scholarly journals Seismic Analysis of Deep Water Pile Foundation Based on Three-Dimensional Potential-Based Fluid Elements

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Kai Wei ◽  
Wancheng Yuan
Keyword(s):  
Experimental Data ◽  
Deep Water ◽  
Pile Foundation ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Time History ◽  
Water Systems ◽  
Interface Elements ◽  
Complex Effect ◽  
Structure Interaction

This paper investigates the use of three-dimensional (3D) ϕ-u potential-based fluid elements for seismic analyses of deep water pile foundation. The mathematical derivations of the potential-based formulations are presented for reference. The potential-based modeling technique is studied and validated through experimental data and analytical solutions. Earthquake time history analyses for a 9-pile foundation in dry and different water environments are conducted, respectively. The seismic responses are discussed to investigate the complex effect of earthquake-induced fluid-structure interaction. Through the analyses, the potential-based fluid and interface elements are shown to perform adequately for the seismic analyses of pile foundation-water systems, and some interesting conclusions and recommendations are drawn.

A simple approach for optimal allocation of dampers in nonsymmetrical 3D multi-storey structures

2014 ◽  
Vol 14 (03) ◽  
pp. 1350074 ◽  
Author(s):  
L. J. Leu ◽  
J. T. Chang
Keyword(s):  
Optimal Allocation ◽  
Seismic Analysis ◽  
Search Algorithm ◽  
Three Dimensional ◽  
Time History ◽  
Simple Approach ◽  
Optimal Placement ◽  
Drift Ratio ◽  
History Analysis ◽  
Stop Criterion

A new simple approach is proposed to search for the optimal placement of dampers in nonsymmetrical three-dimensional (3D) structures. Dampers are placed uniformly and initially at each storey of two selected bays of the bare structures and the time-history seismic analysis is performed. The maximal inter-storey drift ratio is chosen as the performance index. Then the inter-storey drift ratio is checked for the locations where dampers were added. The damper in the location with the minimal inter-storey drift ratio is moved to the location having the maximal inter-storey drift ratio. This process is repeated until the prescribed stop criterion is met. Both linear and nonlinear viscous dampers are used in this study. The damping coefficient of added dampers for the initial damper placement is determined by setting the maximal inter-storey drift ratio of the whole structure equal to a certain value when a ground motion is applied. In the proposed relocation process, the maximal inter-storey drift ratio will be reduced significantly. Three examples, including two 10-storey and one 20-storey 3D nonsymmetrical structures, are used to demonstrate the efficiency and accuracy of the proposed approach. The results are compared with those obtained using the simplified sequential search algorithm (SSSA). It is found that the proposed approach requires fewer number of time-history analysis than that using the SSSA while their accuracy is comparable.

3D Numerical Simulation on Failure of Cement Sheath of Macondo Well-#1 in Deep Water Gulf of Mexico

2014 ◽  
Vol 1044-1045 ◽  
pp. 197-204
Author(s):  
Xin Pu Shen ◽  
Xiao Chun Wang
Keyword(s):  
Gulf Of Mexico ◽  
Pore Pressure ◽  
Deep Water ◽  
Three Dimensional ◽  
Interface Element ◽  
Interface Elements ◽  
Setting Process ◽  
Dimensional Finite Element ◽  
Cement Sheath ◽  
Three Dimensional Finite Element

Aim of this work is to provide a quantitative solution which clarifies the integrity of cement sheath under given underground environmental conditions at bottom section of Macondo well #1 in deep water Gulf of Mexico. With three-dimensional Finite Element Method, mechanical behavior of the model for Macondo #1 well has been investigated, with particular concerns on continuum damage variable and pore pressure distribution within interface element. Quantitative results are obtained for distribution of mechanical variables. Principal conclusions are: 1) With regular properties of cement material, it is shown that the integrity of cement ring is good, no damage could occur within interface elements, and consequently no oil could escape through cement ring. 2) With poor mechanical properties of weak cement, which could be true because of disturbance occurred in its setting process, there are two damage bands existing within interface elements. These two damage bands form two channels at where values of pore pressure are obviously higher than that its neighboring matrix. These phenomena indicate that oil could escape through these interface elements.

scholarly journals Seismic bridge pier analysis for pile foundation by force and displacement based approaches

2015 ◽  
Vol 13 (2) ◽  
pp. 155-166
Author(s):  
NP.R. Singh ◽  
Hemant Vinayak
Keyword(s):  
Pile Foundation ◽  
Seismic Analysis ◽  
Slenderness Ratio ◽  
Soft Soil ◽  
Time History ◽  
Bridge Pier ◽  
Base Shear ◽  
Displacement Based ◽  
Shear Demand ◽  
Analytical Approaches

Seismic analysis of bridge pier supported on pile foundation requires consideration of soil-pile-structure (kinematic and inertial) interactions. This paper presents the design forces generated for bridge piers with varying height and constant diameter for medium and soft soils in earthquake probability zones considering contribution of soil-pile-structure interactions by developed analytical approaches. The results have shown that the difference in base shear demand between force based and displacement based approach and that between capacity spectrum and displacement based method in general decreases with the increase in slenderness ratio of the pier. The base shear demand by non-linear time history analysis has been found to be much higher compared to that by other methods. The relationship between height and pier cross-section has been developed for different soils and seismic zones such that the base shear demands by force based and displacement based method are of the same order. The overall value of the slenderness ratio works out to be such that failure of the pile shall be as a short column for both medium and soft soil.

scholarly journals Soil-pile-structure interaction effects on high-rise building under seismic shaking

2019 ◽  
Vol 2 (1) ◽  
pp. 153-164
Author(s):  
Umesh Jung Thapa ◽  
Ramesh Karki
Keyword(s):  
Soil Structure ◽  
Seismic Analysis ◽  
Time History ◽  
Soil Structure Interaction ◽  
Base Shear ◽  
Structure Interaction ◽  
High Rise ◽  
High Rise Building ◽  
History Analysis ◽  
Fixed Base

In this paper, study of the response (base shear, time period, storey drift, storey displacement) of a structure is done for the tall building including basement with fixed base and with pile foundation considering Soil Structure Interaction (SSI). Finite element based program ETABS2016 v16.1.0 is used for the analysis of the superstructure. Seismic analysis is done to get the dynamic response of superstructure for two types of model,one model is with fixed baseand second is Model with Winkler spring for Chhaya Center, Thamel, a high rise building with 14 story including double basements. Itisobserved with the consideration of Soil Structure Interaction (SSI). The soil is replaced by spring and assigned at joints. El Centro earthquake (1940) is used for time history analysis. The response obtained due to SSI effect is compared with fixed based model. Results of analysis presented include the comparison of natural periods, base shears, displacements and overturning moment. It is observed that the natural periods increase and the base shears decrease as the base become more flexible.

The Seismic Analysis of Kiewitt Shell Based on the SMA Three-Dimensional Isolator

2010 ◽  
Vol 163-167 ◽  
pp. 4570-4574
Author(s):  
Jin Li Wang ◽  
Hai Qing Liu
Keyword(s):  
Seismic Analysis ◽  
Three Dimensional ◽  
Outer Part ◽  
Time History ◽  
Internal Force ◽  
Rubber Bearing ◽  
Base Isolator ◽  
Laminated Rubber Bearing ◽  
Lattice Damage ◽  
Acceleration Analysis

The SMA 3D isolator is based on a new intelligent material: shape memory alloy, which compensate the weakness in stiffness of the laminated rubber bearing. Through the seismic analysis of the kettlewell double layer shell, the truss horizontal and vertical internal force dropped obviously with the SMA 3D base isolator, especially the outer part which easily happened deformed damage and the structure internal force distribution is more reasonable, the deformation in harmonies, the lattice damage of weakness part is limited and offer efficient protection. Either the acceleration analysis, the peak acceleration reduced significantly and time history tends to slow, the isolating effect of the SMA 3D base isolator is prior to the laminated rubber bearing.

scholarly journals Optimal Design of Earthquake-Resistant Buildings Based on Neural Network Inversion

2021 ◽  
Vol 11 (10) ◽  
pp. 4654
Author(s):  
Carlo Calledda ◽  
Augusto Montisci ◽  
Maria Cristina Porcu
Keyword(s):  
Neural Network ◽  
Optimal Design ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Structural Response ◽  
Time History ◽  
Optimal Choice ◽  
Design Parameters ◽  
Earthquake Resistant ◽  
Non Linear

An effective seismic design entails many issues related to the capacity-based assessment of the non-linear structural response under strong earthquakes. While very powerful structural calculation programs are available to assist the designer in the code-based seismic analysis, an optimal choice of the design parameters leading to the best performance at the lowest cost is not always assured. The present paper proposes a procedure to cost-effectively design earthquake-resistant buildings, which is based on the inversion of an artificial neural network and on an optimization algorithm for the minimum total cost under building code constraints. An exemplificative application of the method to a reinforced-concrete multi-story building, with seismic demands corresponding to a medium-seismicity Italian zone, is shown. Three design-governing parameters are assumed to build the input matrix, while eight capacity-design target requirements are assigned for the output dataset. A non-linear three-dimensional concentrated plasticity model of the structure is implemented, and time-history dynamic analyses are carried out with spectrum-consistent ground motions. The results show the promising ability of the proposed approach for the optimal design of earthquake-resistant structures.

ROCKING OF LARGE BRIDGE CAISSONS DUE TO SEISMIC EXCITATION

2007 ◽  
Vol 01 (04) ◽  
pp. 329-345
Author(s):  
AYMAN A. SHAMA
Keyword(s):  
Three Dimensional ◽  
Yield Condition ◽  
Time History ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Flow Rule ◽  
Interface Elements ◽  
Capacity Curve ◽  
Caisson Foundations ◽  
Nonlinear Static

Caisson foundations are massive structures that respond to seismic loads in a primarily rocking mode. This paper presents a case study on an existing bridge caisson where the capacity spectrum approach was used to evaluate the performance for a specific seismic event. The deformation capacity curve was evaluated from nonlinear static pushover of a three dimensional finite element model of the caisson embedded in the surrounding soil. The model included interface elements to capture gapping, sliding, and rocking of the caisson during the analysis. The nonlinear behavior of the soil was represented by a cap plasticity model, which is based on the well known Drucker–Prager yield condition and a non-associated flow rule. Alternatively, a theoretical approach was developed, using basic principles of structural mechanics and the half-space theory, to determine the capacity curve. Results of nonlinear static pushover methods compared favorably to nonlinear time history analyses.

Seismic Analysis of a Water Release Integrated Structure Part II: Time History Analysis of Service Bridge Pier Structure

2013 ◽  
Vol 470 ◽  
pp. 934-937
Author(s):  
Yong Wang ◽  
Jun Chang Xuan ◽  
Ming Sun ◽  
Bo Ya Dong
Keyword(s):  
Seismic Analysis ◽  
Temporal Integration ◽  
Three Dimensional ◽  
Load Condition ◽  
Time History ◽  
Time History Analysis ◽  
Bridge Pier ◽  
Water Release ◽  
History Analysis ◽  
Design Earthquake

In this study the three dimensional finite element method is employed to analyze the time history response for the service bridge pier of a water release integrated structure under the minimum operation level and the normal storage water level in maximum design earthquake load condition. The Mexico seismic curve is provided to perform the time history analysis for the present project. The temporal integration of time history analysis is carried out by the Newmark method and the stress, deformation results of the service bridge pier structure is discussed in detail.

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