Ports around the world are facing a number of long-term man-made and natural challenges. By helping these facilities adapt to accommodate the demands of larger and larger vessels, and combat the challenges associated with climate change and other natural disasters, COWI North America (COWI) is ensuring the viability of these ports in the global market for years to come. With a track record in resiliency and innovative marine solutions, COWI is playing its part in keeping the world’s commodities moving.
Big keeps getting bigger: Post-Panamax ship size
There has been a rapid increase in the size of container vessels traversing the globe since the late 1960s. It is estimated that there was been a 1,200% increase in container carrying capacity since 1968, with the largest vessels now accommodating up to 19,000 TEU.
As vessels get larger, many ports are struggling to accommodate them, facing challenges with draft (depth) and passing clearance. To keep these ports viable, changes need to be made.
As a standard operating procedure, it is ideal for a vessel to come into port once to unload. In order to do that, there needs to be a minimum water depth to accommodate the vessel. Currently, many of the larger vessels are required to make multiple trips into ports because of lack of available water depth. To resolve this issue, COWI has been involved in a number of wharf deepening projects.
In Oakland, California, COWI performed a wharf deepening and upgrade design for an existing container terminal to accommodate deeper draft vessels. The deepening design consisted of new crane girders and piling with a new underwater bulkhead wall, which allowed for future dredging to a 50 foot berth. The underwater bulkhead wall was designed for a 52 foot berth with a sloping backfill. The face of the berth increased the available draft by 10 feet and provides support to the existing embankment. The 2,000 foot berth deepening was completed in two phases to allow for continuous operation at the terminal.
Passing vessel analysis
Larger vessel size is not only an issue with regard to draft in ports; passing clearances are also a problem. The majority of ports and terminals were designed to accommodate Panamax vessels, which are considerably narrower than the new mega ships of today. As a result, these facilities have smaller clearances in channels than recommended for today’s larger vessels.
When used by larger vessels, these narrow channels subject moored ships to adverse passing effects. These can include shifts in mooring line loads as well as having wider implications for port operations and shoreline erosion.
COWI has provided mooring analyses with passing vessel effects for several marine oil terminals located close to navigational channels. We also coordinated with the local Bar Pilots and reviewed existing navigational data to determine the minimum and average vessel speeds that will allow for safe steerage past these terminals to minimize any impact to port operations.
Resiliency for ports
Climate change is becoming a reality and sea levels are rising. Additionally, there are many weather-related and other natural events (such as earthquakes and tsunamis), which can also result in sudden sea level rises. Therefore, ‘resiliency’ has become a key focus for port operators. Not only are they seeking to mitigate the damage at impact but also to increase the speed of their port being back in operation post-incident.
COWI is a leader in the field of marine resiliency across the Eastern, Western and Gulf coasts. Known for our innovative coastal solutions and for utilizing a mix of engineered and natural solutions to ensure coastal resiliency, we are leading the way in ensuring our cities and ports adapt over the years to come.
At the Port of Redwood City (California), COWI replaced a 60 year-old timber wharf with a new multi-purpose concrete wharf and dolphins that are designed to meet the present demands for operational and seismic conditions, as well as climate change issues in the future.
The new structures are designed for a water depth of 42 feet. The top of the new wharf is +16 feet above mean lower low water (MLLW) and slopes to the seawall. The new seawall extends along the entire project for a total length of 1,000 feet. The wall consists of steel sheet piles driven to 0 feet MLLW with a top of sheet elevation at +13 feet MLLW. The design also allows for a 1 foot extension to accommodate sea level rise past the 50-year design life, if needed.
These are just some of the ways COWI is helping our coastal communities prepare for the future and continue to be important players in our global economy.
Learn more about COWI’s ports and terminals engineering click here.