Erdbebenantwortspektren einer weichen Bodenschicht auf einem Halbraum/Earthquake response spectra of a soft soil layer underlain by a halfspace

Bauingenieur ◽  
2016 ◽  
Vol 91 (04) ◽  
pp. 131-139
Author(s):  
Horst Werkle
Keyword(s):  
Soft Soil ◽  
Soil Layer ◽  
Response Spectra ◽  
Earthquake Response ◽  
Earthquake Response Spectra

Weiche Bodenschichten, wie sie beispielsweise als Tonschichten über steifen Sedimentböden auftreten, beeinflussen die Form eines horizontalen Erdbeben-Antwortspektrums aufgrund von resonanzartigen Effekten der einfallenden SH-Wellen erheblich. Daher werden etwa im EC 8 (deutsches NAD) für weiche Böden mit Scherwellengeschwindigkeiten unter 150 m/s besondere Untersuchungen gefordert. Auf der Grundlage einer intensiven Parameterstudie wurden für das Modell einer homogenen viskoelastischen Bodenschicht auf einem homogenen viskoelastischen Halbraum Gleichungen zur Beschreibung des zugehörigen horizontalen Beschleunigungsantwortspektrums entwickelt. An der Oberfläche des Halbraums wurde ein Antwortspektrum nach EC 8, Boden-/Untergrundklasse C-S angenommen. Die mit den Gleichungen erhaltenen Antwortspektren stimmen mit den nach der Theorie für eindimensionale Scherwellen erhaltenen Ergebnissen gut überein. Sie können unmittelbar zur Ermittlung der Erdbebenbeanspruchungen von Gebäuden auf einer weichen Bodenschicht nach EC 8 verwendet werden.

scholarly journals Design Earthquake Response Spectrum Affected by Shallow Soil Deposit

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Dong-Kwan Kim ◽  
Hong-Gun Park ◽  
Chang-Guk Sun
Keyword(s):  
Soil Depth ◽  
Site Response ◽  
Response Spectrum ◽  
Soft Soil ◽  
Response Spectra ◽  
Earthquake Response ◽  
Ground Acceleration ◽  
Site Class ◽  
Shallow Soil ◽  
Short Period

Site response analyses were performed to investigate the earthquake response of structures with shallow soil depth conditions in Korea. The analysis parameters included the properties of soft soil deposits at 487 sites, input earthquake accelerations, and peak ground-acceleration levels. The response spectra resulting from numerical analyses were compared with the design response spectra (DRS) specified in the 2015 International Building Code. The results showed that the earthquake motion of shallow soft soil was significantly different from that of deep soft soil, which was the basis of the IBC DRS. The responses of the structures were amplified when their dynamic periods were close to those of the site. In the case of sites with dynamic periods less than 0.4 s, the spectral accelerations of short-period structures were greater than those of the DRS corresponding to the site class specified in IBC 2015. On the basis of these results, a new form of DRS and soil factors are proposed.

Amplification Effects of Thin Soft-Surface Layers

2016 ◽  
Vol 32 (4) ◽  
pp. 2109-2126 ◽  
Author(s):  
W. D. Liam Finn ◽  
Francisco Ruz
Keyword(s):  
Soft Soil ◽  
Soil Layer ◽  
Tohoku Earthquake ◽  
Response Spectra ◽  
Surface Layers ◽  
Soft Layer ◽  
The 2011 Tohoku Earthquake ◽  
Amplification Factors ◽  
Soft Surface ◽  
Using Data

The amplification effects of shallow soft-surface layers with respect to an underlying hard-soil layer or rock are studied using data recorded from the 2011 Tohoku earthquake. Twenty-four sites have been studied with depths to rock ranging from 4–30 m. At each site, two records were available: one in rock at the bottom of the borehole at depths of 100–500 m and one on the surface of the soft-soil layer. Analyses of the soil-rock columns were conducted using the program SHAKE. Good agreement was found between calculated and recorded surface spectra, which demonstrated the reliability of SHAKE analyses for the sites under study. Therefore, SHAKE analyses were used to determine the outcrop motions at the top of rock. Amplification factors were determined by comparing characteristics of the surface and outcrop motions such as Fourier and response spectra. Computed amplification factors were correlated with V S30, V soil, and soft layer period, T = 4 H/ V soil. The results show clearly that the most reliable correlations for estimating the amplification of soft shallow surface layers less than 30 m are those based on V S30 and soft layer period, T.

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