Vízügyi Közlemények, 1973 (55. évfolyam)
4. füzet - Rövidebb közlemények és beszámolók
timber structure, and connection was provided by bolting. The same panels were used for casting the navigation lock and the separation pier. The crane girder and the service bridge (Fig. 2.3 — 2) running the entire length of the structure was constructed as part of the main works. For this purpose a steel support of prefabricated elements was assembled. The concrete structures were moulded and poured in a manner to permit the subsequent placement and concreting of the steel structures. The pouring of concrete was continued through the winter period, 6,000 to 8,000 cu.m of concrete having been poured annually under winter conditions. The impermeability of the foundation slab was checked by a special investigation of the power station before the groundwater table was permitted to rise. Concentrated leakages were sealed succesfully by grouting, with high-pressure equipment. For constructing the barrage 4.2 million cu.m of earthwork were performed. The auxiliary earth structures were constructed by scrapers, while the construction pit itself was excavated by power shovels. Excavation was followed progressively by the installation of the groundwater-lowering equipment, the operation of which ensured a normal construction progress even during the extended flood on the Tisza River in 1970. Earthwork outside the construction pit and for the main canals was started in 1969. The latter were excavated with high-powered shovels of 2.5 cu.m capacity. Backfilling of the construction pit of the structure was started in 1970, while earth moving in the flood plain was begun in 1971. In the spring of 1972 preparations were made for demolishing the ring dike. In June 1972 the construction pit was filled with water, using the floating dreger. The ring dike was cut in several stages by means of excavators above the water level in the Tisza River and by floating dredgers under water. In the course of construction work 460 tons of rock and 1200 tons precastt concrete units were placed. In the immidiate vicinity of the barrage the slopes are lined with precast concrete slabs, while farther away a 30 cm thick rip-rap layer is placed between a grid of r.c. beams (Fig. 2.3 — 3). The rock was placed and handled with 5 grabs. The closure of the old channel was realized by a rock mound dam (Fig. 2.3—4) of suitable cross-section, the last 48 m long section of which was dumped from a temporary bridge. At the bridge site a brushwork mattress of 80 by 100 m size was sunk (Fig. 2.3 — 5). At the downstream side 12,000 rock-filled wire baskets of 1 ton weight, whereas on the upstream side loose rocks were dumped. Closure was completed within 22 hours (Fig. 2.3—7). In the construction period the annual average labour force varied from 61 to 842, with the main economics reflected by the data compiled in Fig. 2.3—8. 276
