scholarly journals Effects of Strong Ground Motion with Identical Response Spectra and Different Duration on Pile Support Mechanism and Seismic Resistance of Spherical Gas Holders on Soft Ground

2021 ◽  
Vol 11 (23) ◽  
pp. 11152
Author(s):  
Mio Kobayashi ◽  
Toshihiro Noda ◽  
Kentaro Nakai ◽  
Toshihiro Takaine ◽  
Akira Asaoka
Keyword(s):  
Seismic Response ◽  
Response Spectrum ◽  
Large Earthquake ◽  
Response Spectra ◽  
Response Analysis ◽  
Soft Ground ◽  
Strong Nonlinearity ◽  
Maximum Acceleration ◽  
Support Mechanism ◽  
Strong Ground

Safety measures are required for spherical gas holders to prevent them from malfunctioning even after a large earthquake. In this study, considering the strong nonlinearity of the ground and damage to the pile during an earthquake, a three-dimensional seismic response analysis of the holder–pile–ground interaction system was conducted for an actual gas holder on the soft ground consisting of alternating layers of sand and clay. In the analysis, the seismic response of the structure to strong ground motions of different durations with the same acceleration response spectrum was verified. The results show that the piles were relatively effective in controlling the settlement when the duration of the earthquake motion was long. This is because the axial force acting on the pile increased due to the redistribution of the holder load caused by the lowering of the effective confining pressure of the sand and clay layers during the earthquake, which increased the bearing capacity of the pile. In contrast, when the duration of the seismic motion was short, the piles had little effect on the reduction in the settlement because the maximum acceleration was higher than that in the former case, and the piles immediately lost their support function.

Study on the Characters of Seismic Response Spectra Based on China Financial Information Mansion

2014 ◽  
Vol 580-583 ◽  
pp. 1729-1733
Author(s):  
Ming Li ◽  
Yuan Qing Wang ◽  
Wei Tao ◽  
Bin Wang ◽  
Qing Xian Yu ◽  
...  
Keyword(s):  
Seismic Response ◽  
Response Spectrum ◽  
Response Spectra ◽  
Financial Information ◽  
Amplification Coefficient ◽  
Response Analysis ◽  
Magnification Factor ◽  
Characteristic Period ◽  
Seismic Coefficient ◽  
Dynamic Magnification Factor

Rare study is done on floor response spectrum of super-high rise building, but it is an important condition for the seismic response analysis of floor subsidiary structure. Therefore, based on the early calculation model of China Financial Information Mansion, the floor response spectrum is calculated under different input ground motion. The floor and ground response spectrum is compared with each other from the seismic coefficient, dynamic amplification coefficient, characteristic period and the form of response spectrum. The results shows that: the floor seismic coefficient and the magnification coefficient are greater or smaller than the ground ones, the biggest difference of which is nearly 1 times; all the floor character period are greater than the ground ones, the biggest difference of which is over 60%; there are obvious differences between the floor and ground dynamic magnification factor spectra form under some conditions, of which the second peak of the former one is probably very large, even near to the peak of the first one, while the latter has no such phenomenon. Therefore, during the process of calculating the seismic response of floor subsidiary structure, it is necessary to consider the change of floor seismic coefficient, dynamic magnification factor, characteristic period and spectra form based on the main structure.

Study on Piping Response Under Multiple Excitation: Part 2 — Validation for Multiple Excitation Analysis of Piping

2013 ◽  
Author(s):  
Satoru Kai ◽  
Tomoyoshi Watakabe ◽  
Naoaki Kaneko ◽  
Kunihiro Tochiki ◽  
Makoto Moriizumi ◽  
...  
Keyword(s):  
Seismic Response ◽  
Seismic Design ◽  
Nuclear Power ◽  
Response Spectrum ◽  
Time History ◽  
Response Spectra ◽  
Shaking Table ◽  
Response Analysis ◽  
Multiple Time ◽  
Floor Response Spectra

The piping in a nuclear power plant is laid across multiple floors of a single building or two buildings, which are supported at many points. As the piping is excited by multiple-inputs from the supporting points during an earthquake, seismic response analysis by multiple excitations is needed to obtain the exact seismic response of the piping. However, few experiments involving such multiple excitation have been performed to verify the validity of multiple excitation analysis. Therefore, analysis of the seismic design of piping in Japan is performed by the enveloped Floor Response Spectrum (FRS), which covers all floor response spectra at all supporting points. The piping response estimated by enveloped FRS is conservative in most cases compared with the actual seismic response by multiple excitations. To perform rational seismic design and evaluation, it is important to investigate the seismic response by multiple excitations and to verify the validity of the analytical method by multiple excitation test. This paper reports the validation results of the multiple-excitation analysis of piping compared with the results of the multiple excitations shaking test using triple uni-axial shaking table and a 3-dimensional piping model (89.1mm diameter and 5.5mm thickness). Three directional moments from the analysis and the shaking test were compared on the validation. As the result, it is confirmed that the analysis by multiple time history excitation corresponds with the test result.

Analytical Study on Seismic Response of Piping Under Multiple Support Excitations

2012 ◽  
Author(s):  
Satoru Kai ◽  
Akihito Otani ◽  
Naoaki Kaneko
Keyword(s):  
Seismic Response ◽  
Response Spectrum ◽  
Preliminary Investigation ◽  
Response Spectra ◽  
Response Analysis ◽  
Local Vibration ◽  
Analysis Methods ◽  
Multiple Input ◽  
Multiple Support ◽  
Experimental Researches

Conventional response spectrum analysis is used for piping seismic design in Japan. When piping is supported by restraints and structures fixed on multiple buildings or floors, the envelope of the response spectra of all supporting points is typically applied for the piping under multiple excitations. The local vibration mode of long piping is difficult to excite by the far input from the vibrating part, so the analysis will overestimate the response. Considering each input from each building or floor can estimate more reasonable seismic response of the piping. The researches about seismic response analysis by multiple input excitations have been performed since 1960s and the analysis methods are used for piping design in the United State. There are a few experimental researches to verify the validity of the analysis method by multiple excitations. So an excitation test by multiple excitations planned to verify the validity of the application. This current study was performed as a preliminary investigation for the excitation test and it was to obtain the seismic response of a piping model by multiple excitations. Several kinds of analysis methods are compared and the characteristics of them are discussed.

Study on Piping Response Under Multiple Excitation: Part 1 — Triple Shaking Table Test of Piping Having Three-Supporting Points

2013 ◽  
Author(s):  
Tomoyoshi Watakabe ◽  
Naoaki Kaneko ◽  
Shigekazu Aida ◽  
Akihito Otani ◽  
Makoto Moriizumi ◽  
...  
Keyword(s):  
Seismic Response ◽  
Seismic Design ◽  
Nuclear Power ◽  
Shaking Table Test ◽  
Response Spectrum ◽  
Response Spectra ◽  
Shaking Table ◽  
Response Analysis ◽  
3 Dimensional ◽  
Floor Response Spectra

The piping in a nuclear power plant is laid across multiple floors of a single building or two buildings, which are supported at many points. As the piping is excited by multiple inputs from the supporting points during an earthquake, seismic response analysis by multiple excitations is needed to obtain the exact seismic response of the piping. However, few experiments involving such multiple excitations have been performed to verify the validity of multiple excitation analysis. Therefore, analysis of the seismic design of piping in Japan is performed by the enveloped Floor Response Spectrum (FRS), which covers all floor response spectra at all supporting points. The piping response estimated by enveloped FRS is conservative in most cases compared with the actual seismic response by multiple excitations. To perform rational seismic design and evaluation, it is important to investigate the seismic response by multiple excitations and verify the validity of the analysis method by multiple-excitation test. This paper reports on the result of the shaking test using triple uni-axial shaking tables and a 3-dimensional piping model (89.1mm in diameter and 5.5mm thickness). The piping model was fixed to three shaking tables, meaning three. Different inputs were possible. By the shaking test, dynamic behavior under multiple excitations was confirmed, and data to verify multiple-excitation analysis was obtained.

Sensitivity analysis of geotechnical site conditions effect on the seismic response of a saturated inhomogeneous poroviscoelastic soil profile

2018 ◽  
Vol 15 (6) ◽  
pp. 661-677 ◽  
Author(s):  
Toufiq Ouzandja ◽  
Mohamed Hadid
Keyword(s):  
Soil Properties ◽  
Seismic Response ◽  
Pore Water ◽  
Soil Profile ◽  
Water Saturation ◽  
Free Field ◽  
Response Spectra ◽  
Response Analysis ◽  
Content Type ◽  
Linear And Nonlinear

Purpose This paper aims to present the investigation of the linear and nonlinear seismic site response of a saturated inhomogeneous poroviscoelastic soil profile for different soil properties, such as pore-water saturation, non-cohesive fines content FC, permeability k, porosity n and coefficient of uniformity Cu. Design/methodology/approach The inhomogeneous soil profile is idealized as a multi-layered saturated poroviscoelastic medium and is characterized by the Biot’s theory, with a shear modulus varying continuously with depth according to the Wichtmann’s model. Seismic response analysis has been evaluated through a computational model, which is based on the exact stiffness matrix method formulated in the frequency domain assuming that the incoming seismic waves consist of inclined P-SV waves. Findings Unlike the horizontal seismic response, the results indicate that the vertical one is strongly affected by the pore water saturation. Moreover, in the case of fully saturated soil profile, the same vertical response spectra are found for the two cases of soil behavior, linear and nonlinear. Originality/value This research is a detailed study of the geotechnical soil properties effect on the bi-directional seismic response of saturated inhomogeneous poroviscoelastic soil profile, which has not been treated before; the results are presented in terms of the peak acceleration ratio, as well as the free-field response spectra and the spectral ratio (V/H).

Optimization Design of Core Thickness of Exterior Frame and Core Hybrid Structures in High-Rise Buildings

2012 ◽  
Vol 166-169 ◽  
pp. 14-18
Author(s):  
Shu Yun Zhang ◽  
Wen Wei Zhao ◽  
Hai Hua Wang
Keyword(s):  
Seismic Response ◽  
Optimization Design ◽  
Dynamic Properties ◽  
Response Spectrum ◽  
Optimization Method ◽  
Hybrid Structure ◽  
Hybrid Structures ◽  
Response Analysis ◽  
High Rise ◽  
Core Thickness

Considering core thickness is important issue to performance of exterior frame and core hybrid structure in high-rise buildings, seismic response analysis is conducted by response spectrum method for finite element models with different core thickness. The optimization design of core thickness of hybrid Structures on the basis of the seismic response is studied, the core thicknesses are chosen as design variables, the objective function about core volume is adopted, some specification requirements such as deformation, the ratio of lateral stiffness to gravity, storey shear to gravity, storey shear of exterior frame, axial compression ratio of column and wall limb, bearing capacity of structural member and core construction are regarded as restricting conditions, the optimal mathematical model is established for reflecting integrity dynamic properties of hybrid structure. The ANSYS software is used for optimizing tool, the hybrid structures optimization design are made through different initial values for verifying convergence of optimization method, the optimal result show that the performances of hybrid structure are improved, the internal forces are reduced and the ratios of inner force born by exterior frames are increased in the optimal scheme.

Seismic Response Analysis for Pier in Considering of Uplift Effect

2011 ◽  
Vol 243-249 ◽  
pp. 4052-4055
Author(s):  
Li Dong Zhao ◽  
Bo Song
Keyword(s):  
Seismic Response ◽  
Earthquake Engineering ◽  
Seismic Isolation ◽  
Ground Motions ◽  
Bending Moment ◽  
Element Model ◽  
Simulation Software ◽  
Response Analysis ◽  
Strong Ground ◽  
Maximum Horizontal Acceleration

In earthquake engineering, researchers have found that many structures were not damaged after strong ground motions because of the rocking effect. In order to reveal the potential application value of the uplift effect on seismic isolation, it will be using numerical simulation software OpenSees to research the seismic response of pier considering uplift. Building the pier’s finite element model and considering the plasticity and nonlinear of the pier and soil spring, the ground motion from El Centro and TCU101 are taken as the input respectively. Through analyzing the result, it is shown that at the base of the pier the maximum bending moment is reduced by 36.93% and 46.70%, and the maximum curvature is also reduced by 78.42% and 87.12% respectively. Meanwhile, the maximum horizontal acceleration at the top of the pier is decreased 12.60% and 16.90%. The uplift effect significantly reduces the plastic deformation and plays a base-isolated role according to the results. It has also found that the earthquakes with velocity pulse effect are dangerous to the structures.

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