EP1441083A2

EP1441083A2 - Method of joining beam and a beam joint

Info

Publication number: EP1441083A2
Application number: EP04100106A
Authority: EP
Inventors: Erkki Mäki
Original assignee: Megasiirto Oy
Current assignee: Megasiirto Oy
Priority date: 2003-01-17
Filing date: 2004-01-15
Publication date: 2004-07-28
Also published as: FI20030074A0; EP1441083A3; FI20030074A; FI118927B

Abstract

The invention relates to a method of forming a beam joint and to a beam joint. In the joint, the flanges (2a, 2b) of the beams (1) are connected with a connecting piece (6). Protrusions (4) are formed in the flanges (2a, 2b) of the beams (1) to be joined. The connecting piece (6) connecting the flanges (2a, 2b) comprises recesses at the points corresponding to the protrusions (4) of the flange. Thus, owing to the effect of the protrusions (4) of the flange and the recesses of the connecting piece (6), the beam joint becomes torsion rigid.

Description

BACKGROUND OF THE INVENTION

The invention relates to a method of forming a beam joint.
Further, the invention relates to a beam joint for joining beams together.
Long beams are needed for several different objects of application. For example, when a new underbridge is made for an existing railway, the end-bearing piles are positioned in place, and transfer beams are arranged upon the end-bearing piles in the transverse direction of the railway rails. Upon the transfer beams, adjacent the railway, a new bridge of reinforced concrete, for example, is arranged. After this, a portion of the length of the bridge is removed from the railway, and the bridge is transferred along the transfer beams to its proper place at the railway. When the bridge has been arranged in its place, the excavations for the underpass can be started under the bridge. Such a solution is described in FI patents 96 231, 97 073 and 108 257, for example. Due to the width of the bridge, for instance, the transfer distance may sometimes be rather long, in which case the transfer beam must also be fairly long. Due to the transfer of the beam and, on the other hand, its mounting, it is most often not reasonable to form one beam to be as long as the transfer distance requires. In such a case, therefore, the transfer beam is formed of two or more successive beams joined to each other, the beams being joined together with a beam joint. After the transfer, the transfer beam is typically not left in its place under the bridge, but the bridge remains supported by other support structures and the transfer beam is removed. Therefore, too, the joints of the transfer beam are dismounted.
It is known to form a beam joint by welding the steel beams together by their ends. However, making a welding joint takes rather a long time. Further, it is difficult and laborious to dismount the welding joint, and the dismounting point of the joint will be rough and uneven.
Further, it is known to form the beam joint of such beams that have two flanges and a web plate between them in such a way that the beams are welded together at the point of the flanges. On both sides of the web plates of the beam, connecting plates are arranged that are connected firmly against the beam webs, for instance by joining the connecting plates together with bolts. Upon making such a beam joint, too, welding is required, which takes rather a long time. Still further, also in this case the dismounting of the beam joint is difficult, and the dismounting causes unevenness at the end of the beams. The shearing forces affecting the joint by means of the connecting plates can be transferred from one beam to another reliably, but making the joint torsion rigid is fairly difficult.
Further, a beam joint is known in which beams provided with an upper and a lower flange and a web plate between them are joined to each other in such a way that the upper flanges of the beams are welded together. To connect the beam webs, connecting pieces are welded on both sides of the web plates. Lugs are attached to the lower flanges, and a thread bar is arranged from the lug of the first beam to the lug of the second beam. Nuts are arranged in the thread bar, the intention being to keep the lower flanges together by means of the thread bar. If force is directed above such a joint, the thread bar tends to stretch, in which case it is very difficult to make the joint torsion rigid. Therefore, when using transfer beams, for example, the positions of the end-bearing piles must be defined in such a way that a end-bearing pile is arranged at the point of the joint or at least in its immediate vicinity. Further, making a joint requires time-consuming welding, and the dismounting of the joint causes unevenness on the upper surface of the beam. All in all, the joint is rather cumbersome and complex.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is to provide a reasonably simple and rigid beam joint.
The method according to the invention is characterized by arranging protrusions in the flanges of beams to be joined; forming a connecting piece comprising a part that becomes positioned against the beam flange and has recesses at the points corresponding to the beam protrusions; positioning the beam ends against each other; positioning the connecting piece in its place; and attaching the connecting piece to the beams to be joined.
Further, the beam joint according to the invention is characterized in that there are protrusions in the flanges of the beams; that the beam joint comprises a connecting piece having a part that is positioned against the beam flange and has recesses at the points corresponding to the protrusions; and that the beam joint comprises attaching means for attaching the connecting piece to the beams.
An essential idea of the invention is that protrusions are formed in the flanges of the beams to be joined. In the joint, the beam flanges are connected with a connecting piece. The connecting piece connecting the flanges comprises recesses at the points corresponding to the protrusions of the beam flange. Thus, due to the effect of the protrusions of the flange and the recesses of the connecting piece, the beam joint becomes torsion rigid.
An advantage of the invention is that the beam joint is firm, stabile and rigid. Further, it is quick and easy to form the beam joint. It is also easy to dismount the joint, if required. The welding work required for the assembly and structure can be carried out in the factory before the beams are joined to each other at the construction site. When the beams are actually joined to each other, it may be the case that no welding at all is required. All in all, it is simple, quick and easy to form the beam joint.
The connecting piece can be formed uniform so that it comprises both a part that becomes positioned against the beam web and a part that becomes positioned against the beam flanges. Thus, the connecting piece only needs to be attached at the beam web, and the part that becomes positioned against the webs transfers the shearing forces from one beam to another. A uniform connecting piece allows the joint to be formed particularly easily, simply and securely. Further, a uniform connecting piece thus allows the shearing forces to be transferred and a torsion rigid joint to be provided. The idea of one embodiment is that the beams to be joined comprise two flanges that are connected with a web. The connecting piece can thus be formed in such a way that it has parts both against the web and against both flanges. The idea of a second embodiment is that the beam joint comprises a connecting piece on both sides of the beams to be joined and that the connecting pieces are joined to each other through the beam webs with bolts. The idea of a third embodiment is that the protrusions formed in the flanges are wedge-shaped, the recesses of the connecting piece being correspondingly wedge-shaped. Thus, it is easy to insert the connecting piece to its proper place, and the connecting piece becomes positioned accurately at the correct point when it is mounted, guided by the wedge-shaped protrusions and the recesses. The idea of a fourth embodiment is that the recesses of the connecting piece are formed through the wall of the connecting piece in such a way that the connecting piece comprises openings. The idea of a fifth embodiment is that the openings of the connecting piece are dimensioned in such a way that they extend further than the beam protrusions and over the beam flange. Thus, the connecting piece can be easily removed by means of an iron bar, for example, when the beam joint is dismounted.

BRIEF DESCRIPTION OF THE FIGURES

The invention is explained in more detail in the attached drawings, in which
Figure 1 shows schematically an end view of a beam;
Figure 2 shows schematically a side view of two beams having ends against each other;
Figure 3 shows a cross-section of the solution according to Figure 2 along line A-A of Figure 2;
Figure 4 shows schematically an end view of a connecting piece;
Figure 5 shows a side view of the connecting piece according to Figure 4;
Figure 6 shows a cross-section of a connecting piece according to Figure 5 along line B-B of Figure 5;
Figure 7 shows schematically an end view of a beam joint;
Figure 8 shows a side view of the beam joint according to Figure 7;
Figure 9 shows a cross-section of a beam joint according to Figure 8 along line C-C of Figure 8.
For the sake of clarity, the invention is shown simplified in the figures. Similar parts are denoted with the same reference numerals.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a beam 1. The beam 1 comprises an upper flange 2a and a lower flange 2b as well as a web 3 between them. Such a beam is also called an H beam or an I beam. The beam 1 is typically made of steel. Figure 1 also shows protrusions 4 that are arranged in the vicinity of the end of the beam 1 for a beam joint. The protrusions 4 are preferably also made of steel, being preferably welded into the lower flange 2b of the beam 1. In connection with the beam 1, there may be lifting lugs and/or additional web plates welded thereto. However, the additional web plates do not extend to that portion in the beam ends where protrusions 4 have been arranged. For the sake of clarity, the attached figure does not show the lifting lugs or additional web plates.
Figure 2 shows two beams 1 with the ends arranged against each other. In Figure 2, only a small portion, i.e. an end, can be seen of both beams 1, a beam joint being formed at this end. The length of the beam 1 can vary between 4 to 15 meters, for example. The height of the beam may also vary between 300 to 1 000 millimetres, for example. Figures 2 and 3 indicate that several successive protrusions 4 have been attached to the lower flange 2b on both sides of the web 3. The protrusions 4 are wedge-shaped, in other words the portions on the side of the web 3 are wider than the ones at the outer edge of the flange 2b. The web 3 is further provided with holes 5 to attach a connecting piece by means of bolts.
Figure 4 shows a connecting piece 6. The connecting piece 6 is formed such that it has an upper part 6a, a lower part 6b and a back piece 6c. The upper part 6a of the connecting piece 6 becomes positioned against the upper flange 2a of the beam 2. Correspondingly, the lower part 6b of the connecting piece 6 becomes positioned against the lower flange 2b of the beam 1, and the back piece 6c of the connecting piece 6 becomes positioned against the web 3 of the beam 1. To reinforce the connecting piece 6 and to increase its rigidity, it has support parts 7 welded into it. The support parts 7 are provided with a lift opening 8, from which the connecting piece 6 can be lifted and transferred. The lift openings 8 allow even rather a heavy connecting piece 6 to be handled relatively easily.
Figure 5 indicates that the connecting piece 6 is provided with holes 9 at corresponding points where the beams 1 are provided with holes 5. When the connecting piece 6 is arranged in connection with the beams 1, bolts are inserted through the holes 5 and 9. As becomes obvious from Figures 5 and 6, the connecting piece 6 comprises openings 10 in the lower part 6b. The openings 10 extend to the lower part of the back piece 6c of the connecting piece 6. Thus, the connecting piece 6 can be inserted in the lateral direction between the upper flange 2a and the lower flange 2b of the beam 1. Thus, it is simple and easy to mount the connecting piece 6. Further, the mounting is facilitated by also the openings 10 being wedge-shaped, i.e. their shape corresponding to the shape of the protrusions 4. Due to the wedge-shape, the connecting piece 6 needs not fall exactly at the right place at the initial stage of the mounting, but it suffices that the tip part of the protrusions 4 falls at the point of the rear part of the corresponding opening 10. When the connecting piece 6 is inserted in place, the connecting piece 6 makes its way to the exactly right point, guided by the wedge-shaped protrusions 4 and the openings 10.
Figures 7, 8 and 9 show the structure of a complete beam joint. As mentioned, the connecting piece 6 is connected to the beam 1 with bolts 11. In addition to or instead of a bolted joint, another joint, such as a welded joint, can be used. With regard to the mounting speed and the dismountability of the beam joint, however, a bolted joint is preferable. If the forces directed to the beam joint are not very great, it may in some cases be sufficient that the connecting piece 6 is arranged only on one side of the beams 1, in other words that the beam joint has only one connecting piece 6. Most preferably, however, the beam joint is provided symmetrically with two connecting pieces 6; in other words the connecting piece 6 is arranged on both sides of the web 3. In such a case, the connecting pieces 6 are connected to each other with bolts 11 in such a way that a web 3 remains between them.
Thus, upon forming a beam joint, protrusions 4 are arranged in the flange of the beams 1, and a connecting piece 6 is formed. As mentioned earlier, these measures can be taken in advance in factory conditions. When a beam joint is formed at the construction site, the ends of the beams 1 are positioned against each other, and the connecting pieces 6 are inserted in the lateral direction to their proper places. Subsequently, the connecting pieces 6 are connected immovably to the beams 1.
In a complete beam joint, the back piece 6c of the connecting piece 6 transfers the shearing forces from one beam to another. Transferring the shearing forces means that if the first beam is subjected to a force that presses it downwards, the connecting part 6 transfers the force to affect also the second beam downwards, which second beam is connected to the first beam with a beam joint. The beam joint shown in the figure is particularly applicable to extending transfer beams. In connection with the use of transfer beams, torque is generated in the beam joint, tending to cause the lower flanges 2b of the beams 1 to separate from each other. This tendency is particularly intense in a case where the load to be transferred is at the point of the joint. Thus, the force caused by the load on the upper surface tends to bend the beam in such a way that the point furthest away from the upper surface, i.e. the point where the torque is greatest, is subjected to a force that tends to stretch the lower flange. Owing to the protrusions 4 and the openings 10, the connecting piece 6 can prevent the effect of the torque that tends to separate the lower flanges 2b of the torque from each other, in other words the joint is torsion rigid.
In the use of transfer beams, a sliding surface can further be arranged above the upper flange 2a. The sliding surface is formed of a stainless cold-rolled steel plate, for example. Upon making the beam joint, the sliding surfaces of different beams can be welded together. However, this welding seam does not have a force-transferring function, but the purpose of the welding is to smooth the seam between the sliding surfaces. The seam must be smooth in order to prevent damage of the slide bearing that slides upon the sliding surface. Further, the sliding surface is relatively thin compared with the upper flange 2a, for example. The thickness of the sliding surface may be, for instance, 5 mm. Thus, making such a welding seam does not take unreasonably long. Furthermore, when the beam joint is dismounted, it is neither time-consuming nor difficult to undo the seam neatly. Otherwise, the beam joint is dismounted by removing the bolts 11 and by pulling out the connecting pieces 6 from between the upper flange 2a and the lower flange 2b. If the openings 10 are arranged to extend further than the protrusions 4 and lower flanges 2b, the removal of the connecting piece 6 can be facilitated by means of an iron bar, for example. The iron bar can be inserted through the tip of the opening 10, and it can be made rest against the lower flange 2b or another suitable support point. Thus, also the dismounting of the beam joint is quick, simple and easy.
The drawing and the related description are only intended to illustrate the idea of the invention. The details of the invention may vary within the scope of the claims. Thus, the number of protrusions 4 and openings 10 may vary as required. In the same way, the length and the thickness of the connecting piece 6 may vary as required. For example, the length of the connecting piece 6 may be 500 to 2 000 mm. Further, the connecting piece 6 may be provided with additional reinforcements. In the case of the attached figures, for instance, the lower part 6b of the connecting piece 6 could be reinforced with, for example, an additional plate remaining on its lower surface outside the lower flange 2b. Further, an extra additional reinforcement can be arranged above the lower part 6b, for instance at the middle point of the connecting piece, which reinforcement could extend for instance over two openings 10 in such a way that the ends of the reinforcement would extend to the edges of the openings 10.
In the case shown by the attached figures, the height of the protrusions 4 is greater than the thickness of the connecting piece wall. Therefore, the recesses formed in the connecting piece 6 at the points corresponding to the protrusions 4 extend through the wall of the connecting piece 6, forming openings 10. If the height of the protrusions 4 were smaller than the thickness of the connecting piece wall, no openings would need to be formed by the recesses.
When a beam joint is used for extending transfer beams, it is most preferable to arrange the protrusions 4 in the lower flange 2b, because, as described above, the effect of the torque is most powerful specifically at the lower flanges 2. When the protrusions 4 are arranged only in the lower flange 2b, the upper part 6a of the connecting piece 6 may be narrower than the lower part 6b of the connecting piece 6, as illustrated in Figure 4, for example. The beam joint can be formed in such a way that the protrusions 4 and the recesses in the connecting piece are formed in the upper flange 2a. Thus, the beam joint can be applied for example to extending cantilever beams, where the torque affects most powerfully the upper flange 2a, stretching it. On the other hand, the protrusions and the recesses can be formed both in the upper flange and the lower flange, whereby the joint can be used for an extremely wide variety of objects, irrespective of how the forces affect the beams. The beam joint is thus particularly well applicable to extending transfer beams, but it can also be used for extending other beams, such as bridge beams, such beams as girders used in buildings, or the like. If there is no intention to dismount the beam joint or if a lot of time and different methods can be used for dismounting, it is also possible to use welded joints, for instance instead of or in addition to bolted joints, when the beam is extended. Also other feasible joint manners can be used. Still further, the beam joint can be used for joining beams of different heights. Thus, for example when using transfer beams, the upper flanges of the beams to be extended are arranged at the same level, the lower flanges being positioned at different levels. Thus, the lower part 6b of the connecting piece is formed such that its first end is higher than the second end.

Claims

A method of forming a beam joint, characterized by arranging protrusions (4) in the flanges (2a, 2b) of beams (1) to be joined; forming a connecting piece (6) comprising a part that becomes positioned against the beam (1) flange (2a, 2b) and has recesses at the points corresponding to the beam protrusions (4); positioning the beam (1) ends against each other; positioning the connecting piece (6) in its place; and attaching the connecting piece (6) to the beams (1) to be joined.
A method according to claim 1, characterized by arranging at least two connecting pieces (6) in the beam joint in such a way that at least one connecting piece (6) is positioned on both sides of the beams (1 ).
A method according to claim 1 or 2, characterized by forming the connecting piece (6) such that it has a part that becomes positioned against the web (3) of the beam (1) and a part that becomes positioned against the flange (2a, 2b) of the beam (1).
A method according to any one of the preceding claims, characterized by the connecting piece (6) being attached to the beams with a bolted joint.
A method according to any one of the preceding claims, characterized by the beam (1) comprising an upper flange (2a), a lower flange (2b) and a web (3) connecting them and by the connecting piece (6) comprising a part that becomes positioned against the web (3), a part that becomes positioned against the upper flange (2a) and a part that becomes positioned against the lower flange (2b), and by the connecting piece (6) being inserted to its proper place between the flanges (2a, 2b) by moving the connecting piece (6) in the lateral direction.
A method according to any one of the preceding claims, characterized by the protrusions (4) being arranged in the lower flange (2b) of the beam (1).
A method according to any one of claims 1 to 5, characterized by the beam (1) comprising an upper flange (2a) and a lower flange (2b), and the protrusions (4) being arranged in both the upper flange (2a) and the lower flange (2b).
A beam joint for joining beams (1) together, characterized in that there are protrusions (4) in the flanges (2a, 2b) of the beams (1); that the beam joint comprises a connecting piece (6) having a part that is positioned against the beam (1) flange (2a, 2b) and has recesses at the points corresponding to the protrusions (4); and that the beam joint comprises attaching means for attaching the connecting piece (6) to the beams (1 ).
A beam joint according to claim 8, characterized in that the beam joint comprises at least two connecting pieces (6) in such a way that the connecting pieces (6) are arranged on different sides of the beams (1) to be joined.
A beam joint according to claim 8 or 9, characterized in that the attaching means for attaching the connecting piece (6) to the beams is a bolt (11).
A beam joint according to any one of claims 8 to 10, characterized in that the beam (1) comprises a web (3), and that the connecting piece (6) comprises a part positioned against the flange (2a, 2b) and a part positioned against the web (3).
A beam joint according to any one of claims 8 to 11, characterized in that the beams (1) to be joined comprise an upper flange (2a), a lower flange (2b) and a web (3) connecting them, and that the connecting piece (6) comprises a part positioned against the web (3), a part positioned against the upper flange (2a) and a part positioned against the lower flange (2b).
A beam joint according to any one of claims 8 to 12, characterized in that the protrusions (4) are arranged in the lower flange (2b) of the beam (1).
A beam joint according to any one of claims 8 to 12, characterized in that the beams (1) to be joined comprise an upper flange (2a) and a lower flange (2b), and that the protrusions (4) are arranged in both the upper flange (2a) and the lower flange (2b).
A beam joint according to any one of claims 8 to 14, characterized in that the protrusions (4) and the recesses are formed wedge-shaped.
A beam joint according to any one of claims 8 to 15, characterized in that the recesses in the connecting piece (6) are formed through the wall of the connecting piece (6) in such a way that the recesses form openings (10) in the connecting piece (6).
A beam joint according to claim 16, characterized in that the openings (10) are arranged to extend further than the flange (2a, 2b).
A beam joint according to any one of claims 8 to 17, characterized in that the beams (1) to be joined are transfer beams.