US1331377A - Process for the construction of monolithic structures of basalt - Google Patents

Description

UNITED STATES PATENT. OFFICE.

FRANCOIS RIBBE, 0F MAURIAC, AND PAUL DRE, 0]! PARIS, FRANCE,

PROCESS FOR THE CONSTRUCTION OF MONOLITHIC STRUCTURES OF BASALT.

1,331,377. No Drawing.

To all whom it may concern I Be it known that we, FRANgoIs RIBBE, of No. 26 Avenue de la Gare, Mauriac, Cantal, France, doctor of medicine, and PAUL DH1- of No. 42 ter Rue Notre Dame des Champs,

Paris, France, engineer, and citizens of the -Republ1c of France, have invented certain new and usefulImproved Processes for the Construction of Monolithic Structures of Basalt, of which the following is a specification.

The French Patent No. 449707 applied for on 29 December 1911 contains a description of methods of casting, molding and de- V vitrifying on the actual surface of the ground, various articles of basalt that has een previously melted in cupola furnaces more often in one p1ece and of considerable dimensions,'such asdams, sea-Walls, piers, bridges, fortifications etc.

Hereinafter a description is given by way of example, of the manner of constructing a dam for damming a stream.

The shape of the structure has nothing peculiar in it. Nevertheless in general it is advisable to'arrange that the basalt shall act in compression. The structure will therefore be given a certain amount of curvature with its convex side facing upstream of course.

The ground after having been excavated down to the solid stratum according to the adopted plan and in accordance with the rules of the art, is then dried as far as it is ossible. If any moisture remains, a very lig t layer of basalt ballast Will prevent any excessive formation of air bubbles, The casting operations may then begin.

The furnaces may be fixed or portable. In the former case they should be erected at the most convenient points in the immediate neighborhood, of the structure to be built. They may be of widely varying types; in some cases it may be best to employ an electric furnace. Generall however, it is preferred to use a cupola rnace, when Specification of Letters Patent.

Patented Feb. 1'7, 1920.

Application filed November 5, 1918. Serial No. 261,813.

the dam tobe built is of large size, and it is not feared to change the chemical composition of the material within certain limits, it

will be an advantage to choose apparatus of the blast furnace type.

These allow of a much better utilization of the heat, and by the reduction of a part of the iron oxids of the basalt, they produce a certain amount of iron that can be sold at a fairish price.

The molten basalt is to be convoyed to the points where it is to be cast, by means of portable fore-'hearths, ladles or other suitable vessels ada ted to travel on aerial cable ways or on rai s su ported on scaffolds on each side of the worll.

Portable furnaces, where their use is necessitatedby exceptional circumstances will be mounted on balls or on wheels and will be adapted to travel along the. rails on the scaffolds.

In a case where the width of the dam should render it necessary, the said furnaces would be located on traveling bridges provided with rails extending right across the dam, these traveling bridges bein in their turn adapted to travel on the railsof the scaffolds. -In this manner and owing to the two-fold mobility of the furnaces along the traveling bridges, and of the traveling bridges along the entire structure, there is no point of the dam that cannot be reached by the casting operation. The apparatuses are charged by means of aerial cable ways or any other suitable means.

It is to'be understood that a plurality of furnaces may be arranged to travel simultaneously, and that arrangements are made for removing and replacing any of the apparatusthat may require repair.

It is also to be .understood that the traveling bridges may be used in certain cases for the conveyance of ladles charged with material that has been melted in fixed furnaces.

But whatever ma be the system of melting and conveyance that is adopted, it will be necessary, exce t in rare cases, to employ only a non-bub ly material, which on cooling will form a dense rock of reat strength. This condition is easily sat sfied by basalt which in the state of liquid fusion, allows of a rapid escape of its bubbles in the vessels inwhich it is received as it is runfrom the furnaces.

The shape to be given to the dam is produced in a very simple manner. So long as the work is being built u in the excavation, "the sides of the latter w' I serve as the mold. On leaving the excavation the fluid material is contained at suitable points by a line of frames set side by side lined with bricks which may be porous or non-porous, but-are well talced -or rubbed with cinder if it is desired to prevent adhesion. The frames are allowed to remain in place for a certain number of days so as to prevent thesides of the structure from cooling too quickly, after which they may be removed for re-use.

Instead of bucks, there may be employed slabs of baked earth, cast iron, or plates of.

very-dry cement orother means. In some cases where there is no objection to having sides of very irregular shape and w1th a slope, molding may be dispensed w1th altogether.-

These preliminary arrangements having been made, the following is a description of the manner of making the block,.and how it is possible by means of daily castings .25 to produce a monolithic structure constituting a real natural rock having enormous strength of resistance. p

' When a castin of molten basalt has not great thickness, t e material s00n solidifies,

but if while it is still hot, although its temperature has fallen to below red heat, a fresh 'castin is poured .upon its surface, its more super cial parts will become melted again and an intimate union will be produced between the two masses. Consequently as the dam increases in height, the quantity of m'aterial that is added every day to its surface will become united by autogenous welding to the underlying block and 40 will form absolutely one piece therewith.

Moreover it will serve to complete the devitrification of those portions of the mass of the preceding casting which by having cooled too quickly, may have acquired a vitreous character.

One condition however which must be considered as beingalmost essential to success, is this, namely, the work of constructing the dam when once begun, must never be in terrupted, in other words a sufficient quantity of material must be poured upon each point of the surface of the monolithic structure before the temperature at that point has fallen too close to the temperature of the atmosphere. Consequently every care must be taken in every respect to assure that the dam shall receive each day on its surface so much fresh material as will raise the height of the dam by at least some decimeters approximately uniformly throughout its ex-- tent.

Therefore unless the daily addition of materlal is great, it is necessary at least to provide some protection against a rapid cooling of the liquid basalt that is being continually poured upon the dam in course of construction, Such protection .is necessary 1n order that the autogenous welding shallhold.

Such protection is further necessary to assure the devitrification of the material whereby the rock regains all its resisting. power. Forthis purpose a layer of hot an relatively stagnant air is formed at its sur- ,face by means which may yary considerably.

Among such means, there is one which has proved its efficiency, namely the arrangement of frames lined with porous bricks supported by their ends directly upon the scaffolds when the width of the work is not too great, or resting on stretched ropes or on a metal framework provided for this purpose in other cases, but always arranged side by side in such a manner as to form a continuous horizontal screen for a small helght above the surface of the basalt. When a casting operation has to be done at any point, the corresponding frame will be temporarily moved aside.

If by reason of untoward circumstances the work has been discontinued for so long a time asto cause a complete cooling of its surface, it will be necessary to resume the pourings in the ordinary way, and then some .hours afterward to break up the product of In most cases it will be advantageous to employ reinforced basalt instead of ordinary basalt. The resisting power of the block will be greatly increased thereby, while in the case of an interruption of the construction 'the resumption of the work .will also be facilitated.

With a view to economy, there ma be introduced into the molten material either before or after the casting in sir/w, a certain quantity of basalt, granite, flint or other rocks that will not be liable to become decomposed by the tem erature of the bath, such rocks should e coarsely crushed. These fragments will unite to form one piece with the basalt on the cooling of the I latter. In order to prevent the inconvenient formation of bubbles, only lumps should be used which have'first been freed by suitable heating from their natural water content and the greater portion of their occluded gases, and they are mixed with the'basalt while they are still hot. i

As soon as the monolithic block has reached a certain height it may be called upon to support its own scaffolding. For this purpose pieces of iron in suitable number and of suitable strength are inserted in the block; holes and recessed or projecting parts are formed at suitable points; all for the purpose of providing supports for the scaffolds at the sides. The stepped sloping side of the actual dam may even be utilized for this purpose.

It is scarcely necessary to mention any of the advantages afforded by the use of monolithic basalt structures. The enormous strength of this material will allow of re-- ducing appreciably the total cubic content of such structures compared with the cubic content of the ordinary masonry or brickwork which it replaces, while increasing however the margin of safety. No upkeep, and practically no watching are required.

The improved method allows of building bridges, viaducts, various works of fortification such as parapets, escarpment and counter-escarpment walls, open czaponieres, aprons for armor, emplacements for large guns, and even casemates because basalt, especially when reinforced, is very suitable for the construction of roofs or vaultings. It may also be employed in the construction of wall foundations, and also entire walls, even for dwellings, which, in addition to their unshakable firmness. have the advantage of being capable of very rich ornamentation. This enumeration has no limiting force whatever, because any structures of the kind hercinbefore referred to. can be constructed of the same material and by the same method, barring slight modifications according to the circumstances of each case. Having now particularly described and ascertained the nature of our said invention, and in what manner the same is to be performed We declare that What we claim is 1. A method of constructing constructional works, dams, barrages, fortifications, bridges and the like structures, which consists in casting molten basalt in successive superposed layers in the actual space which the desired structure is to occupy, each new layer being cast while the preceding layer is still sufficiently hot to become welded to the said new layer, whereby the whole forms a monolithic structure.

2. A method of constructing constructional works, dams, barrages, fortifications, bridges and the like structures, which consists in casting molten basalt in successive superposed layers in the actual space which the desired structure is to occupy, the cooling of the top surface of the structure as it is being built, being reduced by means of a screen which placed upon it and which retains a layer of air on the cast basalt.

3. A method of constructing constructional works, dams and the like structures, which consists in casting molten basalt in successive superposed layers in the actual space to be occupied by the desired structure, and incorporating, heated stones successively into the layers of basalt while the said layers are still fluid.

4. A method of constructing constructional works. dams. and the like structures, which consists in casting molten basalt in successive superposed layers in the actual space to be occupied by the desired structure, from casting appliances that are adapted to travel on scaffolds which rest on the actual structure and which are raised according as the said structure increases in height.

FRANCOIS RIBBE. PAUL DHE.