scholarly journals ARMOUR UNIT STRUCTURAL RESPONSE - A PARAMETRIC STUDY

1988 ◽  
Vol 1 (21) ◽  
pp. 176
Author(s):  
C. David Anglin ◽  
William F. Baird ◽  
Etienne P.D. Mansard ◽  
R. Douglas Scott ◽  
David J. Turcke
Keyword(s):  
Wave Height ◽  
Parametric Study ◽  
Structural Integrity ◽  
Design Procedure ◽  
Structural Response ◽  
Design Parameters ◽  
Coastal Structures ◽  
Log Normal ◽  
Wave Induced ◽  
Hydraulic Stability

There is a general lack of knowledge regarding the nature and magnitude of loads acting on armour units used for the protection of rubblemound coastal structures. Thus, a comprehensive design procedure incorporating both the hydraulic stability and the structural integrity of the armour units does not exist. This paper presents the results of a detailed parametric study of the structural response of armour units to wave-induced loading in a physical breakwater model. The effect of the following design parameters is investigated: breakwater slope, armour unit location, wave period and wave height. This research has made a number of significant contributions towards the development of a comprehensive design procedure for concrete armour units. It has identified a linear relationship between the wave-induced stress in the armour units and the incident wave height. In addition, it has shown that the conditional probability of waveinduced stress given wave height can be estimated by a log-normal distribution. Finally, a preliminary design chart has been developed which incorporates both the structural integrity and the hydraulic stability of the armour units.

scholarly journals A UNIQUE INSTRUMENTATION SCHEME FOR MEASURING LOADS IN MODEL DOLOS UNITS

1986 ◽  
Vol 1 (20) ◽  
pp. 163 ◽  
Author(s):  
R.D. Scott ◽  
D.J. Turcke ◽  
W.F. Baird
Keyword(s):  
Structural Integrity ◽  
Design Procedure ◽  
Structural Response ◽  
Load Cell ◽  
Physical Models ◽  
Unit Load ◽  
Overall Design ◽  
The Individual ◽  
Static Point ◽  
Hydraulic Stability

An instrumentation scheme for the measurement of the structural response of dolos units in a physical model due to static and quasistatic forces is presented. This was achieved by the development of a specialized armour unit "load cell". The load cell was tested under a variety of loading conditions ranging from static point loads to the complex forces arising from simulated prototype wave action. In the final stage of testing, a model breakwater was constructed and analyzed. The results of these tests demonstrated the accuracy of the developed instrumentation and the feasibility of its use for measurements conducted in physical models. Knowledge of the structural response of armour units in the breakwater environment may be incorporated into an improved overall design procedure for armour units that considers both the hydraulic stability and the structural integrity of the individual units.

scholarly journals STRUCTURAL DESIGN PROCEDURES FOR CONCRETE ARMOUR UNITS

1984 ◽  
Vol 1 (19) ◽  
pp. 172 ◽  
Author(s):  
Kevin R. Hall ◽  
W.F. Baird ◽  
D.J. Turcke
Keyword(s):  
Structural Design ◽  
Rational Design ◽  
Structural Integrity ◽  
Design Procedure ◽  
Analytical Techniques ◽  
Structural Performance ◽  
Design Procedures ◽  
Design Loads ◽  
Resultant Stress ◽  
Hydraulic Stability

A rational design procedure for rubblemound breakwater protection which will ensure both the structural integrity and hydraulic stability of individual concrete armour units and the overall armour system is presented. The procedure involves new experimental techniques for measuring strains in model concrete armour units in a hydraulic model of a breakwater subjected to simulated prototype wave attack and analytical techniques for determining equivalent prototype loads on units. Selected design loads are used to define the resultant stress distribution to allow the designer to take the necessary measures to ensure the structural performance of the unit in a breakwater environment•

scholarly journals A PROCEDURE FOR THE ANALYSIS AMD DESIGN OF CONCRETE ARMOR UNITS

1986 ◽  
Vol 1 (20) ◽  
pp. 127
Author(s):  
W.F. Baird ◽  
J.S. Readshaw ◽  
R.D. Scott ◽  
D.J. Turcke
Keyword(s):  
Interaction Design ◽  
Structural Integrity ◽  
Design Procedure ◽  
Rational Approach ◽  
Design Alternatives ◽  
Interaction Curves ◽  
Improved Design ◽  
The Cost ◽  
Rubble Mound Breakwaters ◽  
Hydraulic Stability

A rational approach to the design of rubble mound breakwaters that incorporates both the hydraulic stability and the structural integrity of individual concrete armor units is presented. A key element of this improved design procedure is the development of instrumentation to measure loads occurring on armor units in a physical model of a breakwater. Numerical methods have been employed to determine stresses throughout the armor unit once the loads are known and interaction design curves were developed from measured data. These interaction curves provide a useful assessment of the structural integrity of the armor units. The curves clearly demonstrate the overall factor of safety associated with the armor unit and the expected mode of failure. Based on the results of this type of analysis, the cost effectiveness and safety associated with different design alternatives may be explored and a breakwater that is both hydraulically and structurally efficient may be designed.

scholarly journals The capacity design of reinforced concrete hybrid structures for multistorey buildings

1986 ◽  
Vol 19 (1) ◽  
pp. 1-17 ◽  
Author(s):  
T. Paulay ◽  
W. J. Goodsir
Keyword(s):  
Reinforced Concrete ◽  
Design Procedure ◽  
Structural Response ◽  
Hybrid Structures ◽  
Design Parameters ◽  
Capacity Design ◽  
Structural Walls ◽  
Design Procedures ◽  
Fixed Base ◽  
Selection Of

To complement existing capacity design procedures used in New Zealand for reinforced concrete buildings in which earthquake resistance is provided by ductile frames or ductile structural walls, an analogous methodology is presented for the design
of ductile hybrid structures. Modelling and types of structures in which the mode of wall contribution is different are briefly described. A step by step description of a capacity design procedure for a structural system in which fixed base ductile frames and walls, both of identical height, interact, is presented. The rationale for each step is outlined and, where necessary, evidence is offered for the selection of particular design parameters and their magnitudes. A number of issues which require further study are briefly outlined. These relate to irregularity in layout, torsional effects, diaphragm flexibility, shortcomings in the predictions for dynamic shear demands in walls, and to limitations of the proposed design procedure. It is believed that the methodology is logical, relatively simple and that it should ensure, when combined with appropriate detailing, excellent seismic structural response.

scholarly journals RIP CURRENTS AND THEIR CAUSES

1978 ◽  
Vol 1 (16) ◽  
pp. 83 ◽  
Author(s):  
Robert A. Dalrymple
Keyword(s):  
Wave Height ◽  
Bottom Topography ◽  
High Energy ◽  
Rip Current ◽  
Rip Currents ◽  
Coastal Structures ◽  
Submarine Canyons ◽  
Set Up ◽  
Wave Induced ◽  
Made In

"The outworn dogmas of science seem to be particularly concentrated in the discussions of the ocean in geology books". Beginning with this controversial statement, F. P. Shepard in 1936 tried to lay to rest the concept of the undertow, which had been debated in the pages of Science for over a decade. At the same time, he introduced the term, rip current, to describe the rapidly seaward-flowing currents, which were well-known to lifeguards at that time, as these currents were responsible for carrying swimmers offshore at frightening speeds. Subsequent studies by Shepard and his colleagues (Shepard, Emery and LaFond, 1941; Shepard and Inman, 1950a, 1950b) showed that rip currents (1) are caused by longshore variations in incident wave height, (2) are often periodic in both time and in the longshore direction and (3) increase in velocity with increasing wave height. The major reason put forth to explain the variation in wave height was the convergence or divergence of wave rays over offshore bottom topography (such as submarine canyons) or the forced wave height variability caused by coastal structures, such as jetties. McKenzie (1958) and Cooke (1970) in their studies corroborated the findings of the Scripps Institution of Oceanography researchers and also pointed out the persistence of rip currents (once high energy waves in a storm had caused rip channels to be cut into the bottom) after the storm had abated. In fact it appears that on coastlines which are affected by major storms which build offshore bars, that the nearshore circulation may be dominated by the storm-1-induced bottom topography for long afterwards. The researchers up to the late 1960's who attempted to theoretically model rip currents knew the importance of longshore wave height variability and the wave-induced set-up in the formation of rip currents, but it was not until Longuet-Higgins and Stewart (e.g., 1964) codified the wave momentum flux tensor that great strides were made in providing models for rip currents. This paper is intended to categorize and review the more recent theories for rip current generation and to discuss a simple model for rip currents on barred coastlines.

Parametric study and design procedure for planar silos and hoppers

2021 ◽  
Author(s):  
Evgeny Rabinovich ◽  
Haim Kalman ◽  
Per F. Peterson
Keyword(s):  
Parametric Study ◽  
Design Procedure

scholarly journals A Two-Round Optimization Design Method for Aerostatic Spindles Considering the Fluid–Structure Interaction Effect

2021 ◽  
Vol 11 (7) ◽  
pp. 3017
Author(s):  
Qiang Gao ◽  
Siyu Gao ◽  
Lihua Lu ◽  
Min Zhu ◽  
Feihu Zhang
Keyword(s):  
Optimal Design ◽  
Optimization Design ◽  
Design Method ◽  
Fluid Structure Interaction ◽  
Design Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aerostatic Spindle

The fluid–structure interaction (FSI) effect has a significant impact on the static and dynamic performance of aerostatic spindles, which should be fully considered when developing a new product. To enhance the overall performance of aerostatic spindles, a two-round optimization design method for aerostatic spindles considering the FSI effect is proposed in this article. An aerostatic spindle is optimized to elaborate the design procedure of the proposed method. In the first-round design, the geometrical parameters of the aerostatic bearing were optimized to improve its stiffness. Then, the key structural dimension of the aerostatic spindle is optimized in the second-round design to improve the natural frequency of the spindle. Finally, optimal design parameters are acquired and experimentally verified. This research guides the optimal design of aerostatic spindles considering the FSI effect.

Unified Assessment of Unconventional Resource Plays – Implications for Global Exploration and Development

2021 ◽  
Author(s):  
Tarun Grover ◽  
Jamie Stuart Andrews ◽  
Irfan Ahmed ◽  
Ibnu Hafidz Arief
Keyword(s):  
Commodity Prices ◽  
Design Parameters ◽  
First Year ◽  
Well Productivity ◽  
Well Spacing ◽  
Cumulative Production ◽  
Unconventional Resource ◽  
Log Normal ◽  
The Impact ◽  
Sweet Spots

Abstract Unconventional resource plays, herein referred to as source rock plays, have been able to significantly increase the supply of hydrocarbons to the world. However, majority of the companies developing these resource plays have struggled to generate consistent positive cash flows, even during periods of stable commodity prices and after successfully reducing the development costs. The fundamental reasons for poor financial performance can be attributed to various reasons, such as; rush to lease acreage and drill wells to hold acreage, delayed mapping of sweet spots, slow acknowledgement of high geological variability, spending significant capital in trial and errors to narrow down optimal combinations of well spacing and stimulation designs. The objective of this paper is to present a systematic integrated multidisciplinary analysis of several unconventional plays worldwide which, if used consistently, can lead to significantly improved economics. We present an analysis of several unconventional plays in the US and Argentina with fluid systems ranging from dry gas to black oil. We utilize the publicly available datasets of well stimulation and production data along with laboratory measured core data to evaluate the sweet spots, the measure of well productivity, and the variability in well productivity. We investigate the design parameters which show the strongest correlation to well productivity. This step allows us to normalize the well productivity in such a way that the underlying well productivity variability due to geology is extracted. We can thus identify the number of wells which should be drilled to establish geology driven productivity variability. Finally, we investigate the impact of well spacing on well productivity. The data indicates that, for any well, first year cumulative production is a robust measure of ultimate well productivity. The injected slurry volume shows the best correlation to the well productivity and "completion normalized" well productivity can be defined as first year cumulative production per barrel of injected slurry volume. However, if well spacing is smaller than the created hydraulic fracture network, the potential gain of well productivity is negated leading to poor economics. Normalized well productivity is log-normally distributed in any play due to log-normal distribution of permeability and the sweet spots will generally be defined by most permeable portions of the play. Normalized well productivity is shown to be independent of areal scale of any play. We show that in every play analyzed, typically 20-50 wells (with successful stimulation and production) are sufficient to extract the log-normal productivity distribution depending on play size and target intervals. We demonstrate that once the log-normal behavior is anticipated, creation of production profiles with p10-p50-p90 values is quite straightforward. The way the data analysis is presented can be easily replicated and utilized by any operator worldwide which can be useful in evaluation of unconventional resource play opportunities.

Stability of offshore structures in shallow water depth

2011 ◽  
Vol 2 (2) ◽  
pp. 320-333
Author(s):  
F. Van den Abeele ◽  
J. Vande Voorde
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Fossil Fuels ◽  
Oil And Gas ◽  
Structural Response ◽  
Offshore Structures ◽  
Exploration And Production ◽  
Subsea Pipelines ◽  
Wave Induced ◽  
Shallow Water Depth

The worldwide demand for energy, and in particular fossil fuels, keeps pushing the boundaries of offshoreengineering. Oil and gas majors are conducting their exploration and production activities in remotelocations and water depths exceeding 3000 meters. Such challenging conditions call for enhancedengineering techniques to cope with the risks of collapse, fatigue and pressure containment.On the other hand, offshore structures in shallow water depth (up to 100 meter) require a different anddedicated approach. Such structures are less prone to unstable collapse, but are often subjected to higherflow velocities, induced by both tides and waves. In this paper, numerical tools and utilities to study thestability of offshore structures in shallow water depth are reviewed, and three case studies are provided.First, the Coupled Eulerian Lagrangian (CEL) approach is demonstrated to combine the effects of fluid flowon the structural response of offshore structures. This approach is used to predict fluid flow aroundsubmersible platforms and jack-up rigs.Then, a Computational Fluid Dynamics (CFD) analysis is performed to calculate the turbulent Von Karmanstreet in the wake of subsea structures. At higher Reynolds numbers, this turbulent flow can give rise tovortex shedding and hence cyclic loading. Fluid structure interaction is applied to investigate the dynamicsof submarine risers, and evaluate the susceptibility of vortex induced vibrations.As a third case study, a hydrodynamic analysis is conducted to assess the combined effects of steadycurrent and oscillatory wave-induced flow on submerged structures. At the end of this paper, such ananalysis is performed to calculate drag, lift and inertia forces on partially buried subsea pipelines.

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