scholarly journals AN EVALUATION OF THE PHYSICAL IMPACT AND STRUCTURAL INTEGRITY OF A GEOTEXTILE SURF REEF

2012 ◽  
Vol 1 (33) ◽  
pp. 21 ◽  
Author(s):  
Emma Jane Rendle ◽  
Mark Davidson
Keyword(s):  
Wave Field ◽  
Marine Environment ◽  
Structural Integrity ◽  
Wave Climate ◽  
South Coast ◽  
Coastal Protection ◽  
Shallow Marine ◽  
Physical Impact ◽  
The Impact

Geotextile artificial surfing reefs (ASR) are being considered by coastal planners due to their multifunctional potential for coastal protection and habitat provision, as well as additional recreational amenity. However, little research exists on the impact of submerged geotextile structures on the physical marine environment. Europe’s first ASR was constructed in 2009 on the south coast of England in Boscombe and is the case study for this paper. This research investigates the claims regarding the structural resilience of an ASR, the modifications to the inshore wave climate and the shoreline response induced by the introduction of an ASR to a system. The Boscombe ASR has suffered from damage, two major geotextile sand filled containers have degraded in this shallow marine environment in two years post-construction. Observations and simulations presented indicate ameliorated wave field leeward of the ASR. There is little shoreline response, given the structures distance offshore, and no salient or widening of the beach has occurred.

Are artificial reefs an appropriate solution to protect the Danube Delta coast?

2020 ◽  
Author(s):  
Irina Dinu
Keyword(s):  
Wave Climate ◽  
Sediment Supply ◽  
Danube River ◽  
Artificial Reefs ◽  
Coastal Protection ◽  
Danube Delta ◽  
Marine Geology ◽  
Natural Habitats ◽  
Wave Heights ◽  
The Impact

<p><strong>Are artificial reefs an appropriate solution to protect the Danube Delta coast?</strong></p><p>Irina Dinu<sup>1</sup>, Vicente Gràcia<sup>2</sup>, Manuel García-León<sup>3</sup>, Adrian Stănică<sup>1</sup></p><p> </p><p><sup>1</sup> – National Institute for Marine Geology and Geoecology (GeoEcoMar), 23-25 Dimitrie Onciul St., 024053, Bucharest, Romania</p><p><sup>2</sup> - Laboratory of Maritime Engineering, Polytechnic University of Catalonia (LIM-UPC), Campus Diagonal Nord, Building D1, 1-3 Jordi Girona St., 08034 Barcelona</p><p><sup>3</sup> - International Centre for Research of Coastal Resources (CIIRC), 1-3 Jordi Girona St., Mòdul D1, Campus Nord, 08003 Barcelona, Spain</p><p> </p><p>The Danube Delta coast is part of the Danube Delta Biosphere Reserve, thus being aimed to preserve its typical natural habitats. Over the last decades, human interventions along the Danube River, as well as coastal navigation and harbour protection works on the Romanian coast have determined the reduction of sediment supply along the Danube Delta coast, which is nowadays affected by erosion on its widest part.</p><p>Sustainable management plans for the Danube Delta coast include the use of working-with-nature solutions.</p><p>In this work, the effect of artificial reefs on the wave heights along the Danube Delta coast is studied. The results of a previous wave climate study and a wave model have been used for this purpose. Simulations have been performed for different setup of artificial reefs and for extreme storms with various return periods. The effect of sea level rise has also been taken into account.</p><p>Our results show that artificial reefs are significantly effective in reducing the wave heights along the Danube Delta coast. However, further detailed analysis concerning the impact of such a coastal protection solution is still needed.  </p>

The impact of wave energy farms in the shoreline wave climate: Portuguese pilot zone case study using Pelamis energy wave devices

2010 ◽  
Vol 35 (1) ◽  
pp. 62-77 ◽  
Author(s):  
Artur Palha ◽  
Lourenço Mendes ◽  
Conceição Juana Fortes ◽  
Ana Brito-Melo ◽  
António Sarmento
Keyword(s):  
Wave Energy ◽  
Wave Climate ◽  
The Impact

Reliability-Based Crack Threat Assessment and Management

2020 ◽  
Author(s):  
Jason Yan ◽  
Shenwei Zhang ◽  
Shahani Kariyawasam ◽  
Dongliang Lu ◽  
Tammie Matchim
Keyword(s):  
Crack Growth ◽  
Safety Factor ◽  
Structural Integrity ◽  
Threat Assessment ◽  
Assessment Model ◽  
Deterministic Approach ◽  
Safety Level ◽  
Characteristic Values ◽  
The Impact

Abstract Crack or crack-like anomaly is one of the major threats to the safety and structural integrity of oil and gas transmission pipelines. The crack threat is usually managed by hydrostatic test or regular in-line inspection (ILI). For a given crack ILI pipeline tally, operators need to identify critical anomalies, determine appropriate response time, and whether pressure restriction (derate) is required. Traditionally, a deterministic approach is used to determine the mitigation plan based on characteristic values of pipe properties, conservative crack sizing and crack growth rate, and further considering a minimum required safety factor. This study introduces a reliability-based approach to make the mitigation decision with full details. The annual probability of failure (POF) is evaluated for each reported crack anomaly by Monte Carlo simulation technique considering all the uncertainties associated with pipe geometry, material properties, crack size measurement, and assessment model error explicitly. Both environmental and cyclic fatigue load driven crack growth are considered following API RP 1176. A reliability-based mitigation threshold is proposed and calibrated against the deterministic minimum required safety factor for maintaining the system to a consistent safety level. Two case studies were conducted to demonstrate the advantages of the reliability-based assessment approach in this paper. Case Study #1 considers an NPS 20 transmission gas pipeline with more than 2000 ILI reported crack anomalies. Compared to the deterministic approach using conservative characteristic values, the reliability-based approach can reduce the number of required mitigation activities significantly without compromising safety. Case Study #2 assumes a severe crack defect on an NPS 34 liquid pipeline to demonstrate the impact of fatigue driven crack growth on POF. The POF of crack anomalies can be compared and combined with other threats, e.g. external corrosion, to evaluate the quantitative risk throughout pipeline systems. The proposed framework in this study could be used by operators to improve the crack assessment programs.

scholarly journals The Performance of a Spectral Wave Model at Predicting Wave Farm Impacts

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5728
Author(s):  
J. Cameron McNatt ◽  
Aaron Porter ◽  
Christopher Chartrand ◽  
Jesse Roberts
Keyword(s):  
Wave Field ◽  
Wave Energy ◽  
Wave Interaction ◽  
Wave Model ◽  
Skill Score ◽  
Coastal Protection ◽  
Linear Wave ◽  
Ocean Wave Energy ◽  
Wave Farm ◽  
The Impact

For renewable ocean wave energy to support global energy demands, wave energy converters (WECs) will likely be deployed in large numbers (farms), which will necessarily change the nearshore environment. Wave farm induced changes can be both helpful (e.g., beneficial habitat and coastal protection) and potentially harmful (e.g., degraded habitat, recreational, and commercial use) to existing users of the coastal environment. It is essential to estimate this impact through modeling prior to the development of a farm, and to that end, many researchers have used spectral wave models, such as Simulating WAves Nearshore (SWAN), to assess wave farm impacts. However, the validity of the approaches used within SWAN have not been thoroughly verified or validated. Herein, a version of SWAN, called Sandia National Laboratories (SNL)-SWAN, which has a specialized WEC implementation, is verified by comparing its wave field outputs to those of linear wave interaction theory (LWIT), where LWIT is theoretically more appropriate for modeling wave-body interactions and wave field effects. The focus is on medium-sized arrays of 27 WECs, wave periods, and directional spreading representative of likely conditions, as well as the impact on the nearshore. A quantitative metric, the Mean Squared Skill Score, is used. Results show that the performance of SNL-SWAN as compared to LWIT is “Good” to “Excellent”.

The impact of anthropogenic activities on marine environment in Jiaozhou Bay, Qingdao, China: A review and a case study

2016 ◽  
Vol 8 ◽  
pp. 287-296 ◽  
Author(s):  
Yuan Yuan ◽  
Dehai Song ◽  
Wen Wu ◽  
Shengkang Liang ◽  
Yan Wang ◽  
...  
Keyword(s):  
Marine Environment ◽  
Anthropogenic Activities ◽  
Jiaozhou Bay ◽  
The Impact

The impact of sea level rise and climate change on inshore wave climate: A case study for East Anglia (UK)

2010 ◽  
Vol 57 (11-12) ◽  
pp. 973-984 ◽  
Author(s):  
Nicolas Chini ◽  
Peter Stansby ◽  
James Leake ◽  
Judith Wolf ◽  
Jonah Roberts-Jones ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Wave Climate ◽  
East Anglia ◽  
The Impact

scholarly journals Recent Developments of the Linear Matching Method Framework for Structural Integrity Assessment

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Daniele Barbera ◽  
Haofeng Chen ◽  
Yinghua Liu ◽  
Fuzhen Xuan
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Structural Integrity ◽  
Direct Methods ◽  
Matching Method ◽  
Integrity Assessment ◽  
Wide Range ◽  
The Impact ◽  
Linear Matching Method

The linear matching method (LMM) subroutines and plug-in tools for structural integrity assessment are now in extensive use in industries for the design and routine assessment of power plant components. This paper presents a detailed review and case study of the current state-of-the art LMM direct methods applied to the structural integrity assessment. The focus is on the development and use of the linear matching method framework (LMMF) on a wide range of crucial aspects for the power industry. The LMMF is reviewed to show a wide range of capabilities of the direct methods under this framework, and the basic theory background is also presented. Different structural integrity aspects are covered including the calculation of shakedown, ratchet, and creep rupture limits. Furthermore, the crack initiation assessments of an un-cracked body by the LMM are shown for cases both with and without the presence of a creep dwell during the cyclic loading history. Finally, an overview of the in house developed LMM plug-in is given, presenting the intuitive graphical user interface (GUI) developed. The efficiency and robustness of these direct methods in calculating the aforementioned quantities are confirmed through a numerical case study, which is a semicircular notched (Bridgman notch) bar. A two-dimensional axisymmetric finite element model is adopted, and the notched bar is subjected to both cyclic and constant axial mechanical loads. For the crack initiation assessment, different cyclic loading conditions are evaluated to demonstrate the impact of the different load types on the structural response. The impact of creep dwell is also investigated to show how this parameter is capable of causing in some cases a dangerous phenomenon known as creep ratcheting. All the results in the case study demonstrate the level of simplicity of the LMMs but at the same time accuracy, efficiency, and robustness over the more complicated and inefficient incremental finite element analyses.

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