Texas Tower 4: Lessons for Design of Offshore Structures

2002 ◽  
Author(s):  
Robert G. Bea ◽  
Zhaohui Jin
Keyword(s):  
Water Depth ◽  
Early Warning ◽  
East Coast ◽  
Offshore Structures ◽  
Ocean Engineering ◽  
Satisfactory Explanation ◽  
Engineering Technology ◽  
The U.S

The Texas Towers were a series of platforms installed off the U.S. East coast in the 1950’s to support early warning radar facilities. Texas Tower 4 (TT4) was installed in a record setting water depth of 185 feet in 1957. At this time, TT4 was heralded as an ‘engineering marvel’; a major innovative ocean engineering accomplishment. In December 1960, the decision was made to decommission TT4, but before this could be done the platform failed during a storm in January 1961 with the loss of the lives of all personnel that were onboard. A satisfactory explanation was never developed that detailed exactly how the structure failed. In 1999, a study was commissioned by the American Bureau of Shipping to study the failure of TT4. The objective of this study was to see if with modern ocean engineering technology (storm forces, structure capacities), the details of failure of the structure could be re-created. This paper summarizes the results from this study.

Commercial Aviation, A New Era: summary of the 2017 TQA workshop

2021 ◽  
Vol 263 (3) ◽  
pp. 3896-3899
Author(s):  
gregg fleming
Keyword(s):  
Environmentally Friendly ◽  
Federal Aviation Administration ◽  
Global Leadership ◽  
Aviation Industry ◽  
Engineering Technology ◽  
Commercial Aviation ◽  
New Era ◽  
Government Organizations ◽  
Aircraft Engineering ◽  
The U.S

More environmentally friendly aircraft designs, particularly with regard to noise, was a Technology for a Quieter America (TQA) workshop hosted by the National Academy of Engineering (NAE) held in May 2017. This workshop titled "Commercial Aviation: A New Era", centered on the importance of commercial aviation to the U.S. economy, and what it will take for the U.S. to maintain global leadership in the aviation sector, including a forward-looking topic on more environmentally friendly aircraft designs. A principal focus of the workshop was the necessary step-changes in aircraft engineering technology that must be addressed with the development and testing of flight demonstrators together with significantly increased funding of public-private partnerships. Government agencies which participated included NASA, the Federal Aviation Administration, and the Department of Housing and Urban Development (HUD). There was also substantial participation from the aviation industry, airports, airlines, non-government organizations and academia.

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.

Experimental Investigation of Trimaran Models in Shallow Water

2014 ◽  
Vol 30 (02) ◽  
pp. 66-78
Author(s):  
Mark Pavkov ◽  
Morabito Morabitob
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Critical Speed ◽  
Water Effect ◽  
Finite Water Depth ◽  
Speed Regime ◽  
Displacement Speed ◽  
Littoral Combat Ship ◽  
Shallow Water Effect ◽  
The U.S

Experiments were conducted at the U.S. Naval Academy's Hydromechanics Laboratory to determine the effect of finite water depth on the resistance, heave, and trim of two different trimaran models. The models were tested at the same length to water depth ratios over a range of Froude numbers in the displacement speed regime. The models were also towed in deep water for comparison. Additionally, the side hulls were adjusted to two different longitudinal positions to investigate possible differences resulting from position. Near critical speed, a large increase in resistance and sinkage was observed, consistent with observations of conventional displacement hulls. The data from the two models are scaled up to a notional 125-m length to illustrate the effects that would be observed for actual ships similar in size to the U.S. Navy's Independence Class Littoral Combat Ship. Faired plots are developed to allow for rapid estimation of shallow water effect on trimaran resistance and under keel clearance. An example is provided.

scholarly journals Social Samaritan Justice: When and Why Needy Fellow Citizens Have a Right to Assistance

2015 ◽  
Vol 109 (4) ◽  
pp. 735-749 ◽  
Author(s):  
LAURA VALENTINI
Keyword(s):  
East Coast ◽  
Double Standard ◽  
Hurricane Sandy ◽  
Material Resources ◽  
Resource Transfers ◽  
Political Communities ◽  
The Needy ◽  
The U.S ◽  
Do So

In late 2012, Hurricane Sandy hit the East Coast of the U.S., causing much suffering and devastation. Those who could have easily helped Sandy's victims had a duty to do so. But was this a rightfully enforceable duty of justice, or a nonenforceable duty of beneficence? The answer to this question is often thought to depend on the kind of help offered: the provision of immediate bodily services is not enforceable; the transfer of material resources is. I argue that this double standard is unjustified, and defend a version of what I call “social samaritanism.” On this view, within political communities, the duty to help the needy—whether via bodily services or resource transfers—is always an enforceable demand of justice, except when the needy are reckless; across independent political communities, it is always a matter of beneficence. I defend this alternative double standard, and consider its implications for the case of Sandy.

Experimental Investigation on the Dynamic Response of a Three Legged Articulated Type Offshore Wind Tower

2016 ◽  
Author(s):  
Chinsu Mereena Joy ◽  
Anitha Joseph ◽  
Lalu Mangal
Keyword(s):  
Dynamic Response ◽  
Wind Turbine ◽  
Renewable Energy Sources ◽  
Offshore Structures ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Experimental Investigations ◽  
Offshore Wind Turbine ◽  
Ocean Engineering ◽  
Study Results

Demand for renewable energy sources is rapidly increasing since they are able to replace depleting fossil fuels and their capacity to act as a carbon neutral energy source. A substantial amount of such clean, renewable and reliable energy potential exists in offshore winds. The major engineering challenge in establishing an offshore wind energy facility is the design of a reliable and financially viable offshore support for the wind turbine tower. An economically feasible support for an offshore wind turbine is a compliant platform since it moves with wave forces and offer less resistance to them. Amongst the several compliant type offshore structures, articulated type is an innovative one. It is flexibly linked to the seafloor and can move along with the waves and restoring is achieved by large buoyancy force. This study focuses on the experimental investigations on the dynamic response of a three-legged articulated structure supporting a 5MW wind turbine. The experimental investigations are done on a 1: 60 scaled model in a 4m wide wave flume at the Department of Ocean Engineering, Indian Institute of Technology, Madras. The tests were conducted for regular waves of various wave periods and wave heights and for various orientations of the platform. The dynamic responses are presented in the form of Response Amplitude Operators (RAO). The study results revealed that the proposed articulated structure is technically feasible in supporting an offshore wind turbine because the natural frequencies are away from ocean wave frequencies and the RAOs obtained are relatively small.

scholarly journals Predicting Temperature Shifts off the U.S. East Coast

Eos ◽  
2016 ◽  
Vol 97 ◽  
Author(s):  
Sarah Stanley
Keyword(s):  
East Coast ◽  
Relative Importance ◽  
Ocean Temperature ◽  
Middle Atlantic Bight ◽  
Atmospheric Processes ◽  
Middle Atlantic ◽  
New Research ◽  
The U.S

New research reveals the relative importance of oceanic and atmospheric processes in year-to-year changes in ocean temperature along the Middle Atlantic Bight.

scholarly journals Sea-level prediction for early warning information of coastal inundation in Belawan coastal area using Delft3D model

2021 ◽  
Vol 893 (1) ◽  
pp. 012034
Author(s):  
A M N Jaya ◽  
F P Sari ◽  
I J A Saragih ◽  
I Dafitra
Keyword(s):  
Water Level ◽  
Sea Level ◽  
Early Warning ◽  
Hydrodynamic Model ◽  
Coastal Area ◽  
East Coast ◽  
Coefficient Of Determination ◽  
Wind Effect ◽  
Coastal Inundation ◽  
Better Than

Abstract Coastal inundation has a great impact on the environment, such as damage to infrastructure and pollution of land and water. One of the efforts to prevent coastal inundation is to predict the water level. Delft3D is a hydrodynamic model that's able to simulate the water level. Coastal inundation research using the Delft3D model is still rarely done in Indonesia, especially on the east coast of Sumatra. This research is conducted in Belawan coastal area by simulating the water level that caused the coastal inundation using the Delft3D model. The best bathymetry for the prediction of water level and the magnitude of the wind effect was obtained from the simulation. The final step is to predict the water level in Belawan coastal area. The result of this research shows that the Delft3D model can simulate the water level which causes the coastal inundation in the Belawan coastal area. The correlation of the Delft3D model is 0.9, and the RMSE of GEBCO bathymetry is 0.39 meters and the RMSE of NOAA bathymetry is 0.46 meters. The GEBCO bathymetry is better than NOAA bathymetry in describing the water level in the Belawan coastal area. The wind effect on the water level simulations is not significant because the coefficient of determination is 0.47%. Besides, the Delft3D model with GEBCO bathymetry input can predict the water level which causes the coastal inundation with correlation reaches 0.92 and RMSE is 0.39 meters.

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