Development of Site Classification System and Modification of Design Response Spectra Considering Geotechnical Characteristics in Korea

Phytosociology has advanced in various respects since the fundamental groundwork was laid, which was mainly concerned with developing a classification system of vegetation units. Current site classification methods for forests consider not only floristic aspects, but also pedological, topographic and structural characteristics of forest stands. During the summer of 2007, a site mapping was carried out in the ETH Research Forest near Sedrun (Switzerland). This paper describes the methods employed, and it evaluates the applicability thereof based on case studies. Site mapping is based on expert opinion, and as such it includes a certain degree of generalization and subjectivity in the evaluation of stands and their assignment to a site type. However, we propose that site classification constitutes a suitable tool for describing and characterizing the complexity of forest sites. The accurate description of site types strongly facilitates the interpretation and the applicability of a classification system in decision support for sustainable forest management.

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Evaluation of Peak Ground Acceleration and Response Spectra Considering the Local Site Effects

International Journal of Geotechnical Earthquake Engineering ◽

10.4018/jgee.2010090802 ◽

2010 ◽

Vol 1 (1) ◽

pp. 25-41 ◽

Cited By ~ 1

Author(s):

T. G. Sitharam ◽

K. S. Vipin

Keyword(s):

Seismic Hazard ◽

Peak Ground Acceleration ◽

Site Effects ◽

Response Spectra ◽

Probabilistic Logic ◽

Site Classification ◽

Ground Acceleration ◽

Entire Study ◽

Local Site Effects ◽

Local Site

The local site effects play an important role in the evaluation of seismic hazard. The proper evaluation of the local site effects will help in evaluating the amplification factors for different locations. This article deals with the evaluation of peak ground acceleration and response spectra based on the local site effects for the study area. The seismic hazard analysis was done based on a probabilistic logic tree approach and the peak horizontal acceleration (PHA) values at the bed rock level were evaluated. Different methods of site classification have been reviewed in the present work. The surface level peak ground acceleration (PGA) values were evaluated for the entire study area for four different site classes based on NEHRP site classification. The uniform hazard response spectrum (UHRS) has been developed for the city of Bangalore and the details are presented in this work.

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An Empirical Geotechnical Seismic Site Response Procedure

Earthquake Spectra ◽

10.1193/1.1586167 ◽

2001 ◽

Vol 17 (1) ◽

pp. 65-87 ◽

Cited By ~ 107

Author(s):

Adrián Rodríguez-Marek ◽

Jonathan D. Bray ◽

Norman A. Abrahamson

Keyword(s):

Shear Wave ◽

Wave Velocity ◽

Shear Wave Velocity ◽

Classification System ◽

Soil Depth ◽

Site Response ◽

Dynamic Stiffness ◽

Evaluation Procedure ◽

Site Classification ◽

Seismic Site Response

A simplified empirically based seismic site response evaluation procedure that includes measures of the dynamic stiffness of the surficial materials and the depth to bedrock as primary parameters is introduced. This geotechnical site classification scheme provides an alternative to geologic-based and shear wave velocity-based site classification schemes. The proposed scheme is used to analyze the ground motion data from the 1989 Loma Prieta and 1994 Northridge earthquakes. Period-dependent and intensity-dependent spectral acceleration amplification factors for different site conditions are presented. The proposed scheme results in a significant reduction in standard error when compared with a simpler “rock vs. soil” classification system. Moreover, results show that sites previously grouped as “rock” should be subdivided as competent rock sites and weathered soft rock/shallow stiff soil sites to reduce uncertainty in defining site-dependent ground motions. Results also show that soil depth is an important parameter in estimating seismic site response. The standard errors resulting from the proposed site classification system are comparable with those obtained using the more elaborate code-based average shear-wave velocity classification system.

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