FI85901B - Rock shoe - Google Patents

Description

1 85901

Rocky Top

The invention relates to a rock tip of a reinforced concrete pile consisting of a collar and a base plate forming the end of a finished pile and gripping steels for concrete attached to this end structure and a core part resting on the base plate, into which a tip pin is embedded.

10 Today, concrete piles are still generally equipped with a box-shaped plate shoe made of 4 mm * ... · steel sheet. However, equipping piles with a rock tip is becoming more common.

15 It is self-evident that the trend is changing everywhere from the use of slippers to the use of rock tips, because the ground conditions at the time of pile driving are almost invariably rocky and boulder-shaped. In addition, the penetration of the pile into the ground is improved when using a rock tip. The use of a rock tip also prevents the piles from breaking during the impact phase. In addition, their use is necessary when piling up to the bedrock, whereby the tip of the rock tip penetrates 2-6 cm into the bedrock when the pile is struck.

25 Previously known rock tip types are largely in line with the SIS standard. Such a structure is shown in Figures 1 and 2. The rock tip consists of a base plate 14 attached to the lower end of the pile and a box collar 12 attached thereto, and gripping steels 13 attached to the base plate by a weld 20 or nut 19 and a sleeve 17 attached to the base plate 14 and a partially recessed sleeve 17. from the tip pin 18. The box 12 is attached to the bottom plate either by a weld 21 or by a nut 19. In addition, around the sleeve 17 there are radially projecting supports 15, 35 which are attached to the sleeve and the base plate by welds 22. The concrete casting extends into the interior of the box 23.

2 85901

Numerous disadvantages occur in currently known rock tip types. First, the box 12, because it has both sides 24 and a base 25, has to be bent and cut in a complex way, whereby the percentage of material wasted and the workload 5 are high. In addition, based on the rock tip lining regulations (LPO-87), its core portion has had to be made very long due to the box-like collar portion. This requirement and criterion can be seen in Figure 2, according to which it is still uncertain whether the box or block 26 hits the rock or the block 26 or the tip pin 18. If the box first hits the sloping block surface, it bends as the block guides the pile to the side. and eventually breakage. That pile is then useless. In order for the tip pin to hit as securely as possible first, it is required 15 that the edge of the box be within a line of intersection 34 at an angle of 60 ° to the cross-sectional plane drawn from the outer corner of the tip pin. Today, the actual use of the rock tip type in the striking phase also causes a high striking resistance due to the box-like and bottom surface 25.

20

Unsatisfactory manufacturing methods, high material and manufacturing costs, and the technical disadvantages mentioned above have led to high piling costs. In addition, transportation costs are high due to the high weight.

... 25

The object of the invention is to provide a simpler and more technically functional rock tip of a reinforced concrete pile, from which the disadvantages of the previously known corresponding rock tips have been removed. It is a more detailed object of the invention to provide a rock tip which is inexpensive in material and labor costs and which can be manufactured in a fully automated manner.

It is also an object of the invention to provide a rock tip with '.35 better geotechnical properties than at present.

In addition, it is an object of the invention to provide a rock tip solution which: makes their transport space and total cost • 85901 low. Yet another object of the invention is to provide a rock tip solution that allows a faster and more reliable pile casting result for a rock tip.

The objects of the invention are achieved by a rock tip, which is mainly characterized by what is stated in the characterizing part of claim 1.

Numerous advantages are achieved with the rock tip according to the invention. Thanks to the sloping collar of the finished rock tip and the lowered sleeve, considerable savings in material consumption are achieved. The simplified structure also saves labor costs. The rock tip according to the invention can be manufactured in a fully automated manner, whereby its manufacturing costs remain low. Pouring the tip of the rock to the end of the pile is easy because pouring the concrete mass to all its corners is even better. In addition, the shape of this rock tip is geotechnically very advantageous. The penetration resistance of the tip is always lower than that of a traditional tip structure, and in addition, its tip pin hits the rock or boulder more reliably first than with a traditional structure.

The invention will be described in detail below with reference to a preferred embodiment of the invention shown in the figures of the accompanying drawings.

Figure 1 shows a prior art rock tip.

Figure 2 shows the rock tip of Figure 1 in the soil.

Figure 3 shows a rock tip according to the invention in a side view, partly in section.

Figure 4 shows a top view of the rock tip of Figure 3.

In Figures 3 and 4, the rock tip according to the invention is generally indicated by the reference number 9. The rock tip 9 is generally formed of steel plates and round steels of the required thickness as described below, although a steel foundry is a useful alternative in itself.

The rock tip 9 in this case comprises a square base plate 5, a collar 2, a sleeve part 7, support triangles 5, a hardened tip pin 8 and its locking screw 6. The base tip 4 of the rock tip 9 forms the end surface of the pile and is joined by e.g. . Attached to the base plate 4 is a sleeve 7, which is supported by support triangles 10, whereby a uniform impact load at the lower end of the pile is achieved.

The base plate is approximately the size of the area delimited by the outer edges of the support triangles. The edge collar 2 forms a conical or pyramid-shaped part tapering towards the tip pin 8 of the pile 15, which is fastened at its smaller end 29 by welds 33 to the base plate 4, preferably at or near either edge of its edge 28. At least the fastening takes place close to the edge 28, although not close to the edge. The cross-section of the wider end 30 of the collar corresponds to the cross-section of the reinforced concrete part 32 of the pile 31. The sleeve 7 is normally provided with a suitably shaped recess 10 into which a hardened tip pin 8 is embedded. up to end 29 and base plate 4.

The apex angle α of the collar, i.e. the opening angle of the point of intersection of the side extensions of said truncated cone-30 or pyramid shape, is arranged to be less than about 120 ° and most preferably equal to or less than 60 °. It is at this angular value that the effect of the sleeve length L disappears, as required by the standard and shown in Figures 2 and 3, but in Figure 3. The structure of the invention shows an angle α of about 30 °, making it easy to see that the line 34 diverges further from rock tip to pile. towards. The structure of Figure 3 works properly in the soil, keeping the pile intact on considerably steeper rock or boulder surfaces than the prior art structure. In practice, the value of the conical angle is always sufficiently small, so that the length of the sleeve and the base plate 5 can be dimensioned from a purely strength point of view. In principle, the length L of the sleeve 7 can be the same as the immersion depth S of the tip pin, i.e. the sleeve is a mere ring or tube and the tip pin rests directly on the base plate. Since the base plate 4 must then be thicker than usual, it is often advantageous for the strip to use a slightly longer sleeve, the cross-section of which larger than the tip pin distributes the load over a larger area, so that a base plate of normal thickness can be used. A preferred sleeve length L for this purpose is about 1.2-1.5 times the immersion depth S of the tip pin. However, the length 15 of the sleeve never has to be longer than 1.7 times the immersion depth S.

The rock tip 9 according to Figures 3 and 4 is manufactured, for example, as follows:

The collar 2 can be made of, for example, a 3 mm steel plate, the side length of which is determined by the size of the base plate and the width of the side of the pile. Thereafter, the base plate 4 and the core part 7 can be made together or separately as steel casting or guarantee, or 25 then with a separate automatic machining unit from the bar blank, whereby its production takes place completely automatically. If the base plate 4 is made separately, it is automatically cut by cutting from the web. The tip part 8 is manufactured in a machine shop, in the vicinity of which hardening and inspection measurements are performed. The gripping steels 3 and the possible support triangles 5 are also produced by an automatic machine. If the sleeve part 7 and the base plate 4 are manufactured as a guarantee or casting, a support triangle 5 is not required, because the sleeve can be shaped in a suitable manner. Finally, the necessary assembly welds are performed on 35 robots.

Only a preferred embodiment of the invention has been described above, and it will be apparent to those skilled in the art that numerous modifications may be made thereto without departing from the scope of the invention. For example, the collar 2 can be made by deep drawing or other shaping technique. The sleeve 7 and the base plate 4 can be shaped in many different ways. For example, circular and square or other cross-sectional shapes can be used alone or in combination in different ways. If the pile is square in cross section, the collar 2 may be a square of the same size at its wider end 30, but the collar 2 may be round 10 in cross section at the smaller end 29, corresponding to e.g. a round base plate 4.

The shape of the inner surface of the collar may follow or deviate from the above-mentioned shape of the outer surface. The inner surface may contain e.g. protrusions or shapes that promote its adhesion to the concrete.

Claims (8)

7 85901 A rock tip of a reinforced concrete pile consisting of a collar (2) forming the end of a finished pile and a base plate (4) and gripping steels (3) for concrete attached to this end structure and a sleeve part (7) resting on the base plate and embedded with a tip pin (8) , characterized in that the collar (2) is at least substantially truncated cone or pyramid, the smaller end (29) of which is formed by said base plate (4) to which the gripping blades (3) are attached and that said conical or pyramid-shaped the collar (2) is open at its wider end (30), whereby the concrete of the pile extends through it to the base plate (4). Rock tip according to Claim 1, characterized in that the cross-sectional shape of the cone or pyramid at least at its wider end (30) corresponds to the cross-sectional shape of the pile (31) at that point. Rock tip according to Claim 2, characterized in that the smaller end (29) of the conical or pyramid-shaped collar (2) either corresponds to its alternating cross-sectional shape or alternatively differs therefrom. Rock tip according to one of the preceding claims, characterized in that the length (L) of the core part (7) is equal to or greater than the immersion depth (5) of the tip pin (8), but not more than approx. 1.7 times the immersion depth. Rock tip according to Claim 4, characterized in that the length (L) of the core part is approximately 1.2 to 1.5 times the immersion depth (S). A rock tip according to any one of the preceding claims, characterized in that the tip angle (α) of the conical or pyramidal shape of the collar (2) is at most about 120 °, most preferably * about 30-60 °. 8 85901 Rock tip according to one of the preceding claims, characterized in that the collar (2) is fastened at its smaller end (29) substantially around one of the edges of the base plate edge (28) or in their vicinity. 5 Rock tip according to one of the preceding claims, characterized in that the collar (2) has an air outlet hole or holes (11) at or near its edge against the base plate (4). 10