Design of Container Yard at Port of Balboa

Committed to converting the Port of Balboa into a major transshipment hub, Panama Ports Company (PPC) launched in 2006 a $300-million expansion program to increase berthing and stacking space that would almost triple the port capacity. The site's history of marine-related activities, deteriorating facilities, buried structures, and poor soils mandated significant investment in clearing and preparation. Of the 25-hectare container yard to be built, about 15 hectares were dredged to remove poor soils and reclaimed by filling/compacting with imported sand. Ground conditions in a 5-hectare area were also improved by a wick drain and surcharge program. Most container yards in North America are built with continuous asphalt or jointed portland cement concrete (JPCC) pavement. However, the Balboa yard features a discrete paving system for container stacking that is suited for rubber-tire gantry (RTG) crane operations. It consists of narrow reinforced concrete (RC) beams (serving as container bases) with a thin asphalt sealed crushed rock base around them. Support for the RTGs consists of continuous jointed RC strip footings, with JPCC pavement provided at yard tractor lanes and other roads for circulation of reach stackers and empty container handlers. In addition to providing savings relative to the continuous PCC solution, this discrete system eliminates container stacking on sloped planes, which is undesirable for very high stacking. This paper describes the design and construction processes associated with site improvement and the pavement system. Traffic demand on truck and passing lanes was evaluated based on estimated throughput including the effects of container type, size, block size and dwell time. The design followed the 1993 AASHTO Guidelines. Load equivalency factors were used to account for non-linearity of axle load effects from different yard equipment. Finite element modeling was used to determine short-term load demands on pavement elements to account for complex loading conditions.