Seismic Design and Safety Evaluation Analysis of Reinforced Slope with Geogrid in 200m High Core Rock-Fill Dams

2012 ◽  
Vol 204-208 ◽  
pp. 2539-2549
Author(s):  
Hong Jun Li ◽  
Zu Wen Yan ◽  
Yan Yi Zhang
Keyword(s):  
Seismic Design ◽  
Ant Colony Algorithm ◽  
Permanent Deformation ◽  
Evaluation Criteria ◽  
Safety Evaluation ◽  
Time History ◽  
Vertical Acceleration ◽  
Rock Fill ◽  
Sliding Method ◽  
Fill Materials

The reinforcement technique with strengthening geogrid has been widely used in modern seismic design of 200m high rock-fill dams. However, how to evaluate accurately the effects of reinforcement in seismic design and safety evaluation has become a key problem. As compared with the minimum safety factors which are conventionally employed as the evaluation criteria, the earthquake-induced deformation can better reflect the characteristics of rock-fill materials, input motion and the performance of reinforced dams for the earthquake loading. In the improved Newmark sliding method, the effects of reinforcement in enhancing the stability of slope in high rock-fill dams and restricting the permanent deformation of dams are investigated. Firstly, the limit tensile intensity and limit coordinating strain of reinforcement is determined based on the stress-strain relationship of reinforcement-composite and rock-fill materials. Secondly, the location of critical failure face is determined via a combination of ant colony algorithm and Holland method. The yielding acceleration of potential sliding bodies, which considers the limited stress of reinforcement layers and time-history vertical acceleration, is obtained. Finally, the transient movements are accumulated for all the overloadings. It is guaranteed that the reinforcement can reduce the permanent deformation up to 80% and improve the seismic design and safety evaluation of high rock-fill dams subjected to strong ground motion effectively.

scholarly journals A Modified Newmark Methodology for Permanent Deformation Analysis of Rock-Fill Dams

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Hongjun Li ◽  
Hong Zhong ◽  
Zuwen Yan ◽  
Jianming Zhao
Keyword(s):  
Shear Strength ◽  
Safety Evaluation ◽  
Time History ◽  
Deformation Analysis ◽  
Vertical Acceleration ◽  
Seismic Safety ◽  
Critical Acceleration ◽  
Cyclic Shear ◽  
Rock Fill ◽  
Seismic Safety Evaluation

Newmark sliding block approach has been extensively studied by many researchers in the past decades. Significant progress has been made to alleviate its deficiencies and overcome its simplifying assumptions, but some aspects such as the cyclic shear strength and time history vertical acceleration in the Newmark sliding displacement analysis are seldom considered strictly. In the presented research, a modified Newmark methodology for sliding deformation analysis of rock-fill dams subjected to strong earthquake is proposed. In order to make the seismic safety evaluation of dams more realistic, the influence of cyclic shear strength (earthquake-induced reduction of shear strength) and time history vertical acceleration obtained from the dynamic response analysis on the critical acceleration and accumulative sliding displacement of the flexible sliding body is considered. Detailed comparison between the proposed method and existing methods is performed via the analysis of two typical dams, that is, a virtual rock-fill dam with a height of 100 m which is assumed to be situated on rock formation and a real core rock-fill dam with a height of 150 m built on deep overburden layers. It is demonstrated that the cyclic shear strength and time history vertical acceleration within flexible sliding body, as highlighted in the proposed method, have significant effect on the seismic safety evaluation, critical acceleration, and accumulation of sliding deformation of rock-fill dams subjected to strong earthquake loading. The existing approaches tend to provide unconservative evaluation on the consequences of earthquakes on rock-fill dams.

Study on Seismic Permanent Deformation of Earth Rock Fill Dam

2011 ◽  
Vol 105-107 ◽  
pp. 1452-1455
Author(s):  
Guo Bin Zhou ◽  
Jian Ming Zhao ◽  
Yan Feng Wen ◽  
Zheng Quan Yang
Keyword(s):  
Wenchuan Earthquake ◽  
Power Function ◽  
Safety Factor ◽  
Evaluation System ◽  
Permanent Deformation ◽  
Safety Evaluation ◽  
Rock Fill ◽  
The Right ◽  
Seismic Deformation

For the flaw of safety evaluation system using safety factor as control index, seismic permanent deformation is used to evaluate the safety of earth rock fill dam. In this study, the seismic deformation of Zipingpu dam after Wenchuan earthquake is measured and analysis. The deformation in the middle of the riverbed on the crest is the largest. The deformation in the left dam abutment is smaller than that in the right. The seismic permanent deformation on the crest grows rapidly in the first three days, and then develops slowly. The results show that deformation grows along the height of dam with the relation of exponential or power function.

scholarly journals Safety Evaluation of High Concrete-Faced Rockfill Dam Based on Site-Related Response Spectrum Using Scenario Earthquake

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Kai-bin Zhu ◽  
Hong-jun Li ◽  
Xiao-gang Wang ◽  
Xiao-sheng Liu ◽  
Jian-ming Zhao
Keyword(s):  
Seismic Design ◽  
Response Spectrum ◽  
Permanent Deformation ◽  
Safety Evaluation ◽  
Economic Cost ◽  
Response Spectra ◽  
Earthquake Ground Motion ◽  
Uniform Hazard Spectra ◽  
Scenario Earthquake ◽  
Rockfill Dam

To clarify how to arrive at earthquake ground motion parameters for use in evaluating the high rockfill dams during seismic loading conditions, as well as to evaluate reasonably the seismic response of dams subjected to strong earthquake, the differences of design response spectra determined by scenario earthquake and uniform hazard spectra theory are investigated in detail. Coupled with the safety evaluation of the Houziyan concrete-faced rockfill dam (CFRD) with a height of 200 m located in meizoseismal regions, comprehensive comparisons of key safety evaluation indices are performed using input motions determined from the abovementioned two design response spectra. The key safety evaluation indices include dynamic response acceleration, permanent deformation, safety of the impervious body, safety factor, and sliding displacement of the potential failure sliding body. Additionally, the ultimate seismic capability of the high CFRD is discussed based on the two response spectra. More considerable results can be achieved and offered to the engineers for the seismic design. It is obvious that the uniform hazard spectra, which are used to adopt in the safety evaluation of high CFRD, typically result in conservative evaluations and unnecessary economic cost for seismic design and reinforcements.

Structural Performance of Automated Multi-Depth Shuttle Warehouses (Amsws) Under Low-to-Moderate Seismic Actions

2021 ◽  
Author(s):  
Aleksei Kondratenko ◽  
Alper Kanyilmaz ◽  
Carlo Andrea Castiglioni ◽  
Francesco Morelli ◽  
Mohsen Kohrangi
Keyword(s):  
Seismic Design ◽  
Brittle Failure ◽  
Structural Characteristics ◽  
Time History ◽  
Steel Structures ◽  
Current Approach ◽  
Structural Performance ◽  
Future Design ◽  
The Future ◽  
Base Connections

Abstract Automated Multi-Depth Shuttle Warehouses (AMSWs) are compact storage systems that provide a large surface occupation and therefore maximum storage density. AMSWs represent the future of storage technology, providing substantial savings in terms of cost, space, and energy with respect to traditional warehouses. Currently, designers refer to the standard building codes for the seismic design of AMSWs. Since structural characteristics of AMSWs are considerably different from the steel structures of typical buildings, this current approach used by designers is questionable in terms of safety and efficiency. In this article, the behavior of 5 AMSW structures has been studied performing 150 time-history analyses by direct integration including P-Delta effects. Demand/capacity ratios calculated for each element showed the dominance of the brittle failure mechanism in AMSWs subjected to low-to-moderate seismic actions. These mechanisms mainly took place in upright columns and their base connections prior to the activation of ductile energy dissipation mechanisms of the structure. Based on the results, further improvements have been recommended for the future design provisions, which may lead to a safer seismic design of AMSWs.

Seismic Safety Evaluation for Mountainous Highway Bridge Based on Risk Matrix

2011 ◽  
Vol 255-260 ◽  
pp. 4212-4216
Author(s):  
Gong Yuan Xie ◽  
Zhang Yue
Keyword(s):  
Seismic Design ◽  
Seismic Risk ◽  
Control Method ◽  
Safety Evaluation ◽  
Technical Support ◽  
Highway Bridge ◽  
Risk Matrix ◽  
Seismic Safety ◽  
Seismic Safety Evaluation

Risk matrix is applied to evaluate seismic risk on mountainous bridge. In this article, a continuous bridge is used as example to analyze the seismic risk of key position under a usual earthquake. Related control method is proposed to provide technical support for bridge seismic design and operation maintenance.

Fluid dynamics of flapping aquatic flight in the bird wrasse:three-dimensional unsteady computations with fin deformation

2002 ◽  
Vol 205 (19) ◽  
pp. 2997-3008 ◽  
Author(s):  
Ravi Ramamurti ◽  
William C. Sandberg ◽  
Rainald Löhner ◽  
Jeffrey A. Walker ◽  
Mark W. Westneat
Keyword(s):  
Fluid Dynamics ◽  
Steady State ◽  
Three Dimensional ◽  
Force Production ◽  
Time History ◽  
The Body ◽  
Vertical Acceleration ◽  
Field Variation ◽  
Pectoral Fin ◽  
Pectoral Fins

SUMMARY Many fishes that swim with the paired pectoral fins use fin-stroke parameters that produce thrust force from lift in a mechanism of underwater flight. These locomotor mechanisms are of interest to behavioral biologists,biomechanics researchers and engineers. In the present study, we performed the first three-dimensional unsteady computations of fish swimming with oscillating and deforming fins. The objective of these computations was to investigate the fluid dynamics of force production associated with the flapping aquatic flight of the bird wrasse Gomphosus varius. For this computational work, we used the geometry of the wrasse and its pectoral fin,and previously measured fin kinematics, as the starting points for computational investigation of three-dimensional (3-D) unsteady fluid dynamics. We performed a 3-D steady computation and a complete set of 3-D quasisteady computations for a range of pectoral fin positions and surface velocities. An unstructured, grid-based, unsteady Navier—Stokes solver with automatic adaptive remeshing was then used to compute the unsteady flow about the wrasse through several complete cycles of pectoral fin oscillation. The shape deformation of the pectoral fin throughout the oscillation was taken from the experimental kinematics. The pressure distribution on the body of the bird wrasse and its pectoral fins was computed and integrated to give body and fin forces which were decomposed into lift and thrust. The velocity field variation on the surface of the wrasse body, on the pectoral fins and in the near-wake was computed throughout the swimming cycle. We compared our computational results for the steady, quasi-steady and unsteady cases with the experimental data on axial and vertical acceleration obtained from the pectoral fin kinematics experiments. These comparisons show that steady state computations are incapable of describing the fluid dynamics of flapping fins. Quasi-steady state computations, with correct incorporation of the experimental kinematics, are useful when determining trends in force production, but do not provide accurate estimates of the magnitudes of the forces produced. By contrast, unsteady computations about the deforming pectoral fins using experimentally measured fin kinematics were found to give excellent agreement, both in the time history of force production throughout the flapping strokes and in the magnitudes of the generated forces.

Safety Evaluation Of Rock-Fill Dam By Seismic (Masw) And Resistivity Methods

2003 ◽  
Author(s):  
Young-chul Oh ◽  
Hae-sang Jeong ◽  
Young-kyu Lee ◽  
Howoong Shon
Keyword(s):  
Safety Evaluation ◽  
Rock Fill

Direct Displacement Procedure for Performance-Based Seismic Design of Mid-Rise Wood-Framed Structures

2009 ◽  
Vol 25 (3) ◽  
pp. 583-605 ◽  
Author(s):  
Wei Chiang Pang ◽  
David V. Rosowsky
Keyword(s):  
Seismic Design ◽  
Response Spectrum ◽  
Design Procedure ◽  
Time History ◽  
Time History Analysis ◽  
Nonlinear Time History Analysis ◽  
Framed Structures ◽  
History Analysis ◽  
Performance Based Seismic Design ◽  
Nonlinear Time History

This paper presents a direct displacement design (DDD) procedure that can be used for seismic design of multistory wood-framed structures. The proposed procedure is applicable to any pure shear deforming system. The design procedure is a promising design tool for performance-based seismic design since it allows consideration of multiple performance objectives (e.g., damage limitation, safety requirements) without requiring the engineer to perform a complex finite element or nonlinear time-history analysis of the complete structure. A simple procedure based on normalized modal analysis is used to convert the code-specified acceleration response spectrum into a set of interstory drift spectra. These spectra can be used to determine the minimum stiffness required for each floor based on the drift limit requirements. Specific shear walls can then be directly selected from a database of backbone curves. The procedure is illustrated on the design of two three-story ATC-63 archetype buildings, and the results are validated using nonlinear time-history analysis.

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