فهرست مطالب

International Journal of Coastal, Offshore and Environmental Engineering
Volume:5 Issue: 4, Autumn 2020

  • تاریخ انتشار: 1399/08/11
  • تعداد عناوین: 6
|
  • Danial Ghaderi, Maryam Rahbani * Pages 1-8
    Coastal areas are one of the most crucial and important area in each country. They are also one the most dynamics area, which undergo significant changes in relatively short periods. Protecting coastlines from erosion and/or sedimentation thus, is one of the most important duties in each country. In this study, shoreline change in the Beris Port - east of Chabahar, Iran, was investigated using remote sensing technique and DSAS tools. Beris Port is located 85 km east of Chabahar, on the Makran coast. Landsat 8 and 5 satellite images were used to detect shoreline change, due to the port's construction date, satellite imagery of 1988, 1990, 2014 and 2019 was used. Using the NSM, SCE, EPR and LRR statistical indexes of the DSAS tool, erosion and accretion rates were calculated in for the area. According to the LRR index, the lowest shoreline change rate is -1.51 m/year and is detected to be to the east of port. The highest rate of shoreline change is 7.44 m/year at the port. According the results, the main reason for this high rate of change is the location of the port, which is in the area perpendicular to its neighborhood coastal area, which causes to trap the current in this area to increase its dynamic activities. Shortly speaking, it was found that the accretion is dominant in port Beris and east of the port is the zone with least amount of accretion.
    Keywords: Beris port, DSAS, Remote Sensing, Shoreline change
  • Seyed Farshid Montazeri, Rouhollah Amirabadi * Pages 9-17
    Ports are the main avenue of global freight transport. In the past, experience has shown that ports are vulnerable to earthquakes, which cause evident economic damage. The port at Kobe, Japan, experienced economic losses of about $11 billion after an earthquake in 1995. The present study used the full-probabilistic PEER-PBEE framework to develop a comprehensive seismic risk assessment approach with which to estimate the total direct and indirect economic loss incurred by a port experiencing an earthquake. In the proposed methodology, the extent of direct economic loss due to the cost of repair of port structures in the Pars Asaluyeh port was estimated. Seismic risk density curves (SRDCs) were employed to determine the seismic performance of different port structures and pieces of equipment as well as the overall seismic performance of the port. The SRDCs show that the mooring structures and breakwater of the port showed appropriate seismic performance, while other port structures and equipment showed weak or average seismic performance.
    Keywords: PEER-PBEE, Seismic Risk Density, economic loss, Probabilistic Direct Loss estimation, Port of Pars Asaluyeh
  • Mojtaba Zoljoodi, Reyhane Zoljoodi * Pages 19-23
    A tsunami is a sea wave of local or distant origin that results from large-scale seafloor displacements associated with strong earthquakes, major submarine slides, or exploding volcanic islands. A tsunami can strike any coast at any time and we cannot predict exactly when or where they will occur. Undersea earthquakes most often cause tsunamis but submarine landslides or volcanic eruptions can also cause them. A tsunami can move as fast as a jet plane across the Open Ocean and can hit land with waves as high as 20 meters or more. The water may wash inland for several kilometers in flat lying areas, and can move up streams and rivers, destroying everything in its path. Waves may continue to strike the shoreline for many hours, and dangerous currents can continue for days following the event. Coastal areas endure   Clear changes in response to ocean changes. The tsunami and tropical storms are among those changes. These changes should be note, Failure to pay attention to them makes opportunities become a threat. Tropical storms are one of the most dangerous hazards. In the first table some costs are mentioned.When a tropical storm occurs, the water level along the waves in the sea changes. In these storms, strong winds are generated that revolve around a central core.it can move from ocean to coastal areas. The Makran seduction is due to the mountain range from Iran to Pakistan. The most important of these are Taftan and Bazman in Iran and Sultan in Pakistan. In hence The coastal area and sea play an important role in the development of country. Tropical storms and tsunamis are one of the most destructive phenomena in the world.it occurred in1945 in Iran, Mokran. The reason for this phenomenon was the large earthquake of 8.25 on the Mokran fault. This tsunami caused a lot of damage That killed more than 4,000 people in Pakistan. Tropical storms are important phenomena in the ocean area. The proper investment in different sectors and special attention to marine hazards and tsunami and also implementation of prevention plans are so necessary. Coastal areas influence economy by the knowledge of the potential of energy, transport, fisheries and tourism in addition to their political, strategic and social importance in the country's economy. Some plans are designed to reduce costs. Some of these programs are for training and some are to prevent damage. Financial limitation causes the need of prioritizing plans based on the knowledge of economical engineering in different periods of time. . In this case we present a modeling for prioritizing plans in order to  Reduce the amount of Economical  losses .with use NPV index to do the task .we have to calculate the amount of cost reduction for each plan. To find the extent of the damage reduction, 100 experts and organizations are surveyed and the results are estimated and then the cost of implementation of plans was found.Historical accounts describe an earthquake and tsunami on 21 July AD 365 that destroyed cities and drowned thousands of people in coastal regions from the Nile Delta to modern-day Dubrovnik. The location and tectonic setting of this earthquake have been uncertain until now.
    Keywords: costal area, engineering, NPV, Tsunami, tropical storm
  • Amirarsalan Shahmohammadi, Naser Shabakhty * Pages 25-33
    Modelling the soil-pile interaction using the Finite Element Method (FEM) might be a time-consuming process and required entirely specific soil properties. Moreover, most of the codes that have been developed for offshore wind turbines use one or more of some simplified linear foundation models suitable for dynamic analysis such as Apparent Fixity (AF) model. In the AF model for pile foundation systems, a fixity length level below the seabed is designated for the pile. It is assumed that the whole structure, including the pile and support structure, is cantilevered at the corresponding fixity length level without surrounding soil while has identical behavior to a pile penetrated the real soil. In this study, the apparent fixity length of the piles sustaining the OC4 offshore wind turbine on the seabed is estimated using a nonlinear soil-pile interaction analysis following a dynamic response analysis of the structure under lateral loads during turbine power production. Given the stiffness coefficients of the pile heads, different apparent fixity lengths are obtained, and the minimum one, verified by modal analysis, is also determined, which can be presumed in fatigue analysis. It is also demonstrated that the estimated minimum fixity length has a smaller value than the piles’ critical length.
    Keywords: Offshore wind turbine, Jacket, Soil-pile interaction, fixity length, lateral loading
  • Mozhgan Aghanezhad, Rouzbeh Shafaghat *, Rezvan Alamian Pages 35-46
    In the past decade, ocean and marine waves like other renewable energy sources attracted attention due to its high energy density. The most important part of a wave energy converter (WEC) is power take-off (PTO) system. In this study, a proper hydraulic power take-off system for centipede WECs has been evaluated and analyzed in experimental scale. Experimental analysis has been done in dry conditions. Important parameters are resistant load of rheostats and the opening percent of the flow control valve. System input is the wave force, which is modeled as an external mechanical force applied to the end of the lever. Resistant load of rheostats is changeable in the range of 9.5 to 55 ohms. In addition, according to the range of valve opening, six positions are selected to study. Results in this research show that, as resistance load increases, output power and efficiency, are enhanced significantly. On the other hand, in all the resistive loads tested, there is a maximum point (2 rev. valve opening) for efficiency, which shows the positive effect of controlling the input flow to the Hydro Motor (HM). The efficiency in this position of the flow control valve opening has enhanced by 40% compared to neighbor situations.
    Keywords: Marine Energy, Centipede Wave Energy Converter, Hydraulic PTO, Experimental analysis, optimization
  • Mehrnaz Farzingohar *, Zabihollah Khakpour, Mohammad Ahmadizadeh Shaghooei, Alireza Soory Pages 47-53
    Bandar Abbas fish quays activities impacted on chemical compounds of the coasts. Three stations as Posht e Shahr (Ps), Sayadan (Sa) and Shilat (Sh) were selected to investigate the oil spill pollution and heavy metal concentrations in the regions. The sediment samples were collected in June and November 2017 then extracted. The highest concentrations were Fe>Zn> Pb>Cu>Cd respectively in the Sh quay. The cluster results indicated that Ni and Zn have the same sources but Pb, Cu and Cd were from different sources. Ni and Zn entered the environment due to the activities of ship repairs and coastal construction. Pb, Cu and Cd sources were from oil spills of fishing boats. The ERLQ and ERMQ toxicity rates of Ni at Ps and Sa were at the occasional but the Sh was at the frequent occurrence level. In November, the Cd toxicity at Sh was at occasional level. The new rules needed to control the pollution of quays operation.
    Keywords: Oil spill, Sediment Analysis, Bandar Abbas, Heavy metal, Fishing port