Vízügyi Közlemények, 1957 (39. évfolyam)

4. füzet - VI. Kisebb közlemények

PREFABRICATED REINFORCED CONCRETE IN HYDRAULIC ENGINEERING CONSTRUCTION IN HUNGARY I. В allô (See figures and pictures on pp. 307—335. of Hungarian text) 024.012.4 : 626/627 Prefabricated concrete pipes on socles, well cylinders (cylinder caissons), and slabs for lining slopes have long been used for hydraulic engineering works, but through the general development of préfabrication a number of new possibilities has been brought about in the field of hydraulic construction, too. This is especially striking in hydraulic engineering structures of smaller dimensions, where the use of prefabricated elements allows great economy of preparatory work, materials, manpower and transportation facilities. In hydraulic construction various requirements have to be met, and the aim is to produce by using few types of units as many a version as possible. The success of concrete préfabrication depends in this field, after all, on the proper choice of types of prefabs. The paper gives account of 4 years of experience in this field of the Szeged District Water Board. During this period 30 05!) reinforced concrete elements of an aggregate volume of 2117 cu.m have been fabricated. Of these 28 000 (1500 cu.m) were concrete pipes, markstones, slabs and other standard elements, 2627 (264 cu.m) elements for building, and 1082 (318 cu.m) elements for hydraulic and civil engineering construction. The latter resulted in the saving of 177 cu.m of shoring lumber, 230 cu.m of sawn timber, 186,2 tons of cement, 40,3 tons of steel and 782 cu.m of gravel amounting to a total of 727 000 Ft. Primitive facilities so far available limited the weight of individual units to I ton, and their maximum dimension to 4 m. By the development of handling and transportation facilities the possibilities can be greatly extended. The most interesting uses of prefabs were the following: In hydraulic engineering service there is a great need of s tarage place (storerooms, sheds). These are, in general, of small size and belong to a pump station, an intake works or supply center. The coal storage bin supported by prefabricated three-hinged reinforced concrete frames was built for similar purposes. The sidewalls of the bin are also braced by prefabricated reinforced concrete beams to withstand the pressure of the coal dump (Picture 2). Similar 3-hinged frames were applied for the buildings of pump stations, with the side walls and the roofing made of reinforced concrete panels (Fig. 1

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2 and Picture 4). A sluice shed of similar construction is shown in Picture 3. The machine shed presented in Fig. 3 and Picture 5 was built of two-hinged prefabricated reinforced concrete frames each composed of 4 identical prefab units with rigid joints made on the site. The shed is covered by a light roofing. Hydraulic engineering structures such as paddles, weirs, siphons, distribution works and small pump wells may readily be constructed using the thin-walled boxtype shaft unit shown in Fig. 4 and Picture 0 and prefabricated in 3 different sizes. For culverts two-compartment reinforced concrete frames were prefabricated (Fig. 5). These are produced in 6 different sizes with base lengths from 75 to 200 cm. Their weight is from 0,5 to 2,0 tons. For siphons and weirs a similar prefab is used where the inclination of the adjoining side plates is 15 . These are fabricated in lengths between 75 and 150 cm. Larger prefabs cannot be handled with facilities available at present. These prefabs represent additional 4 basic models. With the 13 models listed all requirements up to a discharge of 6 cu.m/sec can be met. The use of the prefabs is illustrated in Fig. 0 and 7. The fabrication of thin and ribbed gate leaves of reinforced concrete is in the experimental stage. These cost only 20% of the conventional steel structures, require very simple hoists, buL proved not to be perfectly watertight. However, they will often do in irrigation and drainage systems. Л tilting gale is shown in Fig. 8 and a double leaf gate in Fig. 9. Contact surfaces of these leafs are prepared executed after the careful adjustment of the gate, by subsequently finishing the grooves left for this purpose.