scholarly journals Study on the Seismic Effect of the Interbedded Soil Layer in the Yinchuan Alluvial Plain

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Shun Yang ◽  
Xin Han ◽  
Qiyun Lei ◽  
Sihan Yu ◽  
Chao Liu
Keyword(s):  
Seismic Response ◽  
Soil Layer ◽  
Peak Ground Velocity ◽  
Equivalent Linearization ◽  
Silty Clay ◽  
Spectral Acceleration ◽  
Ground Acceleration ◽  
Soil Layers ◽  
Amplification Effect ◽  
Soil Model

This paper presents a numerical analysis of two types of representative site profiles in the Yinchuan Plain under earthquake loading. The analyzed soil profiles, based on borehole investigations performed over the years, are used to explore the seismic response of the sites in this area. In total, eleven stratified soil models are used in this study, which can be grouped into two categories: a single interbedded soil model and multiple interbedded soil model. A one-dimensional equivalent linearization method is applied to evaluate the seismic response of different soil models under four exceeding probabilities in terms of peak ground acceleration (PGA), peak ground velocity (PGV), peak ground displacement (PGD), and spectral acceleration (Sa). The results show that the significant amplification effect of PGA occurs in rare and extremely rare earthquakes, with an amplification ratio of 1.4∼1.7 when the single silty clay layer is located at the model ground. In this scenario, the spectral acceleration is amplified at a period of approximately 1.0 s. For the multilayered soil cases, the amplification effect tends to decrease, whereas the characteristic periods increase with increasing numbers of soil layers and the ground acceleration is deamplified under a high motion intensity when the number of soil layers is ≥ 5. This study, to a certain degree, has reference value for seismic microzonation in this area.

A Direct Time-Domian Integral Method and its Implementation Based on Matlab

2012 ◽  
Vol 166-169 ◽  
pp. 2060-2065
Author(s):  
Mian Shui Rong ◽  
Tao Lu ◽  
Bi Deng Liu
Keyword(s):  
Seismic Response ◽  
Integral Method ◽  
Soft Soil ◽  
Damping Ratio ◽  
Strong Motion ◽  
Equivalent Linearization ◽  
Central Difference ◽  
Skeleton Curve ◽  
Soil Layers ◽  
Domain Integral

The current equivalent linearization method for evaluation of seismic response of soil layers has been widely used by engineers, but it obviously has limits while considering severe earthquake action and dealing with extremely soft soil layers. Developing a direct time-domain integral method is essential. In this paper, a direct-domain integral method is proposed. In the method, the dynamic skeleton curve constitutive model is introduced and it can fit test results of dynamic shear modules ration curve and damping ratio curve simultaneously, central difference integration method is used to solve the dynamic equation, multi-transmitting artificial boundary condition has been conducted to consider the effect of energy transmission through bedrock boundary. In order to implement this method, a program called Dymatlab has been compiled, strong motion records got from the NGA data base for site effects on strong ground motion have been used to analysis the offshore engineering site with thick soft soil layers. The results show that this program can be applied as a reasonable and feasible method for nonlinear seismic response of soil layers.

scholarly journals Seismic Vulnerability Assessment of a Reinforced Concrete Building Located in India

2019 ◽  
Vol 8 (11S) ◽  
pp. 310-314
Keyword(s):  
Vulnerability Assessment ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Equivalent Linearization ◽  
Spectral Acceleration ◽  
Damage State ◽  
Ground Acceleration ◽  
Seismic Vulnerability Assessment ◽  
Performance Point ◽  
Damage States

Over the recent years the natural disaster especially due to the earthquake effect on buildings increases which causes loss of life and property in many places all over the world. The latest development leads to finding the direct losses and damage states of the buildings for various intensities of earthquake ground motions. In the present study, seismic vulnerability assessment was done for a medium rise building (G+5). The design peak ground acceleration of 0.16g and 0.36g were considered for the risk assessment. The nonlinear static pushover analysis was done to fine the performance point, spectral acceleration and corresponding spectral acceleration by Equivalent Linearization (EL) method given by Federal Emergency Management Agency (FEMA-440). The four damage states such as slight, moderate, extreme and collapse has been considered as per HAZUS-MR4. The seismic vulnerability in terms of fragility curves was developed to evaluate the damage probabilities based on HAZUS methodology. The discrete and cumulative damage probability was found for all the damage states of the building which shows the building at 0.16g experience slight damage whereas at 0.36g the moderate damage state equally becomes predominant.

Research of Soil Layers Amplification Effect Based on Strong Seismic Records and Calculations

2014 ◽  
Vol 580-583 ◽  
pp. 1604-1608
Author(s):  
Liang Wang ◽  
Ya Su
Keyword(s):  
Seismic Response ◽  
Response Spectrum ◽  
Soil Conditions ◽  
Predominant Period ◽  
Soil Layers ◽  
Amplification Effect ◽  
Comparison Research ◽  
Program Calculation ◽  
Calculation Results ◽  
Seismic Records

This paper states the comparison research of calculation results from program LSSRLI-1 and program SHAKE2000, with the strong seismic records as well as the site soil conditions by using borehole arrays. The analytical results show that the site soil conditions have an amplification effect on the seismic PGA and response spectrum values, however, the actual seismic records are not consistent with the program calculations on the amplification effect. Besides, the site soil conditions also have an altering effect on the predominant period of seismic response spectrum, where actual seismic records and program calculation results of the altering effect are not the same either.

Intensity Measure Correlations Observed in the NGA-West2 Database, and Dependence of Correlations on Rupture and Site Parameters

2017 ◽  
Vol 33 (1) ◽  
pp. 145-156 ◽  
Author(s):  
Jack W. Baker ◽  
Brendon A. Bradley
Keyword(s):  
Geometric Mean ◽  
Condition Dependence ◽  
Peak Ground Velocity ◽  
Spectral Acceleration ◽  
Intensity Measure ◽  
Ground Acceleration ◽  
Correlation Models ◽  
Continued Use ◽  
S Peak ◽  
Ground Motion Intensity Measure

This manuscript reports ground motion intensity measure ( IM) correlations for a number of IM types, as measured from the NGA-West2 database. IMs considered are Spectral Accelerations with periods from 0.01 s to 10 s, Peak Ground Acceleration, Peak Ground Velocity, and Significant Duration (for 5–75% and 5–95% definitions). Results are shown for correlations of both maximum-direction and geometric mean spectral acceleration values, given the need for such maximum-direction correlations in a new ASCE 7-16 procedure. Additionally, the potential magnitude-, distance- and site-condition-dependence of IM correlations are evaluated. The results are practically important as IM correlations are increasingly used in a range of engineering and seismic hazard calculations. We find that maximum-direction spectral correlations are comparable to correlations for other spectral acceleration definitions, and that the correlations have no practically significant dependence on magnitude, distance or site conditions. These results support the collective understanding that IM correlations are stable across a range of conditions, and as a result, that existing correlation models are generally appropriate for continued use in engineering calculations.

scholarly journals Observations about the seismic response of RC buildings in Mexico City

2020 ◽  
Vol 36 (2_suppl) ◽  
pp. 154-174
Author(s):  
Sergio Alcocer ◽  
Anahid Behrouzi ◽  
Sergio Brena ◽  
Kenneth J Elwood ◽  
Ayhan Irfanoglu ◽  
...  
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Mexico City ◽  
Peak Ground Acceleration ◽  
Structural Damage ◽  
Peak Ground Velocity ◽  
Rc Buildings ◽  
Ground Acceleration ◽  
Better Than

Over 2000 buildings were surveyed by members of the Colegio de Ingenieros (CICM) and Sociedad Mexicana de Ingenieria Estructural (SMIE) in Mexico City following the Puebla-Morelos Earthquake of 2017. This inventory of surveyed buildings included nearly 40 collapses and over 600 buildings deemed to have structural damage. Correlation of damage with peak ground acceleration (PGA), peak ground velocity (PGV), predominant spectral period, building location, and building properties including height, estimated stiffness, and presence of walls or retrofits was investigated for the surveyed buildings. The evidence available suggests that (1) ground motion intensity (PGV) drove the occurrence of damage and (2) buildings with more infill and stiff retrofit systems did better than other buildings.

scholarly journals Probabilistic seismic hazard assessment of the historical peninsula of Istanbul

2012 ◽  
Vol 12 (11) ◽  
pp. 3483-3493 ◽  
Author(s):  
G. Ç. Ince
Keyword(s):  
Seismic Hazard ◽  
Geographical Information Systems ◽  
Ground Movement ◽  
Geographical Information ◽  
Peak Ground Velocity ◽  
Exceedance Probability ◽  
Probabilistic Seismic Hazard Assessment ◽  
Spectral Acceleration ◽  
Ground Acceleration ◽  
Acceleration Parameter

Abstract. In order to design buildings that are resistant to earthquakes, first it is necessary to determine the parameters of ground motion. In this study, the earthquake seismic hazard analysis of the Old City Districts of Istanbul (Fatih and Eminonu) was probabilistically defined. For the analysis, the study zone was divided into 307 cells of 250 × 250 m using geographical information systems, and these cells were used in the mapping of all the data obtained. Then, for a building lifetime of 50 yr, the acceleration parameters of earthquake ground motions, peak ground acceleration, peak ground velocity, and spectral acceleration values of 0.2 s and 1 s were obtained at the bedrock level according to 10% and 40% exceedances. Additionally, in order to produce the artificial acceleration-time records of the ground movement in accordance with the NEHRP acceleration spectrum, the TARSCHTS computer simulation program was utilized. The results of the analysis showed that for the 10% probability of exceedance, the peak bedrock acceleration values ranged from 0.30 g to 0.40 g, and for the 40% exceedance probability the acceleration values ranged from 0.22 g to 0.17 g. The Ss 10% exceedance probability, calculated according to the spectral acceleration parameter, ranged from 0.67 g to 0.85 g and the spectral acceleration parameter S1 varied between 0.22 g–0.28 g. The Ss 40% exceedance probability, calculated according to the spectral acceleration parameter, ranged from 0.46 g to 0.38 g and the spectral acceleration parameter S1 varied from 0.12 g to 0.14 g.

Study on the Influence of Seismic Wave Inputting Interface on the Earthquake Response of Deep Soft Sites

2011 ◽  
Vol 243-249 ◽  
pp. 2523-2528
Author(s):  
Ji Hua Chen ◽  
Ai Hong Zhou ◽  
Qiu Jun Wang ◽  
Ying Jiao Xu
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Response Spectrum ◽  
Soil Layer ◽  
Earthquake Response ◽  
Ground Acceleration ◽  
Vibration Period ◽  
Soil Layers ◽  
Input Interface

Earthquake effects of two typical deep soft sites selected from Tianjin(site 1)and Shanghai(site 2) are studied when the vertical inputting earthquake waves are located in different depth of sites. As far as the shear wave velocity of soil layers is concerned, seven kinds of soil layers in site 1 and eight soil layers in site 2 are selected as the vertical imputing interfaces of earthquake waves. Two acceleration waves recorded during Taft earthquake and Northbridge earthquake are selected, and the peak values of two waves are adjusted to be 0.35m/s2、0 70m /s2 and 0 98m /s2, respectively. The earthquake response of sites is calculated by SHAKE91 program. The results are compared to those of site when the input interfaces of earthquake waves are located in bedrock with shear wave velocity larger than 500m/s. The conclusion is as following: With the depth of input position (or shear wave velocity) increasing, the value of the ground acceleration response spectrum gradually closes to the actual data.; For the general building the soil layer with shear wave velocity for 400m/s or so can be chosen as the input interface, and the building with long natural vibration period should be treated seriously, and the soil layer whose shear wave velocity is above 500m/s can be chosen as the input interface.

scholarly journals Shaking Table Test of Seismic Response of Immersed Tunnels under the Influence of Multiple Factors

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Zhiyong Ouyang ◽  
Jie Cui ◽  
Ruofan Luo ◽  
Peijie Li
Keyword(s):  
Seismic Response ◽  
Influencing Factors ◽  
Seismic Wave ◽  
Structural Damage ◽  
Soil Layer ◽  
Shaking Table ◽  
Site Conditions ◽  
Peak Strain ◽  
Structural Stiffness ◽  
Soil Layers

To explore the dynamic characteristics and influencing factors of immersed tunnels under the action of earthquakes, 5 groups of shaking table model tests were carried out. Three different site conditions (unsaturated sand site, homogeneous saturated sand site, and nonuniform site), structural stiffness, and seismic wave input direction were considered. By comparing the above influencing factors, the seismic response law affecting the immersed tunnels was obtained. The test results show that, under the action of horizontal earthquakes, the liquefaction of sand and the larger tunnel stiffness may influence the acceleration development of the soil layers; seismic wave input directions affect the excellent frequency and frequency range of the soil layers, and the liquefaction of sand and large structural stiffness change the shape of the Fourier spectrum curve of the soil layers; site conditions, structural stiffness, and seismic wave input direction have a significant effect on the internal forces of tunnels. Normally, the strain in the heterogeneous soil layer under the horizontal seismic wave input is the largest, and the peak strain of the upper side of the tunnel side wall and center column is larger than the lower part, while the mechanism of structural damage caused by vertical earthquakes is different.

scholarly journals Three-Dimensional Nonlinear Seismic Response of Immersed Tunnel in Horizontally Layered Site under Obliquely Incident SV Waves

2019 ◽  
Vol 2019 ◽  
pp. 1-17
Author(s):  
Xiaojie Zhou ◽  
Qinghua Liang ◽  
Yueyu Zhang ◽  
Zhongxian Liu ◽  
Ying He
Keyword(s):  
Seismic Response ◽  
Seismic Waves ◽  
Dynamic Stiffness ◽  
Soil Layer ◽  
Three Dimensional ◽  
Equivalent Linearization ◽  
Nonlinear Seismic Response ◽  
Obliquely Incident ◽  
Immersed Tunnel ◽  
Shear Keys

A three-dimensional (3D) detailed numerical model of an immersed tunnel in a horizontally layered site is established in this study. The 3D seismic response of the immersed tunnel in a horizontally layered site subjected to obliquely incident waves is analyzed based on the precise dynamic stiffness matrix of the soil layer and half-space via combined viscous-spring boundary and equivalent node stress methods. The nonlinear effects of external and internal site conditions on the whole model were determined by equivalent linearization algorithm and Mohr–Coulomb model, respectively. The proposed model was then applied to investigate the nonlinear seismic response of an immersed tunnel in the Haihe River subjected to seismic waves of oblique incidence. The dislocation (opening) of pipe joints in the immersed tunnel were analyzed to determine the response characteristics of the shear keys and overall displacement of the tunnel; the dynamic responses of the immersed tunnel subjected to obliquely incident seismic waves markedly differ from those of vertically incident seismic SV waves. The maximum stress value of shear keys and the maximum dislocation of the pipe joint appear as upon critical angle. The overall displacement of the tunnel increases as incident angle increases. Under severe earthquake conditions, both the pipe corners and midspan section of the roof and floor are likely to produce crack. These areas need careful consideration in the seismic design of immersed tunnel structures.

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