FI66451C - FOERFARANDE FOER UPPFOERANDE AV SKYDDSVAEGG VID BYGGNING AV UNERVATTENSGRUND - Google Patents

Description

$ 66451

Method for making a protective wall in the construction of an underwater foundation - Förfarande för uppförande av skyddsvägg vid byggning av undervattensgrund

The invention relates to a water pressure resistant protective wall, which is required for making an underwater structure as dry work in a space bounded by said protective wall. Underwater foundation means here the underwater part of a bridge, pier or other structure to be made in water 5 which is not concreted by an underwater method (so-called Contractor casting).

Protective walls made of wood or steel grooves are known from the bottom of the water above the water surface 10. In this case, in the wood groove wall, the part at its base plate has been used as the base plate mold, and the part above it as a protective wall for dry work. Correspondingly, in the steel groove walls, the part at the base plate has been wholly or partly as a mold surface, in which case in the latter case 15 part of the wall is clad with a wooden mold. The top has been a protective wall similar to the wood groove wall.

Em. the disadvantages of the methods are the high costs due to expensive pre- and post-work (work bridges), the large amount and loss of material-20 Iin, and the higher overall costs caused by the longer construction time.

The most significant advantages of using the method according to the invention are achieved when making a steel groove wall and increasing the water depth. However, savings can also be made by using a wood groove wall or a protective wall made of other types of vertically separable elements. The main benefits are as follows: 2 66451

Material consumption decreases. The part of the steel groove wall at the base slab is left out, and in the wood groove wall, each part wall can be dimensioned in the most suitable way for the construction work.

5

The protective wall can be easily dismantled, as a result of which its elements are not damaged and can therefore be used several times.

10 The wall elements can be put in place and dismantled with a much smaller machine than in the previous methods. For example, if the depth from the water surface to the bottom is 10 m and the base plate to the top 5 m and grooves 12 and 7 m long are available, the lifting point must be at least 9 m above the water surface in the previously known method and at least 6 m above the water surface. This avoids the use of large cranes and the construction of work bridges that may be built on them. Often the pontoons can be set with a small excavator placed on top of the pontoons.

20

The transport costs of the wall elements are reduced.

If the construction site or work sites involve more than one underwater structure, the following procedure 25 could be economical: Build a raft with anchoring devices, eg bottom-supported legs, equipped with equipment suitable for underwater concreting. The base plate mold is placed on the bottom, the raft is placed on it, the base plate is cast, the raft is removed and replaced by a prefabricated pontoon-supported protective wall structure, which is lowered onto the base plate and supported from the base plate mold at a predetermined location.

In order to obtain the above effects, the invention 3,6451 is mainly characterized by the elements set out in the claims.

The accompanying drawing shows an embodiment of the invention which illustrates the use of the method in bridge construction work. Figure 1 shows a vertical section of a current pillar in the longitudinal direction of the bridge. Figure 2 shows the same section supplemented by an overhead steel scaffold structure. Reference numeral 1 denotes pe-10 base plate, 2 base plate molds, 3 work and protective wall support brackets, 4 protective walls, 5 cast column parts to be cast in a dry space bounded by the protective wall, 6 deck structure support columns, 7 above the water surface of the current column. 8 deck structure scaffolding, 9 bridge deck structure and 10 support walls for the concreted part of the power column 5.

In the solution according to Figure 1, the protective wall 4 is supported at its lower end in the mold 2 of the base plate. The wall can also be made by hanging it on an upper rack. The protective wall is thus made shorter, but on the other hand the cost increases, 20 due to the need for a stronger rack 3.

The solution according to Figure 2 simplifies the construction of the intermediate support 7. Since the width of the wall part 5 of the power column in the longitudinal direction of the bridge is usually small, when using steel scaffolding, when the scaffolding columns are supported on 25 cm structure 5, the work must first be done with a frame supporting the column 7 mold, then the mold, casting molds and casting racks and only then has it been possible to put the support columns of the rack supports in place. If the columns are supported on a steel grooved wall, they can be used as a 30 concreting scaffold and to support a column formwork, saving time and cost. There would also be other benefits to be gained from using this method. The span of the steel supports would be reduced and since the length of the base plate 1 in the transverse direction of the bridge is greater than the corresponding dimension of the pillar 5 on top of it, the support surface of the shaped steel beam under the scaffolding columns would become longer. Therefore, beams with a lower profile could be used than in previous methods.

Claims (1)

4 66451 where. However, in the application according to Fig. 2, in which the scaffold loads are brought through the protective wall to the base plate and further to the base ground, the construction and execution of the work must consider 5 more eccentric loads on the structure and the ground. The thickness of the base plate of the current pillar is usually determined by the water depth, i.e. the thickness of the base slab must be at least so great that its weight corresponds to the water pressure acting on the base of the slab. When using the method, the thickness of the base plate can be somewhat reduced. It may be necessary at least when the height of the top surface of the base slab is affected by the depth of the channel in the bridge opening and when the subsoil is difficult to remove. A method of making a protective wall (4) in the construction of an underwater foundation (5) using separable elements of a vertical seam, characterized in that the protective wall (4) is constructed inside the area delimited by the outer edge of the base plate mold (2) to the top of the base slab (1) to be concreted or concreted by the method.