Method for providing structure, steel beam, and structure
By calculating temperature distribution and using reinforcement elements, the method ensures steel beams meet fire resistance standards without fireproofing, addressing unnecessary costs in existing methods.
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- NORDEC OY
- Filing Date
- 2025-11-12
- Publication Date
- 2026-05-20
AI Technical Summary
Existing methods unnecessarily apply fireproofing to steel beams in structures, despite the beams being capable of meeting fire resistance requirements without it, leading to increased costs.
A method for determining the fire resistance of steel beams by considering the temperature distribution along the beam's length and using reinforcement elements to enhance local strength, eliminating the need for fireproofing.
Enables steel beams to meet fire resistance standards without fireproofing, reducing costs while maintaining structural integrity.
Smart Images
Figure IMGAF001_ABST
Abstract
Description
FIELD OF THE INVENTION
[0001] The present invention relates to construction and more particularly to a method for providing a structure. The present invention further concerns a steel beam and a structure.BACKGROUND OF THE INVENTION
[0002] When providing a structure comprising vertical supports and a steel beam supported by the vertical supports, the vertical supports and the steel beam are normally treated with a fireproofing treatment to fulfil the requirements of the desired fire resistance class.
[0003] However, fireproofing treatment is often added to the steel beam needlessly, because the steel beam could fulfil the requirements of the fire resistance class even without the fireproofing treatment. This is because during determining the properties of the steel beam required for the structure, the calculation of the temperature of the steel beam in the event of fire may be performed in a single point, the result of which is then used to represent the temperature of the whole steel beam. This unprecise result is then used to dimension the steel beam on which a fireproofing is added to make sure that the structure is able to withstand in the case of fire. Fireproofing the elements of the structure is expensive, adding to the costs of providing the structure.BRIEF DESCRIPTION OF THE INVENTION
[0004] An object of the present invention is to provide a method for providing a structure, a steel beam, and a structure to overcome above problems.
[0005] The objects of the invention are achieved by the method, the steel beam and the structure which are characterized by what is stated in the independent claims. The preferred embodiments of the invention are disclosed in the dependent claims.
[0006] The invention is based on the idea of providing a method for providing a structure comprising a vertical support arrangement and a steel beam supported by the vertical support arrangement, wherein the method comprises a) providing a vertical support arrangement comprising at least three vertical supports for supporting a horizontal beam in vertical direction, wherein each vertical support comprises an upper surface for supporting a beam, the vertical supports are arranged in a straight line, and the distances between adjacent vertical supports differ 0 to 35 % from each other, b) providing a steel beam, wherein the steel beam is a closed hollow steel beam comprising a top flange, a bottom flange, a first web attached to the top flange and to the bottom flange, a second web attached to the top flange and to the bottom flange and spaced out from the first web, an inner space defined by the top flange, bottom flange, the first web and the second web, a first end, and a second end opposite the first end, wherein the top flange, the bottom flange, the first web and the second web extend from the first end to the second end, and wherein the steel beam contains no fireproofing, and c) supporting the steel beam in horizontal position in vertical direction by the upper surfaces of the vertical supports from the bottom flange of the steel beam; wherein providing the steel beam comprises defining a desired fire resistance class for the structure, determining an ultimate limit state and a serviceability limit state for the steel beam based on the distances between the adjacent vertical supports in the vertical support arrangement, the predetermined vertical load applied to the steel beam, and the desired fire resistance class of the structure, determining estimated properties of the steel beam based on the ultimate limit state and the serviceability limit state, calculating the temperature distribution over the length of the steel beam in the structure in the event of fire based on the standard fire curve according to ISO 834, determining the required properties of the steel beam based on the ultimate limit state, the serviceability limit state the calculated temperature distribution of the steel beam in the structure, determining modified estimated properties of the steel beam based on the estimated properties of the steel beam, the required properties of the steel beam and the presumption that no fireproofing is used in the steel beam, and selecting the steel beam based on the modified estimated properties.
[0007] The invention is also based on the idea of providing a steel beam in the form of a closed hollow steel beam comprising a top flange, a bottom flange, a first web attached to the top flange and to the bottom flange, a second web attached to the top flange and to the bottom flange and spaced out from the first web, an inner space defined by the top flange, bottom flange, the first web and the second web, a first end, and a second end opposite the first end; wherein the top flange, the bottom flange, the first web and the second web extend from the first end to the second end; the steel beam has a length between the first end and the second end; the first web comprises an outer surface facing away from the inner space; the second web comprises an outer surface facing away from the inner space; the steel beam contains no fireproofing; the steel beam comprises a reinforcement arrangement for increasing the local strength of the steel beam; the reinforcement arrangement comprises a first reinforcement element having an elongated shape, comprising a first end, a second end opposite the first end, and a midpoint halfway between the first end and the second end, and having a length between first end and the second end; the first reinforcement element is attached to the outer surface of the first web; the length of the first reinforcement element is 2 to 30 % of the length of the steel beam; and the first reinforcement element is arranged in such a way that the midpoint of the first reinforcement element is at a first distance E from the first end of the steel beam, wherein the first distance E is 20 to 80 % of the length of the steel beam.
[0008] The invention is further based on the idea of providing a structure comprising a) a vertical support arrangement (11) comprising at least three vertical supports for supporting a horizontal beam in vertical direction, wherein each vertical support comprises an upper surface for supporting a beam, the vertical supports are arranged in a straight line, and the distances between adjacent vertical supports differ 0 to 35 % from each other, b) a steel beam (12) as described above supported in horizontal position in vertical direction by the upper surfaces of the vertical supports (111, 112, 113, 114) from the bottom flange (122) of the steel beam (12).
[0009] An advantage of the invention is that the method allows taking into consideration the fact that the structure may be able to withstand fire even without fireproofing, thus allowing selecting a steel beam having no fireproofing to be used in the structure. As a result, the steel beam may be the same as with the traditional method of sizing the steel beam, or slightly stronger, for example comprising a locally placed reinforcement, while fulfilling the requirements of the fire resistance class, and the cost for fireproofing treatment is saved.BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The invention is described in detail with reference to the enclosed drawings, in which Figure 1 is a schematic side view of a structure according to some embodiments of the invention; Figure 2 is a schematic cross-sectional view of a steel beam; Figure 3 is a schematic side view of a structure according to some embodiments of the invention; Figure 4 a schematic cross-sectional view of a steel beam according to some embodiments of the invention; Figure 5 a schematic side view of a steel beam according to some embodiments of the invention; Figure 6 is a schematic side view of a structure according to some embodiments of the invention; Figure 7 a schematic side view of a steel beam according to some embodiments of the invention; and Figure 8 is a schematic side view of a structure according to some embodiments of the invention. DETAILED DESCRIPTION OF THE INVENTIONMethod
[0011] The invention relates to a method for providing a structure 1. For example, the structure is a part of a building.
[0012] The structure 1 comprises a vertical support arrangement 11 and a steel beam 12 supported by the vertical support arrangement 11.Providing vertical support arrangement
[0013] The method comprises providing a vertical support arrangement 11. The vertical support arrangement 11 comprises at least three vertical supports 111, 112, 113, 114 for supporting a horizontal beam in vertical direction. In other words, the resulting structure 1 comprises at least two spans between the vertical supports 111, 112, 113, 114.
[0014] According to some embodiments, each vertical support 111, 112, 113, 114 is independently selected from a group consisting of a pillar, a vertical wall oriented transversally to the steel beam 12, and a support beam oriented horizontally and transversally to the steel beam 12.
[0015] According to some embodiments, the vertical support arrangement 11 comprises at least four vertical supports 111, 112, 113, 114, as exemplified in Figures 3 and 8. In other words, the resulting structure 1 comprises at least three spans between the vertical supports 111, 112, 113, 114.
[0016] According to some embodiments, each vertical support 111, 112, 113, 114 contains a fireproofing. In other words, each vertical support 111, 112, 113, 114 has been treated with a fire-proofing treatment. The purpose of the fireproofing is to facilitate meeting the requirements of the fire resistance classification selected for the structure 1.
[0017] According to some alternative embodiments, if the vertical support 111, 112, 113, 114 is made of concrete or contains a composite of concrete and steel, the vertical support 111, 112, 113, 114 contains no fireproofing. This is because concrete is sufficiently fireproof in itself.
[0018] Each vertical support 111, 112, 113, 114 comprises an upper surface 1111, 1121, 1131, 1141 for supporting a beam.
[0019] The vertical supports 111, 112, 113, 114 are arranged in a straight line L. In other words, the vertical supports 111, 112, 113, 114 are arranged in such a way that the upper surfaces 1111, 1121, 1131, 1141 are arranged in the straight line L. In still other words, the vertical supports 111, 112, 113, 114 are arranged in such a way that a straight beam would be supported by the vertical supports 111, 112, 113, 114.
[0020] Each vertical support 111, 112, 113, 114 has a width of at least 75 %, preferably at least 85 %, such as at least 90 %, for example at least 95 %, of the width of the steel beam 12, wherein the width is measured horizontally in a direction perpendicular to the straight line L.
[0021] The distances D1, D2, D3 between adjacent vertical supports 111, 112, 113, 114 differ 0 to 35 %, preferably 0 to 20 %, more preferably 0 to 10 %, such as 0 to 5 %, from each other. In other words, the distances D1, D2, D3 between adjacent vertical supports 111, 112, 113, 114 are essentially identical. This is to make sure that uniform conditions are provided on both sides of the vertical support or vertical supports arranged in the middle, i.e. between the vertical supports arranged at the ends of the vertical support arrangement 11.Providing steel beam
[0022] The method comprises providing a steel beam 12. The steel beam 12 is a closed hollow steel beam, for example a welded box beam.
[0023] The steel beam 12 comprises a top flange 121, a bottom flange 122, a first web 123 attached, preferably welded, to the top flange 121 and to the bottom flange 122, and a second web 124 attached, preferably welded, to the top flange 121 and to the bottom flange 122 and spaced out from the first web 123.
[0024] The steel beam 12 comprises an inner space 127 defined by the top flange 121, bottom flange 122, the first web 123 and the second web 124. The inner space 127 is not filled, e.g. with concrete, to create a composite beam but it is left empty to maintain the lightness of the steel beam 12.
[0025] The steel beam 12 comprises a first end 125 and a second end 126 opposite the first end 125. The top flange 121, the bottom flange 122, the first web 123, and the second web 124 extend from the first end 125 to the second end 126.
[0026] The steel beam 12 contains no fireproofing. In other words, the steel beam 12 has not been treated with a fire-proofing treatment. This is to reduce the costs relating to providing the structure 1.
[0027] The steel beam 12 has a width determined as the maximum distance between the first web 123 and the second web 124.
[0028] Providing the steel beam 12 comprises defining a desired fire resistance class for the structure 1. Preferably, the fire resistance class is selected from the fire resistance classes determined in EN 13501-2. According to some embodiments, the fire resistance class of the structure 1 is selected from a group consisting of R30, R45, R60, R90 and R120, each according to EN 13501-2. In other words, the structure 1 is able to maintain its mechanical durability for 30 min, 45 min, 60 min, 90 min or 120 min, correspondingly, in the event of fire.
[0029] Providing the steel beam 12 comprises determining an ultimate limit state and a serviceability limit state for the steel beam 12. "Ultimate limit state" refers to the maximum loads or forces that a structure can withstand without collapsing or experiencing any irreversible damage. Determining the ultimate limit state may contain as a factor the situation in which the structure is exposed to accidental design situations, such as fire. "Serviceability limit state" is the state of design beyond which a structure loses operationally its serviceability for the actual service load that the structure is subjected to.
[0030] The ultimate limit state and the serviceability limit state are determined based on the distances D1, D2, D3 between the adjacent vertical supports 111, 112, 113, 114 in the vertical support arrangement 11, and the predetermined vertical load applied to the steel beam 12.
[0031] The predetermined vertical load applied to the steel beam 12 depends, for example, on the intended use of the structure, the predetermined requirements for the structure and the standards determined for the structural design and development of buildings, such as Eurocodes.
[0032] Providing the steel beam 12 comprises determining estimated properties of the steel beam 12. The estimated properties of the steel beam 12 are determined based on the ultimate limit state and the serviceability limit state. This provides an estimate of the steel beam 12 required for the structure 1.
[0033] Providing the steel beam 12 comprises calculating the temperature distribution of the steel beam 12 in the structure 1, i.e. the steel beam 12 supported by the vertical support arrangement 11, according to the desired fire resistance class in the event of fire based on the standard fire curve according to ISO 834. The calculation of the temperature distribution is performed over the length of the steel beam 12. In other words, the temperature of the steel beam 12 is calculated in a plurality of points over the length of the steel beam 12. In the calculation, the materials and the thermal conductivities of the vertical supports 111, 112, 113, 114 are taken into consideration. For example, the distance between the points is 1 to 50 cm to give sufficient information about the temperature distribution. Preferably, the distance is smaller, such as 1 to 5 cm, at the location of the vertical support(s), in which the stresses to the steel beam 1 are the largest. Calculating the temperature distribution of the steel beam 12 in the event of fire allows selecting durable enough steel beam 12 for the structure that fulfils the requirements of the selected fire resistance class without using fireproofing in the steel beam 12.
[0034] Providing the steel beam 12 comprises determining the required properties of the steel beam 12. The required properties of the steel beam 12 are determined based on the ultimate limit state, the serviceability limit state, and the calculated temperature distribution of the steel beam 12 in the structure 1.
[0035] Providing the steel beam 12 comprises determining modified estimated properties of the steel beam 12 based on the estimated properties of the steel beam 12, the required properties of the steel beam 12 and the presumption that no fireproofing is used in the steel beam 12. In other words, the estimation of the steel beam 12 is modified based on the knowledge obtained from calculating the temperature distribution of the steel beam 12 in the structure 1.
[0036] Providing the steel beam 12 comprises selecting the steel beam 12 based on the modified estimated properties.
[0037] According to some embodiments, the steel beam 12 is a steel beam as described below under "Steel beam".Embodiments with three vertical supports
[0038] The vertical support arrangement 11 comprises a first vertical support 111, a second vertical support 112 and a third vertical support 113. In other words, resulting structure 1 comprises two spans between the vertical supports 111, 112, 113. The third vertical support 113 is arranged between the first vertical support 111 and the second vertical support 112.
[0039] The third vertical support 113 defines a first imaginary central plane P1 oriented in vertical direction, i.e. in parallel with the third vertical support, and perpendicularly to the straight line L. In other words, the straight line L is normal to the first imaginary central plane P1. The first imaginary central plane P1 divides the third vertical support 113 in the middle, i.e. in two halves.
[0040] According to some embodiments, when the steel beam 12 is a steel beam as described below under "Steel beam", the first reinforcement element 131 and the second reinforcement element 132 are arranged in such a way that the midpoint 1313 of the first reinforcement element 131 and the midpoint 1323 of the second reinforcement element 132 are located on the first imaginary central plane P1, as exemplified in Figures 6 and 8. In other words, the midpoints 1313, 1323 of the first reinforcement element 131 and the second reinforcement element 132 are arranged in the steel beam 12 directly above the third vertical support 113.
[0041] The first reinforcement element 131 and the second reinforcement element 132 provide reinforcement for the steel beam 12 at the location of the third vertical support 113. This facilitates in providing a steel beam 12 that is durable enough to fulfil the requirements of the selected fire resistance class without using fireproofing in the steel beam 12.Embodiments with four vertical supports
[0042] According to some further embodiments, the vertical support arrangement 11 comprises a fourth vertical support 114, as exemplified in Figure 8. In other words, the vertical support arrangement 11 comprises four vertical supports 111, 112, 113, 114, i.e. the first vertical support 111, the second vertical support 112, the third vertical support 113, and the fourth vertical support 114. In still other words, resulting structure 1 comprises three spans between the vertical supports 111, 112, 113, 114.
[0043] The fourth vertical support 114 is arranged between the second vertical support 112 and the third vertical support 113. In other words, the third vertical support 113 and the fourth vertical support 114 are arranged between the first vertical support 111 and the second support 112. In still other words, the vertical supports 111, 112, 113, 114 listed in order along the straight line L are the first vertical support 111, the third vertical support 113, the fourth vertical support 114 and the second vertical support 112.
[0044] The fourth vertical support 114 defines a second imaginary central plane P2 oriented in vertical direction and perpendicularly to the straight line L. In other words, the straight line L is normal to the second imaginary central plane P2. The second imaginary central plane P2 divides the fourth vertical support 114 in the middle, i.e. in two halves.
[0045] In these embodiments, the reinforcement arrangement 13 comprises a third reinforcement element 133 having an elongated shape. The third reinforcement element 133 has a first end 1331, a second end 1332 opposite the first end 1331, and a midpoint 1333 halfway between the first end 1331 and the second end 1332. The third reinforcement element 133 is attached to the outer surface 1233 of the first web 123.
[0046] In these embodiments, the reinforcement arrangement 13 comprises a fourth reinforcement element 134 having an elongated shape. The fourth reinforcement element 134 has a first end 1341, a second end 1342 opposite the first end 1341, and a midpoint 1343 halfway between the first end 1341 and the second end 1342. The fourth reinforcement element 134 is attached to the outer surface 1243 of the second web 124.
[0047] The third reinforcement element 133 and the fourth reinforcement element 134 are arranged in such a way that the midpoint 1333 of the third reinforcement element 133 and the midpoint 1343 of the fourth reinforcement element 134 are located on the second imaginary central plane P2. In other words, midpoints 1333, 1343 of the third reinforcement element 133 and the fourth reinforcement element 134 are arranged in the steel beam 12 directly above the fourth vertical support 114.
[0048] The third reinforcement element 133 and the fourth reinforcement element 134 provide reinforcement for the steel beam 12 at the location of the fourth vertical support 114. This facilitates in providing a steel beam 12 that is durable enough to fulfil the requirements of the selected fire resistance class without using fireproofing in the steel beam 12 when the vertical support arrangement 11 comprises four vertical supports 111, 112, 113, 114.Supporting the steel beam
[0049] The method comprises supporting the steel beam 12 in horizontal position in vertical direction by the upper surfaces 1111, 1121, 1131, 1141 of the vertical supports 111, 112, 113, 114 from the bottom flange 122 of the steel beam 12. Preferably, the steel beam 12 is attached to the upper surfaces 1111, 1121, 1131, 1141 by welding or by bolts.Steel beam
[0050] The invention relates to a steel beam 12. The steel beam 12 is a closed hollow steel beam, for example a welded box beam.
[0051] The steel beam 12 comprises a top flange 121, a bottom flange 122, a first web 123 attached, preferably welded, to the top flange 121 and to the bottom flange 122, and a second web 124 attached, preferably welded, to the top flange 121 and to the bottom flange 122 and spaced out from the first web 123.
[0052] The first web 123 has a top edge 1231 and a bottom edge 1232 opposite the top edge 1231. According to some embodiments, the first web 123 is attached to the top flange 121 from the top edge 1231 and to the bottom flange 122 from the bottom edge 1232.
[0053] The second web 124 has a top edge 1241 and a bottom edge 1242 opposite the top edge 1241. According to some embodiments, the second web 124 is attached to the top flange 121 from the top edge 1241 and to the bottom flange 122 from the bottom edge 1242.
[0054] The steel beam 12 comprises a first end 125, a second end 126 opposite the first end 125, and an inner space 127 defined by the top flange 121, bottom flange 122, the first web 123 and the second web 124. The inner space 127 is not intended to be filled, e.g. with concrete, to create a composite beam but it is intended to be left empty to maintain the lightness of the steel beam 12. The top flange 121, the bottom flange 122, the first web 123 and the second web 124 extend from the first end 125 to the second end 126.
[0055] The first web 123 has an outer surface 1233 facing away from the inner space 127. The second web 124 has an outer surface 1243 facing away from the inner space 127. The top flange 121 has an outer surface 1211 facing away from the inner space 127.
[0056] The steel beam 12 defines an imaginary horizontal plane P3 arranged halfway between the top flange 121 and the bottom flange 122. In other words, the imaginary horizontal plane P3 divides the steel beam 12 in two halves, i.e. in an upper half and a lower half.
[0057] The steel beam 12 has a length between the first end 125 and the second end 126.
[0058] The steel beam 12 contains no fireproofing. In other words, the steel beam 12 has not been treated with a fire-proofing treatment. This is to reduce the costs relating to providing the structure 1.
[0059] According to some embodiments, the distance between the top edge 1231 of the first web 123 and the top edge 1241 of the second web 124 is smaller than the distance between the bottom edge 1232 of the first web 123 and the bottom edge 1242 of the second web 124, as exemplified in Figure 4. In other words, the first web and the second web are not parallel but have an angle greater than 0 ° between each other. In still other words, the steel beam 12 is a slanted web steel beam.
[0060] The steel beam 12 comprises a reinforcement arrangement 13 for increasing the local strength of the steel beam 12. In other words, the purpose of the reinforcement arrangement 13 is to reinforce the steel beam 12 at locations where the greatest stress is applied. The reinforcement arrangement 13 compensates for the missing fireproofing in the steel beam 11 to fulfil the requirements of the selected fire resistance class without using fireproofing.Reinforcement arrangement
[0061] The reinforcement arrangement 13 comprises a first reinforcement element 131 having an elongated shape. For example, the first reinforcement element 131 is a reinforcement bar, such as a round bar or a square bar, or a reinforcement plate. The first reinforcement element 131 comprises a first end 1311, a second end 1312 opposite the first end 1311, and a midpoint 1313 halfway between the first end 1311 and the second end 1312. The first reinforcement element 131 has a length between first end 1311 and the second end 1312. The first reinforcement element 131 is attached to the outer surface 1233 of the first web 123. For example, the first reinforcement element 131 is attached to the outer surface 1233 of the first web 123 by welding or by bolts. The length of the first reinforcement element 131 is 2 to 30 %, preferably 2 to 15 %, of the length of the steel beam 12. The first reinforcement element 131 is arranged in such a way that the midpoint 1313 of the first reinforcement element 131 is at a first distance E1 from the first end 125 of the steel beam 12. The first distance E1 is 20 to 80 % of the length of the steel beam 12.
[0062] According to some embodiments, the reinforcement arrangement 13 comprises a second reinforcement element 132 having an elongated shape. For example, the second reinforcement element 132 is a reinforcement bar, such as a round bar or a square bar, or a reinforcement plate. The second reinforcement element 132 comprises a first end 1321, a second end 1322 opposite the first end 1321, and a midpoint 1323 halfway between the first end 1321 and the second end 1322. The second reinforcement element 132 has a length between first end 1321 and the second end 1322. The second reinforcement element 132 is attached to the outer surface 1243 of the second web 124. For example, the second reinforcement element 132 is attached to the outer surface 1243 of the second web 124 by welding or by bolts. The length of the second reinforcement element 132 is 2 to 30 %, preferably 2 to 15 %, of the length of the steel beam 12. Preferably, the length of the second reinforcement element 132 corresponds to the length of the first reinforcement element 131. The second reinforcement element 132 is arranged in such a way that the midpoint 1323 of the second reinforcement element 132 is at the first distance E1 from the first end 125 of the steel beam 12.
[0063] According to some embodiments, the reinforcement arrangement 13 consists of the first reinforcement element 131 and the second reinforcement element 132, as exemplified in Figure 5. In other words, the reinforcement arrangement 13 is formed by the first reinforcement element 131 and the second reinforcement element 132. In this case, the first distance E1 is 43 to 57 %, preferably 48 to 52 %, of the length of the steel beam 12. In other words, the first reinforcement element 131 and the second reinforcement element 132 are arranged essentially halfway of the steel beam 12. These embodiments are suitable for using with a vertical support arrangement 11 consisting of three vertical supports 111, 112, 113 arranged in a straight line L and distributed essentially evenly. In such a case, the first reinforcement element 131 and the second reinforcement element 132 are arranged at the location of the vertical support 111, 112, 113 positioned in the middle.
[0064] According to some embodiments, the reinforcement arrangement 13 comprises a third reinforcement element 133 having an elongated shape. For example, the third reinforcement element 133 is a reinforcement bar, such as a round bar or a square bar, or a reinforcement plate. The third reinforcement element 133 comprises a first end 1331, a second end 1332 opposite the first end 1331, and a midpoint 1333 halfway between the first end 1331 and the second end 1332. The third reinforcement element 133 has a length between first end 1331 and the second end 1332. The third reinforcement element 133 is attached to the outer surface 1233 of the first web 123. For example, the third reinforcement element 133 is attached to the outer surface 1233 of the first web 123 by welding or by bolts. The length of the third reinforcement element 133 is 2 to 30 %, preferably 2 to 15 %, of the length of the steel beam 12. Preferably, the length of the third reinforcement element 133 corresponds to the length of the first reinforcement element 131.
[0065] According to some embodiments, the reinforcement arrangement 13 comprises a fourth reinforcement element 134 having an elongated shape. For example, the fourth reinforcement element 134 is a reinforcement bar, such as a round bar or a square bar, or a reinforcement plate. The fourth reinforcement element 134 has a first end 1341, a second end 1342 opposite the first end 1341, and a midpoint 1343 halfway between the first end 1341 and the second end 1342. The fourth reinforcement element 134 has a length between first end 1341 and the second end 1342. The fourth reinforcement element 134 is attached to the outer surface 1243 of the second web 124. For example, the fourth reinforcement element 134 is attached to the outer surface 1243 of the second web 124 by welding or by bolts. The length of the fourth reinforcement element 134 is 2 to 30 %, preferably 2 to 15 %, of the length of the steel beam 12. Preferably, the length of the fourth reinforcement element 134 corresponds to the length of the first reinforcement element 131.
[0066] In other words, the reinforcement arrangement 13 may comprise, in addition to the first reinforcement element 131, any combination of the second reinforcement element 132 arranged on the opposite side of the steel beam 12, the third reinforcement element 133 arranged on the same side of the steel beam 12 at a different location of the steel beam 12, and the fourth reinforcement element 134 arranged on the opposite side of the steel beam 12 at a different location of the steel beam 12.
[0067] According to some alternative embodiments, the reinforcement arrangement 13 consists of the first reinforcement element 131, the second reinforcement element 132, the third reinforcement element 133, and the fourth reinforcement element 134, as exemplified in Figure 8. In other words, the reinforcement arrangement 13 is formed by the first reinforcement element 131, the second reinforcement element 132, the third reinforcement element 133, and the fourth reinforcement element 134.
[0068] According to some embodiments, when the reinforcement arrangement comprises the third reinforcement element 133 or the fourth reinforcement element 134, the first distance E1 is 25 to 40 %, preferably 29 to 47 %, more preferably 31 to 35 %, of the length of the steel beam 12. In other words, the midpoint 1313 of the first reinforcement element 131 and the midpoint 1323 of the optional second reinforcement element 132 are preferably at a distance of about 1 / 3 of the length of the steel beam 12 from the first end 125 of the steel beam 12.
[0069] According to some embodiments, the third reinforcement element 133 is arranged in such a way that the midpoint 1333 of the third reinforcement element 133 is at a second distance E2 from the first end 125 of the steel beam 12. The second distance E2 is 60 to 75 %, preferably 62 to 70 %, more preferably 64 to 68 %, of the length of the steel beam 12. In other words, the midpoint 1333 of the third reinforcement element 133 is at a distance of about 2 / 3 of the length of the steel beam 12 from the first end 125 of the steel beam 12.
[0070] According to some embodiments, the fourth reinforcement element 134 is arranged in such a way that the midpoint 1343 of the fourth reinforcement element 134 is at the second distance E2 from the first end 125 of the steel beam 12. In other words, the midpoint 1343 of the fourth reinforcement element 134 is at a distance of about 2 / 3 of the length of the steel beam 12 from the first end 125 of the steel beam 12.
[0071] Embodiments comprising the third reinforcement element 133 or the fourth reinforcement element 134 are suitable for using with a vertical support arrangement 11 consisting of four vertical supports 111, 112, 113, 114 arranged in a straight line L and distributed essentially evenly. In such a case, the first reinforcement element 131 and the second reinforcement element 132 are arranged at the location of the vertical supports 113, 114 positioned between the vertical supports 111, 112 positioned at the ends of the vertical support arrangement 11.
[0072] According to some embodiments, the reinforcement arrangement 13 is arranged between the outer surface 1211 of the top flange 121 and the imaginary horizontal plane P3, as exemplified in Figure 4. In other words, the reinforcement arrangement 13, i.e. comprising the first reinforcement element 131, the second reinforcement element 132, the optional third reinforcement element 133 and the optional fourth reinforcement element 134, is arranged in the upper half of the steel beam 12. When these embodiments are used together with the embodiments relating to the slanted web steel beam, the steel beam does not require as much space as with a parallel web steel beam as the slanted webs compensate for the space required by the reinforcement arrangement 13.
[0073] According to some embodiments, the reinforcement arrangement 13 is attached to the top flange 121. In other words, the first reinforcement element 131, the second reinforcement element 132, the optional third reinforcement element 133 and the optional fourth reinforcement element 134 are attached to the top flange 121 in addition to the corresponding web 123, 124. For example, the reinforcement arrangement 13 is attached to the top flange 121 by welding or by bolts.Structure
[0074] The invention relates to a structure 1. For example, the structure is a part of a building.
[0075] The structure 1 comprises a vertical support arrangement 11 comprising at least three vertical supports 111, 112, 113, 114 for supporting a horizontal beam in vertical direction. In other words, the structure 1 comprises at least two spans between the vertical supports 111, 112, 113, 114.
[0076] According to some embodiments, each vertical support 111, 112, 113, 114 is independently selected from a group consisting of a pillar, a vertical wall oriented transversally to the steel beam 12, and a support beam oriented horizontally and transversally to the steel beam 12.
[0077] According to some embodiments, the vertical support arrangement 11 comprises at least four vertical supports 111, 112, 113, 114, as exemplified in Figures 3 and 8. In other words, the structure 1 comprises at least three spans between the vertical supports 111, 112, 113, 114.
[0078] According to some embodiments, each vertical support 111, 112, 113, 114 contains a fireproofing. In other words, each vertical support 111, 112, 113, 114 has been treated with a fire-proofing treatment. The purpose of the fireproofing is to facilitate meeting the requirements of the fire resistance classification selected for the structure 1.
[0079] According to some alternative embodiments, if the vertical support 111, 112, 113, 114 is made of concrete or contains a composite of concrete and steel, the vertical support 111, 112, 113, 114 contains no fireproofing. This is because the concrete is sufficiently fireproof in itself.
[0080] Each vertical support 111, 112, 113, 114 comprises an upper surface 1111, 1121, 1131, 1141 for supporting a beam.
[0081] The vertical supports 111, 112, 113, 114 are arranged in a straight line L. In other words, the vertical supports 111, 112, 113, 114 are arranged in such a way that the upper surfaces 1111, 1121, 1131, 1141 are arranged in the straight line L. In still other words, the vertical supports 111, 112, 113, 114 are arranged in such a way that a straight beam would be supported by the vertical supports 111, 112, 113, 114.
[0082] The distances D1, D2, D3 between adjacent vertical supports 111, 112, 113, 114 differ 0 to 35 %, preferably 0 to 20 %, more preferably 0 to 10 %, such as 0 to 5 %, from each other. In other words, the distances D1, D2, D3 between adjacent vertical supports 111, 112, 113, 114 are essentially identical. This is to make sure that uniform conditions are provided on both sides of the vertical support or vertical supports arranged in the middle, i.e. between the vertical supports arranged at the ends of the vertical support arrangement 11.
[0083] The vertical support arrangement 11 comprises a first vertical support 111, a second vertical support 112 and a third vertical support 113. The third vertical support 113 is arranged between the first vertical support 111 and the second vertical support 112.
[0084] The third vertical support 113 defines a first imaginary central plane P1 oriented in vertical direction, i.e. in parallel with the third vertical support, and perpendicularly to the straight line L. In other words, the straight line L is normal to the first imaginary central plane P1. The first imaginary central plane P1 divides the third vertical support 113 in the middle, i.e. in two halves.
[0085] The structure 1 comprises a steel beam 12 as described above. The steel beam 12 is supported in horizontal position in vertical direction by the upper surfaces of the vertical supports 111, 112, 113, 114 from the bottom flange 122 of the steel beam 12. Preferably, the steel beam 12 is attached to the upper surfaces 1111, 1121, 1131, 1141 by welding or by bolts.
[0086] According to some embodiments, the first reinforcement element 131 and the second reinforcement element 132 are arranged in such a way that the midpoint 1313 of the first reinforcement element 131 and the midpoint 1323 of the second reinforcement element 132 are located on the first imaginary central plane P1, as exemplified in Figures 6 and 8. In other words, the midpoints 1313, 1323 of the first reinforcement element 131 and the second reinforcement element 132 are arranged in the steel beam 12 directly above the third vertical support 113.
[0087] The first reinforcement element 131 and the second reinforcement element 132 provide reinforcement for the steel beam 12 at the location of the third vertical support 113. This facilitates in providing a steel beam 12 that is durable enough to fulfil the requirements of the selected fire resistance class without using fireproofing in the steel beam 12.
[0088] According to some further embodiments, the vertical support arrangement 11 comprises a fourth vertical support 114, as exemplified in Figure 8. In other words, the vertical support arrangement 11 comprises four vertical supports 111, 112, 113, 114, i.e. the first vertical support 111, the second vertical support 112, the third vertical support 113, and the fourth vertical support 114. In still other words, resulting structure 1 comprises three spans between the vertical supports 111, 112, 113, 114.
[0089] The fourth vertical support 114 is arranged between the second vertical support 112 and the third vertical support 113. In other words, the third vertical support 113 and the fourth vertical support 114 are arranged between the first vertical support 111 and the second support 112. In still other words, the vertical supports 111, 112, 113, 114 listed in order along the straight line L are the first vertical support 111, the third vertical support 113, the fourth vertical support 114 and the second vertical support 112.
[0090] The fourth vertical support 114 defines a second imaginary central plane P2 oriented in vertical direction and perpendicularly to the straight line L. In other words, the straight line L is normal to the second imaginary central plane P2. The second imaginary central plane P2 divides the fourth vertical support 114 in the middle, i.e. in two halves.
[0091] In these embodiments, the reinforcement arrangement 13 comprises a third reinforcement element 133 having an elongated shape. The third reinforcement element 133 has a first end 1331, a second end 1332 opposite the first end 1331, and a midpoint 1333 halfway between the first end 1331 and the second end 1332. The third reinforcement element 133 is attached to the outer surface 1233 of the first web 123.
[0092] In these embodiments, the reinforcement arrangement 13 comprises a fourth reinforcement element 134 having an elongated shape. The fourth reinforcement element 134 has a first end 1341, a second end 1342 opposite the first end 1341, and a midpoint 1343 halfway between the first end 1341 and the second end 1342. The fourth reinforcement element 134 is attached to the outer surface 1243 of the second web 124.
[0093] The third reinforcement element 133 and the fourth reinforcement element 134 are arranged in such a way that the midpoint 1333 of the third reinforcement element 133 and the midpoint 1343 of the fourth reinforcement element 134 are located on the second imaginary central plane P2. In other words, midpoints 1333, 1343 of the third reinforcement element 133 and the fourth reinforcement element 134 are arranged in the steel beam 12 directly above the fourth vertical support 114.
[0094] The third reinforcement element 133 and the fourth reinforcement element 134 provide reinforcement for the steel beam 12 at the location of the fourth vertical support 114. This facilitates in providing a steel beam 12 that is durable enough to fulfil the requirements of the selected fire resistance class without using fireproofing in the steel beam 12 when the vertical support arrangement 11 comprises four vertical supports 111, 112, 113, 114.
[0095] The invention has been described above with reference to the examples shown in the figures. However, the invention is in no way restricted to the above examples but may vary within the scope of the claims.
Claims
1. A method for providing a structure (1) comprising a vertical support arrangement (11) and a steel beam (12) supported by the vertical support arrangement (11), characterized in that the method comprises c) providing a vertical support arrangement (11) comprising at least three vertical supports (111, 112, 113, 114) for supporting a horizontal beam in vertical direction, wherein - each vertical support (111, 112, 113, 114) comprises an upper surface (1111, 1121, 1131, 1141) for supporting a beam, - the vertical supports (111, 112, 113, 114) are arranged in a straight line (L), and - the distances (D1, D2, D3) between adjacent vertical supports (111, 112, 113, 114) differ 0 to 35 % from each other, d) providing a steel beam (12), wherein the steel beam (12) is a closed hollow steel beam comprising - a top flange (121), - a bottom flange (122), - a first web (123) attached to the top flange (121) and to the bottom flange (122), - a second web (124) attached to the top flange (121) and to the bottom flange (122) and spaced out from the first web (123), - an inner space (127) defined by the top flange (121), bottom flange (122), the first web (123) and the second web (124), - a first end (125), and - a second end (126) opposite the first end (125), wherein the top flange (121), the bottom flange (122), the first web (123) and the second web (124) extend from the first end (125) to the second end (126), and wherein the steel beam (12) contains no fireproofing, and e) supporting the steel beam (12) in horizontal position in vertical direction by the upper surfaces of the vertical supports (111, 112, 113, 114) from the bottom flange (122) of the steel beam (12); wherein providing the steel beam (12) comprises - defining a desired fire resistance class for the structure (1), - determining an ultimate limit state and a serviceability limit state for the steel beam (12) based on the distances (D1, D2, D3) between the adjacent vertical supports (111, 112, 113, 114) in the vertical support arrangement (11) and the predetermined vertical load applied to the steel beam (12), - determining estimated properties of the steel beam (12) based on the ultimate limit state and the serviceability limit state, - calculating the temperature distribution of the steel beam (12) in the structure (1) according to the desired fire resistance class over the length of the steel beam (12) in the event of fire based on the standard fire curve according to ISO 834, - determining the required properties of the steel beam (12) based on the ultimate limit state, the serviceability limit state and the calculated temperature distribution of the steel beam 12 in the structure 1, - determining modified estimated properties of the steel beam (12) based on the estimated properties of the steel beam (12), the required properties of the steel beam (12) and the presumption that no fireproofing is used in the steel beam (12), and - selecting the steel beam (12) based on the modified estimated properties.
2. The method according to claim 1, characterized in that the vertical support arrangement (11) comprises at least four vertical supports (111, 112, 113, 114).
3. The method according to claim 1 or 2, characterized in that each vertical support (111, 112, 113, 114) is independently selected from a group consisting of a pillar, a vertical wall oriented transversally to the steel beam (12), and a support beam oriented horizontally and transversally to the steel beam (12).
4. The method according to any one of the preceding claims, characterized in that each vertical support (111, 112, 113, 114) contains a fireproofing.
5. The method according to any one of the preceding claims, characterized in that the fire resistance class of the structure (1) is selected from a group consisting of R30, R45, R60, R90 and R120, each according to EN 13501-2.
6. The method according to any one of the preceding claims, characterized in that the steel beam (12) is a steel beam according to any one of claims 9 to 13.
7. The method according to claim 6, characterized in that the vertical support arrangement (11) comprises a first vertical support (111), a second vertical support (112) and a third vertical support (113); the third vertical support (113) is arranged between the first vertical support (111) and the second vertical support (112); the third vertical support (113) defines a first imaginary central plane (P1) oriented in vertical direction and perpendicularly to the straight line (L), the first imaginary central plane (P1) dividing the third vertical support (113) in the middle; the first reinforcement element (131) and the second reinforcement element (132) are arranged in such a way that the midpoint (1313) of the first reinforcement element (131) and the midpoint (1323) of the second reinforcement element (132) are located on the first imaginary central plane (P1).
8. The method according to claim 7, characterized in that the vertical support arrangement (11) comprises a fourth vertical support (114); the fourth vertical support (114) is arranged between the second vertical support (112) and the third vertical support (113); the fourth vertical support (114) defines a second imaginary central plane (P2) oriented in vertical direction and perpendicularly to the straight line (L), the second imaginary central plane (P2) dividing the fourth vertical support (114) in the middle; the reinforcement arrangement (13) comprises a third reinforcement element (133) having an elongated shape and having a first end (1331), a second end (1332) opposite the first end (1331), and a midpoint (1333) halfway between the first end (1331) and the second end (1332); the reinforcement arrangement (13) comprises a fourth reinforcement element (134) having an elongated shape and having a first end (1341), a second end (1342) opposite the first end (1341), and a midpoint (1343) halfway between the first end (1341) and the second end (1342); the third reinforcement element (133) is attached to the outer surface (1233) of the first web (123); the fourth reinforcement element (134) is attached to the outer surface (1243) of the second web (124); the third reinforcement element (133) and the fourth reinforcement element (134) are arranged in such a way that the midpoint (1333) of the third reinforcement element (133) and the midpoint (1343) of the fourth reinforcement element (134) are located on the second imaginary central plane (P2).
9. A steel beam (12) in the form of a closed hollow steel beam comprising - a top flange (121), - a bottom flange (122), - a first web (123) attached to the top flange (121) and to the bottom flange (122), - a second web (124) attached to the top flange (121) and to the bottom flange (122) and spaced out from the first web (123), - an inner space (127) defined by the top flange (121), bottom flange (122), the first web (123) and the second web (124), - a first end (125), and - a second end (126) opposite the first end (125); wherein - the top flange (121), the bottom flange (122), the first web (123) and the second web (124) extend from the first end (125) to the second end (126); - the steel beam (12) has a length between the first end (125) and the second end (126); - the first web (123) comprises an outer surface (1233) facing away from the inner space (127); and - the second web (124) comprises an outer surface (1243) facing away from the inner space (127); characterized in that - the steel beam (12) contains no fireproofing; - the steel beam (12) comprises a reinforcement arrangement (13) for increasing the local strength of the steel beam (12); - the reinforcement arrangement (13) comprises a first reinforcement element (131) having an elongated shape, comprising a first end (1311), a second end (1312) opposite the first end (1311), and a midpoint (1313) halfway between the first end (1311) and the second end (1312), and having a length between first end (1311) and the second end (1312); - the first reinforcement element (131) is attached to the outer surface (1233) of the first web (123); - the length of the first reinforcement element (131) is 2 to 30 % of the length of the steel beam (12); and - the first reinforcement element (131) is arranged in such a way that the midpoint (1313) of the first reinforcement element (131) is at a first distance (E1) from the first end (125) of the steel beam (12), wherein the first distance (E1) is 20 to 80 % of the length of the steel beam (12).
10. The steel beam (12) according to claim 9, characterized in that the reinforcement arrangement (13) comprises a second reinforcement element (132) having an elongated shape, comprising a first end (1321), a second end (1322) opposite the first end (1321), and a midpoint (1323) halfway between the first end (1321) and the second end (1322), and having a length between first end (1321) and the second end (1322); the second reinforcement element (132) is attached to the outer surface (1243) of the second web (124); the length of the second reinforcement element (132) is 2 to 30 % of the length of the steel beam (12), and preferably the length of the second reinforcement element (132) corresponds to the length of the first reinforcement element (131); and the second reinforcement element (132) is arranged in such a way that the midpoint (1323) of the second reinforcement element (132) is at the first distance (E1) from the first end (125) of the steel beam (12).
11. The steel beam (12) according to claim 10, characterized in that the reinforcement arrangement (13) consists of the first reinforcement element (131) and the second reinforcement element (132); and the first distance (E1) is 43 to 57 % of the length of the steel beam (12).
12. The steel beam (12) according to claim 10, characterized in that the reinforcement arrangement (13) comprises a third reinforcement element (133) having an elongated shape; the reinforcement arrangement (13) comprises a fourth reinforcement element (134) having an elongated shape; the reinforcement arrangement (13) consists of the first reinforcement element (131), the second reinforcement element (132), the third reinforcement element (133), and the fourth reinforcement element (134); the third reinforcement element (133) comprises a first end (1331), a second end (1332) opposite the first end (1331), and a midpoint (1333) halfway between the first end (1331) and the second end (1332), has a length between first end (1331) and the second end (1332), and is attached to the outer surface (1233) of the first web (123); the fourth reinforcement element (134) comprises a first end (1341), a second end (1342) opposite the first end (1341), and a midpoint (1343) halfway between the first end (1341) and the second end (1342), has a length between first end (1341) and the second end (1342), and is attached to the outer surface (1243) of the second web (124); the length of the third reinforcement element (133) is 2 to 30 % of the length of the steel beam (12), and preferably the length of the third reinforcement element (133) corresponds to the length of the first reinforcement element (131); the length of the fourth reinforcement element (134) is 2 to 30 % of the length of the steel beam (12), and preferably the length of the fourth reinforcement element (134) corresponds to the length of the first reinforcement element (131); the first distance (E1) is 25 to 40 % of the length of the steel beam (12); the third reinforcement element (133) is arranged in such a way that the midpoint (1333) of the third reinforcement element (133) is at a second distance (E2) from the first end (125) of the steel beam (12), wherein the second distance (E2) is 60 to 75 % of the length of the steel beam (12); and the fourth reinforcement element (134) is arranged in such a way that the midpoint (1343) of the fourth reinforcement element (134) is at the second distance (E2) from the first end (125) of the steel beam (12).
13. The steel beam (12) according to any one of claims 9 to 12, characterized in that the first web (123) has a top edge (1231) and a bottom edge (1232); the second web (124) has a top edge (1241) and a bottom edge (1242); the distance between the top edge (1231) of the first web (123) and the top edge (1241) of the second web (124) is smaller than the distance between the bottom edge (1232) of the first web (123) and the bottom edge (1242) of the second web (124).
14. The steel beam (12) according to any one of claims 9 to 13, characterized in that the steel beam (12) defines an imaginary horizontal plane (P3) arranged halfway between the top flange (121) and the bottom flange (122); and the reinforcement arrangement (13) is arranged between the top flange (121) and the imaginary horizontal plane (P3).
15. A structure (1) characterized in that the structure (1) comprises a) a vertical support arrangement (11) comprising at least three vertical supports (111, 112, 113, 114) for supporting a horizontal beam in vertical direction, wherein - each vertical support (111, 112, 113, 114) comprises an upper surface (1111, 1121, 1131, 1141) for supporting a beam, - the vertical supports (111, 112, 113, 114) are arranged in a straight line (L), and - the distances (D1, D2, D3) between adjacent vertical supports (111, 112, 113, 114) differ 0 to 35 % from each other, b) a steel beam (12) according to any one of claims 9 to 13 supported in horizontal position in vertical direction by the upper surfaces of the vertical supports (111, 112, 113, 114) from the bottom flange (122) of the steel beam (12).