

This paper proposes a simple approach to the generalized optimal locations of linear viscous dampers in elastic two-way asymmetrical buildings under bi-directional ground excitations. The control target used in this optimization process is to maximize the average dissipation rate of the overall strain energy of the two-way asymmetrical building under the ground excitation of two bi-directional unit impulses. The proposed control target, referred to as the smeared damping ratio, is an intrinsic property of the building system. Two advantages of the proposed approach appeal to engineering practice. First, the proposed approach does not require a complicated optimization algorithm. Second, due to the employment of an intrinsic property rather than a certain response parameter as the target performance index, the optimal damper locations resulting from the proposed approach are generalized, which are independent on the characteristics of input ground motions.

A Simple Approach for Estimating the First Resonance Peak of Layered Soil Profiles

2018 ◽  
Vol 12 (01) ◽  
pp. 1850005 ◽  
Author(s):  
Haizhong Zhang ◽  
Yan-Gang Zhao
Keyword(s):  
Soil Profile ◽  
Single Layer ◽  
Resonance Peak ◽  
Layered Soil ◽  
Soil Profiles ◽  
Simple Method ◽  
Amplification Ratio ◽  
Local Site ◽  
The One ◽  
Input Motion

The first resonance peak, Gs1, represents the amplification ratio of seismic motion when resonance between input motion and the local site occurs. The Gs1 is important for understanding amplification characteristics of local site, thus it has been adopted for evaluating site effects in the Japanese Seismic Code. Herein, a simple method for estimating the Gs1 of layered soil profiles is proposed. By replacing a multi-layer soil profile on bedrock with an equivalent one-layer soil profile, the Gs1 and fundamental period are easily obtained. To realize the one-layer profile, we develop a procedure to replace a two-layer soil profile on bedrock with an equivalent single-layer profile. This procedure is then applied successively to a multi-layer soil profile to obtain an equivalent single-layer soil profile. The validity of the proposed method is demonstrated by evaluating 67 representative sites. The results obtained using the proposed procedure agree well with those produced by the wave propagation method.

scholarly journals A 10-MHz FREE-FREE BEAM MICROMECHANICAL RESONATOR FABRICATION PROCESS USING SURFACE-MICROMACHINED TECHNOLOGY

2022 ◽  
Vol 36 (06) ◽  
Author(s):  
TAN-LOC NGUYEN
Keyword(s):  
Mode Shape ◽  
Fundamental Mode ◽  
Layout Design ◽  
Fabrication Process ◽  
Q Value ◽  
Standard Process ◽  
Mems Resonator ◽  
Second Mode ◽  
Motional Resistance ◽  
Free Beam

The fabrication process for the designed MEMS resonator using surface-micromachined technology is presented in this paper. A 10-MHz Free-Free beam MEMS resonator is designed to vibrate in the second-mode shape, which is significant improvement compare to the fundamental mode. The design showed a Q value as high as 75,000, which is significant improvement compared to 8,400 VHF F-F beam MEMS resonator by K. Wang; and very low motional resistance (18kΩ). The surface-micromachined technology is used as the standard process for the design. The process is briefly described from the layout design to the experimental fabricated device.

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