Vízügyi Közlemények, 1956 (38. évfolyam)

2. füzet - VII. Kisebb közlemények

(15 > Aus diesen Verschiebungen sind die Scheibenspannungen mittels Formeln (40, 47) berechenbar. Die Endergebnisse sind der Tafel V. und der Abb. 18. ersichtlich. Die in den untersten Querschnitten auftretenden Hingkräfte sind in Tafel VI. enthalten. Dem Beispiele ist ersichtlich, dass die in den Zylinderwänden von Stahlbetonbehältern mit flacher Boden- und Deckplatte auftretenden Biegungsmomente und Ringkräfte annähernd gut berechnet werden können, indem man den unteren Knotenpunkt als waagerecht gestützt annimmt. Andererseits können die Scheibenkräfte bestimmt werden, indem man die in der Plattenebene wirksamen, durch die Zylinderwand übertragenen Kräfte gemäss ihrer Steifigkeitszahlen auf die sich anschliessenden Scheibenelemente verteilt. Nach der Ausführung der Berechnung auf diese Weise, wurden deren Ergebnisse auf Tafel VII. veranschaulicht. Daraus ersieht man, dass sich die Näherungswerte (Tafel VII.) von den genauen Werten (Tafel V.) kaum unterscheiden. ANALYSIS OF CIRCULAR DISCS OF CYLINDRICAL TANKS Gy. Márkus (Figures, formulas on pp. 97-117 of Hungarian Text.) 624.073.112 : 624.953 The floor and very often also the cover plate of cylindrical storage tanks are circular plates subjected to bending, but at their joints with the cylindrical wait radial tensiona) and compressive stresses also arise in their planes under the effect of fluid pressure ; therefore the circular plate is working as a circular disc tooSurplus stress due to disc effect is generally disregarded, though in calculation, and in spacing reinforcings it has to be considered without doubt. This paper presents a calculation method of disc stresses in more specific, more complicated cases and points out their importance and order of magnitude. Under alinéa 2. the theory of the circular disc is demonstrated. Start is made from the Airy stress function (I) ; formulas of principal stresses are set up (8), then the equation of radial extension of the disc is set up (9) ; afterwards the individual loading cases are treated. Under alinéa 3. a circular disc (Fig. 1.) is dealt with, along the periphery of which uniformly distributed load P is acting. Stress formulas o> ander,, are derived (10

1 from boundary conditions in the centre and along the margin of the disc, afterwards from the dislocation of point with radius a (11), — after the analogy of frames with joints free to translate — the stiffness coefficient z is determined (12)

r which expresses the rigidity of the disc edge towards extension (z = P/u

a

). We may use 1 /Е times the value of P/u

a instead of P/u

a. Under alinéa 4. the circular annular disc (Fig. 2.) with uniformly distributed load over its inner edge is treated. Here too, formulas of stresses (13), of radial dislocations (14) and of the stiffness coefficient (16) are derived. Similar formulas are set up for tbe disc loaded on its outer edge (Fig. 3.) under alinéa !>. (16 — 18). Under alinéas 6. and 7. similar loading cases (Fig. 4. and 5.) are treated, but the edges of the disc opposite the load are assumed to be strutted (laterally restrained). Formulas of stresses, of radial extension and of stiffness coefficients are found under (19 — 22) and (23-20). Under alinéa 8. the application of the derived results is shown on examples and stress diagrams are drawn for each case. In example 1. the disc effect of the floor plate of the storage reservoir, having two concentric compartments of the same capacity (b — У 2a) is investigated, fn case a) the outer (Fig. 6.), in case b) the inner compartment is assumed to be filled (Fig. 7.). For the sake of simplicity radial forces transmitted by the inner and by the outer cylindrical wall are assumed to be identical (P). The computed stresses are tabulated under I. and II. and graphed in Fig. 8.