Optimum Open Cell Sheet Pile (OCSP) Quay Wall System in Port Said, Egypt

The principal intent of this paper was to propose a new quay wall system, whose validity was verified; to play the same role of the existing diaphragm quay wall at East Port Said Port in Egypt as an optimum quay wall. Firstly, the background information of the proposed Open Cell Sheet Pile (OCSP) was introduced. Then, a parametric study was conducted including 24 cases using soil constitutive Hardening Soil Model (HSM) by the PLAXIS 3D Finite Element Software. The behavior of the proposed system was presented graphically, and the effectiveness of the OCSP system was found satisfactory with the possibility to increase the seabed depth in front of the wall up to four meters. The system also was consisted of a bored piles group to carry the heavy loads generated by the gantry crane. Finally, the construction cost of the OCSP was compared to the existing quay wall structure system for evaluating the system design optimization.

URANS Simulations of a Cruise Ship in Crabbing Motion

In ship manoeuvrability, the crabbing test is critical to evaluate the hydrodynamic quantities for the guidance of an efficient and safe berthing or unberthing manoeuvres. In the present study, the crabbing performance of a cruise ship is investigated by an unsteady Reynolds-averaged Navier-Stokes (URANS) method considering the instantaneous relative motion between the ship and the quay. In the numerical simulations, the cruise ship is approaching the quay wall at a constant lateral speed. The crabbing motion with five degrees of freedom is modeled by the dynamic overset mesh technique, while the free surface elevation is simulated by the Volume of Fluid method. For reliable predictions of the crabbing performances, the timestep dependency study is conducted and a suitable time step is determined. From the computations, the hydrodynamic performances of the cruise ship, including forces and moments, as well as the surge, sinkage, roll, trim and yaw motions are predicted. The numerical results indicate variations of the hydrodynamic quantities under the impacts of ship speed and blockage effects by the quay wall. The present results can be used to evaluate the crabbing ability of the cruise ship and to provide guidance for estimating and designing the crabbing model test in further investigations.

Improvement of mooring tests of main engine running to fixed pitch propeller

The most important stage in vessel’s construction is acceptance tests. By testing the main power plant of the vessel the design solutions adopted to ensure stable operation of the main engine and the propeller are checked. Such a check of the main engine according to design characteristics at the quay wall can significantly reduce sea trials cost. In practice, the peculiarities of the propeller operation at zero free-flow velocity at the quay wall limit the operating modes of the main power plant and the possibilities of mooring tests. There are considered the traditional and innovative simulation methods and tools used in mooring tests. The methods allow unloading the engine in terms of torque bringing its operation mode closer to the design parameters. An urgent scientific and technical problem has been solved to reduce the mechanical stress of the main engine, which operates according to the mooring characteristic on a fixed pitch propeller. The factors influencing the value of the resistance moment of the propeller at a zero vector of the incident flow are determined. Possible directions for improving the acceptance tests of the main power plant by supplying an additional environment, i.e. air to the suction surface of the propeller blade, are substantiated. In the complex of computational fluid dynamics, a computational model of a fixed pitch propeller has been created. The amount of air required to change the propeller operating mode has been estimated. Resistance moment of the propeller for various methods of air supply to the propeller has been analyzed. Additional means of controlling the main engine operating mode at the stages of the ship's life cycle are proposed.

Dynamic Behavior of Quay Walls According to N-values of Backfill and Amplitude of Seismic Accelerations

Sand soil discharge, which seemed to be the liquefaction damage, was observed in the backfill of a quay wall structure during the Pohang earthquake in 2017. This discharge occurred because the bearing capacity decreased owing to the loss of effective stress, which was caused by the increase in the excess pore-water pressure with the dynamic loads from the earthquake. In this study, the effects of the variations in the N-value of the backfill of the quay structure and the seismic acceleration coefficient were investigated for increasing excess pore-water pressure and decreasing effective stress, owing to the dynamic load from earthquakes.