RAUTARUUKKI OY (Fredrikinkatu 51-53, Helsinki, FIN-00100, FI)
Tarkkonen, Jyrki (Ristiniementie 26 H 20, Espoo, FIN-02320, FI)
| 1. | Method for manufacturing a tube fundament for a mast (5), especially for an electrifying mast of a railway line, characterized in that at least two steel tubes (1) are driven adjacently into the ground, each steel tube (1) is filled with concrete (2), an anchoring tube (3a, 3b) is introduced into each steel tube (1) filled with concrete (2), the upper end of said bond tube is provided with means (4a, 4b) for the attachment of said bond tube (3a, 3b) to the corresponding attachment means (4b, 4a) of the other bond tubes (3b, 3a) of the tube fundament and to the mast (5), and the position of the bond tubes (3a, 3b) are adjusted before the concrete (2) hardens. |
| 2. | Method according to claim 1, characterized in that for each mast (5) two adjacent steel tubes (1) are driven into the ground on the opposite sides of a mast line to be erected so that said tubes (1) form a small angle with each other. |
| 3. | Method according to claim 2, characterized in that the first steel tube (1) to be installed on the outermost side of the embankment of a railway line is driven into the ground entirely vertically and the other steel tube (1) to be installed closer to the railway line is driven into the ground in a position, which forms an angle of about 10 degrees to about 20 degrees with the first steel tube (1). |
| 4. | Method according to claim 3, characterized in that the the position of the anchoring tubes (3a, 3b) in the con crete (2) is adjusted so that the attachment means (4a, 4b) provided at the upper end of both anchoring tubes (3a, 3b) will be positioned horizontally upon each other, whereafter said attachment means (4a, 4b) are attached to each other. |
| 5. | Method according to claim 1, characterized in that the steel tube (1) to be driven into the ground is thin walled and after filling the concrete, an additional thickwalled steel tube (11) is introduced into this steel tube (1) before the bond tube (3a, 3b) is installed. |
| 6. | Tube fundament for a mast (5), especially for an elec trifying mast of a railway line, characterized by at least two steel tubes (1) driven adjacently into the ground and filled with concrete (2), which form a small angle with each other, an anchoring tube (3a, 3b) embedded in the concrete (2) filled into each steel tube (1), the upper end of said anchoring tube (3a, 3b) is provided with means (4a, 4b) for the attachment of said anchoring tube (3a, 3b) to the corresponding attachment means (4b, 4a) of the other anchoring tubes (3b, 3a) of the tube fundament, and a plate (6) for the attachment of the mast (5), which plate is attached to one of the attachment means (4a). |
| 7. | Tube fundament according to claim 6, characterized in that the tube fundament comprises two steel tubes (1) and the attachment means (4a, 4b) are positioned horizontally upon each other, whereby the plate (6) for the attachment of the mast (5) is welded to the upper attachment means (4a) of the tube fundament. |
| 8. | Tube fundament according to claim 7, characterized in that the surfaces of the attachment means (4a, 4b) and at least the upper end of the bond tube (3a, 3b) are treated, preferably hot galvanized, against corrosion. |
| 9. | Tube fundament according to claim 6, characterized in that a cutter shoe (10) is attached to the lower end of each steel tube (1) driven into the ground. |
| 10. | Tube fundament according to claim 7, characterized in that the attachment means (4a, 4b) are shaped as Ubeams attached to corresponding anchoring tubes (3a, 3b) in such a way that said means (4a, 4b) will be positioned horizontally when the anchoring tubes (3a, 3b) are properly positioned and the upper Ubeam is broader and downwards open and the lower Ubeam is upwards open, and so much narrower that it fits into the upper Ubeam. |
| 11. | Tube fundament according to claim 6, characterized in that the steel tube (1) to be driven into the ground has a length of between 1500 to 6000 mm, a diameter of between 114 to 273 mm and a wall thickness of between 4 to 12 mm, and the anchoring tube (3a, 3b) to be intro duced into the the steel tube (1), has a length of between 1000 to 2000 mm, a diameter of 85 to 170 mm and a wall thickness of 5 to 25 mm. |
| 12. | Tube fundament according to claim 6, characterized in that the steel tube (1) is thinwalled, and an additional thickwalled steel tube (11) is embedded in the concrete (2), the external diameter of which is smaller than the diameter of the steel tube (1) and the internal diameter of which is greater than the external diameter of the bond tube (3a, 3b). |
In the past, the electrifying masts for railway lines were mainly founded on a concrete element, dug into the ground. Such a solution of foundation is expensive, time- consuming and it involves safety hazards, a minimization of which makes it necessary to stop the traffic on the railway line occasionally during the work. The most sig- nificant problems relate to the installation of the fun- dament but problems have also been observed in geotechni- cal action of a concrete element fundament.
The installation of a concrete element fundament requires quite a deep excavation to be made into the ground, whereby the ground will slacken in a wide area surround- ing the excavation. Depending on the ground, the sides of such an excavation may constitute a considerable safety hazard due to the danger of their collapsing. Making of an excavation requires a considerable working space around the excavation, which is a hindrance both to pas- sing traffic and to other activities at the work site.
Due to the slacking of the ground, constructions close to the excavation may be damaged and may cause for instance a setting of the railway line. Later repair of ground settings will cause further disturbances to the traffic.
The installation of element fundaments for electrifying masts of railway lines causes interruptions in the traf- fic, limitations of time table and a great deal of paper work. Line reservations cause considerable additional expenses for the traffic as is generally known.
A significant problem related to the installation is
caused by a rock close to the surface of the ground, which hinders a rapid progress of the installation work and increases work expenses, because it is necessary to mobilize a special work team to quarry the rock hindering the installation.
The constructional dimensioning of a concrete element fundament is problematic, because the ground conditions often vary considerably. It is unreasonable for a con- structor to dimension each fundament separately, where- fore both under- and overdimensions often appear in the same object.
Also a method is known, in which an electrifying mast for railway lines is founded in the ground so that a hole, having a diameter of about 400 mm and a depth of about 4 m, is drilled into the ground, a steel tube element of substantially same size is introduced into the hole, the upper end of which is provided with a plate for the attachment of the electrifying mast, concrete glue is pumped into the steel tube under pressure until the conc- rete glue is pressed out through an aperture provided around the tube. A drawback related to this previously known method is that a tube to be driven into the ground as well as the driving equipment are in the practice so massive that said equipment must be installed in railway carriage, where-fore the railway line to be electrified cannot be in normal operation during the installation.
For said reasons, the installation involves great total expenses also by this method.
All above mentioned problems involve expenses for the society. It is therefore an object of the present inven- tion to overcome the above problems and hence to minimize expenses. This aim has been achieved by a method which is characterized in that at least two steel tubes are driven adjacently into the ground, each steel tube is filled
with concrete, an anchoring tube is introduced into each steel tube filled with concrete, the upper end of the anchoring tube is provided with means for the attachment of said anchoring tube to the corresponding attachment means of the other anchoring tubes of the tube fundament as well as to the mast, and the position of the anchoring tubes is adjusted before the concrete hardens.
The invention relates also to a tube fundament for a mast, especially for an electrifying mast of a railway line, which tube fundament is characterized by at least two steel tubes driven adjacently into the ground and filled with concrete and forming a small angle with each other, an anchoring tube embedded in the concrete filled into each steel tube, whereby the upper end of the anchoring tube is provided with means for the attachment of said anchoring tube to the attachment means of the other anchoring tubes of the tube fundament as well as a plate for the attachment of the mast, which plate is attached to one of the attachment means.
Among others the following advantages are achieved when, instead of one tube, at least two steel tubes are used according to the invention as the tube fundament for an electrifying mast: Due to their size, the steel tubes can be driven into the ground from railway embankment so that the passing traf- fic will not be disturbed.
A significant cost saving is reached by the fact that when using a tube having a diameter of about 200 mm, it is still possible to use an eccentrical driving method, whereby it is economical to leave said steel tube direct- ly in place as fundament. Said driving method does not work in a satisfactory manner, if said tube has a diam- eter of approximately 400 mm, which tube size must be
used in a single-tube fundament for an electrifying mast of a railway line.
The moment directed to an electrifying mast is different in the direction of the railway line and vertically to said line, which fact can easily be taken into consider- ation when the fundament comprises more than one steel tube.
When using a double-tube fundament, in addition to the flexural resistance of the tubes, also the skin friction between the tubes and the ground can be utilized, whereby also the stiffness (strength) of the system can be utilized.
When it is not necessary to make an excavation into the embankment of the railway line, damages of waterproofing, frost protection and other substructures can be pre- vented.
The method and the tube fundament according to the pres- ent invention is suitable for all ground conditions. No excavations are needed, and each fundament can be dimen- sioned individually without any difficulties.
The tube fundament is ideal for an electrifying mast of a railway line, because the length of each tube to be driven into the ground, can be determined individually in each case in accordance with the ground conditions.
Therefore, it is possible to provide an individual fun- dament for each mast, when necessary, which enables to secure that the fundament works reliably. In contrast to the concrete element fundament, the occurrence of a rock close to the surface of the ground is especially desir- able when using the tube fundament according to our invention, because a tube driven to a depth of 0,5 metres of an unbroken rock constitutes an ideal fundament for
masts of all kinds.
In addition to the application as a fundament for elec- trifying and light masts, the tube fundament according to the invention is well suitable also for the use as a fundament for noise barriers or other protective fences and portals.
Further characterizing features of the tube fundament according to the invention will become apparent from accompanying dependent claims.
In the following the invention will be described more in detail with reference to the drawings in which Fig. 1 shows a diagrammatic representation of an embodi- ment of a tube fundament according to the invention, intended for an electrifying mast of a railway line, Fig. 2 shows a side view of an anchoring tube for a steel tube to be driven into the ground vertically, Fig. 3 shows a bottom view of the anchoring tube shown in Fig. 2, Fig. 4 shows a side view of an anchoring tube for a steel tube to be driven into the ground diagonally and Fig. 5 shows a bottom view of the anchoring tube shown in Fig. 4.
The tube fundament comprises at least two steel tubes 1 to be driven adjacently into the ground, which, after having been driven into the ground, are filled with con- crete 2. A steel anchoring tube 3a, 3b is introduced or inserted into each steel tube 1 filled with the concrete 2, the upper end of said anchoring tube is provided with
means 4a, 4b for the attachment of said anchoring tubes 3a, 3b to the corresponding attachment means 4b, 4a of the other anchoring tubes 3b, 3a of the tube fundament, as well as to the mast 5 to be founded. Before the concrete hardens, the position of the anchoring tubes 3a, 3b is adjusted so that the attachment means 4a and 4b will be positioned horizontally one upon another, and the attachment means 4a and 4b are attached to each other, for instance by means of bolts. After the concrete 2 has hardened, the mast 5 to be founded can be erected and attached to an attachment plate 6 welded to an upper sur- face of the upper attachment means 4a. During casting, the consistency of the concrete 2 is such that the anchoring tubes 3a, 3b, together with the attachment means 4a, 4b thereof, remain in the accurately adjusted position during the hardening process. Due to this, the fine adjustment of the attachment means 4a, 4b can easily be carried out while introducing the bond tubes 3a, 3b into the concrete 2 in the steel tubes 1.
The ground consists of several earth layers (stratums), wherefore the ground is generally non-homogeneous, anisotropic and discontinuous. Due to the discontinuity, rules of stress-strain dependence of a material which are derived in the mechanics of solid matter, are not appli- cable to ground materials. The mechanical properties of ground materials are affected by various factors such as particle form, particle size distribution and the density of the ground.
A deformation generally will comprise an elastic part and a plastic part. Characterizing properties of ground materials are an unlinear elastic behaviour, hysteresis and Bauschinger phenomenon. A gap appearing behind the tube fundament and local collapsing of the ground are the main reasons for unlinear load-dislocation behaviour. The hysteresis phenomenon means a non-uniform load and
release stress-strain path. The Bauschinger phenomenon means the fall of yield stress when the direction of load changes.
When the tube fundament is loaded horizontally, the col- lapse of the ground close to the ground surface occurs as a sliding surface collapse and at a deeper level of the ground as a horizontal motion of the ground. Side capac- ity of the tube fundament means the greatest horizontal load resistance of the tube fundament, which corresponds to the collapse load of the ground or the yield moment of the tube fundament. The side capacity comprises the resistance of the surrounding ground and the flexural strength of the tube fundament. In planning, the permiss- ible side capacity is often determined by the permissible horizontal dislocation, because deformations may grow significantly much before the side capacity corresponding to the collapse load of the ground or of the pile is exceeded. The flexural strength of the tube fundament according to the invention is extremely good, especial- ly at the upper end of the tube fundament, due to the strength of the system, which is achieved by the cooperation of the steel tubes 1, the concrete 2 casted to said tubes 1, the anchoring tubes 3a, 3b and the attachment means 4a, 4b.
In foundation of electrifying masts of a railway line, by means of the tube fundament according to the invention, comprising two adjacent steel tubes, it is possible rea- sonably to utilize the knowledge that the moment directed to an electrifying mast in the direction of the line dif- fers from the moment directed to it perpendicularly to the line. Due to this, the steel tubes 1 are driven into the ground as shown in figure 1 so that the steel tubes 1 of each fundament, after they have been driven down into the proper position, are located on opposite sides of the mast line to be erected, whereby said tubes are directed
so that a small angle is formed between them. The first steel tube 1 is driven down entirely vertically into the embankment of the railway line, outside the mast line to be erected, and the other steel tube 1 is driven down into the embankment in the area between the railway line and the mast line to be erected, whereby this other tube is driven down slightly diagonally, preferably at an angle of about 10 degrees to about 20 degrees with respect to the vertical level, so that the lower end of the steel tube 1 extends below the railway line. The anchoring tube 3b shown in Figs. 4 and 5, which is pro- vided with the attachment means 4b, is introduced into the diagonally positioned steel tube 1 filled with con- crete 2. Said attachment means 4b, having a shape of an upwards open U-beam, is welded to the upper end of the anchoring tube 3b so that said attachment means 4b, when the anchoring tube 3b is properly positioned in the diagonally positioned steel tube 1, will be positioned entirely horizontally, when directed towards the verti- cally positioned steel tube 1. Thereafter, the anchoring tube 3a, shown in Figs. 2 and 3, which is provided with the attachment means 4a, is introduced into the ver- tically positioned steel tube 1 filled with concrete 2 so that the attachment means 4a will be positioned upon the attachment means 4b. The attachment means 4a has a shape of a downwards open U-beam and is entirely perpendicular- ly welded to the upper end of the anchoring tube 3a. The attachment means 4a is so much broader than the attach- ment means 4b that said prior installed attachment means 4b fits into the attachment means 4a. The plate 6 for the attachment of the mast 5 is welded to the upper surface of the attachment means 4a. After the installation and the fine adjustment of both anchoring tubes 3a and 3b, the attachment means 4a and 4b are attached to each other, for instance by means of bolts. For this purpose, the attachment means 4b is provided preferably with three centrically located threaded fixing holes 7, and the
attachment means 4a is provided correspondingly with three centrically situated fixing apertures 8, through which the bolts to be screwed into the attachment holes 8 are brought, and due to which apertures 8 the mutual position of the attachment means 4a and 4b can practi- cally be regulated in accordance with the mutual distance of the installed steel tubes 1 of the tube fundament.
The plate 6 for the attachment of an electrifying mast has preferably a rectangular shape and is provided with holes (9) or corresponding means for the attachment of the electrifying mast 5 to the tube fundament, for instance by means of bolts. In order to prevent damages caused by corrosion, the surfaces of the attachment means 4a and 4b and the upper ends the bond tubes 3a and 3b are treated. Suitable surface treatment is for instance hot galvanizing.
In order to facilitate the driving of the steel tube 1 into the ground, a cutter shoe, known as such, is attacted to the lower end of the steel tube.
Depending on the size of the mast 5 to be erected and on the soil, the steel tube 1 to be driven into the ground <BR> <BR> <BR> may have a length of between 1 500 mm to 6 000 mm a<BR> may diameter of between 114 mm to 273 mm and a wall thickness of between 4 mm to 12 mm. Correspondigly, the anchoring tube 3a and 3b may have a length of between 1 000 mm to 2 000 mm, a diameter of between 85 mm to 170 mm and a wall thickness of between 5 mm to 25 mm. The plate 6 for the attachment of the mast 5 is to be dimensioned in accordance with the bottom plate of the mast 5 to be erected, and may e.g. for an electrifying mast 5 of a railway line have a rectangular shape and a length of 524 mm, a width of 400 mm and a thickness of 20 mm.
According to an advantageous embodiment, a steel tube 1
to be driven into the ground, used in the double-tube fundament for an electrifying mast 5 of a railway line, has a diameter of 193 mm and a wall thickness of 4 mm.
After filling of the concrete 2, an additional thick- walled steel tube 11, having a diameter of 168 mm and a wall thickness of 10 mm, is first embedded in the con- crete, and only thereafter the bond tube 3a respectively 3b together with their attachment means 4a respectively 4b, are introduced into the concrete.
In practice, the steel tubes 1 are first driven into the ground for the tube fundaments for all masts 5 to be erected and only after the driving works are carried out, the steel tubes 1 are filled with concrete 2 and the other parts 11, 3a, 3b of the tube fundament are introduced and installed in the manner described above.
In case that great moment loads are expected to be directed to the mast or the portal to be erected from different sides, it is possible according to the inven- tion to provide a tube fundament, in which said loads are taken into consideration in the number, the location and the dimensioning of the steel tubes driven in the ground.