Comparison of seismic responses of a reticulated dome under stochastic uniform and spatially correlated and coherent multiple-support excitation for a scenario seismic event

2020 ◽  
Vol 35 (4) ◽  
pp. 113-125
Author(s):  
YG Li ◽  
TJ Liu ◽  
F Fan ◽  
HP Hong
Keyword(s):  
Spatial Correlation ◽  
Seismic Event ◽  
Amplitude Spectrum ◽  
Spatial Coherence ◽  
Single Layer ◽  
Seismic Load ◽  
Seismic Responses ◽  
Spatially Correlated ◽  
Multiple Support ◽  
Support Excitation

Structures with multiple supports can be sensitive to spatial coherence and spatial correlation. Since the historical recordings are insufficient for selecting records that match predefined inter-support distances of a structure, desired seismic magnitude (or intensity) and site to seismic source distance for structural analysis, such records need to be simulated. In this study, we use a procedure that is extended based on the stochastic point-source method to simulate records for scenario events. The application of the simulated records to a single-layer reticulated dome with multiple supports is presented. The application is aimed at investigating the differences between the responses subjected to spatially uniform excitation and to spatially correlated and coherent multiple-support excitation for a scenario seismic event, assessing the relative importance of the spatial coherence and spatial correlation on the responses, and evaluating the effect of the uncertainty in the spatially correlated and coherent records for a scenario event on the statistics of the seismic responses. The analysis results indicate that the spatial correlation of the Fourier amplitude spectrum has a predominant influence on the linear/nonlinear responses, and the consideration of spatially correlated and coherent excitation at multiple supports is very important. The consideration of uniform excitation severely underestimates the seismic load effects as compared to those obtained under spatially correlated and coherent multiple-support excitation.

Vertical and Horizontal Seismic Response Analyses of Long-Span and Single-Layer Spherical Lattice Shell Structure

2014 ◽  
Vol 602-605 ◽  
pp. 602-605
Author(s):  
Jin Sheng He ◽  
She Liang Wang
Keyword(s):  
Vibration Control ◽  
Shell Structure ◽  
Response Spectrum ◽  
Single Layer ◽  
Internal Force ◽  
Seismic Load ◽  
Seismic Responses ◽  
Long Span ◽  
Current Design ◽  
Lattice Shell

The dynamic characteristics of 80 m single-layer spherical lattice shell structure are analyzed to control its vibration under seismic load. Through the response spectrum curve of current design specification, the analyses for the vertical and horizontal seismic responses of the single-layer spherical lattice shell structure are made by CQC, and the displacement response of the nodes and internal force of the rods unit are calculated respectively. The calculation results show that the vertical and horizontal seismic responses of the long-span lattice shell structure are in great difference, and should be performed in vibration control at the same time, which could provide certain references for the seismic design and vibration control of single-layer spherical lattice shell structure.

scholarly journals Estimation of resonance characteristics of single-layer surface-plasmon sensors in liquid solutions using Fano’s approximation in the visible and infrared regions

2019 ◽  
Vol 43 (4) ◽  
pp. 596-604 ◽  
Author(s):  
D.V. Nesterenko ◽  
R.A. Pavelkin ◽  
S. Hayashi
Keyword(s):  
Surface Plasmon ◽  
Single Layer ◽  
Field Enhancement ◽  
Coupled Mode Theory ◽  
Mid Infrared ◽  
Coupled Mode ◽  
Sensing Applications ◽  
Resonance Response ◽  
Liquid Solutions ◽  
Support Excitation

In this work, we consider the use of planar sensing structures, which support excitation of surface plasmon polarition (SPP) modes, for detecting changes in solvents, i.e. water, ethanol, isopropanol. In the structures under study, SPP modes propagate along the interfaces between metals and general solvents. The analysis of characteristics of the resonance response is based on Fano’s approximation within the coupled-mode theory in the visible and infrared regions. The maximum sensitivity and field enhancement are revealed in the near- and mid-infrared regions in the case of ethanol and isopropanol, which enables sensing applications beyond the regions of water absorption.

scholarly journals Influence of Multiple-Support Excitation on Seismic Response of Reinforced Concrete Arch Bridges

2019 ◽  
Vol 10 (1) ◽  
pp. 17 ◽  
Author(s):  
Marta Savor Novak ◽  
Damir Lazarevic ◽  
Josip Atalic ◽  
Mario Uros
Keyword(s):  
Reinforced Concrete ◽  
Spatial Variation ◽  
Seismic Response ◽  
Ground Motion ◽  
Seismic Analysis ◽  
Numerical Study ◽  
Relative Significance ◽  
Multiple Support ◽  
Arch Bridges ◽  
Support Excitation

Although post-earthquake observations identified spatial variation of ground motion (i.e., multiple-support excitation) as a frequent cause of the unfavorable response of long-span bridges, this phenomenon is often not taken into account in seismic design to simplify the calculation procedure. This study investigates the influence of multiple-support excitation accounting for coherency loss and wave-passage effects on the seismic response of reinforced concrete deck arch bridges of long spans founded on rock sites. Parametric numerical study was conducted using the time-history method, the response spectrum method, and a simplified procedure according to the European seismic standards. Results showed that multiple-support excitation had a detrimental influence on response of almost all analyzed bridges regardless of considered arch span. Both considered spatial variation effects, acting separately or simultaneously, proved to be very important, with their relative significance depending on the response values and arch locations analyzed and seismic records used. Therefore, it is suggested that all spatially variable ground-motion effects are taken into account in seismic analysis of similar bridges.

scholarly journals Fluid Flow and Heat Transport Computation for Power-Law Scaling Poroperm Media

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Peter Leary ◽  
Peter Malin ◽  
Rami Niemi
Keyword(s):  
Fluid Flow ◽  
Spatial Correlation ◽  
Fluid Velocity ◽  
Flow Property ◽  
Well Log ◽  
Advective Flow ◽  
Spatially Correlated ◽  
Scale Temperature ◽  
Flow Transport ◽  
Neutron Porosity

In applying Darcy’s law to fluid flow in geologic formations, it is generally assumed that flow variations average to an effectively constant formation flow property. This assumption is, however, fundamentally inaccurate for the ambient crust. Well-log, well-core, and well-flow empirics show that crustal flow spatial variations are systematically correlated from mm to km. Translating crustal flow spatial correlation empirics into numerical form for fluid flow/transport simulation requires computations to be performed on a single global mesh that supports long-range spatial correlation flow structures. Global meshes populated by spatially correlated stochastic poroperm distributions can be processed by 3D finite-element solvers. We model wellbore-logged Dm-scale temperature data due to heat advective flow into a well transecting small faults in a Hm-scale sandstone volume. Wellbore-centric thermal transport is described by Peclet number Pe ≡ a0φv0/D (a0 = wellbore radius, v0 = fluid velocity at a0, φ = mean crustal porosity, and D = rock-water thermal diffusivity). The modelling schema is (i) 3D global mesh for spatially correlated stochastic poropermeability; (ii) ambient percolation flow calibrated by well-core porosity-controlled permeability; (iii) advection via fault-like structures calibrated by well-log neutron porosity; (iv) flow Pe ~ 0.5 in ambient crust and Pe ~ 5 for fault-borne advection.

Influence of Incoherence and Wave Passage Effects on Seismic Performances of Long Immersed Tunnel

2019 ◽  
Vol 16 (05) ◽  
pp. 1840012 ◽  
Author(s):  
Z. Y. Chen ◽  
S. B. Liang ◽  
C. He
Keyword(s):  
Axial Compression ◽  
Time History ◽  
Earthquake Ground Motion ◽  
Seismic Responses ◽  
Low Frequencies ◽  
Passage Effect ◽  
Immersed Tunnel ◽  
Support Excitation ◽  
Wave Passage ◽  
Wave Passage Effect

This paper conducts time history analysis to explore the influence of spatially varying earthquake ground motion (SVEGM) on seismic responses of the long immersed tunnel. Incoherence effect and wave passage effect are mainly focused here. Moreover, three coherency models are adopted to investigate the sensitivity of the computed responses to the models. The calculation results show that SVEGM enlarges seismic responses of the immersed tunnel significantly than uniform excitation. Considering wave passage effect and incoherence effect simultaneously makes the seismic responses increase more sharply than considering the latter only. The deformation of Gina gasket is barely sensitive to coherency model, while the axial compression force is sensitive to coherency model. It indicates suppressing that the fundamental mode and dominating higher-mode response are the hallmark of multi-support excitation. The great differences of three models decay with separation at low frequencies and their coherency in frequency domain are the main reasons that cause the variations of the axial compression forces.

Analysis of Cylindrical Tanks under the Seismic Load

2016 ◽  
Vol 691 ◽  
pp. 285-296 ◽  
Author(s):  
Norbert Jendzelovsky ◽  
Lubomir Balaz
Keyword(s):  
Seismic Event ◽  
Static Load ◽  
Hydrodynamic Pressure ◽  
The Other ◽  
Seismic Load ◽  
Hydrostatic Load ◽  
Symmetrical Loading ◽  
Cylindrical Tanks ◽  
Symmetric Load ◽  
And Storage

The paper deals with cylindrical tanks. Structures of this type have been used in hydraulic engineering, e.g. water towers, sewerage plant tanks. In recent years, cylindrical tanks have been also used in biogas management as fermentation and storage tanks.While the standard hydrostatic load acts symmetrically, it evokes the rotary symmetric load. During the seismic event, the load acts in one direction only, i.e. in the direction of earthquake. This load imposes a non-symmetrical loading of a structure. By a combination of individual loads the resulting forces are slightly non-symmetrical.Specific tank has been modeled. In one model, the solution is made using the quasi-static load induced by the hydrodynamic pressure according to the standard EC1998, part 4 [12]. The other model is presented as a calculation using the modal and spectral analyses under the seismic load. At the conclusion, these two solutions have been compared.

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