The new Lauenburg lock

Transcription

1 The new Lauenburg lock on the Elbe-Luebeck Canal (ELC) at km On 12 May 2006 the new lock Lauenburg on the Elbe-Luebeck Canal was inaugurated. This structure is the third lock at the site Lauenburg which has been used for the operation of shipping between the Elbe and the Baltic Sea for several centuries. History A waterway crossing with the Elbe near Lauenburg has been in existence since the 14 th century. In 1398 the first artificial waterway between the Elbe and Luebeck, the Stecknitzfahrt, was inaugurated. It was in operation until the middle of the 19th century and especially served for the transport of salt from Lueneburg to Luebeck. A relict from this time is the lock Palmschleuse in Lauenburg which is considered to be one of the oldest chamber locks in Europe. The Stecknitzfahrt consisted of 17 locks most of which were designed and operated as flash locks. Due to the increasing decay of the Stecknitzfahrt and the increasing transport demand which required the use of bigger vessels a new canal link from Lauenburg to Luebeck was planned in the 19 th century. In 1900, after a construction period of less than five years, the German Emperor Wilhelm II opened the Elbe-Trave Canal (today Elbe-Luebeck Canal). The ELC consists of seven single locks, two of them ascending from the Elbe to the upper pond and five descending from this pond to the Trave. The Lauenburg lock separates the pond Lauenburg-Witzeeze with a length of about 10 km from the Elbe. It has a rise of approx m at normal water level of the Elbe. All the locks of the ELC have had the same dimensions with a usable length of 80 m and a usable width of 12 m. The ELC is part of the inland waterway system of the Federal Republic of Germany and an important link between this system and the Baltic Sea port of Luebeck. Currently approximately 1 million tons of cargos are transported every year on the ELC. Since cargo transhipment in the Luebeck ports is increasing also the increasing of the cargo quantities on the ELC can be expected in the future. Furthermore, this waterway is growing used by the strongly expanding pleasure boat traffic. As a federal waterway the ELC is in the competency of the Waterways and Shipping Administration of the Federal Government, represented by the Waterways and Shipping Directorate East with the Waterways and Shipping Office Lauenburg.

2 2 Instigation and planning From the beginning of the nineteeneighties all the locks of the ELC were examined as to their constructional status. It was found that with the exception of the Lauenburg Lock it was possible for all the others to be refurbished and afterwards operated again. Only the constructional status of the Lauenburg lock was so bad that neither a safe continuation of operations nor repair work to achieve this were possible any more. Therefore it was decided in 1992 to build a new lock at Lauenburg. The new structure was based on larger usable dimensions. The usable length is 115 m, the usable width m and the depth over the sills 4 m. The construction agency is the Waterways and Shipping Office Lauenburg. It was responsible for the planning and preparation of the construction measure. Part of the planning work was the implementation of a plan approval procedure according to the Federal Waterways Act. In 2000 the plan approval decision was taken by the Waterways and Shipping Directorate East. Construction process The construction work began in the same year 2000 with the preparatory measures. The actual construction measure was broken down into four construction lots. Because of the expected amount of the contract all the lots were advertised for bids in a Europe-wide invitation to tender. The contraction lots and contract amounts were as follows: Preparatory measures Construction period: Summer 2000 to the beginning of 2001 approximately 1 million Euros Lot 1: Excavation and solid structure Construction period: Spring 2001 until the end of 2004 approximately 19 million Euros Lot 2: Construction period: Lot 3: Construction period: Lot 4: Construction period: Hydraulic steel and mechanical engineering 2001 until opening to traffic approximately 4 million Euros Fore bays, dismantling of the old lock, exterior facilities 2005 until opening to traffic approximately 9 million Euros Control house, electrical and communications engineering 2005 until opening to traffic approximately 2 million Euros

3 3 A large number of sub-contractors were charged with special lots. The total cost for the new lock amounted to approximately 40 million Euro. The construction work was carried out in a way which meant that during the major part of the construction period shipping on the ELC was not stopped or impeded. It was possible to guide the ships past the excavation for the new structure and through the old lock which was still in operation. It was only necessary to close the ELC for about five months from middecember 2005 for the dismantling of the old lock and the construction of the new upper fore bay. Essential constructional parts of the new lock facility Excavation In order to guarantee the stability of the adjacent buildings and not to endanger the steep slope of the Elbe valley next to the construction area extensive damming measure s were required for the excavation. The western wall of the excavation bordering at the slope of the Elbe valley, for example, was built as an anchored slurry wall. It served as an excavation wall and as a securing wall for the slope during the construction period. The slurry wall was built with a wall thickness of Excavation with slurry wall (r.) and up to 1.50 m and with a depth of up to 30 m. The hori- cofferdam (l.) zontal forces were introduced deeply into the slope of the Elbe valley by means of about 350 temporary injection anchors. The other walls of the excavation were built as water-tight steel sheet pile walls. During construction the longitudinal side of the chamber formed a double-walled cofferdam. To secure the excavation walls at the two heads horizontal reinforcements were constructed in them. Lowering the ground-water level for this construction measure was not permitted. The excavation work therefore was carried out under water. To prevent ingress of ground-water from below, an underwater concrete base was built in which had to be secured against upward pressure with nearly 700 piles. In its final state the depth of the excavation was 15 m. Solid structure The new lock is a steel concrete lock. To the upper fore bay the lock is limited by the upper head which was designed as an open frame with gravity-retaining walls. It contains the upper gate and the required machinery and electro-technical equipment. In analogy to the upper head, the lower head with its lower gate separates the lock from the lower fore bay. The lock chamber forms a bend-proof steel concrete half-frame which is also upwardly open.

4 4 The solid structures of the heads and the chamber are shallow foundation structures on the underwater concrete floor. The base of the lock which was planned as a monolithic structure was concreted as a continuous floor and provided with force-closed construction joints. The walls of the excavation served as lost formwork for the base and the exterior walls of the heads. The exterior walls were built in one working cycle. The concreting height was 10 m. The blocks of the chamber walls (block length 15 m each) were concreted in two work steps. The parts for hydraulic structure, for the propulsion technology and for the equipment were to a large extent built into the secondary concrete layer. Hydraulic steel structure and mechanical engineering The hydraulic steel structure consists of the lock gates and the sluices in the short side channels at the lower head. The lower gate is designed as a pressure-dependent segmental gate. Apart from its function as a barrage structure it also serves the filling of the lock chamber. By means of a slight downward turn a filling shell is opened which allows the water to flow inside. This construction makes it possible to fill the lock quickly. The vessels which are in the lock are not much moved. The lower gate was built in folded slab construction as a traditional mitring gate. This type of construction offers advantages for the operation and maintenance of this gate, especially by avoiding dirt deposits in the latches. In the short side channels in the lower head are segmental sluices which control the emptying of the lock. The propulsion for all movable parts is affected by a hydraulic assembly. To achieve sufficient operational safety it contains all units twice, including the hydraulic motor. A pumping station, built in the upper head, allows pumping water from the lower water level in the chamber to the upper pond in dry seasons. Building in the radial gate and and a leaf of the mitre gate Operational building and operation of the installations A three-floor operating building on the top of the east side of the lower head allows a good view into the lock chamber. Despite this the entire lock installation, including the both fore bays, is monitored by cameras. Thus the highest possible extend of safety for the ships passing is achieved. The new lock is equipped with a one-man control position. The lock operator has to handle the equipment and additional to collect the charges for the passage of the Canal.

5 5 The fore bays and other installations Since the new lock is in a different location from the old one, the two fore bays also had to be restructured. The lower fore bay is now situated on the west side of the ELC. On the east side there is now a berth for the pleasure boats. The location of the upper fore bay has not changed. Both basins now allow two motor cargo vessels to lie side by side. The entrance from the upper fore bay into the lock is now in the area of the location of the old lock. This was completely dismantled up to a depth of 1 m below the original floor. The banks of the canal in this area on both sides were enclosed with a bore pile wall and sheet walls. Between the upper lay-by basin and the mouth of the tributary Delvenau a separation mole was built which has a length of approximately 140 m and consists of two sheet pile walls filled with soil. This measure made it possible to leave the water level of the Delvenau - which is the same as the one of the Elbe - unchanged. For reasons of the permanent stability of the slope of the Elbe valley bordering the lock the base in the area of the separation mole was constructed as a load-bearing concrete floor. Dismantling of the old lock Sheet pile wall at the bank of the upper fore bay Large amounts of material were moved - More than m 3 of concrete and app. 2,500 t concrete steel; - app. 210 t total mass for the lock gates; - 9,500 m 3 of underwater concrete; - 4,700 t sheet piling steel and app. 1,700 pieces of different types of anchorage; - app m 3 of soil and 16,500 bricks for hydraulic engineering; - app m 3 of debris from the old lock. Perspective The new construction of the lock will guarantee shipping on the ELC - which is the only German inland waterway link between the European waterway network and the Baltic Sea region - also in the future. At the same time the extension of the usable dimensions has improved the conditions for shipping. The new lock can cope with the present and future requirements of shipping.

6 6 Project management Master of the works: German Federal Water and Shipping Administration represented by the Water and Shipping Directorate East and by the Water and Shipping Authority Lauenburg Design planning, tender publishing and orderer of the construction works: Wasser- und Schifffahrtsamt Lauenburg: Dornhorster Weg 51, Lauenburg Report about the subsoil conditions: Federal Waterways Engineering and Research Institute; Department Hamburg Inspection engineer and inspection services for the steel construction:: Dr.-Ing. Karl Morgen WTM Engineers GmbH Hamburg Germanischer Lloyd Hamburg The direct contractors: Strabag AG, Tief- und Wasserbau, Niederlassung Stralsund Hochtief Construction AG, Niederlassung Hamburg Mölders Baugesellschaft mbh Hannover Bauer Spezialtiefbau GmbH Schrobenhausen Fa. Klaas Siemens GmbH Emden ABB Utilities Magdeburg