Schwing

Panama Canal

Pumping Flat Out in Panama

Four SCHWING truck pumps concreting on one of the world’s biggest jobsites

With a traffic volume of around 14,000 passages per year, the Panama Canal is one of the most important waterways in the world. The locks on  both the Pacific and Atlantic entrances of the canal are now being extended by a further three, each with 3 water-saving basins. The new locks are each 427 m long,  55 m wide and with a draft of 18.3 m. The passages in the Gatun Lake are also being deepened and widened. The extension works will in future allow Post-Panamax class vessels (with more than 10,000 containers on board) to use the canal route.

In all of this work, the placing of concrete plays an essential role and is being carried out round the clock, 7 days a week.

Big-aggregate concrete and high ambient temperatures are only part of the challenge being faced by the four SCHWING pumps on site where a total of more than 6 million m3 need to be placed.
The canal today has two lanes, each with its own set of locks. The expansion project will add a third lane at both ends of the canal. Each of these new lock complexes will have three consecutive chambers designed to move vessels from sea level to the level of a large artificial lake that forms a major part of the Panama Canal. Each chamber will have three lateral water-saving basins, for a total of nine basins per lock and 18 basins total. The new locks and their basins will be filled and emptied by gravity, without the use of pumps.
The new locks are being constructed using two different concrete mix designs, a Structural Marine Concrete (SMC) and an Interior Mass Concrete (IMC). A typical concrete section consists of an IMC core with SMC facing.

The SMC facing is typically 61 cm thick while the IMC varies. A lock wall monolith is approximately 20 m wide, 30 m high and 29 m long. Each lock wall monolith contains two 6 m tall culverts for filling and draining the chamber. The monoliths require 210 tons of reinforcing steel and 2,600 m3 of concrete each. A total of about 50 of these massive concrete structures make up each lock chamber.

Working on the eastern locks are four Schwing concrete pumps – a 32 XL, two S 52 SXs and an S 58 SX. According to Jorge Puello Echeverri, GUPC supervisor of concrete pumping operations, “All the pumps are doing well. We are getting 100 m3 per hour working twenty-two hours per day with multiple set-ups. The long booms are equipped with the 2525H pump kit with the Big Rock which is well suited to the application.” Filling efficiency of the large diameter  250 mm pumping cylinders is facilitated with the Big Rock’s extended hopper to handle 32 to 63 mm aggregate which is specified in some of the mix designs. All of the boom pumps are equipped with five-inch (125 mm) pipeline.

Despite the massive scope of the project, job-site conditions are congested. The S 52 SX and S 58 SX are well suited to the fast set-up in confined spaces with Super X outriggers that can telescope out and around obstacles on the site. Agitator trucks and conventional truck mixers feed the pumps from on-site batch plants that feature customized aggregate cooling systems, that are necessary to control the exothermic heat generated during the concrete curing process. Average ambient temperatures are in the mid 80s and the concrete must be between  9°and 12° C when it is placed. To accomplish this, the aggregate stockpiles are protected from the tropical sun by a massive tent. The sand and rock are water cooled before being transferred to an air-conditioned bin. Flake ice is introduced to the mix on the main feed conveyor allowing it to remain chilled as it is transported by the agitator trucks.

“The versatility of a concrete pump on a mega-project like this is essential to production, “ according to Echeverri, “The five section booms on the S 52 SXs offer the articulation to reach everywhere, whether on the floor of the lock reaching out or placing up on a wall.” The overhead Roll and Fold boom design features a 270-degree articulating tip section which offers maximum versatility especially when combined with the main section’s 180 degrees of working range. Operators can coordinate the movements of the main and tip sections, which combine for 450 degrees of articulation, to navigate over and under obstacles to reach further into tight spots. The S 58 SX is doing  the majority of the work with the 32 m machines filling in on smaller pours.

Another challenge is working in a remote area where reliability is paramount to the continued progress of the massive pumping project. All of the Schwing concrete pumps are equipped with Vector controls which allow two-way communication between the pump and operator. In addition to continuous reporting of vital data to the operator, the Vector system also tracks the total number of hours of operation for the concrete pump and boom, the number of strokes, stroke rate and pumped volume. In addition it tracks usage hours for the agitator, vibrator and oil cooler. This data is automatically stored and easily retrieved for analysis. “This allows us to predict maintenance based on monitoring flow and pressure during concrete placement operations, “ according to Echeverri, “The Vector has become my right hand to take the first step in making diagnoses and I am convinced that it is a vital tool for maintenance. Because our personnel live and feel the concrete placement operation, the Vector creates a harmonious link between operator and technician and our maintenance method is based on a logical procedure.”

In the harsh, demanding conditions of the rural Panama Canal environment, where it rains every other day and concrete pours can extend beyond 24 hours of continuous operation, Echeverri has a slogan – our lack of resources is supplemented with human quality…and reliable equipment.