Steel reinforced concrete column

Abstract

A steel reinforced concrete column for a high rise building comprises a plurality of hot-rolled steel sections extending longitudinally through the concrete column. Each of these steel sections has an outward flange with an outer surface turned outwards in the concrete column, an opposite inward flange with an outer surface turned inwards in the concrete column, and a web connecting the outward flange to the inward flange. The steel sections are arranged in the concrete column so that the outer surfaces of their inward flanges at least partially delimit therein a central concrete core with n lateral sides and a transversal cross-section that forms an n-sided polygon, n being at least equal to three, and each of then lateral sides of the central concrete core being coplanar with the outer surface of the inward flange of at least one steel section.

Claims

1. A steel reinforced concrete column for a high rise building comprising: a plurality of hot-rolled steel sections extending longitudinally through the steel reinforced concrete column, each of these steel sections having an outward flange with an outer surface turned outwards in the steel reinforced concrete column, an opposite inward flange with an outer surface turned inwards in the steel reinforced concrete column, and a central web connecting the outward flange to the inward flange; wherein: all the steel sections that extend longitudinally through the steel reinforced concrete column are arranged in the steel reinforced concrete column so that the outer surfaces of all their inward flanges delimit therein a central concrete core with n lateral sides and a transversal cross-section that forms an n-sided polygon, n being at least equal to three, each of the n lateral sides of the central concrete core being coplanar with the outer surface of the inward flange of at least one steel section of the plurality of hot-rolled steel sections; the steel reinforced concrete column has a longitudinal axis along which the steel sections extend, so that a longitudinal axis of each steel section is parallel to the longitudinal axis of the steel reinforced concrete column; and the central concrete core having a central axis coincident with the longitudinal axis of the steel reinforced concrete column, and the central axis of the central concrete core formed of only concrete or concrete with one or more transversal steel members interconnecting the inward flange of one of the plurality of hot-rolled steel sections with the inward flange of another of the plurality of hot-rolled steel sections.

2. The steel reinforced concrete column according to claim 1, wherein at least 30% of the surface of each of the n lateral sides of the concrete core are limited by the outer surface of the inward flange of one or more steel sections of the plurality of hot-rolled steel sections.

3. The steel reinforced concrete column according to claim 1, wherein: a first side of the n lateral sides of the central concrete core that is coplanar with the outer surface of the inward flange of a single steel section of the plurality of hot-rolled steel sections has the inward flange of the single steel section centred relative to the width of the first side of the central concrete core.

4. The steel reinforced concrete column according to claim 1, wherein all the inward flanges of the plurality of steel sections have the same width.

5. The steel reinforced concrete column according to claim 1, wherein all the steel sections have the same dimensions.

6. The steel reinforced concrete column according to claim 1, wherein the central concrete core has a transversal cross-section that forms an n-sided convex polygon.

7. The steel reinforced concrete column according to claim 1, wherein the central concrete core has a transversal cross-section that forms a regular polygon.

8. The steel reinforced concrete column according to claim 1, wherein the n lateral sides of the central concrete core all have the same width.

9. The steel reinforced concrete column according to claim 1 having a longitudinal axis, wherein for a side of the n lateral sides of the central concrete core that is coplanar to the outer surface of the inward flange of a single steel section of the plurality of hot-rolled steel sections, the web of the corresponding steel section has a midplane containing the longitudinal axis of the steel reinforced concrete column.

10. The steel reinforced concrete column according to claim 1, wherein the steel sections form an arrangement of which the longitudinal central axis of the steel reinforced concrete column is an axis of rotational symmetry.

11. The steel reinforced concrete column according to claim 1, wherein each inward flange comprises a multitude of shear connectors penetrating into the central concrete core.

12. The steel reinforced concrete column according to claim 1, wherein each of the steel sections comprises a multitude of shear connectors penetrating into the concrete between its outward and inward flanges and/or into the concrete surrounding the outer surface of its outward flange.

13. The steel reinforced concrete column according to claim 1, comprising longitudinal and/or transversal rebars.

14. The steel reinforced concrete column according to claim 1, comprising an outer reinforcement cage formed of longitudinal and transversal rebars and enclosing the plurality of hot-rolled steel sections.

15. The steel reinforced concrete column according to claim 14, wherein the outer reinforcement cage comprises a multitude of closed circular rebar rings connected to the longitudinal rebars.

16. The steel reinforced concrete column according to claim 1, wherein the concrete comprises an inner reinforcement cage arranged between the outer flanges and the inward flanges so as to enclose the central concrete core.

17. The steel reinforced concrete column according to claim 16, wherein the inner reinforcement cage comprises a multitude of closed circular rebar rings passing through holes in the webs of the steel sections.

18. The steel reinforced concrete column according to claim 16, wherein the inner reinforcement cage comprises cage comprises arc-shaped segments of rebar rings welded with their ends to the webs of the steel sections.

19. The steel reinforced concrete column according to claim 1, further comprising: at least two longitudinally spaced beam-to-column connection nodes for connecting thereto load bearing beams, wherein, between two successive beam-to-column connection nodes of the at least two longitudinally spaced beam-to-column connection nodes, there is no structural steel interconnecting the steel sections.

20. The steel reinforced concrete column according to claim 1, comprising at least one beam-to-column connection element on the outward flange of at least one steel section of the plurality of hot-rolled steel sections.

21. The steel reinforced concrete column according to claim 1 having a round or oval or generally curvilinear cross-section.

22. The steel reinforced concrete column according to claim 1 having a polygonal cross-section.

23. The steel reinforced concrete column according to claim 22, having a polygonal cross-section with 2n sides.

24. A steel structure for a steel reinforced concrete column comprising: a plurality of hot-rolled steel sections arranged so as to extend longitudinally through the steel structure, so that in the steel reinforced concrete column a longitudinal axis of each steel section of the plurality of hot-rolled steel sections is parallel to a longitudinal axis of the steel reinforced concrete column, each of the steel sections of the plurality of hot-rolled steel sections having an outward flange with an outer surface turned outwards in the steel structure, an opposite inward flange with an outer surface turned inwards in the steel structure, and a web connecting the outward flange to the inward flange; wherein all the steel sections that extend longitudinally through the steel structure are arranged so that: the outer surfaces of all their inward flanges delimit a central core volume with n lateral sides and a transversal cross-section that forms a n-sided polygon, n being at least equal to three; each of the n lateral sides of the central core volume being coplanar with the outer surface of the inward flange of at least one steel section of the plurality of hot-rolled steel sections, the central core volume having a central axis coincident with to the longitudinal axis of the steel reinforced concrete column, and the central axis of the central core volume is fillable with only concrete or concrete with one or more transversal steel members interconnecting the inward flange of one of the plurality of hot-rolled steel sections with the inward flange of another of the plurality of hot-rolled steel sections are located, so as to form a central concrete core of the steel reinforced concrete column.

25. The steel structure according to claim 24, further comprising: at least two longitudinally spaced beam-to-column connection nodes for connecting thereto load bearing beams, wherein between two successive beam-to-column connection nodes of the at least two longitudinally spaced beam-to-column connection nodes, there is no structural steel interconnecting the steel sections.

26. A high-rise building comprising at least one steel reinforced concrete column according to claim 1.

27. The high rise building according to claim 26, the at least one steel reinforced concrete column comprising at least two longitudinally spaced beam-to-column connection nodes, at least two successive floors supported by the steel reinforced concrete column at two successive beam-to-column connection nodes of the at least two longitudinally spaced beam-to-column connection nodes, wherein: at each of the beam-to-column connection nodes of the at least two longitudinally spaced beam-to-column connection nodes, the steel sections are structurally interconnected by means of structural steel; and between the two successive beam-to-column connection nodes, there is no structural steel interconnecting the steel sections of the plurality of hot-rolled steel sections.

28. A composite steel-concrete column for a high rise building comprising: concrete, the concrete being steel-reinforced concrete; and a plurality of hot-rolled steel sections extending longitudinally through the composite steel-concrete column, each of these steel sections having an outward flange with an outer surface turned outwards in the composite steel-concrete column, an opposite inward flange with an outer surface turned inwards in the composite steel-concrete column, and a central web connecting the outward flange to the inward flange; wherein all the steel sections that extend longitudinally through the steel reinforced concrete column are arranged in the composite steel-concrete column so that the outer surfaces of all their inward flanges delimit within the concrete a central concrete core with n lateral sides and a transversal cross-section that forms an n-sided polygon, n being at least equal to three, each of the n lateral sides of the central concrete core being coplanar with the outer surface of the inward flange of at least one steel section of the plurality of hot-rolled steel sections; wherein the steel sections block transversal expansion of the central concrete core under compression forces and thereby provide confinement of the central concrete core; wherein the composite steel-concrete column has a longitudinal axis along which the steel sections extend, so that a longitudinal axis of each steel section is parallel to the longitudinal axis of the composite steel-concrete column, and the central concrete core having a central axis coincident with to the longitudinal axis of the composite steel-concrete column, and the central axis of the central concrete core formed of only concrete or concrete with one or more transversal steel members interconnecting the inward flange of one of the plurality of hot-rolled steel sections with the inward flange of another of the plurality of hot-rolled steel sections.

29. The steel reinforced concrete column according to claim 1, wherein the steel reinforced concrete column comprises n steel sections, n being the number of lateral sides of the central concrete core.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The afore-described and other features, aspects and advantages of the invention will be better understood with regard to the following description of several embodiments of the invention and upon reference to the attached drawings, wherein:

(2) FIG. 1: is a cross-section of a first embodiment of a steel reinforced concrete column in accordance with the invention;

(3) FIG. 2: is a cross-section of a second embodiment of a steel reinforced concrete column in accordance with the invention;

(4) FIG. 3A: is an elevation view of a first embodiment of a steel concrete reinforcement cage to be used in a steel reinforced concrete column in accordance with the invention;

(5) FIG. 3B: is a cross-section of the steel concrete reinforcement cage of FIG. 3A;

(6) FIG. 4A: is an elevation view of a second embodiment of a steel concrete reinforcement cage to be used in a steel reinforced concrete column in accordance with the invention;

(7) FIG. 4B: is a cross-section of the steel concrete reinforcement cage of FIG. 4A;

(8) FIG. 5: is a cross-section of a steel section to be used in a steel reinforced concrete column in accordance with the invention;

(9) FIG. 6: is a cross-section of a third embodiment of a steel reinforced concrete column in accordance with the invention;

(10) FIG. 7: is a cross-section of a fourth embodiment of a steel reinforced concrete column in accordance with the invention;

(11) FIG. 8: is a cross-section of a fifth embodiment of a steel reinforced concrete column in accordance with the invention;

(12) FIG. 9: is a cross-section of a sixth embodiment of a steel reinforced concrete column in accordance with the invention;

(13) FIG. 10: is a cross-section of a steel reinforced concrete column as shown in FIG. 2, showing a beam-to-column connection, in which horizontal bearing beams are affixed to the steel reinforced concrete column; and

(14) FIG. 11: is an elevation view of a column as shown in FIG. 1, 2 or 6, wherein concrete and concrete reinforcement bars are not shown.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

(15) It will be understood that the following description and drawings describe embodiments of the invention by way of example and for illustration purposes. They shall not limit the scope, nature or spirit of the claimed subject matter. In the drawings, equivalent elements in different embodiments bear the same reference numbers.

(16) FIG. 1 schematically shows a cross-section of a first embodiment of a steel reinforced concrete column 10 in accordance with the invention (also designated in a shortened form as “the column 10”). The column 10 comprises a longitudinal central axis 12 and a shell surface (or outer envelope) 14. The longitudinal central axis 12 is perpendicular to the drawing plane. In the column of FIG. 1, the shell surface 14 is a right circular cylindrical surface having the longitudinal central axis 12 as cylinder axis. It follows that the column of FIG. 1 has a circular cross-section.

(17) Four hot-rolled steel sections 16.sub.1, 16.sub.2, 16.sub.3, 16.sub.4 with an H-shaped section (hereinafter also designated in a shortened form as “steel sections 16.sub.i”, where i=1, 2, 3, 4) extend longitudinally along the longitudinal central axis 12 of the column 10. Each of these column beams 16.sub.i has an inward flange 18.sub.i with a substantially planar outer surface 20.sub.i turned inwards (i.e. turned to the longitudinal central axis 12), an opposite outward flange 22.sub.i with a substantially planar outer surface 24.sub.i turned outwards (i.e. turned to the shell surface 14 of the column 10), and a central web 26.sub.i connecting the inward flange 18.sub.i to the outward flange 20.sub.i. The midplane of the web 26.sub.i of each steel section 16.sub.i contains hereby the longitudinal central axis 12 of the column 10.

(18) Preferred hot rolled steel sections are H-shaped steel sections with wide flanges, such as European HEA, HEB or HEM beams according to prEN16828-2015, EN 10025-2:2004, 10025-4:2004, or American wide flange or W-beams according to ASTM A6/A6M-14, or other hot-rolled H-shaped steel section similar to or in line with the aforementioned beams. Relevant mechanical parameters and steel grades of suitable steel sections are for example listed in European standard EN 1993-1-1:2005, Table 3.1 and clause 3.2.6.

(19) The four steel sections 16.sub.i are arranged in the column 10 so that the outer surfaces 20.sub.i of their inward flanges 18.sub.i delimit therein a central core volume 28 with four lateral sides and a transversal cross-section that forms a four-sided polygon. Reference number 30 identifies the outer limit of this central core volume 28 in the plane of the drawing, which outer limit has the form of a square in FIG. 1. In space, the outer limit (i.e. the enveloping surface) of the central core volume 28 is defined by four virtual planes, each of these four virtual planes being coplanar with the outer surfaces 20.sub.i of one of the four inward flanges 18.sub.i. The longitudinal central axis 12 of the column 10 is also the central axis of the central core volume 28.

(20) Concrete 32 (schematically represented by a dotted pattern fill) encases the four steel sections 16.sub.i and also fills the central core volume 28 delimited by the outer surfaces 20.sub.i of the inward flanges 18.sub.i of the four steel sections 16.sub.i. Consequently, the column 10 comprises a central concrete core 28′ with four lateral sides and a transversal cross-section that forms a four-sided polygon, more particularly a square, wherein each of the four lateral sides of the central concrete core 28′ is coplanar with the outer surface 20.sub.i of the inward flange of one of the steel section 16.sub.i.

(21) It follows that confinement of the central concrete core 28′, which is usually solely provided by external reinforced concrete layers, is improved by a specific arrangement of the inward flanges 18.sub.i of the steel sections 16.sub.i. This confinement very efficiently blocks a transversal expansion of the concrete under compression forces. As a result of the improved confinement of the concrete core 28′, a 3D stress state is developed in the concrete core which increases the bearing capacity and ductility of the steel reinforced concrete column 10. Crack expansion and growth are minimized in the axially compressed concrete core. It remains to be noted that the confinement effect is not (yet) taken into consideration in the design codes, but it surely gives an extra safety to the user.

(22) Suitable concrete to be used for encasing the hot-rolled steel sections and filling the central core volume 28 is for example in accordance with European standard EN 1992-1-1:2004 Table 3.1 or with equivalent other standards. If high strength steel material is used for the steel sections, then it is recommended to have high strength concrete material too.

(23) To achieve a sufficient confinement of the central concrete core 28′, at least 30% of the surface of each of the four lateral sides of the concrete core 28′ shall be limited by the outer surface 20.sub.i of the inward flange 18.sub.i of the respective steel section 16.sub.i. In FIG. 1, each of the inward flanges 18.sub.i is centrally located on the respective side of the central concrete core 28′ and limits about 78% of the surface of this side. In other words, the central concrete core 28′ is limited by the inward flanges 18.sub.i over about 78% of its perimeter surface 30.

(24) Combining FIG. 5 with FIG. 1, it will be understood that each inward flange 18.sub.i preferably comprises a multitude of shear connectors 34 protruding from its outer surface 20.sub.i. These shear connectors 34 deeply penetrate into the central concrete core 28′. As a consequence, the central concrete core 28′ is fully bonded to the four inward flanges 18.sub.i of the steel sections 16.sub.i, i.e. the connectors fully transfer shear stresses at the flange-concrete core interfaces. It follows that a composite steel concrete column 10 is formed that takes full advantage of the high compressive strength of the confined central concrete core 28′ and of the high tensile and compressive strength of the steel sections 16.sub.i.

(25) As solely illustrated in FIG. 5, each of the steel sections 16.sub.i may further comprise shear connectors 36 penetrating into the concrete 32 between its outward flange 22.sub.i and its inward flange 18.sub.i and/or shear connectors 38 penetrating into the concrete 32 surrounding the outer surface 24.sub.i of its outward flange 22.sub.1. All the shear connectors 34, 36, 38 shown in the drawings are headed shear studs, but it is not excluded to use other types of shear connectors, as long as they are capable of properly transferring the shear stresses at the respective concrete-steel interfaces.

(26) In FIG. 1, reference number 40 identifies an outer reinforcement cage surrounding the four steel sections 16.sub.i in the concrete 32. A preferred embodiment of such a concrete reinforcement cage 40 is illustrated by FIGS. 4A and 4B, wherein a side view thereof is shown in FIG. 4A and a cross-section thereof is shown in FIG. 4B. In this preferred embodiment, the concrete reinforcement cage 40 comprises reinforcement bars 42 longitudinally extending through the column 10 (also called longitudinal rebars 42) and closed circular reinforcement rings 44 (also called closed circular rebar rings). The closed circular reinforcement rings 44 are manufactured from at least one rebar, which is bent to have the shape of a circular ring, which ring is then closed by welding together the two ends of the rebar. The closed circular reinforcement rings 44, which are in the column 10 preferably parallel to a horizontal plane and have their centre located on the longitudinal central axis 12, are secured to all or some of the longitudinal rebars 42 preferably by welding, or alternatively by mechanical connections, such as e.g. tying steel wire or mechanical couplers. Geometrical and material characteristics of the steel rebars are defined for example in EN 1992-1-1:2004, EN 10080, table 6, and EN 1992-1-1:2004, section 3.2.2. (3). It will be appreciated that the closed circular rebar rings 44 efficiently oppose a bursting of the axially compressed concrete 32 by being capable of absorbing substantial circumferential tension stresses (similar to a cylindrical wall of a pressure vessel). FIGS. 3A and 3B show an alternative embodiment of the outer reinforcement cage 40. In this embodiment, a continuous rebar 48 is wound in a helical form around the longitudinal rebars 42. The helically wound continuous rebar 48 is secured to all or some of the longitudinal rebars 42 preferably by welding, or alternatively by mechanical connections, such as e.g. tying steel wire or mechanical couplers. It remains to be noted that the outer concrete reinforcement cage 40 warrants an outer confinement of a peripheral concrete layer encaging the steel sections 16.sub.i. It opposes in particular a bulging of this peripheral concrete layer under axial compression forces, so that this peripheral concrete layer may contribute up to higher loads to the bearing capacity of the steel reinforced concrete column 10.

(27) Reference number 50 identifies an inner concrete reinforcement cage arranged between the outer flanges 22.sub.i and the inward flanges 18.sub.i so as to enclose the central concrete core 28′. Preferred embodiments of this inner concrete reinforcement cage 50 are also illustrated by FIG. 3A, 3B and FIG. 4A, 4B. Just as the outer reinforcement cage 40, the inner reinforcement cage 50 advantageously comprises vertical reinforcement bars 52 (also called longitudinal rebars 52) and closed circular reinforcement rings 54 as shown in FIG. 4A and FIG. 4B or a continuous rebar 58 that is wound in a helical form around the longitudinal rebars 52 as shown in FIG. 3A and FIG. 3B. The closed circular reinforcement rings 54 and the helically wound continuous rebar 58 advantageously pass through small holes drilled into the webs 26.sub.i. Alternatively, to avoid drilling of holes into the webs 26.sub.i, a closed circular reinforcement ring 54 may be replaced by four arcs of a circle, wherein the ends of each of these arcs are welded to two adjacent webs 26.sub.i. It will be appreciated that the inner concrete reinforcement cage 50 warrants in particular a confinement of an intermediate concrete layer immediately surrounding the central concrete core 28′. It thereby blocks a transversal expansion of the concrete under compression forces, so that this intermediate concrete layer may contribute up to higher loads to the bearing capacity of the steel reinforced concrete column 10.

(28) It remains to be noted that an embodiment with four steel sections 16.sub.i in a cross-shaped arrangement as shown FIG. 1, but also the embodiments of FIGS. 2 and 6 described hereinafter, are of particular interest, if the column 10 has to support horizontal bearing beams arranged according to two perpendicular directions, which is the most common case.

(29) The column 10 of FIG. 2 distinguishes over the column 10 of FIG. 1 mainly by the following features. It has a square-shaped cross-section (instead of a circular cross-section), wherein its shell surface comprises four planar side surfaces 14.sub.i, which are basically parallel to the outer surfaces 24.sub.i of the four outward flanges 22i. Each of the inward flanges 18.sub.i limits about 52% of the surface of the respective side of the 4-sided central concrete core 28′. In other words, the 4-sided central concrete core 28′ is limited by the inward flanges 18.sub.i over about 52% of its perimeter surface 30. The outer concrete reinforcement cage 40′ and the inner concrete reinforcement cage 50′ comprise closed reinforcement rings 44′ that are square-shaped. Rebar corner brackets 60 stiffen the square-shaped reinforcement rings 44′, so that they are better suited for opposing a bulging of the concrete 32 under axial compression forces. This embodiment with square-shaped reinforcement rings 44′ remains however less efficient for reducing a bulging of the concrete 32 than the embodiment with closed circular reinforcement rings 44.

(30) The column 10 of FIG. 6 distinguishes over the column 10 of FIG. 1 by mainly the following features. It has an octagonal cross-section, wherein its shell surface comprises eight planar side surfaces 14.sub.i, of which every second side surface is basically parallel to the outer surface 24.sub.i of one of the four outward flanges 22.sub.i. Each of the inward flanges 18.sub.i limits about 52% of the surface of the respective side of the central concrete core 28′. In other words, the central concrete core 28′ is limited by the inward flanges 18.sub.i over about 52% of its perimeter surface 30. It is to be noted that closed circular reinforcement rings 44 fit very well in the octagonal section of the column 10, in which the concrete is much better used than in the column of FIG. 2.

(31) The column 10 of FIG. 7 distinguishes over the column 10 of FIG. 1 by mainly the following features. It only includes three steel sections 16.sub.i confining a central concrete core 28′ that has a triangular cross-section 30′. The column 10 as a whole has a hexagonal cross-section, wherein its shell surface comprises three small planar side surfaces 14.sub.1, 14.sub.2, 14.sub.3, which are basically parallel to the outer surfaces 24.sub.i of the three outward flange 22.sub.i, and which alternate with three large planar side surfaces 14.sub.4, 14.sub.5, 14.sub.6 (“large” and “small” referring here to the width of the side surfaces). Each of the inward flanges 18.sub.i covers about 75% of the surface of one of the three sides of the central concrete core 28′. The outer concrete reinforcement cage 40″ comprises hexagonal reinforcement rings 44″ having a similar outline as the hexagonal cross-section of the column 10. Such a column 10 is of particular interest if it has to support three horizontal beams arranged according to three different directions (here three directions mutually separated by angles of) 120°. (It remains to be noted that in FIG. 7 the longitudinal rebars are not shown.)

(32) The column 10 of FIG. 8 distinguishes over the column 10 of FIG. 6 by mainly the following features. It includes five steel sections 16.sub.i that confine a central concrete core 28′ having a pentagonal cross-section 30″. The column 10 as a whole has a decagonal cross-section, wherein its shell surface comprises ten planar side surfaces 14.sub.i, of which every second surface is basically parallel to the outer surface 24.sub.i of one of the five outward flange 22.sub.i. Each of the inward flanges 18.sub.i covers about 93% of the surface of the respective side of the central concrete core 28′. In other words, the central concrete core 28′ is limited by the inward flanges 18.sub.i over about 93% of its perimeter surface 30″. Such an embodiment is of particular interest, if the column 10 has to support five horizontal beams arranged according to five different directions (here five directions separated by angles of 72°). (It remains to be noted that in FIG. 8 the longitudinal rebars are not shown.)

(33) The column 10 of FIG. 9 distinguishes over the column 10 of FIG. 2 by mainly the following features. Along each side of the central concrete core 28′, which also has a square-shaped cross-section 30, are arranged the inward flanges 18.sub.i, 18′.sub.i of a pair of steel sections 16.sub.i, 16′.sub.i. The two inward flanges 18.sub.i, 18′.sub.i limit about 85% of the surface of the respective side of the central concrete core 28′. Such an embodiment is of particular interest, if the column 10 has to support two parallel horizontal bearing beams on each of its four sides or if a particularly strong steel reinforced concrete column is required. Arranging the inward flanges 18.sub.i of more than one steel sections 16.sub.i along a side of the central concrete core 28′ allows to design larger concrete cores 28′ and, consequently, larger columns despite a limitation of the flange width of the commercially available steel sections.

(34) In a further embodiment of the column (not shown), which comprises six steel sections and in which the central concrete core has a rectangular cross-section with two long sides and two short sides, the inward flanges of two steel sections are arranged along each of the two long sides and the inward flange of one steel section is arranged along each of the two short sides. Such an embodiment is of particular interest, if the column has to support two parallel horizontal bearing beams along a first direction and single (or no) horizontal bearing beams according to a second direction.

(35) In all embodiments shown in the drawings, all the steel sections 16.sub.i have the same dimensions and have inward flanges, respectively outward flanges having the same width. However, it is not excluded to have in the same steel reinforced concrete column: smaller and larger steel sections 16.sub.i; steel sections 16.sub.i having inward flanges, respectively outward flanges with different widths.

(36) In all embodiments shown in the drawings, the n sides of the central concrete core 28′ all have the same width. However, it is not excluded to have a central concrete core whose sides have different widths. This would e.g. be the case for a central concrete core having a rectangular cross-section or a cross-section that is an irregular polygon.

(37) In the embodiments of FIGS. 1, 2, 6, 7 and 8, the web of each of the steel sections 16.sub.i has a midplane containing the longitudinal central axis 12 of the column 10. As shown e.g. by FIG. 9, this is however not necessarily the case.

(38) While the columns shown in the drawings either have a circular, square-shaped, hexagonal, octagonal or decagonal cross-section, it will be understood that a column in accordance with the invention may have any kind of cross-section, including, for example: rectangular, cross-shaped and oval cross-sections, cross-sections that are regular or irregular polygons, cross-sections composed of curved lines etc.

(39) It will further be understood that the cross-section of the column may decrease with the height. In such a case, the cross-section of the central concrete core may also decrease in the same proportion, so that the inward flanges of the steel sections may not be parallel to the longitudinal central axis of the column.

(40) FIG. 10 is cross-section of a column 10 as shown in FIG. 2, more particular at a so-called beam-to-column connection node 70, where—at a specific vertical location or level along the column 10—a horizontal bearing beam 72.sub.i is secured to each of the outward flanges 22.sub.i of the vertical column 10. Such horizontal bearing beams 72.sub.i support e.g. a floor in a high rise building. Arrow 74 points to optional transversal structural steel advantageously interconnecting the inward flanges 18.sub.i at the connection node 70, at the same level where the horizontal bearing beams 72.sub.i are connected to the outward flanges 22.sub.i of the column 10.

(41) FIG. 11 is an elevation view of a column as shown in FIG. 1, 2 or 6, wherein concrete and concrete reinforcement steel are not shown. This column 10 comprises at least two longitudinally spaced beam-to-column connection nodes 70, 70′ as shown in FIG. 10, for supporting two successive floors. It will be noted that between the two longitudinally spaced beam-to-column connection nodes 70, 70′ there is no structural steel interconnecting the steel sections 16.sub.i. In other words, between the two longitudinally spaced connection nodes 70, 70′ of the column 10, the steel sections 16.sub.i are structurally interconnected exclusively by the steel reinforced concrete 32.

(42) While the present invention has been described more specifically with regard to a steel reinforced concrete column for a high rise building, it will be understood that a steel reinforced concrete column in accordance with the invention may also be used in nonbuilding structures such as e.g. huge halls, platforms, bridges, pylons etc.

(43) TABLE-US-00001 Reference signs list 10 steel reinforced concrete column 12 longitudinal central axis of 10 14 shell surface of 10 14.sub.i side surfaces of 14 16.sub.i hot-rolled steel section 18.sub.i inward flange of 16.sub.i 20.sub.i outer surface of 18.sub.i 22.sub.i outward flange of 16.sub.i 24.sub.i outer surface of 22.sub.i 26.sub.i web of 16.sub.i 28 n-sided central core volume 28' n-sided central concrete core (= 28 filled with concrete) 30 outer limit of 28 (= perimeter surface of 28’) 32 concrete 34 shear connector 36 shear connector 38 shear connector 40 outer reinforcement cage 42 vertical reinforcement bar (vertical rebar) 44 closed circular reinforcement ring 44' closed square-shaped reinforcement ring 46 mesh of 40 48 helically wound continuous rebar 50 inner reinforcement cage 52 vertical reinforcement bars 54 closed circular reinforcement ring 58 helically wound continuous rebar 60 corner bracket 70, 70' beam-to-column connection node of 10 72.sub.i horizontal bearing beam 74 transversal structural steel interconnecting 18