International Journal of Coastal, Offshore and Environmental Engineering
Volume:5 Issue: 3, Summer 2020

This is the final part of a three-part paper that presents the methodology, data needed, code check of 12-inch ID rigid pools, describing the design methodology, and key design parameters for performing the analyses. Discussion of the state of art regarding the soil data is covered in Part I. Part II is dedicated to describing ISO 19901 and 19902 seismic qualification and the derivation of design time histories. For each cluster end, there are two parallel flowlines each individually terminated with a Flowline Termination Assembly (FTA). The FTA is free to move axially on its foundation to absorb movement caused by the flowline expansion and walking. Lateral movement is restricted by lateral stops on the foundation. Two separate spools will then be connected to a single Pigging Loop Module with a piled foundation. A diver-less horizontal collet connector system will be used for the tie-in at both ends of the spool. The analysis methodology which assumes the seabed is a compliant plate, is described in this paper. For validation purposes, a couple of configurations were used to create a full three-dimensional model where the soil was modeled using the solid element with Moh-Columb behavior. These results are not presented in this paper.

In this paper, we present a new method for terrain and gravity aided navigation. Gravity aided navigation and terrain aided navigation are map aided navigation methods for correcting Inertial Navigation System (INS) errors of Autonomous Underwater Vehicles (AUV). Map aided navigation uses the information of the geophysical field maps. For achieve the highest accuracy and reliability two or three map aided navigation systems are combined. In this paper, we proposed a new method that simultaneously uses gravity map data and terrain map data. For maps data fusion we use a Kalman filter which its measurement equation defined based on gravity and terrain of the experiment area. The experimental results are encouraging.

Sand dunes are crucial factors related to stability of the coasts, and vegetation plays a decisive role in their creation. In this research paper, analyzing the effects of the Caspian Sea level fluctuations and human intervention on transformation of habitats and biodiversity of coastal plants on sand dunes is assumed as the main goal. The morphological structure of coastal sand dunes and the biodiversity of their plant species were investigated by selecting 11 transects in the eastern coast of the central Mazandaran (Babolsar-Amirabad), also the major changes of the sand dunes in coastal lands were evaluated during the period of the Caspian Sea water level rise, 1978-1995, using the remote sensing. The results showed that coastal dunes in the southern coasts of the Caspian Sea are divided into three groups, intact or healthy, semi-healthy and completely destructed. In total, 174 plant species belonging to 134 genera and 75 families were identified in coastal embankment ecosystems as well as in active, middle and back sand dunes of the coast. The impacts of human intervention (changes in land cover and land use) and some increase in the Caspian Sea level during 1978-1995 were identified as factors affecting the damage of coastal sand dunes.

In the past few years, the location prediction played a critical role in many applications like intelligent self-learning vehicle, ocean location prediction because of the security and speed issues of GPSs. In this study, we proposed a model for location prediction on Oman’s gulf using a NetCDF Data set. The proposed model is based on classification and regression which means it first mapped the data in a region on Oman’s Gulf using classification and then using regression models to predict a specific location. This progress effect both response time and error of the system. And to the best of our knowledge, no researches are using the same idea. We used multiple classification models for classification tasks (both ensemble models and simple models) and two regression models (linear and XGboost regressor). The result shows reduce of man square error after using classification for regression task. Also, the result and explanation of the data capturing model are provided in the paper.

Addressing the interaction of the presence of coastal structures, breakwaters for instance, and morphological changes is of great importance. The purpose of this paper is to investigate the influences of the extended breakwaters of Astara Port on sediment transport and beach morphological evolution in the vicinity of them so as to identify how the extension of breakwaters altered the sea bed topography. In order to describe evolving cross-shore profiles in the study area, beach profile surveys were conducted by a single-beam echo sounder. Results showed that the breakwaters considerably affected their surroundings, and scouring in front of them was obvious. Furthermore, comparisons of measured beach profiles with Dean's profile model for the equilibrium beach profile illustrated that the Dean's profile was not able to precisely represent the time- mean profiles. As a result, Dean's equilibrium profile was modified and a new model was developed so that it can represent more correctly cross-shore morphodynamics of the study area. The results revealed that modified equilibrium profile can be a better representative for the cross-shore profiles of the study area.

Pipelines are an economical way for offshore oil and gas transportation. In operation conditions, flowing high pressure/high temperature (HP/HT) fluids may induce axial expansion. If this expansion is constrained, axial stresses will be created and they may cause pipeline buckling. In order to reduce damages and avoid buckling in unpredictable places, the controlled buckling concept is introduced. To use this concept in the present study, buckling is triggered at some predetermined locations by using the snaked laying method. This paper analyzes the global buckling process of a pipeline by using numerical simulation methods and the effects of loading (internal pressure and temperature) and section properties (diameter and thickness) are investigated on the critical buckling force of snaked lay pipelines under HP/HT conditions. Then, the analysis results of the finite element method (FEM) are compared with analytical solutions and previous simulation methods. This work includes performing nonlinear finite element analysis and modeling pipe-soil interaction of as-laid pipelines by the use of spring elements. The results show that the use of equivalent temperature instead of pressure difference, as already applied in previous studies, is not an authentic method and cannot introduce an accurate outcome. The analysis shows that by increasing pressure and decreasing temperature, the critical buckling force is decreased and the pipeline buckling occurs sooner. The investigation of section properties indicates that the most effective parameter is thickness. It is remarkable to know that at low values of thickness, the effect of diameter is negligible and by increasing thickness, the influence of diameter is increased. Comparing the analytical and numerical results reveals that at low values of circumferential stiffness (ratio of diameter to thickness), there are minor differences between numerical and analytical results.