FCC Construcción

The city of Seville has always been closely linked to the Guadalquivir River and to the activity of its port, the only inland port in Spain, connected to the sea by a navigable watercourse of international importance measuring 80 km in length, the E60-02, pertaining to the European network of 27,700 kms of inland channels and navigable watercourses.

The progressive increase in the Port of Seville's sea traffic has made it necessary for the Port Authority to opt to create new infrastructures which will make it possible for this growth to take place. Worthy of special note, due to its magnitude and future projection, is the new lock which is the key element for providing the City with a high potential for moving transport from Seville to other foreign markets. This project is being jointly funded by the European Union (44%) and the Cohesion Fund.

This new lock replaces the former one, which was more than 60 years old, making it possible to enlarge and improve the ship channel. Set out in the development plan, this lock opens the doors to a considerable increase in short-distance sea transport, which could total up to 12 million tons over the next few years, as compared to the current 5 million tons. This would mean: eliminating 15,000 road transport round trips, saving 14 million euros/year on fuel, reducing NOC and CO2 emissions by 350 and 250 tons; creating 15,000 new jobs within the next ten years and guaranteeing the protection of Seville.

The project

This lock is an enclosed area closed off by gates, allowing ships to navigate the different levels of the river and the port. Its functioning is simple, similar to that of an elevator. A ship positions itself between the gates, the water level is raised or lowered, the ship rises or lowers and, lastly, the gate opens and the ship sails out onto the new level. The lock also has another function, which is that of providing the city of Seville with a barrier wall for preventing flooding. When high flood waters rise, the lock closes to prevent flash flooding.

This project was designed by the project design engineers who designed the access of the Pacific side of the Panama Canal. Having required more than 16,000 hours of engineering, it is taking an average of 260 workers working for 3 years to build it, incorporating European technology in the valving, in the hydraulic systems and in the gate and bridge design.

This new lock is 434 m in length by a usable 35 m. breadth, which will allow entry of ships of up to 20,000 DWT and 290 m. draught. The base of the new lock will be located at -11 grade, the draught in the ship channel being increased up to level-9 downstream and -7.70 upstream. The gates on the river side are 42 m in width, 23.3 m in height and 6 m. in thickness, whilst the gates on the port side are 42 m in width, 17.50 m in height and 5 m. in thickness.

The gates slide over two large rails, an upper and a lower rail. The inner faces of the gates are 293.65 m. apart. Also included are three mobile bridges, two road bridges measuring 44 m in length by 12 m in width and another railway bridge of the same length by 6.10 m in width. These bridges are erected using a jointed parallelogram device, preventing the need of sealed chambers on positioning the counterweights at a higher level. This structure is completed with two supporting docks comprised of sheet pilings 173 m in length and two mooring dolphins, plus the supervisory buildings: offices, machinery and general facilities, occupying an area totaling 282 m2 on a developed area totaling 69,000 m2.

The accesses to the lock include roadways comprised of 110,000 m2 of blacktop and 3,350 m of railways.

For building the lock, a sealed area had to be created and excavated to a depth of 23.5 m. This sealed area was outfitted with different access ramps for bringing in machinery and materials. Construction began with an initial excavation and the construction of a closing barrier which was recessed into the sealed layers. Once the water had been completely removed from inside the sealed area, the excavation was continued up to the final level. For building this lock, two concreting plans were installed with mixers next to the sealed area, tower cranes and climbing formwork also having been used. The bridges will be erected at the time time as said construction so that they will be operative on completing the lock structure. Meanwhile, work has begun on building the gates at the Seville shipyard. Additionally, the building complex has been built in the developed area so that they would be completed for the commissioning of the bridges and gates.

While these activities and others such as the pegging of roadways and railways are being carried out, the river traffic will be kept to the current watercourse.

The sealed area will then be flooded and the accesses to the new lock dredged, tranfering sea traffic but still keeping the current lock for some time until the river and port sides have been filled and dredged and the new flood barriers are in place.

In addition to improving transport and facilitating this city's development, this project has a highly important environmental aspect, have been designed within a scheme of new integrated approaches in environmental sustainability endorsed by the different environmental institutions. The preliminary measures included a geotechnical prospecting, the preparation of an archaelogical intervention project, as well as a report on the protected flora and fauna and strict compliance with the environmental surveillance program.