Investigation Into Float-Over Installations of Minimal Platforms by Hydrodynamic Model Testing

2005 ◽  
Author(s):  
J. Xia ◽  
S. Hayne ◽  
G. Macfarlane ◽  
D. Field ◽  
Y. Drobyshevski
Keyword(s):  
Model Test ◽  
Load Transfer ◽  
Test Results ◽  
Numerical Predictions ◽  
Wave Basin ◽  
Transfer Operation ◽  
Response Amplitude Operators ◽  
Jack Up ◽  
Standard Software ◽  
Insight Into

The idea of using float-over installations for minimal facilities platforms was shown to offer significant advantages, especially when coupled with a substructure installed by a jack-up rig. Recently, float-over installations of minimal facilities have been conducted by the cantilevered method by ICON Engineering Pty Ltd (ICON). The operation involves the platform topsides being loaded and transported to site on a barge, skidded over the barge bow, and lowered onto the jacket. The paper presents results of a research project undertaken by the Australian Maritime College (AMC) in conjunction with ICON, with the objective to investigate motions of a barge and loads exerted on the jacket when the two are docked together for a smooth load transfer operation. The model of an installation barge has been tested in the AMC wave basin and response amplitude operators of the barge motions have been determined for both the free floating and docked conditions. A range of wave periods and heights has been investigated. Model test results have been used to verify numerical predictions used in the design, and to get insight into uncertainties, which may otherwise be difficult to assess using standard software.

Float Over Installation Method—Comprehensive Comparison Between Numerical and Model Test Results

2006 ◽  
Vol 128 (3) ◽  
pp. 256-262 ◽  
Author(s):  
Arcandra Tahar ◽  
John Halkyard ◽  
Atle Steen ◽  
Lyle Finn
Keyword(s):  
West Africa ◽  
Gulf Of Mexico ◽  
Model Test ◽  
Test Results ◽  
Sea State ◽  
Numerical Predictions ◽  
Single Piece ◽  
Heavy Lift ◽  
Compliant Tower ◽  
Comprehensive Comparison

Installing a large deck onto a platform, such as a spar, using the floatover method is gaining popularity. This is because the operational cost is much lower than other methods of installation, such as modular lifts or a single piece installation by a heavy lift barge. Deck integration can be performed on land, at quay side and will not depend on a heavy lift barge. A new concept for a floatover vessel has been developed for operations in the Gulf of Mexico and West Africa. In this application sea state conditions are essential factors that must be considered in the Gulf of Mexico, especially for transportation. In West Africa, swell conditions will govern floatover deck (FOD) installation. Based on these two different environmental conditions, Technip Offshore, Inc. developed the FOD installation concept using semi-submersible barge type vessels. A significant amount of development work and model testing has been done on this method in recent years on spar floatover. These tests have validated our numerical methods. Another test was conducted to investigate the feasibility of a deck float-over operation onto a compliant tower for a West Africa project. The project consists of a compliant tower supporting a 25,401metricton(28,000s.ton) integrated deck. This paper will describe comparisons between model test data and numerical predictions of the compliant tower floatover operation.

A Truss Semisubmersible Optimized for the Post Katrina Environment in Gulf of Mexico Correlated With Model Test

2009 ◽  
Author(s):  
Chan K. Yang ◽  
John Murray ◽  
Hanseong Lee ◽  
Myoungkeun Choi ◽  
Cheng-Yo Chen ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Model Test ◽  
Oil And Gas ◽  
Vertical Motion ◽  
Scale Model ◽  
Natural Period ◽  
Steel Catenary Riser ◽  
Numerical Predictions ◽  
Wave Basin ◽  
Global Performance

This paper presents a Truss Semisubmersible (Truss Semi) design optimized to meet the post-Katrina Gulf of Mexico (GoM) environment criteria, with global performance correlated in 1:50 scale model tests in a wave basin. A conventional semisubmersible with a ring pontoon is facilitated with heave plates supported by the truss structure to increase heave natural period. The size of the semisubmersible hull and the configuration of the heave plates are optimized through frequency domain analysis to minimize the vertical motion enough to allow the dry trees to accommodate top tensioned production risers. The system includes eight production top tension risers (TTRs) connected to the production deck and a single drilling riser connected to the drilling deck. All of the TTRs are connected through the hydro-pneumatic tensioner system. One gas export and one oil export steel catenary riser (SCR) export the oil and gas to the storage facility. Structures designed for this deepwater area (4,300 ft) of the central Gulf of Mexico (GoM) must be designed to meet newly proposed environmental criteria [1]. The optimized Truss Semi was tested in the Offshore Technology Research Center (OTRC) model basin, to confirm the global performance, such as motion, air gap and loads on the heave plates. The numerical predictions correlate well with the model test results.

Study on Numerical Simulation of Jacket Launching Progress

2013 ◽  
Author(s):  
Lingzhi Xiong ◽  
Jianmin Yang ◽  
Xin Li ◽  
Xin Xu
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Scale Effect ◽  
Model Test ◽  
Hydrodynamic Force ◽  
Shallow Waters ◽  
Test Results ◽  
Physical Model Tests ◽  
Wave Basin ◽  
Similarity Law

Jacket type structures are widely used in shallow waters. The size of a jacket is determined by the dimensions of the deck and piles, as well as the environment loads. The jackets are usually transported with barges to the operation water after they have been fabricated in the shipyard, then the jackets slip into the water. Launch operation is the most hazardous stage during the installation of a jacket. The main purpose of this study is to evaluate the physical modeling test results for the launch, and compared to those of numerical simulation. It is found that there are some differences between the numerical simulations and physical model tests. The scale effect cannot be ignored in the prediction of the jacket launching process. The model test is based on the Froude similarity law, and the effect of Reynolds number is neglected. The drag coefficient depending on the Reynolds number plays a crucial role in determining the launch process. With different Reynolds number, the structure has different hydrodynamic force that results to different pitch angle, heave, launch time, acceleration and so on. Thus, a scale effect emerges when we convert the results of a wave basin model test to the prototype scale. This study also includes a sensitivity analysis about some key parameters in the launch process, such as initial barge trim and draft, frictions between barge and jacket.

How Does Barge-Master Compensate for the Barge Motions: Experimental and Numerical Study

2012 ◽  
Author(s):  
Frederick Jaouen ◽  
Joris van den Berg ◽  
Haite van der Schaaf ◽  
Eelko May ◽  
Jim Koppenol
Keyword(s):  
Time Domain ◽  
Environmental Conditions ◽  
Numerical Study ◽  
Model Tests ◽  
Test Results ◽  
Theoretical Formulation ◽  
Wave Basin ◽  
The Time Domain ◽  
Jack Up ◽  
Economical Alternative

To increase workability and safety in tough environmental conditions, and to create a more economical alternative for jack-up barges, Barge-Master has developed a wave compensating platform for marine and offshore installation barges. To minimize the motions of the crane positioned on top of it, the platform is driven by three hydraulic actuators that compensate for the roll, pitch and heave motions of the barge. To quantify the performance of the platform for different environmental conditions and crane configurations MARIN performed both wave basin model tests and time-domain simulations on the platform. In this paper, the experimental setup is first described and the model test results are presented. Then, the theoretical formulation of the time-domain aNySIM model is described and the numerical results are reported. It is shown that the model tests and time-domain results are in good agreement. The results indicate that the barge motions can be compensated by the platform for more than 90% in 1.2m high sea states. However, it is also shown that the instrumentation, data acquisition and controller system need to be fast and tuned to achieve this optimal compensation.

scholarly journals Racking strength of paperboard based sheathing materials

BioResources ◽  
2006 ◽  
Vol 2 (1) ◽  
pp. 3-19
Author(s):  
Wu Bi ◽  
Douglas W. Coffin
Keyword(s):  
Elastic Modulus ◽  
Load Transfer ◽  
Full Scale ◽  
Small Scale ◽  
Test Results ◽  
Wall Construction ◽  
Materials Used ◽  
Insight Into

Small-scale racking testers were developed for use as a means to evaluate paperboard-based sheathing materials used in framed wall-construction. For the purpose of evaluating the performance of different sheathing materials, the tester provides an economic alternative to standard full-scale racking tests. In addition, results from testing provide practical insight into the racking response of framed and sheathed walls. The load-deformation responses of three commercial sheathing boards were measured, and initial racking stiffness and racking strength were proposed as parameters for characterizing the board. The racking test results showed that the initial paperboard racking stiffness correlated to elastic modulus and caliper, but the response was insensitive to paperboard orientation or test dimensions. Observations and results showed that both panel buckling and paperboard cutting at the staples affected the racking response, but the dominating factor influencing the racking response appears to be load transfer through the staples.

UJI TARIK HIDRODINAMIKMODEL KAPAL BERSAYAP WiSE DENGAN LAMBUNG DASAR BERSTEP

2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Iskendar Iskendar ◽  
Andi Jamaludin ◽  
Paulus Indiyono
Keyword(s):  
Comparative Study ◽  
Model Test ◽  
Hydrodynamic Model ◽  
Surface Effect ◽  
Center Of Gravity ◽  
Test Results ◽  
Flat Bottom ◽  
Towing Tank ◽  
Test Models ◽  
Wetted Surface Area

This paper describes hydrodynamic model tests of Wing in Surface Effect (WiSE) Craft. These craft  was fitted with  stephull  form in different location on longitudinal flat bottom (stepedhull planning craft) to determine the influences of sticking and porpoising motion performances. These motions are usually occured when the craft start to take-off from water surfaces. The test models with scale of 1 : 7 were comprised of 4 (four) stephull models and 1 (one) non-stephull model  as a comparative study. The hydrodynamic  tests were performed with craft speed of 16 – 32 knots (prototype values) in Towing Tank at UPT. Balai Pengkajian dan Penelitian Hidrodinamika (BPPH), BPPT, Surabaya. The resistance (drag) was measured by dynamo meter and the trim of model (draft changing at fore and aft  of model due to model speed) was measured by trim meter. By knowing the value of model trim, the wetted surface area can be determined. Then, the lift forces were calculated based on these measured values. The model test results were presented on tables and curves.  Test results show that models  with step located far away from center of gravity of the WiSE craft tend to porpoising and sticking condition, except if the step location on the below of these center of gravity. While model without step tends to sticking conditions.

Inclined Loading Capacity of Embedded Suction Anchors in Clay

2009 ◽  
Author(s):  
Y. S. Kim ◽  
K. O. Kim ◽  
Y. Cho ◽  
S. Bang ◽  
K. D. Jones
Keyword(s):  
Analytical Solution ◽  
Model Test ◽  
Inclination Angle ◽  
Load Application ◽  
Centrifuge Model Test ◽  
Loading Capacity ◽  
Test Results ◽  
Pullout Capacity ◽  
Centrifuge Model ◽  
Inclined Loading

An analytical solution has been developed to estimate the inclined pullout capacity of an embedded suction anchor in clay seafloor. Validation has been made through comparisons with a limited number of centrifuge model test results. Results indicate that the inclined pullout capacity of an embedded suction anchor in clay decreases as the load inclination angle to the horizontal increases. As the point of the load application moves downward, the inclined pullout capacity increases, reaches its peak, and then starts to decrease.

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