Vízügyi Közlemények, 1970 (52. évfolyam)

4. füzet - Rövidebb közlemények és beszámolók

(91) b) From data of the mid-lake station: H n = 0.0827( U a — 1)°> 72 5 tf„ = 1.101# a; H m = 2.2H n ; Я т„ = 2.64Я а. 2. Szilágyi, L., Civ. Engr. : Corrosion control for a gated culvert by a liner pipe oï polyesther (For the Hungarian text see pp. 497) The gated culvert shown in Fig. 1 serves purposes of irrigation water diversion in the valley of the Tisza River. It crosses the left-hand levee of the Körös River with a diameter of 1.2 m. Severe cracking was observed on the structure and the concrete was found to deteriorate starting from the interior of the pipe. A liner pipe of polyesther was used to offer protection to the surface. The pipe sections were 2 m long, 1.2 m in diameter and of 6 mm wall thickness (Fig. 2). Reinforcement was provided by three layers of wown glass fibre and two layers of glass fibre felt located alternatingly. The resin used was "Eupol-2" polyesther of Hungarian manufacture. Each pipe section was provided with 2 grouting pipe stubs along the same line. The bell joints were filled with plastic glue. The costs of the plastic pipe lining amounted to 7700 Ft/running metre, repre­senting a considerable saving over the construction of a new structure. In view of the experimental character of the structure, supervision and checks are run at regular intervals. Similar measures, i.e., surface corrosion control with plastics may be the answer to many problems in hydraulic construction. 3. Deli M. and Dombi, M., Civ. Engrs. : Characteristic values of domestic water demand at settlements (For the Hungarian text see pp. 505) The characteristic values of domestic water demand, most frequently used in technical-economic computations are the average demand, the daily peak demand and the hourly peak demand. The average specific demand is higher than the household demand and depends on a wide variety of factors. The seasonal uniformity coefficient ( Fig. 1 ) depends on meteorological conditions, the number of inhabitants of the settlement, the type of settlement and the ratio of cold and hot water used. The time at which the peak demand occurs differs from town to town ( Fig. 2). For a reliable estimate of demands an adequate number of long and reliable records is essential. Borbélg, J., Physicist: Stress distribution in hydraulic structures determined on a model using resistance strain gages (For the Hungarian text see pp. 511) Resistance strain gages are applied successfully for determining the distribution of stresses in the structural models of hydraulic structures, especially at the unloaded boundaries. In structural model testing the similarity conditions (1) to (3) must be satis­fied, whence Eq. (6) follows, if Hook's law is considered valid. When tests are con­ducted beyond the elastic limit, the model most be made of the same material as the prototype. The suitable model material must be selected before the tests (Figs. 2, 3). remembering that the character of stresses and strains should be. identical (Fig. 5). In the first pilot test the cross section of a lock chamber (Fig. 4) was con­structed on four different types of soil, characterized by a Young's modulus of elasticity of E = 133 800 kp/sq.cm. The loads and points of measurement are shown in Figs. 4 and G, respectively. The prototype stresses computed from the model results are shown in Fig. 7. The different efforts (normal forces, shears and moments) together with the stresses in­duced by them are indicated in Fig. 8. Analytical and actually measured values are compared. Stresses in the base slab depend appreciably on the elasticity of the soil, so that allowance for elastic bedding in the computations is justified.

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