COMPOSITE-STRUCTURE BUILDING FRAMEWORK

Abstract: A composite-structure building framework, which comprises horizontal steel girders (21) and vertical steel columns (12), which have been joined together with bolts (14). The vertical column (12a) has been placed from above against the bottom (22) or side flanges (27a) of the horizontal girder and fastened to the lower column (12b) at the corresponding point with bolts (14) going through the bottom (22) or the side flanges of the horizontal girder. Concrete reinforcements (19) are, if necessary, placed both in the U-shaped trough or box formed by the horizontal girder and inside the columns, and these spaces are filled with concrete.

Description: COMPOSI E-STRUCTURE BUILDING FRAMEWORK The object of the invention is a composite-structure building framework, which comprises horizontal steel girders and vertical steel columns, the horizontal girders and columns having mainly been prefabricated so that they can be joined at the construction site, for example, by means of bolts, after which concrete reinforcements are inserted, if necessary, into the structure, and concrete is poured inside the steel structure so that a composite structure is created by the steel framework and the concrete. According to a known method, steel is used in building frameworks in such a way that the building framework is assembled of prefabricated steel components at the construction site. This kind of construction method is economical, particularly in multi-storey buildings. Components to be assembled at the construction site can then be prefabricated in favourable production conditions, for example, at an engineering workshop, when high quality and dimensional accuracy of components can be achieved. In fact this is one of the greatest advantages of a prefabricated steel framework. Although such a steel framework requires prior planning, the use of accurately dimensioned construction components substantially speeds up the erection of a building framework and other outfitting of the frame at the construction site. One solution for a steel structure is disclosed in the applicant's previous international patent application no. PCT/FI93/00286, to which Finnish patent application 950054 corresponds. In it, the building framework consists mainly of widely available, box-shaped steel profile components. In this case, steel columns made of standard tubular girders are used in the building framework. The horizontal girders are so-called Delta-girders or HQ-girders, for example. So-called U-girders can also be used. In a Delta- girder, the side plates between upper and lower plates, i.e. the web plates, are inclined towards each other and provided with holes. On the lower edge of the girder, extending outwards from the bottom plane of the girder, there are horizontal flanges on either side of the girder. The box-shaped HQ-girder differs from the Delta-girder in that its web sections are vertical. The essential feature of the patent application PCT/FI93/00286 is that separate connecting members are used at the junction points of the building framework to join columns and girders to each other. However, it is difficult to meet the strength and other durability requirements set for a building framework by using building frameworks made entirely of steel. A structure made of concrete alone also has its own advantages and disadvantages. Therefore, a combination of a steel framework and a concrete framework, i.e. a so-called composite structure, has proved a feasible solution. In such a case, concrete is poured inside the steel frame or on the steel slab assembly forming a rigid and strong composite structure combining the advantages of both the steel structure and the concrete structure. The above-mentioned applicant's international patent application PCT/FI93/00286 discloses a composite structure consisting of a steel structure and concrete, in which columns and girders and the connecting members between them are filled with concrete. The strength and fire resistance of the structure is further increased by placing concrete reinforcements in the cast concrete inside the girders and columns in the usual manner. However, the disadvantage of this, in itself excellent, known structure is the fact that pouring concrete inside the steel structure is sometimes problematic. If the girders used are box-shaped girders, it is difficult to fill them with concrete through the openings in the web plates. It is not always possible to be certain that the girders are completely filled with concrete in such a way that a flawless composite girder structure is produced. In addition to problems in pouring concrete, the separate connecting members used at the junction points of the columns and girders in the method increase the amount of installation work needed to some extent. On the other hand, an easily manageable whole is obtained with this kind of structure, and the connecting member makes it possible to assemble intersecting girders. The object of this invention is to provide a composite- structure building framework which is simpler, stronger and more rapidly installed than known structures. The invention is characterized in - that the upper column is situated vertically mainly at the same point as the column below the horizontal girder that the horizontal girder is situated between the upper column and the lower column, and that the upper column is supported on the lower column via the horizontal girder. The horizontal girder can, at least partially, be open at the top and wide enough to allow the upper column to fit inside the horizontal girder from above against the bottom of the horizontal girder. In this case, the column below the horizontal girder has been fastened to the bottom of the horizontal girder at the same point as the upper column. With this kind of structure, the load of the column above the horizontal girder can be directed exactly at the point where the lower column is located. This kind of structure is advantageous, because no bending moment caused by eccentric loading remains in the structure. In this way, the advantages of both U-girder and box girder can be combined. The result is a structure which is easy to reinforce and to fill with concrete. It is obvious that it is clearly easier to reinforce and pour concrete into a box girder, which is at least partly open at the top, than to carry out the same procedure with a box girder. The construction relating to the invention makes it possible to have the vertical column and the horizontal girder function as a continuous structure at the junction point, which also helps to achieve the rigidity at the junction point of the column and the horizontal girder made possible by the in-situ-casting technique. With this construction, unbroken, continuous structures are formed in the building; in other words, the framework structure is rigid, without any articulated joints. According to one advantageous embodiment, the column above the horizontal girder and the column below it are joined with bolts passing through the horizontal girder bottom. In this way, the joints above and below the horizontal girder can be made simultaneously. According to another advantageous embodiment the column above the horizontal girder and the column below it have been joined together at the extension point of the horizontal girder in such a way that some of the fastening bolts go through the bottom of the first horizontal girder, and some through the bottom of the second horizontal girder. According to a further advantageous embodiment, the column is wide enough to fit outside the horizontal girder. A suitable opening is made in the column for the horizontal girder, and both the columns and the horizontal girders are joined together with bolts through external flanges. In the following, the invention is described using examples with reference to the accompanying drawings, in which Figure 1 shows the junction point of a building framework relating to the invention seen from the side. Figure 2 shows the junction point of a building framework relating to the invention seen from above. Figure 3 shows a detail of the framework in Figures 1 and 2 in perspective. Figures 4 to 6 show various profiles of the different embodiments of the horizontal girder relating to the invention. Figure 7 corresponds to Figure 3 and shows in perspective a detail of the building framework according to the second embodiment. Figure 8 corresponds to Figure 3 and shows in perspective a detail of the building framework according to the third embodiment. Figure 9 shows the structure in Figure 8 seen from the side. Figure 10 shows the structure in Figure 8 seen from above. Figure 11 corresponds to Figure 9 and shows the framework structure seen from the side according to the fourth embodiment. Figure 12 shows the structure in Figure 11 seen from above. Figure 1 shows from the side a detail of a building framework relating to the invention, in which one can see the junction point of a steel-constructed vertical column 12 and a steel horizontal girder 21. At the junction point, the vertical column 12 comprises two parts, which are column 12a above the horizontal girder 21 and column 12b below the horizontal girder 21. Flanges 17a and 17b have been attached at the ends of both parts 12a and 12b of the vertical column. According to the invention, the horizontal girder 21 used in the structure is a U-shaped girder open at the top comprising a bottom plane 22, vertical webs 23a and 23b, and mounting flanges 27a and 27b extending to the sides of the bottom. The bottom plane 22 of the horizontal girder 21 rests on the attachment flange 17b of the vertical girder 12b directly below the horizontal girder. Correspondingly, the attachment flange 17a of the vertical column 12a above the horizontal girder 22 rests directly on the bottom plane 22 of the horizontal girder 22 from above. In the structure in Figure 1, openings for bolts have been made in the bottom 22 of the horizontal girder 21, and correspondingly, openings for bolts have been made at the corresponding points on the attachment flanges 17a and 17b of the vertical column 12a and 12b, above and below the horizontal girder 21. When the horizontal girder 21 has, during the erection of a building framework, been installed in its place between the flanges 17a and 17b of vertical columns 12a and 12b, the openings for bolts in these are also in alignment with each other. In this case, flanges 17a and 17b and the horizontal girder 21 between them can be fastened to each other with bolts 14. The joint is then ready as far as the steel structure is concerned. The joint between the horizontal girders can, if necessary, be further reinforced with vertical elements made of steel plate that are bolted inside the vertical webs of the horizontal girders. After the erection of the steel structures, the structures of the intermediate floor 11 of the building are mounted in place. For this purpose, the horizontal girder 21 in Figure 1 has mounting flanges 27a and 27b extending to both sides of it. Concrete slabs or steel profiles acting as casting formwork for the intermediate floor are placed on top of these flanges 27a and 27b. When the steel structures and intermediate floor elements of the building framework are in place, concrete reinforcements are installed in both the horizontal girder 21 and the vertical column 12. In the horizontal girder 21 in Figure 1, concrete reinforcements 19 are placed both in the openings 15 made for them and also in the openings 16 made for filling with concrete. Finally, filling with concrete is performed in such a way that both the vertical column 12 and the horizontal girder 21 are filled with concrete. In Figure 1, the top surface of cast concrete is, for example, at the level that corresponds to the upper surface of the intermediate floor elements. Figure 2 shows the junction point of the framework structure in Figure 1 seen from above. In it, the column 12 has been placed at the extension 13 of the horizontal girder 21. It can be seen from Figure 2 that two fastening bolts 14 of the upper vertical column 12a go through the attachment flange 17a and the bottom 22a of the first horizontal girder 21a. Correspondingly, two bolts 14 go through the attachment flange 17a and the bottom 22b of the second horizontal girder 21b. At the junction point, underneath the vertical column 12a and below the horizontal girders 21a and 21b, at the same place, is the lower vertical column shown in Figure 1. Figure 3 shows a detail of the building framework in Figures 1 and 2 in perspective. Columns 12a and 12b have been fastened together with bolts so that the ends 21a and 21b of both horizontal girders remain between the attachment flange 17a of the upper column 12a and the corresponding attachment flange of the lower column 12b. Figure 3 also shows the concrete reinforcements 19 of the structure in place. Horizontally the concrete reinforcements 19 go inside the U-shaped horizontal girder 21 parallel with it in such a way that part of the reinforcements 19 pass along one side between the vertical web flange 23a and the vertical column 12a. Correspondingly, at the other side of the U-girder 21, the concrete reinforcements pass between the other vertical web flange 23b and column 12a. In addition, horizontal concrete reinforcements 19 have been inserted to pass through the vertical column 12a. For this purpose, openings 15 have been made in the vertical column 12a. In Figure 3, one concrete reinforcement 19 has also been taken through the opening 16 for filling with concrete. Correspondingly, vertical concrete reinforcements 19 have been positioned inside the column 12a in the framework structure in Figure 3. Horizontal and vertical intersecting concrete reinforcements 19 form, together with steel girders 21 and steel columns 12, a sufficient reinforcement. When the girder structure is filled with concrete, the rigid and strong composite structure relating to the invention is created. Figure 3 also clearly shows the advantage of the structure relating to the invention that the structure formed by columns 12 and horizontal girders 22 have no such projecting parts that require the notching of intermediate floor structures. In Figure 3, intermediate floor structures, such as profile slabs, for example, can be installed as such, resting directly on the mounting flanges 27 at the edges of the horizontal girders 22 without any notching: the vertical column 12 is out of the way of the intermediate floor structures between the vertical webs 23 of the horizontal girder 22. Figure 4 shows the profile of an embodiment relating to the invention, in which the web flanges 23a and 23b have been welded with a welded joint 24 to the bottom plane 22. In this way, a U-shaped girder structure is formed, into which the concrete can easily be poured from above. Web flanges 23a and 23b have been placed at a distance from the edge of the bottom flange 22 in such a way that mounting flanges 27a and 27b of the intermediate floor are formed outside the web flanges 23a and 23b. Figure 5 shows the profile of another embodiment of the horizontal girder 21 relating to the invention, which is asymmetric. One web flange 23b is made from the bottom plate 22 by bending it. The web flange 23a on the opposite side has been welded by means of a welded joint 24 to the bottom sheet 22. The asymmetric U-girder 21 can be used, for example, near the outer wall of a building in a place where there is an intermediate floor only on one side of the horizontal girder 21. Figure 6 shows the profile of a third embodiment of the horizontal girder 21 relating to the invention, in which no welded joints have been used. In such a case the U-girder 21 and its mounting flanges 27a and 27b have been made out of one sheet by bending. Figure 7 shows in perspective a detail of the framework according to the second embodiment. In it horizontal girders 21c and 21d are box girders, in the top surface of which openings 25a and 25b have been made. The openings 25a formed at the junction point of horizontal girders 21c and 2Id are large enough to allow the end of the vertical column 12a with its attachment flanges 17 to pass through the opening 25a to rest against the bottom of the horizontal girder 21. Vertical columns 12a and 12b are fastened at the bottom of the horizontal girder 21 in the same way as in the embodiment in Figures 1-3. Filling with concrete is easily done through the openings 25b on the upper surface of the horizontal girder 21. If more columns are needed in the structure, these openings 25b can also be used as mounting openings for columns. In addition, vertical, slab-like reinforcement flanges 26 have been fastened to the upper surface of the bottom plane of the horizontal girder in Figure 7. They have been perforated or profiled to ensure adhesion of the concrete. The horizontal girder 21 can be reinforced with reinforcement flanges 26 to such an extent that it is not always necessary to use separate horizontal concrete reinforcements at all. In any case, the amount of additional reinforcement needed is clearly lower than without reinforcement flanges 26. Figure 8 shows in perspective a detail of a building framework according to the third embodiment. In this embodiment, column 12 is wide enough to allow horizontal girder 21 to fit inside it. In the structure in Figure 8, an opening 18 for the horizontal girder 21 has been made in the column 12c above the horizontal girder 21, in which case the attachment flanges 17 remain outside the horizontal girder 21. In this case, the mounting flange 27 of the horizontal girder 21 remains between the attachment flange 17c of the upper column 12c and the attachment flange 17d of the lower column. Attachment flanges 17c, 27 and 17d are fastened together with bolts 14. In Figure 8, the column 12 has concrete reinforcements 19 and the horizontal girder 21 has reinforcement flanges 26, which also remain inside the concrete to be poured into the structure. It is also possible to furnish the column 12 with internal reinforcement flanges 26, in which case no separate concrete reinforcements are needed. Figure 9 shows the structure in Figure 8 seen from the side. It can be seen from the Figure that the opening 18 made in the column 12c matches the size of the horizontal girder 21, in such a way that the horizontal girder 12 fits into the opening that has been made. Figure 10 shows the structure in Figure 8 as seen from above. The attachment flanges 17 of the column 12c rest on the attachment flanges 27a and 27b of the horizontal girder. Figures 8-10 do not show the openings for pouring concrete, but they are, however, essential to the invention. The columns in these Figures 8-10 shall have openings for pouring concrete as necessary, in the same way as shown in Figures 1, 3 and 7. The essential is that the concrete can be poured into the structure in such a way that both the columns and the horizontal girders are full of concrete and thus form a rigid composite structure within the structure. Figure 11 shows a framework structure corresponding to Figure 1 seen from the side, and in Figure 12, the same seen from above. The difference in this embodiment is, however, that column 12e is so wide that it only just fits inside the horizontal girder 21. Therefore a slightly larger opening has to be made on the top surface of horizontal girder 21 for column 12e. The advantage of this structure is that, if necessary, the column 12e can be fastened with a bolt 14a directly to the web 23 of the horizontal girder 21. In this way, greater strength is obtained. For the final strength of the structure it has no significance, because the strength is determined by the properties of the composite structure formed by the concrete and steel. It is obvious to a person skilled in the art that the different embodiments of the invention may vary within the scope of the claims presented below.

Claims: CLAIMS 1. A composite-structure building framework, which comprises horizontal steel girders (21) and vertical steel columns (12), the horizontal girders and columns having mainly been prefabricated so that they can be joined at the construction site, for example, by means of bolts (14), after which concrete reinforcements (19) are inserted, if necessary, into the structure, and concrete is poured inside the steel structure so that a composite structure is formed by the steel framework and the concrete, c h a r a c t e r i z e d in that the upper column (12a) is situated vertically mainly at the same point as the column (12b) below the horizontal girder - that the horizontal girder (21) is situated between the upper column (12a) and the lower column (12b), and that the upper column (12a) is supported on the lower column (12b) via the horizontal girder (21). 2. A building framework as claimed in claim 1, c h a r a c t e r i z e d in that the upper column (12a) is supported from above on the bottom (22) of the horizontal girder (21) or on its side flange (27a), and that the lower column (12b) rests from below mainly on the corresponding point on the bottom (22) of the horizontal girder (21) or on its side flange (27a). 3. A building framework as claimed in claim 1 or 2, c h a r a c t e r i z e d in that the column (12a) above the horizontal girder (21) and the column (12b) below it have been joined together with bolts (14) passing through the bottom (22) of the horizontal girder. 4. A building framework as claimed in claim 1, 2 or 3, c h a r a c t e r i z e d in that the column (12a) above the horizontal girder (21) and the column (12b) below it have been joined together at the extension point (13) of the horizontal girder in such a way that some of the fastening bolts (14) go through the bottom (22a) of the first horizontal girder (21a), and that some of the fastening bolts (14) go through the bottom (22b) of the second horizontal girder (21b). 5. A building framework as claimed in any of the claims 1 to 4, c h a r a c t e r i z e d in that the horizontal girder (21) is at least partly open at the top and wide enough so that the column (12a) above it fits from above inside the horizontal girder resting against its bottom (22), and that the column (12b) below the horizontal girder (21) has been fastened to the bottom of the horizontal girder mainly at the same point as the upper column (12a). 6. A building framework as claimed in any of the claims 1 to 5, c h a r a c t e r i z e d in that the horizontal girder (21) is U-shaped so that it comprises a bottom plane (22) and webs (23), between which the column (12) can be mounted against the bottom of the horizontal girder. 7. A building framework as claimed in any of the claims 1 to 6, c h a r a c t e r i z e d in that the upper column (12a) is situated between the vertical webs (23) of the horizontal girder (21) and against both webs, in which case the column can be fastened, for example with bolts. 8. A building framework as claimed in any of the claims 1 to 7, c h a r a c t e r i z e d in that the horizontal girder (21) is a box girder, in the top surface of which openings (25) have been made to allow the vertical column (12) to be installed against the bottom of the horizontal girder. 9. A building framework as claimed in any of the claims 1 to 8, c h a r a c t e r i z e d in - that the upper column (12a) is wide enough so that at least part of it can be placed outside the horizontal girder (21) , - that the upper column (12a) is supported on the side flanges (27a) of the horizontal girder (21) from above, - and that the lower column (12b) rests on the side flanges (27a) of the horizontal girder (21) from below. 10. A building framework as claimed in any of the claims 1 to 9, c h a r a c t e r i z e d in that vertical webs (23) have been fastened to the horizontal girder (21) by welding or at least one vertical web (23) has been formed by bending from the same plate as its bottom plane (22). 11. A building framework as claimed in any of the claims 1 to 10, c h a r a c t e r i z e d in that at least one vertical reinforcement flange (26) has been fastened to the bottom plane (22) of the horizontal girder (21). AMENDED CLAIMS [received by the International Bureau on 16 July 1997 (16.07.1997); original claims 1-11 replaced by amended claims 1-10 (3 pages] 1. A composite-structure building framework, which comprises horizontal steel girders (21) and vertical steel columns (12), the horizontal girders and columns having mainly been prefabricated so that they can be joined at the construction site, for example, by means of bolts (14), after which concrete reinforcements (19) are inserted, if necessary, into the structure, and concrete is poured inside the steel structure so that a composite structure is formed by the steel framework and the concrete, where in the framework the upper column (12a) is situated vertically mainly at the same point as the column (12b) below the horizontal girder, and the horizontal girder (21) is situated between the upper column (12a) and the lower column (12b) , and which the upper column (12a) is supported on the lower column (12b) via the horizontal girder (21) , c h a r a c t e r i z e d in that the upper column (12a) is supported from above to the lower part of the of the horizontal girder (21) , as on the bottom (22) of the horizontal girder (21) or on its side flange (27a) , and that the lower column (12b) rests from below mainly on the corresponding point on the bottom (22) of the horizontal girder (21) or on its side flange (27a) . 2. A building framework as claimed in claim 1, c h a r a c t e r i z e d in that the column (12a) above the horizontal girder (21) and the column (12b) below it have been joined together with bolts (14) passing through the bottom (22) of the horizontal girder. 3. A building framework as claimed in claim 1 or 2, c h a r a c t e r i z e d in that the column (12a) above the horizontal girder (21) and the column (12b) below it have been joined together at the extension point (13) of the horizontal girder in such a way that some of the fastening bolts (14) go through the bottom (22a) of the first horizontal girder (21a) , and that some of the fastening bolts (14) go through the bottom (22b) of the second horizontal girder (21b) . 4. A building framework as claimed in claim 1, 2 or 3, c h a r a c t e r i z e d in that the horizontal girder (21) is at least partly open at the top and wide enough so that the column (12a) above it fits from above inside the horizontal girder resting against its bottom (22) , and that the column (12b) below the horizontal girder (21) has been fastened to the bottom of the horizontal girder mainly at the same point as the upper column (12a) . 5. A building framework as claimed in any of the claims 1 to 4, c h a r a c t e r i z e d in that the horizontal girder (21) is U-shaped so that it comprises a bottom plane (22) and webs (23), between which the column (12) can be mounted against the bottom of the horizontal girder. 6. A building framework as claimed in any of the claims 1 to 5, c h a r a c t e r i z e d in that the upper column (12a) is situated between the vertical webs (23) of the horizontal girder (21) and against both webs, in which case the column can be fastened, for example with bolts. 7. A building framework as claimed in any of the claims 1 to 6, c h a r a c t e r i z e d in that the horizontal girder (21) is a box girder, in the top surface of which openings (25) have been made to allow the vertical column (12) to be installed against the bottom of the horizontal girder. 8. A building framework as claimed in any of the claims 1 to 8, c h a r a c t e r i z e d in - that the upper column (12a) is wide enough so that at least part of it can be placed outside the horizontal girder (21) , - that the upper column (12a) is supported on the side flanges (27a) of the horizontal girder (21) from above, and that the lower column (12b) rests on the side flanges (27a) of the horizontal girder (21) from below. 9. A building framework as claimed in any of the claims 1 to 8, c h a r a c t e r i z e d in that vertical webs (23) have been fastened to the horizontal girder (21) by welding or at least one vertical web (23) has been formed by bending from the same plate as its bottom plane (22) . 10. A building framework as claimed in any of the claims 1 to 9, c h a r a c t e r i z e d in that at least one vertical reinforcement flange (26) has been fastened to the bottom plane (22) of the horizontal girder (21) .

Inventors: JUOLA TUOMO, TIUSANEN KIMMO, JUOLA, TUOMO, TIUSANEN, KIMMO
Applicants: JUOLA TUOMO, TIUSANEN KIMMO, JUOLA, TUOMO, TIUSANEN, KIMMO
Application year: 1997
Main classification: E04B1
IPC codes: E04B1, E04C3