Oceans make up 70 percent of our earth. Not only do they contain vital food sources for people around the globe, but they are also critical to the transportation networks that support global trade. Oceans provide a source of sustainable energy when we harness the power of wind, current and wave energy. The ocean floor contains large reservoirs of raw materials such as petroleum and other hydrocarbons. In fact, the ocean is so rich with resources, we are still discovering new ways to capitalize on the power and assets held within the world’s largest water sources. Current research is even exploring ways to use plankton and marine algae as biofuels.
However, none of these incredible resources can be utilized without marine structures. Marine structures open all kinds of possibilities and opportunities. Marine structures are as diverse as the plants and sea life contained within the ocean’s waters. These structures are often massive, capital-intensive feats of engineering. They must be designed to withstand harsh environmental conditions and complex forces. Their design and construction must meet ever-increasing standards, permits and regulations. These structures are designed to withstand significant weather events, like hurricanes, and to faithfully fulfill their role for decades of use.
Costal, Offshore & Deepwater Structures
Since marine structures are so diverse, it’s often helpful to first classify them by their location relative to land. Closest to land are coastal structures. Generally speaking, the term “costal” refers to structures that are on the waterfront or within 20 miles of land and in shallow water. Offshore structures are within about 150 miles of land and at mid-depths. Deepwater generally starts more than 150 miles from land and at 5,000 feet or more water depth.
Next, marine structures can be categorized based on their function. However, even structures that serve the same basic function can vary widely based on size, complexity and support structures.
Let’s take a look at some of the most common marine structures and their uses.
Port Facilities: Transportation Terminals for Every Kind of Cargo
A port is an area that contains one or more docks where the man-made marine structures are located for berthing ships or barges for loading/unloading people or cargo. A berth is essentially a parking place for a ship when not at sea. Ports can have simple structures with a single berth or more sophisticated with many berths and specialized equipment to load and unload cargo.
A cargo port handles bulk cargo or finished goods. Bulk cargo requires a ship loader, a large machine used to continuously load solid bulk materials such as coal, fertilizer, liquid fuels or grains. Other cargo ports are equipped with cranes to transfer shipping containers. Often, large cargo ports are divided into terminals that handle different types of cargo.
A dry port is a specialized port that connects land and sea. Cargo can be unloaded directly from a ship and placed on trucks for land transportation or on train for rail transportation.
Most ports are located directly on the waterfront, but some berthing facilities are offshore. These offshore berths are designed to minimize risk while potentially hazardous cargo such as oil or gas is being transferred.
Shipyards: Construction Sites for Marine Projects
Shipyards are specialized for the purpose of building, maintaining and repairing ships. The most important berth within a shipyard is the dry dock. Dry docks can be flooded to allow a ship to float in and rest on a platform. Then water can be pumped out or drained away from the ship to allow for maintenance and repairs.
In the case of new construction, a dry dock provides a protected space for the ship’s hull to be constructed. Once the hull is watertight, water can be allowed in the dry dock to lift the ship off of the platform and out into open water or to another berth while the interior of the ship is completed. There are several types of dry docks: floating dry docks, graving dry docks, and vertical synchro lifts.
Coastal Protection Structures: The First Line of Defense
Coastal Protection Structures are waterfront structures designed to protect naturally occurring or man-made structures from erosion, sea waves, sand movements, changing currents, and weather events.
Seawalls or bulkheads are perhaps the most basic waterfront structure. They are retaining walls built using rock, granite masonry or reinforced concrete. Seawalls are built to protect coastal structures and inland structures from waves and flooding caused by storms. There are a variety of seawall designs to combat the specific forces at a given location. They are also used to prevent erosion.
Jetty is a generic term to describe a structure that projects out from the land into the water. They are usually built from concrete, stone, steel or timber. They can be built to serve primarily as a dock or they can be designed to serve a more structural function. When built as a dock, they have a solid surface on top. They can also be built at a river estuary or harbor entrance and extend into deeper water to prevent sandbars from forming and to minimize currents or waves. In this instance, they may be built at or just slightly above the water level.
Offshore Drilling Structures: Floating Cities in Open Ocean
Offshore oil platforms and offshore drilling rigs are interchangeable terms used to describe large structures with the equipment and facilities needed to extract petroleum or natural gas from beneath the ocean floor. Although these structures are commonly referred to as “offshore”, their locations may technically be considered deepwater. Marine engineering companies can design the offshore drilling platform to remain fixed to the ocean floor, float or sit on top of an artificial island. These facilities are incredibly complex and capital intensive. To put their size in perspective, some rigs are two or three football fields wide and more than 40 stories tall. Due to their remote nature, offshore drilling rigs typically contain living quarters, space for recreation and everything needed to support a workforce of hundreds of people for weeks or even months at a time.
Important considerations for Marine Structures
As you can see, marine engineering companies take on some of the most challenging and fascinating projects. The ocean creates many dynamic, quickly changing and highly variable forces that must be accounted for in the design process. Fluctuating tides, seasonal weather patterns and harsh environmental conditions make construction a challenge too. Environmental impact, design codes, local laws and regulations must all carefully be included in project planning.
At Matrix PDM Engineering, we understand all of the potential challenges with marine industrial construction. We proactively coordinate with the Army Corps of Engineers, State DOT, Levee District, State EPA, Coast Guard and Pilot’s Associations.
We draw from our extensive experience to help circumvent scheduling difficulties caused by changing water levels and seasonal or weather-based construction windows. We are good stewards of our resources and the natural resources that surround us. We help protect the environment and vital marine life by complying with environmental impact restrictions and regulations.
Most importantly, we understand that marine structure engineering and the design of marine structures is multifaceted. Even structures that appear simple on the surface have carefully considered reinforcement and design features. When you choose to partner with Matrix, you can count on our expertise and experience to see that your project meets your performance goals, budget and schedule. Whether you are building a single berth or multiple docks at your facility you can expect our best from design to commissioning.