cover
Contact Name
-
Contact Email
-
Phone
-
Journal Mail Official
-
Editorial Address
-
Location
Kota surabaya,
Jawa timur
INDONESIA
IJOCE (International Journal of Offshore and Coastal Engineering)
ISSN : -     EISSN : 25800914     DOI : -
Core Subject : Engineering,
IJOCE, International Journal of Offshore and Coastal Engineering, is an academic journal on the issues related to offshore, coastal and ship science, engineering and technology. Published quarterly in February, May, August, and November.
Arjuna Subject : -
Articles 202 Documents
Impact of Reclamation Development on Sedimentation and Current Pattern in East Coast Surabaya (Pamurbaya) Suntoyo Suntoyo; Hasan Ikhwani; Mohammad Iqbal Hidayah
International Journal of Offshore and Coastal Engineering Vol. 1 No. 2 (2017)
Publisher : Department of Ocean Engineering

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v1i2.7055

Abstract

Reclamation is an effort to establish a new land area either in coastal areas or in the middle of the ocean. In Pamurbaya area a number of property projects both housing and apartments is still continuing. Environmental impacts of the coastal reclamation project is in the potential increase of flooding. The changes include the extent of the cluster, the composition of river sediments, the tidal pattern, the pattern of ocean currents along the coast and damaging the water system. This study examines changes in current patterns, morphology, and sedimentation rate due to the reclamation modeled using Delft3D software. The pattern of current flow after the reclamation has changed. Basic surface changes that occur before and after reclamation in each crossection is by difference, crossection 1 = +0.22 m, crossection 2 = -0.19 m, and crossection 3 = +0.11 m. The sign (+) shows the occurrence of sedimentation, while (-) is erosion. The condition after the reclamation in crossection 1 is sedimentation, crossection 2 is erosion, and crossection 3 is sedimentation. The difference in intensity is very small, therefore the erosion and sedimentation which took place after reclamation is not too significant.
Prelimenary Modeling for Assessing Tidal Stream Energy Potential at the Alas Strait, Indonesia Mukhtasor Mukhtasor; Sujantoko Sujantoko; Luli Bangkit Sugito
International Journal of Offshore and Coastal Engineering Vol. 1 No. 2 (2017)
Publisher : Department of Ocean Engineering

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v1i2.7056

Abstract

This study is on ocean current prelimenary modelling in Alas Strait, Indonesia, to be compared with the field observation data. The model maps coordinate for ocean current so that the potential energy resource can be identified. The model simulation is established with two different scenarios; the first scenario is using windspeed factor and the second without using that factor. Complementary variables such as bathymetry, water elevation, bottom friction, and eddy viscosity have the same value for both scenarios. This ocean current modelling use finite element method with flexible mesh. This method use two dimension numerical solution from the average incompressible Reynolds Navier – Stokes equation with the assumption from Boussinesq dan hydrostatic pressure. This model consists of continuity equation and momentum which closed by turbulen scheme. This study concludes the first scenario is a success and valid with the water surface elevation mean error is 4.2% and water current speed mean error is 10.7%. The second scenario is unseccesful as indicated by the water surface elevation mean error of 13.4% and the water current speed mean error of 11,7%, and also the phase and the trend of current speed is verging the field observation data.
Risk Analysis on Leakage Failures of Pipelines Using Hybrid Risk Analysis Method Daniel Mohammad Rosyid; Bassam Muhammad Drehem; Agro Wisudawan
International Journal of Offshore and Coastal Engineering Vol. 1 No. 2 (2017)
Publisher : Department of Ocean Engineering

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v1i2.7057

Abstract

In this final project has been conducted a study on risk analysis on subsea pipeline leakage by using hybrid risk analysis method. The study begins by determining the scope of the analysis using fault tree analysis which can be determined the main event of the leakage failure of subsea pipeline until the basic event. After determining the scope of the analysis then proceeded to calculate the frequency of each event using the quantitative method. In this calculation is known the frequency of basic event through data from scientific paper programming and scientific research and then calculated the frequency result of top event using Boolean Equation until we get the frequency of failure due to leakage pipelines for 0.0141213. After knowing how big the probability of failure, followed by determining how much impact or consequence of the failure. The consequences of failure are determined based on their impact on safety, environment, and business. In the determination of the impact with the qualitative method using questionnaires interviews to some respondents. After obtaining the result of questionnaire interview then calculated the mean of the questionnaire result to determine how big impact of the failure is based on safety, environment, and business. After knowing how big the probability and consequences of the failure, then determine the position of the risk zone on the risk matrix that refers to DNV RP-G101. After knowing the position of the risk zone, it can be determined how to control risk based on cause-effect.
Analitical Study of Vertical and Lateral Buckling on Pipeline Using Hobbs Method Yoyok Setyo Hadiwidodo; Herman Pratikno; Muhammad Makki Romadhoni
International Journal of Offshore and Coastal Engineering Vol. 1 No. 2 (2017)
Publisher : Department of Ocean Engineering

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v1i2.7058

Abstract

Influence of Pre-Weld Heat Treatment and Aging Post-Weld Heat Treatment on Tensile Test and Microstructure of Aluminium 6061 Weld Joint Herman Pratikno; Hasan Ikhwani; Tin Rachmatullah
International Journal of Offshore and Coastal Engineering Vol. 4 No. 1 (2020)
Publisher : Department of Ocean Engineering

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v4i1.8701

Abstract

Aluminium 6061 is an aluminium composition with Al-Mg-Si alloy which is often used for offshore structure material due to its high strength, good ductility and good corrosion resistance as well as its mechanical properties that can be enhanced by heat treatment. The purpose of this paper is to show the effect of heat treatment variations, in the form of preheating and aging PWHT, on tensile strength and microstructure of aluminium 6061 welding connection with GTAW process using electrode ER 5356. The pre-heat temperature variations used were 80°C, 100°C, and 120°C and the aging PWHT temperature variations used were 180°C and 260°c. The result shows that specimen with preheat treatment temperature of 120°C and aging pwht temperature of 260°C had the largest ultimate strength of 246.74 MPa and yield strength of 125.21 MPa. The highest percentage of Mg2Si formed was also found on the same specimen with a percentage of 48.84% in weld metal, 58.75% in HAZ, and 43.54% in base metal.
Analysis of Inspection Scheduling on Free Spanning Subsea Pipeline Using Risk Based Inspection (RBI) Method Daniel Mohammad Rosyid; Yoyok Setyo Hadiwidodo; Abizar Giffari
International Journal of Offshore and Coastal Engineering Vol. 4 No. 1 (2020)
Publisher : Department of Ocean Engineering

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v4i1.8703

Abstract

The subsea pipeline system of PT. X located at north of West Java transports natural gas with 19 kilometers long and 16 inches standard pipe size. The rough seabed causes free span problem. The system will be threatened by a structural failure of fatigue due to Vortex Induced Vibration (VIV) and local buckling as the effects of free span. In this Final Project, a total of 136 free spans on subsea pipeline system due to the uneven seabed are analyzed. The screening will be done for spans with length and diameter ratio more than 30 to figure out the free span which pass the screening and know the risk level of the subsea pipeline due to free span. The result for fatigue screening due to VIV, spans with a length more than 25 meters did not pass the screening. Local buckling occurred at the longest free span with a length of 62 meters. The level of risk to structural failure caused fatigue due to VIV has the highest level in terms of business and the environment, namely in the medium category. The level of risk to local buckling failures for safety, environmental, and business terms was in low category.
The Study of Mooring Buoy Operability to Support Offloading Operation of Shuttle Tankers with Various Capacities Eko Budi Djatmiko; Murdjito Murdjito; Mochammad Afif Zahiru Fajar
International Journal of Offshore and Coastal Engineering Vol. 4 No. 1 (2020)
Publisher : Department of Ocean Engineering

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v4i1.8704

Abstract

This study was conducted to analyse of the operability of mooring buoy initially designed for offloading operation of 35,000 DWT shuttle tankers enhanced to serve the offloading operations of shuttle tankers with 50,000 DWT, 75,000 DWT, and 111,000 DWT capacities. Operability is reviewed in term of mooring line tensions induced by each new variation of tanker capacity under environmental conditions of 1-year, 10-year, and 100-year recurrence. The governing criteria is that the safety factor should meet the appropriate limit as stated in the API RP2SK. Tension on the mooring line increases in parallel with the increasing of tanker capacity. For the case of 35,000 DWT and 50,000 DWT shuttle tankers the operation can be performed in all environmental conditions. For the case of 75,000 DWT shuttle tanker with full load and 67% DWT capacity can fully operate in all environmental conditions, but with 47% DWT capacity could not be operated in the 100-year environmental condition with significant wave height 3.31 m for the direction of inline-L1, inline-L2, and between line-L1&L4. For the case of 111,000 DWT shuttle tanker at all capacity conditions can fully operate in the 1-year environmental condition with significant wave height up to 1.48 m.
Risk Analysis of Decommissioning Process: Case Studies of Lima-Compresor Platform Daniel Mohammad Rosyid; Murdjito Murdjito; Arif Windiargo
International Journal of Offshore and Coastal Engineering Vol. 4 No. 1 (2020)
Publisher : Department of Ocean Engineering

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v4i1.8705

Abstract

The process of petroleum exploration and exploitation is a crucial activity in the fulfillment of energy needs in the world. The process of petroleum exploration and exploitation is currently centred on shallow water regions in the continental shelf. In the process of petroleum exploration and exploitation in shallow waters, the structure of which is commonly used is the jacket structure. In Southeast Asia there are about 1300 platforms, of which 80% is over 20 years old. When the platform has reached its operational limit, according to the ministerial regulation of ESDM number 1 year 2011 The platform must be decommissioning in accordance with existing technical standards. In the process of demolition, there are certainly risks and hazards that can interfere with the process of decommissioning. It is necessary to do a risk analysis to map the risks that can occur while preparing the mitigation steps. In this study, risk analysis arel conducted by determining the activity that has a significant degree of hazard where it is concluded that activities that have a significant risk level are activities related to construction, lifting, maintenance, well service, and maintenance. From each activity that has a significant hazard level, there was a process of determining the cause of risk using the Fault Tree Analysis (FTA) method while determining the barrier that serves to prevent a risk occurring. The next is to determine the impact that can be inflicted from risk by using the Event Tree Analyis (ETA) method while determining the barrier that serves to prevent and reduce the impact that occurs when there is a peril. These two FTA and ETA diagrams are combined to create a Bowtie diagram to explain in detail the risk management performed at each stage of the decommisiioning process.
Analyzing the Effect of Variation in Shielding Gas Flow Rate and V Groove Type Towards Tensile and Metallographic Testing of GMAW Weld Joint of ASTM A53 and A36 Herman Pratikno; Wimala Lalitya Dhanistha; Andrea Novia Samiyono
International Journal of Offshore and Coastal Engineering Vol. 4 No. 1 (2020)
Publisher : Department of Ocean Engineering

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v4i1.8706

Abstract

Steel is a metal that commonly used in fabrication, engineering, and reparation activities in the structure construction industry. ASTM A53 steel is a low carbon steel with 0.25% to 0.3% of carbon content so it has a high weldability. ASTM A36 steel is a low carbon steel with carbon content of 0.25% to 0.29% and is often used in the floating building industry. This study aims to determine the effect of shielding gas flow rate and V-groove type to the tensile strength of A53 steel welded with A36 steel by Gas Metal Arc Welding (GMAW) method. The shielding gas level used is 100% CO2 with flow rate variations, including 15 liters/minute, 20 liters/minute, and 25 liters/minute. The groove types used are Single V-Groove and Double V-Groove. Tensile strength test result showed that in the welding process in this study, specimen with 25 liters/minute flow rate on the Double V-Groove had the highest tensile strength value of 516.73 MPa, with the narrowest HAZ width of 0,87 mm on A36’s HAZ and 1,22 mm on A53’s HAZ, and the smallest percentage of ferrite in the microstructure as much as 56.34% and 43.66% pearlite.
The Effect Analysis of Coating Thickness Variation and Mixed Composition of Zinc - Graphite on Epoxy Coating with Steel Plate ASTM A36 Herman Pratikno; Wimala Lalitya Dhanistha; Andry Febrianto
International Journal of Offshore and Coastal Engineering Vol. 4 No. 1 (2020)
Publisher : Department of Ocean Engineering

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j2580-0914.v4i1.8707

Abstract