Jetties In The Niger Delta Region

Jetties are structures that project from the land into the water. Often, jetties refer to a walkway accessing the center of an enclosed water body. These structures also play an important role in the transportation of goods and passengers to and from the seas and also in inland waterways. They are mooring structures used in berthing of ships. Jetties are found at the entrance of harbors, lagoon outlets, and inland waterways. Generally, berthing structures are constructed away from the shoreline inside the sea to get sufficient water depth for anchorage of ships. Jetties are supported by piles which are embedded in the sloping ground. Jetties are built parallel to the navigation channel, which is usually perpendicular to the shore. The jetty

There are many loads acting on a berthing structure such as dead load, live load, wind force, seismic force, berthing force and mooring force (Gudmesta and Moe 1996). Berthing structures are also subjected to hydrodynamic forces such as wave force, current force and differential water pressure (Gudmesta and Moe 1996). The Niger Delta region being a coastal region hosts hundreds of jetties. Many of these jetties are dilapidated due to bad structural design and non-consideration of hydrodynamic environment prevalent in the region. This is why in some jetties during low tide, ships cannot access the jetty because the water level has reduced but a well-designed jetty should be accessible to ships during both high tide and low tide. This research focuses on calculating the hydrodynamic forces on a jetty column structure based on the Morrison equation using Niger delta sea data, obtaining the shear forces acting on the member of the structure

The most common currents considered in the offshore structural analysis are tidal currents and wind drift currents, the latter arising from the drag of local wind on the water surface. Both these currents are usually regarded as horizontal and varying with depth (Chakrabarti 2005). Pressure due to current will be applied to the area of the vessel below the waterline when fully loaded. It is approximately equal to wv2/2g per square meter of area, where v is the velocity in m/s and w is the unit weight of water in t/m2. The ship is generally berthed parallel to the current. On piles parallel to the direction of the water current, there are two types of ocean current, the surface circulation current, and the deep circulation