The sluices in the Haringvliet

As an element of the Delta Plan, the Haringvliet tidal reach is being closed to safeguard the hinterland against flooding

The Haringvliet is the main outlet for wa\er and ice from the Rhine and Maas; hence a set of sluices will be incorporated in the enclosing dam. There will be seventeen sluices each 185 feet wide, with as sill level 18 feet below mean sea level. The sluice gates will be opened.only when the sea level is below the river level, thus forming a reservoir of fresh water; during dry periods in the summer the sluices will be kept closed. This is of great importance for the fresh water economy of the whole country.

cross s e c t i o n o f the sluices

M.S.L.

e l e v a t i o n o f o n e sluice

The sluices are built of reinforced concrete; the gates are of steel. Tbe bridges between the piers are of prestressed concrete; they are triangular in cross section with a flat deck. The deck carries a wide road, and the sluice gates are attached to hinges on the other two sides. To reduce the forces exerted on them by waves, the seaward gates extend only 10 ft. above mean sea level, but the shoreward gates extend 1 6 ' - 6 " above m.s.1. Moreover, the sluice floor is deepened on the seaward side, and chambers are built into the abutments to dissipate wave energy. Each sluice gate will weigh 450 long tons, and will be raised by hydraulic jacks situated in machinery rooms on the tops of the piers. The sluice structures are carried on 22 000 reinforced concrete piles, varying in length from 20 to 80 feet. To prevent seepage under the floors of the sluices, a . steel-sheet-pi led cut-off, filled with concrete, has been constructed on both sides. In six of the piers fishpasses will be built; fish using the passes can be observed from inspection chambers. Culverts are b u i l f into the abutments to flush out. brackish water with a minimum loss of fresh water. Operation of the sluices will be controlled from a building erected near the Southern end of the sluices.

the construction of the sluices V O O R N E

Construction is being carried out inside a ring embankment, built in 1957 in the middle of the Haringvliet. The riverbed v^'as raised as far as was practicable with sand, dumped from bottom-opening barges; then floating cranes built a retaining bank of clay, behind which the sand core of the embankment was placed hydraulically. The embankment was shaped by draglines and surfaced with a double skin comprising sand asphalt and asphaltic concrete. Inside the ring embankment, large areas of sand are protected against wind erosion by mixed growths of barley, rye and bent-grass. When the sluices are completed in 1965, the ring embankment will be dredged away. Part of the river will then discharge through the sluices, so if will be possible fo close the gullies on both sides of the sluices between 1966 and 1968.

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Since 1958 the site has been kept dry by 90 deep well-points and a large number of vacuum pumps. The quantity of water pumped is about 6,000 cu. yds. per hour. To guarantee an uninterrupted power supply for the pumps, a power-station has been built on the ring embankment, which can cover the total requirements of the job with an ample margin of safety. The site can be reached over land from the island of Goeree, by crossing two Bailey bridges and a dam. This route is used by the majority of the seven hundred men employed there.

In the power-station, seven diesel engines each of 925 H. P. are installed, driying generators each of 770 kVA.

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christlaTil & nielsen

van hatbim en biankevoort

hollandsche beton maatschappij

Internationale gewapendbeton bouw

nederlandsche beton maatschappij bato

For the construction of the sluices 750 000 cubic yards of concrete must be mixed. The central plant has two 3.1 cubic yard drum mixers with a total capacity of 200 cu. yds per hour. Two 5-ton cranes unload aggregate from ships into the bunkers of the mixing plant. Ships carrying blast furnace cement in bulk are unloaded with a screw pump of 40 tons per hour capacity. The mixed concrete is transported in 6-ton rear-dump trucks. For placing concrete in the sluice floors, a travelling Bailey bridge gantry was used; the trucks dumped the mixture through hatches in the deck of the bridge, from which a funnel and trunking could reach any part of the floor.

For assembling the bridge beams, Holland Cranes con-structed a gigantic gantry crane with a lifting capacity of 250 long tons. The span of this gantry is 250 feet, and its legs are 140 feet and 157 feet long on the river and sea sides respectively.

1957

The first stage was the con-struction of a ring embank-ment, enabling a building site to be reclaimed from the middle of the river.

1958-1964

Inside the ring embankment the concrete structures for the sluices are being built by a group of leading Dutch contractors, known as NES-TUM.

1962-1965

The 34 steel sluice gates are being constructed and partly assembled in several large works. The final assembly will take place on site.

1965-1968

When the ring embankment has been dredged away, the river will flow through the sluices. The gullies on both sides can then be dammed.

The name " N a b I a " beam for the bridge beams originates from the Greek word for lyre, reproduced by a triangle pointing downwards. Each beam must resist ver-tical loads from its own weight and from traffic; very large horizontal loads from the sea when, during storms, heavy seas pound the gates; and a seaward-directed horizontal load at low water. Hence the prestressing cables follow a curved path. D e a d W e i g h t + T r a f f i c L o a d 5 4 t / f o o t

For longitudinal tensioning, each beam has 193 cables, the net force per cable being 137 tons; they are anchored according to the Swiss B.B.R.V. system. Trans-verse tensioning is obtained with about 1250 cables, each giving a force of 43 tons; these cables are

anchored according to the French Freyssinet system. During assembly, sections are lifted on eyes, anchored with 46-tons-tension bolts, according to the German Dywidag system. Reactions from the beams are trans-mitted to the piers through a number of steel-reinforced rubber blocks; this allows some movement. Design of the beams was verified on a

store t i l t i n g d e v i c e g a n t r y crane

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A NabIa beam is assembled from 22 sections between

two end blocks that rest on the piers. The sections and parts of the end blocks with a maximum weight of 250 tons, are cast in steel shutters on the sluice floor. Ducts are spaced in the sections, for the longitudinal tensioning cables. The Freyssinet cables for the transverse tensioning are placed in the steel shutters before the concrete is cast. They are wrapped in tin sheaths. The transverse tension in the end blocks is obtained with 48 B.B.R.V. cables of 137 tons and 96 Freyssinet cables of 43 tons. To speed up the hard-ening of the concrete a big tent is put over a section after it has been cast, and it is then warmed with steam to a temperature of 1 1 0 ° F. After 36 hours the shutters are struck.

t o p v i e w

sea side

The gantry crane lifts a seciion by its three corners in a horizontal plane, and places the base of the triangle on a tilting device, and the two other corners on supports. Next, the crane lifts the section at these two corners and tilts it into the upright position; this procedure prevents damaging the base. The sections are stored in the vertical position. The precast parts of the end blocks are assembled on the tops of the piers. The sections are then placed in position on centering, and they are spaced 20 inches apart.

The cable ducts are aligned and the longitudinal tensioning cables inserted. The joints are poured, and very soon, the tensioning begins, thus uniting the sections into one strong beam. The beam is jacked up a few inches to allow the centering to be removed, and the beam is placed on its rubber blocks. When the beam carries its own weight, the tension is increased simultaneously in longitudinal and trans-verse direction to its final value. The ducts are grouted to prevent the cables from rusting. A NabIa beam is completed every seven weeks.