Steel girders, resting on friction collars attached to precast concrete piles, support plywood soffit forms for a new wharf. Pan forms create longitudinal and transverse beams of waffle slab design.

In recent decades, the global economy has increasingly relied on containerized shipping to move raw materials, agricultural commodities, and manufactured goods from one corner of the world to another. More and more cargo is transported not in bulk holds but in closed containers, stacked on the decks of giant ships, then unloaded directly onto trucks or railroad cars for delivery to inland destinations.

Expanding global trade has driven an expansion of the size and capacity of these container ships, which has required an expansion of pier facilities to accommodate them. Larger ships require ports with wider berths, deeper channels, heavier-duty cranes, and expanded landside space for staging, truck traffic, and rail lines. Concrete plays a significant role in building and refurbishing port infrastructure, and concrete contractors may benefit from an anticipated surge in such projects.

Pushing the Panamax

Many older container ships were designed to the so-called Panamax standard, limited by the length, beam (width), and weight/draft that the Panama Canal could accommodate. Panamax ships have a maximum 965-foot length, 106-foot beam, and a capacity of 4,800 TEU (20-foot equivalent unit, equal to a 20-foot-long metal shipping container). Newer ships, called Post-Panamax vessels, are up to 1,200 feet long, 160 feet across, and can hold 12,000 TEU or more.

Panamax ships need a minimum channel depth of 39.5 feet. By contrast, Post-Panamax ships need a channel at least 50 feet deep. The newest and largest container ships now are Triple E-class Maersk vessels that are 1300 feet long, have a beam of about 194 feet, and a capacity of 18,000 TEU.

The Post-Panamax ships in use today are generally limited to trans-Atlantic or trans-Pacific routes, but that will change next year when the ongoing Panama Canal expansion is completed (See the February 2013 issue). Once the larger vessels can pass through the canal, some U.S. cargo that now goes overland to and from deep-water West Coast ports could be loaded and unloaded in East and Gulf Coast ports.

Currently, Baltimore and Norfolk, Va., are the only East Coast ports with deep enough channels for Post-Panamax vessels, but other port cities are dredging their channels and refurbishing their facilities in hopes of capturing some of that traffic. To maintain a competitive edge, West Coast ports are gearing up to handle larger container ships.