Importance of Site-Specific Dynamic Soil Properties for Seismic Ground Response Studies

2018 ◽  
Vol 9 (1) ◽  
pp. 78-98 ◽  
Author(s):  
Shiv Shankar Kumar ◽  
Arindam Dey ◽  
A. Murali Krishna
Keyword(s):  
Soil Properties ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Site Specific ◽  
Dynamic Soil Properties ◽  
Acceleration Time Histories ◽  
Seismic Ground Response

This article highlights the implication of site-specific properties on seismic ground response studies. One-dimensional equivalent linear ground response analysis was carried out using site-specific dynamic properties of locally available soils of Guwahati city, and the results are compared with those obtained using existing strain-dependent dynamic properties. Acceleration time histories from three strong motions were used. It was observed that an input motion having a higher peak bedrock acceleration, utilizing experimentally obtained dynamic soil properties, exhibits 38% and 24% lower peak ground acceleration and peak spectral acceleration, respectively, in comparison to the results obtained using standard VD-SI soil models. The amplification characteristics of the strong motions are observed to be significantly influenced by the degradation of damping ratio beyond 1% shear strain. The results highlight the necessity of conducting GRA of any region considering its regional dynamic soil properties to obtain more realistic outcomes.

Dynamic Characterization and Site Response Studies for an Offshore Site Based on Detailed Geotechnical Tests

2015 ◽  
Vol 6 (1) ◽  
pp. 50-80
Author(s):  
T. G. Sitharam ◽  
Naveen James ◽  
Monalisha Nayak
Keyword(s):  
Ground Motion ◽  
Dynamic Properties ◽  
Damping Ratio ◽  
Site Characterization ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Undisturbed Soil ◽  
Design Response Spectrum ◽  
Laboratory Test Results

The uniqueness of this paper is large amount of field test data and in addition laboratory test results on undisturbed soil samples, has been analyzed to capture the effect of local site condition and material properties of overlying soil on seismic ground motion characteristics. This study involves the seismic site characterization and ground response analysis of an offshore site in Western Yemen. From the results of field and laboratory tests, dynamic properties such as shear modulus and damping ratio for a very low to high strain levels was determined and site characterization was also carried out. Using seismic cone penetration test (SCPT) data a new correlation has been developed to predict the shear wave velocity. Synthetic ground motion was generated using Boore's stochastic modeling technique for ground response analysis and peak ground acceleration (PGA) was evaluated and presented in the paper. This paper also presents a site specific design response spectrum based on Eurocode, corresponding to 475 and 2500 year return period.

scholarly journals Evaluation of Dynamic Properties and Ground-Response Analysis of Soil Reinforced with Cement and Biopolymer

2020 ◽  
Vol 20 (5) ◽  
pp. 291-296
Author(s):  
Seongnoh Ahn ◽  
Kwangkuk Ahn ◽  
Changho Lee ◽  
Jun-Dae Lee ◽  
Jongwon Jung
Keyword(s):  
Seismic Performance ◽  
Dynamic Properties ◽  
Ground Improvement ◽  
Damping Ratio ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Ground Acceleration ◽  
Design Earthquake ◽  
Earthquake Damages

In Korea, earthquakes have continued to occur even after the occurrence of Gyeongju and Pohang earthquakes of 2016 and 2017, respectively, raising awareness of earthquakes. Because earthquakes cause damage to not only structures but also humans, it is essential to improve the seismic performance and design earthquake-resistant structures to minimize earthquake damages. If the seismic performance of a structure is improved through ground improvement and reinforcement, ground response analysis should be performed considering the dynamic properties of the site of the structure. In addition, cement has been widely used as a material for ground improvement, but recently, ground improvement methods in which biopolymers are utilized for ecofriendly construction have been investigated extensively. However, studies on the changes in the dynamic properties of ground improved using biopolymers, and the ground-response analysis has not been investigated in detail. In this study, resonant column tests were performed using samples mixed with cement and sodium alginate to evaluate the effects o f ground improvement using a biopolymer. In addition, the dynamic properties of the improved samples were adopted in performing the ground response analysis, which demonstrated confirmed the ground stability after ground improvement. From the results, the ground dynamic properties, shear modulus, and damping ratio were influenced when the biopolymer and cement were mixed with the soil. Furthermore, the ground response analysis confirmed that the maximum ground acceleration on the surface decreased.

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