Ársrit Verkfræðingafjelags Íslands - 01.01.1914, Blaðsíða 34

Ársrit Verkfræðingafjelags Íslands - 01.01.1914, Blaðsíða 34
34 of the minimum thicknesses. Breymann is of the opinion, that average walls should be 3 cm thicker than this and strong walls should be still 3 cm thicker. The rules are adapted to limed brickwalls. By means of these rules, it is an easy malter to make convenient precepts as to the thickness of the walls of concrete houses, the proportions could be about the same, for according to our usual working me- thods we can not expect, that concrete of 1 : 4 : 8 has a greater bearing-strength, than an ordinary brick- wall. Regarding the internal walls similar provisions could be made. The increase of the thickness ofwalls, which are not sustaining, could of course be a dilferent and a smaller one. Only I should tliink it unadvis- able to allow to make any outer wall thinner than 23 cm — supposing it was not an absolutely water- proof one, and walls of that thinness are not warm enough for dwellingrooms. Therefore it seems to me, that when the question is of outer walls, thinner than 32 cm (12"), a prolective lining should be de- manded. At last, some bounds should be set to the length of concreted walls, going belween cross walls made from the same material. As a rule their length should not exceed 10 m. In a similar way rules could be made with re- gard to the use of reinforced concrete for walls, stairs, floors and ceilings. I suppose that, in future, concrete lloors will be more commonly used, the price of timber being so enormous, that concrete floors hardly will prove more expensive, (at least not in houses where tlie interval belween the supporting walls is large, so the girders must be high) even if the layer of concrete was floored with wooden boards laid on joists, the void being filled with potters clay or the like. On the olher hand, wooden girders do not fit in very well wilh concreted walls, at least their ends should not be wrapped up in any way, only carbolinated. I do not think there would be any danger of straining although the ends of the girders were co- vered with concrete, in the course of time the wood will shrink sufficiently as to preclude tliat possibility. I do not wish to enter into a greater length re- garding the provisions of the build. reg. as to build- ing from concrete. As regards carpentry the building regulations need nol be much allered. Still I think, that the space between the floor-girders should be adjusted to the thiekness of the flooring-boards. But before leaving this subject, I wish lo empha- size, that as far as possible the building regulations should be made to contribute to a more careful build- ing and withstand hasty and careless working. Al- though these measures apparently should result in increased expenses, thal would only be at the very beginning, in the long run they would pay. There- fore people who build would not have any reason to be discontented on account of the expenses imposed. Owing to the rough climate of our country, the need of preservation is greater here, than almost everywhere in our neighbourcountries. Therefore I think it very advisible, that the building regulations should authorize the building commiltee to claim, that every work, belonging to ils sphere of act- ion, should be managed by a man whose ability was recognised by the commiltee. In support of my argument I will mention, that provisions tending towards this are to be found both in the building regulations of Christiania (from 1899) and in the »Betankande med förslag till byggnadsstadga för rikel«, before menlioned. 3. Einige Mitteilungen iiber isliindisches „Mel“-Korn und Algern. (Auszug aus einem im Ingenieur-Verein Islands von Herrn Ingenieur-Cliemiker Ásgeir Torfason am 30. Jan. 1913 gehaltenen Vortrag). Island ist so zu sagen ein brotloses Land. Keine der ublichen Getreide-arten wachsen hier unbebaut und werden nur im ganz geringen Masse bebaut. Allerdings erzahlt man zu alten Zeiten vom Kornbau (Gerste) und darf wohl annehnen, dass das Korn viel- leicht in guten Jahren reif geworden ist. Wie viel der Kornbau auch zu diesen Zeiten gewesen sein mag, ist derselbe jedoch iin Lauf der Jahre aufgegeben und vergessen worden; ist auch wahrscheinlich nie- mals lohnend gewesen. In den letzten Jahren sind einige Versuche wieder gemacht worden, die trotz eini- germassen guten Gelingens gezeigt haben, dass der Kornbau liier im Lande weniger lohnend als der Wiesenbau (Tunbau) ist. Trolzdem wir aber nicht die iiblichen Getreidear- ten haben, so haben wir doch hier eine Pllanze, die Brotkorn liefert, namlich der »Melur« (glymus are- narius). Allerdings wáchst der Melur lange nicht úberall auf Island, er gedeiht nur dort gut, wo Sand- wehen ist. Wo aber die Bodenverháltnisse fúr ihn gúnstig sind, wird er gross und kann jedes Jahr reifes Korn tragen. Die weiteste Verbreitung hat der Melur in dem Distrikt Vestur-Skaftafellssýsla gefunden, wo er sogar als Nahrungsmiltel fúr Menschen benutzt worden ist. In frúheren Jahrhunderten, als der Handel nur schwierig und schlecht war, hatle der Melur eine grosse Bedeu-


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