Effects of Coincident Response of Structures Subjected to Horizontal and Vertical Ground Motions on Evaluation of Peak Response

2004 ◽  
Author(s):  
Tomoyo Taniguchi ◽  
Mitsuru Takeshita
Keyword(s):  
Normal Distribution ◽  
Soil Structure ◽  
Response Spectrum ◽  
Ground Motions ◽  
Structural Response ◽  
Absolute Maximum ◽  
Peak Response ◽  
Vertical Ground Motions ◽  
Vertical Ground ◽  
Conventional Methods

A response spectrum rule, which considers the coincidence between horizontal and vertical responses, for dynamic analysis of structures subjected to horizontal and vertical ground motions is developed. The ratio of response coincidence, the vertical response to its absolute maximum at the maximum horizontal response, is introduced to express the intensity and direction of the coincident vertical response. It forms a certain normal distribution and is independent of types of earthquake, soil, structure and linearity/non-linearity of structural response. The combination of the maximum expected value of the ratio based on the allowable probability of exceedance and the modal responses gives the maximum expected coincident vertical response at the maximum horizontal response. Comparison of the combined response by the proposed method with the conventional methods highlights the conservativeness of conventional methods in evaluating the vertical response 38% and the combined response 7%.

Empirical Site Amplification Modelling for Horizontal and Vertical Ground Motions in Taiwan

2020 ◽  
Author(s):  
Chun-Hsiang Kuo ◽  
Shu-Hsien Chao ◽  
Che-Min Lin ◽  
Jyun-Yan Huang ◽  
Kuo-Liang Wen
Keyword(s):  
Ground Motion ◽  
Amplification Factor ◽  
Ground Motions ◽  
Free Field ◽  
Site Amplification ◽  
Amplification Factors ◽  
Taipei Basin ◽  
Vertical Ground Motions ◽  
Vertical Ground ◽  
Site Amplification Factor

<p>Site amplification behavior are important in ground motion prediction. Seismic waves were amplified and caused significant building damages in the Taipei Basin by the 1986 Hualien offshore (subduction interface) and the 1999 Chi-Chi earthquakes (crustal), for which both of the epicentral distances were nearly 100 km. To understand local site amplifications in Taiwan, empirical site amplification factors for both horizontal and vertical ground motions are studied using recently constructed strong motion and site databases for the free-field TSMIP stations. Records of large magnitude earthquakes of M<sub>W</sub> larger than 5.5 from 1991 to 2016 were selected for this study. Site amplification factors at site conditions with Vs30 between 120 m/s to 1600 m/s and bedrock accelerations up to 0.8 g were evaluated using ratios of spectral accelerations at different periods. The reference site condition, i.e. the engineering bedrock, is assumed as Vs30 of 760 m/s (B/C boundary) in this study. Our empirical site amplification form are borrowed from the site response function of ASK14 and CY14 ground motion models in NGA-West2 project with slight modification. Therefore our site amplification model includes a linear amplification term and a nonlinear deamplification term. The coefficients of the empirical models were obtained by a nonlinear regression analysis using the selected Taiwan data. Site amplification factor is a function of Vs30 and spectral intensity in the model. Similar linear site amplification factor to the NGA models is derived in our model; however, more significant soil nonlinearity behavior than the NGA models is likely captured from the empirical data. The amplification factor in vertical component is smaller than that in horizontal.</p>

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