The Experts below are selected from a list of 2420316 Experts worldwide ranked by ideXlab platform

Adem Dogangun - One of the best experts on this subject based on the ideXlab platform.

  • Effect of foundation Embedment on seismic behavior of elevated tanks considering fluid-structure-soil interaction
    Soil Dynamics and Earthquake Engineering, 2007
    Co-Authors: Ramazan Livaoglu, Adem Dogangun
    Abstract:

    This paper investigates the effects of foundation Embedment on the seismic behavior of fluid-elevated tank-foundation–soil system with a structural frame supporting the fluid containing tank. Six different soil types defined in the well-known seismic codes were considered. Both the sloshing effects of the fluid and soil-structure interaction of the elevated tanks located on these six different soils were included in the analyses. Fluid-elevated tank-foundation–soil systems were modeled with the finite element (FE) technique. The fluid-structure interaction was taken into account using Lagrangian fluid FE approximation implemented in the general purpose structural analysis computer program, ANSYS. FE model with viscous boundary was used to include elevated tank-foundation–soil interaction effects. The models were analyzed for the foundations with and without Embedment. It was found that the tank roof displacements were affected significantly by the Embedment in soft soil, however, this effect was smaller for stiff soil types. Except for soft soil types, Embedment did not affect the other response parameters, such as sloshing displacement, of the systems considered in this study.

  • seismic evaluation of fluid elevated tank foundation soil systems in frequency domain
    Structural Engineering and Mechanics, 2005
    Co-Authors: Ramazan Livaoglu, Adem Dogangun
    Abstract:

    An efficient methodology is presented to evaluate the seismic behavior of a Fluid-Elevated Tank-Foundation/Soil system taking the Embedment effects into accounts. The frequency-dependent cone model is used for considering the elevated tank-foundation/soil interaction and the equivalent spring-mass model given in the Eurocode-8 is used for fluid-elevated tank interaction. Both models are combined to obtain the seismic response of the systems considering the sloshing effects of the fluid and frequency-dependent properties of soil. The analysis is carried out in the frequency domain with a modal analysis procedure. The presented methodology with less computational efforts takes account of; the soil and fluid interactions, the material and radiation damping effects of the elastic half-space, and the Embedment effects. Some conclusions may be summarized as follows; the sloshing response is not practically affected by the change of properties in stiff soil such as S1 and S2 and Embedment but affected in soft soil. On the other hand, these responses are not affected by Embedment in stiff soils but affected in soft soils.

  • Seismic evaluation of fluid-elevated tank-foundation/soil systems in frequency domain
    Structural Engineering and Mechanics, 2005
    Co-Authors: Ramazan Livaoglu, Adem Dogangun
    Abstract:

    An efficient methodology is presented to evaluate the seismic behavior of a Fluid-Elevated Tank-Foundation/Soil system taking the Embedment effects into accounts. The frequency-dependent cone model is used for considering the elevated tank-foundation/soil interaction and the equivalent spring-mass model given in the Eurocode-8 is used for fluid-elevated tank interaction. Both models are combined to obtain the seismic response of the systems considering the sloshing effects of the fluid and frequency-dependent properties of soil. The analysis is carried out in the frequency domain with a modal analysis procedure. The presented methodology with less computational efforts takes account of; the soil and fluid interactions, the material and radiation damping effects of the elastic half-space, and the Embedment effects. Some conclusions may be summarized as follows; the sloshing response is not practically affected by the change of properties in stiff soil such as S1 and S2 and Embedment but affected in soft soil. On the other hand, these responses are not affected by Embedment in stiff soils but affected in soft soils.

Ramazan Livaoglu - One of the best experts on this subject based on the ideXlab platform.

  • investigation of seismic behavior of fluid rectangular tank soil foundation systems in frequency domain
    Soil Dynamics and Earthquake Engineering, 2008
    Co-Authors: Ramazan Livaoglu
    Abstract:

    Abstract Main purpose of this study is to evaluate the dynamic behavior of fluid–rectangular tank–soil/foundation system with a simple and fast seismic analysis procedure. In this procedure, interaction effects are presented by Housner's two mass approximations for fluid and the cone model for soil/foundation system. This approach can determine; displacement at the height of the impulsive mass, the sloshing displacement and base forces for the soil/foundation system conditions including Embedment and incompressible soil cases. Models and equations for proposed method were briefly explained for different tank–soil/foundation system combinations. By means of changing soil/foundation conditions, some comparisons are made on base forces and sloshing responses for the cases of Embedment and no Embedment. The results showed that the displacements and base shear forces generally decreased, with decreasing soil stiffness. However, Embedment, wall flexibility, and soil–structure interaction (SSI) did not considerably affect the sloshing displacement.

  • Effect of foundation Embedment on seismic behavior of elevated tanks considering fluid-structure-soil interaction
    Soil Dynamics and Earthquake Engineering, 2007
    Co-Authors: Ramazan Livaoglu, Adem Dogangun
    Abstract:

    This paper investigates the effects of foundation Embedment on the seismic behavior of fluid-elevated tank-foundation–soil system with a structural frame supporting the fluid containing tank. Six different soil types defined in the well-known seismic codes were considered. Both the sloshing effects of the fluid and soil-structure interaction of the elevated tanks located on these six different soils were included in the analyses. Fluid-elevated tank-foundation–soil systems were modeled with the finite element (FE) technique. The fluid-structure interaction was taken into account using Lagrangian fluid FE approximation implemented in the general purpose structural analysis computer program, ANSYS. FE model with viscous boundary was used to include elevated tank-foundation–soil interaction effects. The models were analyzed for the foundations with and without Embedment. It was found that the tank roof displacements were affected significantly by the Embedment in soft soil, however, this effect was smaller for stiff soil types. Except for soft soil types, Embedment did not affect the other response parameters, such as sloshing displacement, of the systems considered in this study.

  • seismic evaluation of fluid elevated tank foundation soil systems in frequency domain
    Structural Engineering and Mechanics, 2005
    Co-Authors: Ramazan Livaoglu, Adem Dogangun
    Abstract:

    An efficient methodology is presented to evaluate the seismic behavior of a Fluid-Elevated Tank-Foundation/Soil system taking the Embedment effects into accounts. The frequency-dependent cone model is used for considering the elevated tank-foundation/soil interaction and the equivalent spring-mass model given in the Eurocode-8 is used for fluid-elevated tank interaction. Both models are combined to obtain the seismic response of the systems considering the sloshing effects of the fluid and frequency-dependent properties of soil. The analysis is carried out in the frequency domain with a modal analysis procedure. The presented methodology with less computational efforts takes account of; the soil and fluid interactions, the material and radiation damping effects of the elastic half-space, and the Embedment effects. Some conclusions may be summarized as follows; the sloshing response is not practically affected by the change of properties in stiff soil such as S1 and S2 and Embedment but affected in soft soil. On the other hand, these responses are not affected by Embedment in stiff soils but affected in soft soils.

  • Seismic evaluation of fluid-elevated tank-foundation/soil systems in frequency domain
    Structural Engineering and Mechanics, 2005
    Co-Authors: Ramazan Livaoglu, Adem Dogangun
    Abstract:

    An efficient methodology is presented to evaluate the seismic behavior of a Fluid-Elevated Tank-Foundation/Soil system taking the Embedment effects into accounts. The frequency-dependent cone model is used for considering the elevated tank-foundation/soil interaction and the equivalent spring-mass model given in the Eurocode-8 is used for fluid-elevated tank interaction. Both models are combined to obtain the seismic response of the systems considering the sloshing effects of the fluid and frequency-dependent properties of soil. The analysis is carried out in the frequency domain with a modal analysis procedure. The presented methodology with less computational efforts takes account of; the soil and fluid interactions, the material and radiation damping effects of the elastic half-space, and the Embedment effects. Some conclusions may be summarized as follows; the sloshing response is not practically affected by the change of properties in stiff soil such as S1 and S2 and Embedment but affected in soft soil. On the other hand, these responses are not affected by Embedment in stiff soils but affected in soft soils.

Mark Randolph - One of the best experts on this subject based on the ideXlab platform.

  • shear strength of soil berm during lateral buckling of subsea pipelines
    Applied Ocean Research, 2019
    Co-Authors: A Rismanchian, Mark Randolph, David White, C M Martin
    Abstract:

    Abstract The soil resistance developed during temperature- and pressure-induced large lateral movements of shallowly embedded subsea flowlines is an important input parameter for the structural design process. A major source of uncertainty in calculation of the soil resistance is the undrained shear strength of the soil berm produced as the flowline moves across the seabed, which is affected by the level of remoulding. To investigate the effect of pipeline Embedment and displacement amplitude on the shear strength of the berm, a set of centrifuge model tests was conducted on kaolin clay, involving laterally moving pipelines with constant Embedments in the range 5%–35% of the pipe diameter. Back-analysis of the test results, using finite element limit analysis, showed that the shear strength of the soil berm is a function of pipe displacement amplitude, pipe Embedment, and soil sensitivity. On the basis of these results, we propose that the overall berm undrained shear strength may be determined as a convolution of the shear strengths of its constituent soil elements. Finally, a formula is presented for calculating the shear strength of soil elements within the soil berm, and this is used to back-analyse the overall soil berm resistance from the model tests.

  • analytical solution for ultimate Embedment depth and potential holding capacity of plate anchors
    Geotechnique, 2015
    Co-Authors: Yinghui Tian, Mark Randolph, Mark Cassidy
    Abstract:

    This paper proposes an analytical approach to evaluate the ultimate Embedment depth and holding capacity that plate anchors can potentially achieve. Based on a plasticity model for anchor–soil interaction and compatible chain solution, detailed derivations are presented that allow the main dimensionless groups of input parameters to be identified. For typical cases where the weight of the anchor is negligible relative to its holding capacity, explicit expressions are provided in non-dimensional form for ultimate Embedment and anchor capacity. A thorough parametric sensitivity study highlights the major factors affecting these quantities. Two practical examples are considered that demonstrate the proposed analytical approach for different types of anchors, in one case revealing significant scope for improved design of plate anchors in order to optimise performance.

  • modelling the Embedment process during offshore pipe laying on fine grained soils
    Canadian Geotechnical Journal, 2013
    Co-Authors: Z J Westgate, David White, Mark Randolph
    Abstract:

    Subsea pipelines are becoming an increasingly significant element of offshore hydrocarbon developments as exploration moves into deep-water environments further from shore. During the lay process, pipelines are subject to small amplitude vertical and horizontal oscillations, driven by the sea state and lay vessel motions. Centrifuge model tests have been used to simulate these small-amplitude lay effects, with varying degrees of idealization relative to the real lay process. In the soft soils found in deep water, pipe Embedment can exceed a diameter or more, thus significantly affecting the lateral pipe–soil interaction, axial resistance, and thermal insulation. In this paper, results from centrifuge model tests are used to calibrate a model for calculating the dynamic Embedment of a subsea pipeline. The model uses elements of plasticity theory to capture the effects of combined vertical and horizontal loading, and incorporates the softening of the surrounding soil as it is remoulded due to the pipelinemotions. Influences from the lay rate, lay geometry, and sea state are included in the calculation process. The model is compared with observed as-laid pipeline Embedment data fromfield surveys at three different offshore sites. Using site-specific soil parameters obtained from in situ testing and idealized pipe loads and motions to represent the load and displacement patterns during offshore pipe-laying, respectively, the model is shown to capture well the final as-laid Embedment measured in the field surveys.

  • the influence of sea state on as laid pipeline Embedment a case study
    Applied Ocean Research, 2010
    Co-Authors: Z J Westgate, Mark Randolph, David White
    Abstract:

    Abstract The as-laid Embedment of an offshore pipeline is an important parameter for design as it affects lateral and axial stability, exposure to environmental loads, and thermal insulation. For soft clay seabeds, the as-laid Embedment can be significantly higher than predicted using methods based on the static penetration resistance due to dynamic lay effects. There are very few published field surveys showing the as-laid Embedment of a pipeline following installation. Back-analysis of field survey data has the potential to improve existing design methods, as well as gain insights into the effects of the installation conditions, including the vessel response, the lay angle and tension, weather and sea state, and downtime events. This study describes the as-laid field survey carried out for a 12-inch flowline installed on a soft clay seabed in the North Sea. The dynamic lay effects are examined by studying the influence of sea state, manifested through the vessel response which leads to pipeline motions at the seabed. The findings show that a clear correlation exists between sea state and pipeline Embedment. The ratio between the mean observed Embedment and the Embedment that would be predicted using a conventional static penetration analysis (termed the dynamic Embedment factor, F dyn ) ranged from 2.5 up to 4 for normal pipelay conditions, increasing with wave height. Downtime events, during which pipelay is temporarily suspended, significantly increase the Embedment. In this study they led to maximum Embedment values greater than one diameter, corresponding to F dyn of up to 10, due to the larger numbers of cyclic pipeline motions at the seabed.

  • the effect of Embedment depth on the undrained response of skirted foundations to combined loading
    Soils and Foundations, 1999
    Co-Authors: Fraser M Bransby, Mark Randolph
    Abstract:

    ABSTRACT The response of skirted foundations to combined vertical (V), moment (M) and horizontal (H) undrained loading is investigated using finite element and upper bound plasticity analysis. The study has focused in particular on the effect of the foundation Embedment depth on the size and shape of the combined V-M-H yield locus. The yield locus was found to be of similar shape to that of a surface foundation but the size of the yield locus was increased. Normalisation of the yield locus by the single load bearing capacities (V0, M0 and H0) allowed the yield locus to be generalised for varying soil profiles and footing Embedment depths. Upper bound plasticity analysis was carried out to calculate V0, M0 and H0 for a range of footing Embedment depths and undrained soil shear strength profiles and design charts are presented for their determination.

Josef Eberhardsteiner - One of the best experts on this subject based on the ideXlab platform.

  • load to grain angle dependence of the Embedment behavior of dowel type fasteners in laminated veneer lumber
    Construction and Building Materials, 2016
    Co-Authors: Michael Schweigler, Thomas K. Bader, Georg Hochreiner, Gerhard Unger, Josef Eberhardsteiner
    Abstract:

    Abstract Load-to-grain angle dependence of the Embedment behavior of steel dowels in laminated veneer lumber, as a consequence of the anisotropic material behavior of wood, is experimentally investigated in this study. As a novel issue, in addition to the stress dependence, the displacement path of the dowel depending on the load-to-grain angle, is discussed. Full-hole Embedment tests of screw-reinforced LVL specimens up to dowel displacements of two times the dowel diameter and thus, representative for highly ductile dowel connections were conducted. Tests were performed with unconstrained lateral displacement boundary conditions of steel dowels with a diameter of 12 mm and 16 mm. Surface deformations were monitored with a full-field deformation measurement system. Increasing the load-to-grain angle caused reduced quasi-elastic limits and loading stiffness. However, for load-to-grain angles of 60° and higher, a pronounced displacement-hardening effect, leading to high Embedment stresses at large dowel displacements, was observed. For the investigated dowel diameters, surface strains and plastic deformations around the dowel indicate an almost dowel diameter independent load bearing area, which might explain higher nominal Embedment stresses and consequently a more pronounced hardening effect of the smaller dowel diameter. Dowel displacements perpendicular to the initial loading direction, i.e., nonlinear displacement paths of the dowel, were related to the anisotropic stiffness of wood and densification effects close to the dowel. The established experimental dataset was compared to current European timber engineering design equations and could serve as input to analytical and numerical models of dowel connections.

  • Load Direction Dependency of the Embedment Behaviour of Dowel-Type Fasteners in Laminated Veneer Lumber
    2016
    Co-Authors: Michael Schweigler, Thomas K. Bader, Josef Eberhardsteiner
    Abstract:

    Load Direction Dependency of the Embedment Behaviour of Dowel-Type Fasteners in Laminated Veneer Lumber

Michael Schweigler - One of the best experts on this subject based on the ideXlab platform.

  • load to grain angle dependence of the Embedment behavior of dowel type fasteners in laminated veneer lumber
    Construction and Building Materials, 2016
    Co-Authors: Michael Schweigler, Thomas K. Bader, Georg Hochreiner, Gerhard Unger, Josef Eberhardsteiner
    Abstract:

    Abstract Load-to-grain angle dependence of the Embedment behavior of steel dowels in laminated veneer lumber, as a consequence of the anisotropic material behavior of wood, is experimentally investigated in this study. As a novel issue, in addition to the stress dependence, the displacement path of the dowel depending on the load-to-grain angle, is discussed. Full-hole Embedment tests of screw-reinforced LVL specimens up to dowel displacements of two times the dowel diameter and thus, representative for highly ductile dowel connections were conducted. Tests were performed with unconstrained lateral displacement boundary conditions of steel dowels with a diameter of 12 mm and 16 mm. Surface deformations were monitored with a full-field deformation measurement system. Increasing the load-to-grain angle caused reduced quasi-elastic limits and loading stiffness. However, for load-to-grain angles of 60° and higher, a pronounced displacement-hardening effect, leading to high Embedment stresses at large dowel displacements, was observed. For the investigated dowel diameters, surface strains and plastic deformations around the dowel indicate an almost dowel diameter independent load bearing area, which might explain higher nominal Embedment stresses and consequently a more pronounced hardening effect of the smaller dowel diameter. Dowel displacements perpendicular to the initial loading direction, i.e., nonlinear displacement paths of the dowel, were related to the anisotropic stiffness of wood and densification effects close to the dowel. The established experimental dataset was compared to current European timber engineering design equations and could serve as input to analytical and numerical models of dowel connections.

  • Load Direction Dependency of the Embedment Behaviour of Dowel-Type Fasteners in Laminated Veneer Lumber
    2016
    Co-Authors: Michael Schweigler, Thomas K. Bader, Josef Eberhardsteiner
    Abstract:

    Load Direction Dependency of the Embedment Behaviour of Dowel-Type Fasteners in Laminated Veneer Lumber