METHOD OF MANUFACTURING A DOME- OR TUNNEL-SHAPED STRUCTURE

Abstract: Method of manufacturing a dome- or tunnel-shaped structure by spraying a hardening material against the inner side of an inflated sheet (1) between rib-shaped supports (4) which rib-shaped supports are temporary supports in particular in flatable tubes (5) which define spaces between which the hardening material (8) can be sprayed and after removal leave open spaces which thereafter are filled with the hardening material allowing a stepwise relatively fast process.

Description: Method of manufacturing a dome- or tunnel-shaped structure. Description: The invention relates to a method of manufacturing a dome- or tunnel- shaped structure by inflating an airtight sheet which by itself or with a foundation in inflated condition defines the basic shape of the structure and by spraying a hardening substance upon the sheet in its inflated condition in areas which lie between rib-shaped supports of the sheet. In the recently filed not yet published International patent application PCT/NL91/00130 a method has been described according to which the inflated sheet is supported by means of ribs which are manufactured by spraying a hardening material such as concrete, in particular a concrete having a microsiiica content such that it has inherent stability in the not yet hardened condition. According to said older method said ribs are manufactured prior to the spraying of the final concrete layer or layers upon the inflated sheet. The invention aims at a method which opens the possibility of manufacturing dome- or tunnel-shaped structures, in particular tunnel-shaped structures with high efficiency. According to the invention this is achieved in the first place in that the rib- shaped supports are temporary supports which are placed after inflation and removed after the application of hardening material in areas between said supports, whilst the spaces initially occupied by the temporary supports are filled by spraying after the removal of said supports. Thus according to the method of the present invention the inflated sheet is given greater stability for the spraying operation, not as disclosed in the older proposal by first manufacturing the ribs which form part of the final structure, but by supporting the sheet at spaced apart locations by means of temporary supports between which the hardening material is sprayed. After the spraying of said hardening material the said supports are removed and the spaces initially occupied by said supports are thereafter filled by spraying the said hardening material. Said temporary supports may be formed by any type of profile which easily can be taken away. According to the invention a temporary support is preferred which is formed by an inflatable tube. Such a tube, which of course has the required shape adapted to the inner shape of the structure to be made, gives in its inflated condition sufficient stability to the large inflated sheet which stability is required because said sheet is subjected to vibrations generated e.g. by wind and/or rain. By making use of inflatable tubes which can be or not be supported by a rigid profile, the removal of said temporary supports is a matter of decreasing the air pressure inside said tubes. If one places said tubes with the rigid profile behind said tubes with the profiles on a movable frame, tunnel-shaped structures can be manufactured fast by moving the frame stepwise, applying the said tubes by inflation of said tubes to support the innerside of the sheet, spraying the hardening material between the tubes, deflating the tubes to remove them and thereafter moving the frame a further step forwards after which the spraying device can fill the spaces which initially were occupied by said tubes. It is well known in the manufacturing of said dome- or tunnel-shaped structures that the hardening material primarily comprises a layer of synthetic resin foam such as a polyurethene foam, which layer gives initial stability and adherence upon the sheet. Thereafter the concrete is sprayed upon the foam layer. The invention includes a method according to which the temporary supports are placed after the spraying of the foam layer. Accordingly they support a sheet covered already on the inner side with a foam layer. Said supports now give further stability and define spaces for the spraying of the concrete. An advantage of delimiting the spaces within which concrete has to be sprayed by means of said temporary supports, in particular by means of inflatable tubes is that one need not to pay too much attention to the fact that during spraying concrete also is deposited on the said temporary supports. They are withdrawn and in particular if this is done by deflation a little deposit of concrete in its not yet hardened condition does not effect the operation. Due to the fact that no particular attention has to be paid to said spraying the spraying operation is speeded up. In case the concrete layer has to have a reinforcement said reinforcement according to the invention is placed adjacent but spaced apart from the foam layer and between the foam layer and the supports. Said temporary supports can at least partly support the reinforcing rods or they are in engagement with spacing profiles which define the space for the reinforcing rods. It will be clear that if the inflatable tubes engage the reinforcing rods or network the entire operation can take place with high efficiency. E.g. it is possible to place a reinforcing network with spacers against the inner side of the foam layer, inflate the tubes so that they press against said network and through the spacers press against the foam layer without special precautions being necessary. The invention now will be further elucidated with reference to the drawings: Figure 1 is a cross section through a tunnel-shaped structure under construction; Figures 2, 3 and 4 show cross sections, e.g. according to the line ll-ll in Figure 1 disclosing different faces of the manufacturing. In figure 1 the outer sheet has reference 1 which sheet is connected to a base not shown and inflated. Against the inner side of said sheet 1 a foam layer 2 has been applied in known manner. Inside the structure under construction a frame 3 is shown which is movable by not shown means and carries rigid profiles 4. Upon the outer side of said profiles 4 inflatable tubes 5 are placed which with their outer side press against a reinforcing network 6 and spacing profiles 7. Figure 2 shows the position of said tubes 5 against the inner side of that part of the structure which has already been made and comprises the outer sheet 1 , the foam layer 2 and the reinforcing network 6 with spacing profiles 7. Figure 3 discloses the spraying of a concrete layer 8 between the already manufactured concrete part 9 and one of the tubes 5 and between two subsequent tubes 5. After hardening of said parts 8 the temporary supports are removed, e.g. by deflation, and with the frame 3 moved a further step as shown in figure 4. The spaces initially occupied by a tube, such as 10 in figure 4, then are filled by spraying during which spraying a finishing layer 11 with or without reinforcing rods 12 is applied.

Claims: C L A I M S 1. Method of manufacturing a dome or tunnel-shaped structure by inflating an airtight sheet which by itself or with a foundation in inflated condition defines the basic shape of the structure and by spraying a hardening substance upon the sheet in its inflated condition in areas which lie between rib-shaped supports of the sheet, characterized in that the rib-shaped supports are temporary supports which are placed after inflation and removed after the application of hardening material in areas between said supports, whilst the spaces initially occupied by the temporary supports are filled by spraying after the removal of said supports. 2. Method according to claim 1 in which the spraying of hardening material primarily comprises a spraying of a synthetic resin foam layer upon which foam layer a concrete layer is sprayed, characterized in that the temporary supports are placed after the spraying of the foam layer. 3. Method as claimed in claim 2, characterized in that after the application of the foam layer a plurality of concrete reinforcing rods or a network of said rods is placed adjacent to but spaced apart from the foam layer and between the said foam layer and the temporary supports. 4. Method as claimed in claim 3, characterized in that the temporary supports support at least partly the said reinforcing rods or network. 5. Method as claimed in claim 3, characterized in that the supports are placed in engagement with spacing profiles which are placed against the foam layer and which define a space for the reinforcing rods or network. 6. Temporary support for carrying out the method of one or more of the preceding claims, characterized in that said supports are formed by inflatable tubes. 7. Support as claimed in claim 6, characterized in that the tubes are supported on the inner side by a rigid profile. 8. Support as claimed in claim 6 or 7, characterized in that the supports or profiles are carried by a movable frame.

Inventors: VAN EEDEN JOHANNES PETRUS, VAN EEDEN, JOHANNES, PETRUS
Applicants: INT DOME SYSTEMS, INTERNATIONAL DOME SYSTEMS
Application year: 1991
Main classification: E04G11
IPC codes: E04G11