Building structure damper comprising two twisted cables and a building assembly comprising such damper

Abstract

A building structure damper (9) comprises two cables (1, 2) that are twisted together forming an elongate damper element. The damper (9) comprises a first and a second end. The ends comprise a respective first and second anchor arrangement (18a, 18b), each comprising a first anchor and a second anchor for the respective cables (1, 2). The first and second anchors are separated by an anchor distance. In some embodiments at least one anchor arrangement comprises a teeter element (3) comprising a pivot (15) and two functional levers (6, 7) extending outwards from the pivot (15) in substantially opposite directions. Each cable (1, 2) is attached at its respective end to a respective functional lever (6, 7). A building assembly may in some embodiments comprise at least two building structure dampers (9) arranged in an intersecting manner between opposing elements of the building assembly.

Description

[0001]CABLE ARRANGEMENT FOR FRAMED STRUCTURES Field of the invention The present invention relates to a building structure damper comprising two cables that are twisted together forming an elongate damper element, the damper comprising a first and a second end, wherein the ends comprise respective anchor arrangements, comprising a first anchor and a second anchor for the respective cables. The invention also relates to a building assembly. Background JP2013249603 discloses a vibration proof brace, directed to suppress vibrations from earthquakes, winds traffic, etc, in order to protect buildings, in particular buildings made from wood or light-weight steel or similar materials. In order to reinforce the building, wire braces are attached to the housing in a diagonally crossing state. Such wire braces have the advantage of being easier to transport to a building site than rigid metal rods. This prior art brace comprises two cords that are twisted together. The ends of the twisted cords are fixed in a metal fitting. The metal fitting is in its turn fixed to a pillar in the building via a fixing member. The most obvious application for the invention is tall and light buildings. Most tall buildings so far have been relatively heavy and rigid structures made of either concrete or steel, that have thus not been severely affected by wind loads. When building lighter tall buildings, these become more sensitive to vibrations during wind loads. This may apply to more resource-efficient buildings with less material or for example more sustainable building materials such as wood, or materials that have high strength in relation to weight in general. For instance, regarding structural strength timber building structures require in general less self-weight to carry the structural loads of self-weight and the additional service weights, depending on the purpose and classification of the building. However, the decrease in mass and stiffness makes a building more sensitive, more prone, to vibrate when applying a certain dynamic load on the building. An example of such a load is wind loading. Residential buildings and office buildings that have humans in it are sensitive to certain small levels of global vibrations where the entire building is swaying. There are regulations of the acceleration and the maximum vibration magnitudes (related to vibration frequencies) that these buildings must not exceed during their use. There are solutions to decrease the first vibration mode, by, for instance, Tuned Mass Dampers, which are in use in for instance the skyscraper Taipei 101. There are also solutions for handling earthquake loads that include for instance additional dampers. One such example is the 181 Fremont Tower in San Francisco. These solutions require additional damping components, other than the parts that take the structural loads. Although braces according to the prior art may work fairly well in comparison with rigid metal rods, there is still room for improvement of the damping properties. In particular, there is a need for an improved damping in buildings made of lightweight material, such as wood. This problem is not addressed to a sufficient degree in JP2013249603 which is primarily focused on vibrations caused by earthquakes. Summary It is an object of the present disclosure to solve, or at least mitigate, parts or all of the above-mentioned problems. To this end, there is provided a damper wherein the first and second anchors are separated by an anchor distance. Hereby the ends of the damper may be arranged between two parts of a solid construction, e. g. a building, a civil engineering construction, such as a bridge, an offshore construction, etc. When the solid construction is subjected to a force, e. g. from the wind, a vibration, or an impact from the users of the construction, or from the surroundings, the distance between those parts of the construction where the ends of the damper are attached may increase or decrease slightly. Tension in the cables may increase or decrease, possibly repeatedly, and since the cables are arranged separated from one another in at least the anchor arrangement at the first end of the damper, the cables may slide relative to one another. Since the cables are, at least partly, twisted together, the contact between them is enhanced, and their relative motion results in heat due to friction. Hereby their relative motion is impeded, and any motions or vibrations at the parts where the ends of the damper are attached are reduced. The anchor distance between the first and second anchors may be in an interval of 1 cm to 10m, preferably between 1 cm and 1m, even more preferably between 1 cm and 40 cm. However, the ideal distance depends on the application, and should be calculated for each practical application, with consideration of the dimensions and other properties of the cables that are comprised in the damper. In an embodiment of the damper, the first anchor arrangement includes a device comprising a teeter element comprising a pivot and two functional levers extending outwards from the pivot in substantially opposite directions, and each cable is attached at its respective end to a respective functional lever by the firs and second anchors. Hereby the effect of the separation of the cables may be further enhanced. The teeter element comprising the pivot may turn around the pivot depending on the forces exerted from each wire component thereon. By a “functional lever” is to be understood a lever in the geometrical sense of the word, i. e. a distance between a point of application of a force and a fulcrum about which the system turns. The functional levers are hence the distance between the respective anchors and the pivot, regardless of the structural components arranged to realize the levers and the fulcrum. Hereby any variations in the force from the cables result in a varying torque around the pivot. The torque caused by one cable continuously balances the torque from the other. At the same time, the turning motions around the pivot may contribute to the motions of the cables in their longitudinal directions, and the damping effect may be enhanced. Due to the balancing action of the teeter element, these longitudinal motions of the cables take place in opposing directions. As mentioned above, the cables are at least partly twisted around one another and are in close contact. Hence the relative motions due to the action of the teeter element give rise to an improved dampening by friction. In a further embodiment, the lengths of the respective levers, from the pivot, are mutually different. Hereby the action from the teeter element on the two cables may be enhanced. A certain pulling force F1 from one of the cables acting on the longer lever, must be balanced by a larger force F2 from the other wire component acting on the shorter lever. Before a balance of the torques is attained, there may be relative motions in the two cables. These motions are gradually attenuated. The combined length of the two functional levers, i. e. the anchor distance, may be in an interval of 1 cm to 10 m, preferably between 1 cm and 1 m, even more preferably between 1 cm and 40 cm. However, the ideal distance depends on the application, and should be calculated for each practical application, with consideration of the dimensions and other properties of the cables that are comprised in the damper. In still further embodiments, both the first and the second anchor devices each comprise a respective teeter element comprising a pivot and two functional levers extending sideways from the pivot, and each cable is attached at its respective end to a respective lever. Hereby the action from the respective teeter elements may work together to gradually dampen the vibrations. A relative motion of the cables gives rise to pulling forces acting on both teeter elements. While a balance of torques is in the process of being attained in both teeter elements, any remaining relative motions are attenuated by the friction between the cables. The length of the functional levers may, in some embodiments, be mutually identical, but they may, in other embodiments, be different from one another, in order to provide the desired relative motion between the cables. The longer lever may be two or several more times longer than the shorter one, but the longer lever may, as an alternative, have a length of less than 200 percent of the shorter lever. The dimensions and other properties of the cables may affect the calculation of the relative lengths of the functional levers when a damper is designed for a certain application. In some further embodiments, the shorter levers on the respective teeter elements are interconnected by one of the cables, and the longer levers on the respective teeter elements are interconnected by the other cable. Hereby the relative motion of the cables may, at least initially, be maximised, thus giving rise to a maximised friction force, resulting in a maximised damping of any vibrations. In some embodiments the cables comprise mutually different materials. Hereby the cables may react differently to various ambient conditions. The ambient conditions, as well as the materials of the cables, may affect the damping function and should be taken into consideration at the design stage for each practical application. For example, any heat resulting from the friction, during use of the dampers, may enhance the dampening function, e.g. if the heat causes a larger extension of one of the cables than of the other. Such an extension may, in itself, result in a motion of the teeter element around the pivot, and further dampening of the vibrations. Another example is that some materials may be subject to an increased friction coefficient with an increased temperature, while the friction coefficient of other materials may be diminished with an increased temperature. In further embodiments the cables have mutually different moduli of elasticity. Hereby one of the cables may be more easily stretched than the other, when a force is applied thereto, and the dampening effect from a relative motion of the cables may be further enhanced. In some embodiments the cables have mutually different stiffness. Hereby the ability of the cables to twist may be influenced. For example, one cable may be more or less wound around the other, stiffer, cable. The contact surface between the cables and their relative motion when vibrations are dampened may be affected by their respective stiffness. The stiffness may be dependent on the selected material or materials as well as on the geometrical properties of the cables. In some embodiments the cables have mutually different cross sections. Hereby the contact areas and thereby the friction forces between the cables may be influenced and optimized for the field of application of the damper. For instance, pairing a cable with a large cross-sectional area with a cable with a smaller cross-sectional area may mean that the cable with the smaller cross-sectional area is more bendable than the other cable with the larger cross-sectional area, even when the cables are manufactured from the same material. The thinner, more bendable cable may e. g. be wrapped around the thicker cable to a larger degree than vice versa. Another way to influence the contact areas and friction forces between the cables may be to use cables with mutually different contours of their cross-sections In some embodiments the surface of at least one cable has an outer layer comprising a different material than the core of the cable. Hereby a number of beneficial effects may be achieved. The outer layer may be applied to keep oxides, e. g. rust, from forming on the surface. In some cases the outer layer of the cable may be formed of a durable material, while the inner core is formed from a less expensive but less durable material. The cables may hereby be less prone to abrasive wear. In some cases, an outer layer which increases the friction may be applied, for increased damping properties. In a second aspect of the disclosure, the building assembly comprises the building structure damper according to any of the above embodiments. The building structure damper may be arranged in a wide variety of constructions such as residential houses, office buildings, towers, platforms, industrial buildings, offshore constructions, bridges, tunnels, sports arenas, outdoor theaters, airplane hangars, storage constructions, etc. In further embodiments at least two building structure dampers are arranged in an intersecting manner between opposing elements of the building assembly. Hereby one of the dampers may be arranged diagonally from one corner of an assembly, or part of an assembly, to a diametrically opposed corner. The other damper may be arranged between two other corners of the assembly. The dampers may be joined loosely or solidly where they intersect. Several dampers or pairs of intersecting dampers may be arranged as needed in different parts of the building assembly. Hereby vibrations caused by loads affecting the building assembly may be dampened efficiently, regardless of their direction. It is noted that embodiments of the invention may be embodied by all possible combinations of features recited in the claims. Further, it will be appreciated that the various embodiments described for the device are all combinable with the method as defined in accordance with the second aspect of the present invention, and vice versa. Brief description of the drawings The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non- limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, where the same reference numerals will be used for similar elements, wherein: Fig.1 is a diagrammatic view in perspective of a damper according to the disclosure; Fig.2 is a view similar to that of Fig.1, illustrating parts of the damper in further detail; Fig.3 is a schematic view, not necessarily to scale, of a framed structure in a building assembly; and Fig.4 is a view similar to that of Fig 3 showing an example of an exaggerated sway deformation of the framed. All the figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the embodiments, wherein other parts may be omitted. Detailed description of the exemplary embodiments The present disclosure comprises a wire, or cable, solution aimed to merge tension stiffness and dynamic damping of motions in one single component. The suggested inventive construction is intended to be used in framed structural designs to provide shear damping and shear stabilisation of the same structure. Herein a wire, or cable, solution is presented, which is providing shear stability between the storeys (frames) in a building in the same way as common tensile bracings. The cables also provide structural damping when there is any tensile stress and elongation in the wire / cables. The term “structural damping” here refers to the transformation of motion energy, to heat energy, which in its turn is sufficiently cooled off to the ambient surroundings. Thus, any vibrational motion is reduced. The solution is applicable to various structures in both a large and a small scale. For instance, the solution is applicable to other building-like structures, e. g. bridges that have a similar structural construction principle as framed structure buildings, albeit with a horizontal orientation. The object of the damping property of these shear stabilizing wires / cables is to attenuate any global or local sway and shear motions in orthogonal framed structures, such as buildings, when they are exposed to high dynamic loads from wind, earthquakes, etc. The dampened motions may be of the lowest orders of natural frequencies of tall buildings. Fig.1 illustrates a building structure damper 9 according to the disclosure in a schematic manner. For the sake of clarity, the drawing does not show the damper 9 according to scale. The building structure damper 9 is arranged between two segments 14a, 14b of a building assembly in Fig.1. A first set of ends of the cables 1, 2 are attached side by side to an anchor arrangement 18a, which is attached to a first segment 14a (to the right, as seen in Fig.1) of the building assembly. In figs.1 and 2, the anchor arrangement 18a comprises a teeter element 3. The teeter element 3 comprises a hinge or pivot 15, which is attached to the segment 14a. Two functional levers 6, 7 extend in opposite directions from the pivot 15, preferably in directions perpendicular to the rotational axis of the pivot 15. The length of the respective functional levers 6, 7 from the pivot 15, may be identical, but they may in many practical embodiments differ from one another. The function of the damper 9 may be enhanced by mutually different lengths of the functional levers 6, 7. However, a common feature of the different embodiments of this disclosure is that the first set of ends of the cables 1, 2 are attached to the first segment 14a at a distance from one another. Different attachment points may, for geometrical reasons, give rise to mutually different forces applied to the two cables 1, 2. The likelihood of a difference in the applied forces may increase with the distance between the attachment points. The cables 1, 2, are attached side by side, at a second end, to a second segment 14b of the building assembly. At this end the attachment may or may not include an anchor arrangement of the same type as that of the first end of the damper 9, i. e. an anchor arrangement 18b with a distance between the two cables 1, 2, possibly a teeter element 3. The anchors forming the attachments are only schematically shown in Fig.1, and they may be physically realised in any efficient manner according to the prior art. The distance between the anchors may be different from the drawings. The anchors may, for example, include screws and bolts for the attachment of the teeter element 3 to the segment 14b, and hooks and thimbles for the attachment of the cables 1, 2 to the first segment 14a and to the teeter element 3. Further, there may also be applied devices, known in the art, for tensioning the cables 1, 2, such that the desired function of the damper 9 may be obtained, as described later herein. The cables 1, 2 of the building structure damper 9 are twisted together in a portion 8 extending at least a part of the length of the cables 1, 2. When the segments 14a, 14b move, vertically, horizontally, or both, the distance between them may vary. Also, the relative positions of the ends of the cables 1, 2 may shift in case they are attached a distance apart. These motions of the ends of the cables 1, 2, give rise to pulling forces applied to the cable ends. If the pulling force applied to one cable 1, 2 is greater than the pulling force applied to the other, or if the forces are acting in opposite directions, the cables 1, 2 may move relative to one another. Since they are in close contact with one another in the twisted portion 8, any relative motion of the cables 1, 2 result in friction, which serves to attenuate the motion (Coulomb damping), and any vibrations in the building assembly may be dampened. The pulling forces may also stretch the cables 1, 2 to some extent. Such an elongation contributes to a relative motion between the cables 1, 2. The cables 1, 2 may be pre- stretched in order not to slack when there is some compression of the building assembly which comprises the two segments 14a, 14b. A pre-stretching force may also affect the friction between the cables, and hence the damping efficiency. The purpose of the teeter element 3 is to allow some sliding between the two wires or cables 1, 2, when there is relative motion between the ends of the cables 1, 2. The sliding between the two cables 1, 2 may occur since the two cables 1, 2 have different strain rates or elongation, when the entire damper 9 is exposed to tension. The different elongation in the two different wire or cable components may be achieved by different principles The dimensions, the materials, or surface structures of the cables 1, 2 affect the friction between them, which is illustrated in Fig.2. For example, a cable 1, 2 with a smaller cross-section 4, 5 may be more easily twisted around another cable 1, 2 than a cable with a larger cross-section 4, 5. Both cables 1, 2 may have the same size of the cross-section 4, 5, or they may be considerably different. The size of the cross-section 4, 5 may also affect the heat-dissipating properties, the ability to stretch when subjected to a longitudinal force, etc., of the cables 1, 2. The choice of material in the cables 1, 2 may also affect their respective stiffness, and a relative motion between the cables 1, 2 may be enhanced. The shape of the cross-section 4, 5 may also affect the performance of the cables 1, 2. For instance, an approximately circular cross-section 4, 5 may result in a cable 1, 2 which is equally bendable in all radial directions, whereas an approximately oval cross-section 4, 5 may result in a cable 1, 2, which is more easily bendable in the direction of its minor axis, than in the direction of its major axis. Other cross-sectional shapes, e. g. square, rectangular, triangular, which affect the bendability in different directions, are also conceivable. By the bendability properties, the shape of the cross-section 4, 5 affects the ability of a cable 1, 2 to twist around another cable 1, 2, as well as the mutual area of contact between the cables 1, 2. Various degrees of contact between the twisted cables may also be attained, depending on whether only one or both of the cables 1, 2 have a non-circular cross- section 4, 5.A rough surface structure on one or both of the cables 1, 2, may increase the friction between them. The material selected for the cables 1, 2 may be identical for both cables, but they may also be mutually different. The material for each cable 1, 2 may be selected such that its stiffness (Young’s modulus), its elongation rate, its heat dissipation, and other properties related to the material are balanced relative to its outer physical factors, such as its length, cross-sectional area, surface roughness, surface treatment, number of twists, etc., and relative to the properties of the other cable 1, 2, in order to attain a damper with suitable properties for its intended application. The lengths of the cables are in an open interval of 2 m and upwards, preferably between 3 m and 50 m, even more preferably between 3 m and 20 m for many applications. However, the lengths of the cables depend on the dimensions of the building construction. In large scale constructions, the lengths of the cables seem to depend on practical aspects, such as the weight of the cables etc. In some cases, it may be preferable to use several smaller dampers with shorter cables instead of one single larger damper with long cables. In Fig.2 the disclosed damper 9 also illustrates that the twisted portion 8 and number of twists of the two cables 1,2 around one another may be varied. The greater the number of twists, the greater the contact surface, and hence the friction during relative motions of the cables 1, 2.Since a relative motion between the cables 1, 2, is an important factor for the damping of the vibrations, it should be noted that the length of the twisted portion 8, the number of twists per length unit, and the other properties of the cables 1, 2, as such, have to be carefully balanced, such that relative motions are indeed possible from the forces concerned, i. e. from the vibrations that the damper 9 is intended to attenuate. If the cables 1, 2 are twisted too tightly, or for too long a distance, any relative motion between them may be blocked, and they may act as a single cable. In such a case, vibrations may be transferred through the damper 9 unattenuated, i. e. its damping properties have been lost. The effects from the choice of properties of the cables 1, 2 may be combined with the effects from the choice of the lengths of the functional levers 6, 7, in order to design dampers with the desired properties for their applications. Fig.2 further illustrates that the teeter element 3 has two different functional levers 6, 7. A first cable 1 is attached to a longer functional lever 6, i. e. at a longer distance from the pivot 15, while the second cable 2 is attached to a shorter functional lever 7. Hence a vibration motion of the segment 14a, which is transferred via the pivot 15 to the teeter element 3, may result in two different forces acting on the two cables 1, 2. The two different forces may result in a relative motion between the two cables 1, 2, possibly due to elongations of the cables 1, 2, but also from a motion of the teeter element 3 around the pivot 15 until a new balance between the forces acting on the cables 1, 2 has been attained. The vibration is meanwhile attenuated, due to the friction between the cables, and transferred to the other segment 14b only to a very low degree, if any at all. In an opposite, but corresponding case, the segment 14b may be subjected to a vibration motion, which may result in a motion of the teeter element 3 around its pivot 15, and relative motions between the two cables 1, 2. The relative motions are attenuated hereby and only to a low degree transferred to the segment 14a, via the pivot 15, if at all. Regarding the shape of the teeter element 3 and the functional levers 6, 7, it may be noticed that the teeter element 3 is presented in the drawings with a rather flat surface comprising the levers 6, 7. However, the functional levers 6, 7 may, for instance, be attained on a rounded or circular teeter element 3, with the cables 1, 2 arranged tangentially to the periphery of the rounded part of the teeter element 3. The solution principle is still the same as long as there are functional levers 6, 7 causing torque by the tension of the cables 1, 2 in relation to the pivot 15 of the teeter element 3.In further embodiments, not shown in the figures, there is a teeter element 3 arranged at both ends of the damper 9. Any vibration motion of either segment 14a, 14b is transferred via the pivot 15 to the teeter element 3 and may result in two different forces acting on the two cables 1, 2, as described above. The two different forces may result in a relative motion between the two cables 1, 2, possibly due to elongations of the cables 1, 2, but also from a motion of the teeter element 3 around the pivot 15 until a new balance between the forces acting on the cables 1, 2 has been attained. The vibration is meanwhile attenuated, due to the friction between the cables 1, 2 and transferred to the other teeter element 3 only to a very low degree. However, the remaining relative motions of the cables 1, 2, may set the second teeter element 3 into a slight motion around its pivot 15, resulting in forces and relative motions of the cables 1, 2, in opposite directions. The opposing directions of the forces and relative motions derived from the second teeter element 3 may, in themselves serve to dampen the remaining relative motions. Also, by arranging a teeter element 3 at the second end of the damper 9, any remaining vibrations may result in relative motions that are further attenuated by the friction between the cables 1, 2, and not transferred to the other segment via the pivot 15. In particular, if the longer functional levers 6 of two teeter elements 3 are connected to one another, the motions in the cable connecting these levers may be maximised at first, but the motion may also result in a maximised amount of motion energy being dissipated as heat energy as quickly as possible. In many practical cases this would be an optimized solution. However, an embodiment wherein the longer functional lever 6 on one teeter element 3 is connected to the shorter lever of another teeter element 3 may be a preferred selection for some applications. It this case it may be envisaged that there may be a slightly higher number of relative motions back and forth, but the size of the motions is, on the other hand, expected to be smaller. In some embodiments a damper 9, with two teeter elements 3 at its outer ends, may comprise two dampers, each one similar to the damper of fig 1, interconnected at the middle portion of the damper 9. Fig 3 illustrates a building assembly 16, wherein dampers 9 according to the disclosure are arranged diagonally in several sections of the building assembly. Building assemblies 16 of various types may comprise framed structures like that of Fig.3, for instance a tall building with vertical outside beams 11 and sectional stable frames 10, like floor sections in buildings. Such framed structures may have rather small deformation of the section area and the vertical beams 11. To install the wire dampers 9 as shear bracing, as seen in Fig.3, will provide shear stiffness and carry shear loads of the framed structure, when it is exposed to forces that bends or shifts the framed structure or building assembly 16. Fig.4 discloses possible deformations in the framed structure in the building assembly 16. The deformations are exaggerated for illustration purposes, and they are not to scale. The deformations may be seen as representing the forces acting on the building assembly 16, e. g. from the wind. With the disclosed dampers 12, 13 any vibrational motions caused by the forces are dampened efficiently. If there is a low shear bearing capability, there may be a tendency towards a large diagonal deformation of such a structure, as shown in Fig.4, had the dampers not been arranged therein. In the figure the dampers are shown in an unloaded, non- active state 13 and an extended, active state 12. The motion of the framed structure will make the wire dampers extend into the extended, active state 12, as seen in Fig. 4. In this extended state 12, they are activated as described above, and they will thereby attenuate motion energy and oscillatory motions. The purpose is to attenuate dynamic motions of the framed structures and any building assembly 16 when exposed to dynamic loads, such as from wind, earthquakes etc., especially loads that are low orders of global resonances or natural frequencies. For instance, any sway in a light tall building exposed to wind loading may be reduced or eliminated by the disclosed dampers 12, 13. In the example disclosed in Fig 4, some of the active dampers 12 may be subjected to a pulling force, depending on the direction of the loads from the wind, etc. At the same time, there may be other dampers 17 that are not subjected to a load, or even a negative load as compared with the non-active state 13, in the building assembly 16. Such dampers 17 may be temporarily relaxed. The cables 1, 2 in the dampers 12 may be extended and put into relative motion as described above. The relative motions of the cables 1, 2 may then be dampened in the manner described above. If the loads affecting the building assembly 16 change, the previously relaxed dampers 17 may be activated and may serve to dampen vibrations in other directions in the same manner as described previously. Hence the disclosed dampers 9, 12, 13, 17 contribute to stabilizing frame structures in building assemblies 16 and keeping them free from vibrations. The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

Claims

Claims 1. A building structure damper (9, 12, 13, 17) comprising two cables (1, 2) that are twisted together forming an elongate damper element, the damper (9, 12, 13, 17) comprising a first and a second end, wherein the ends comprise respective first and second anchor arrangements (18a, 18b), at least one of the first and second anchor arrangements (18a, 18b) comprising a first anchor and a second anchor for the respective cables (1, 2), wherein the first and second anchors are separated by an anchor distance.

2. The building structure damper (9, 12, 13, 17) according to claim 1, wherein the first anchor arrangement (18a) comprises an anchor device comprising a teeter element (3) including a pivot (15) and two functional levers (6, 7) extending outwards from the pivot (15) in substantially opposite directions, and each cable (1, 2) is attached at its respective end to a respective functional lever (6, 7) by the first and second anchors.

3. The building structure damper (9, 12, 13, 17) according to claim 2, wherein the lengths of the respective levers (6, 7), from the pivot (15), are mutually different.

4. The building structure damper (9, 12, 13, 17) according to claim 2 or claim 3, wherein both the first and the second anchor arrangements (18a, 18b) each comprise a respective teeter element (3) comprising a pivot (15) and two functional levers (6, 7) extending sideways from the pivot (15), and each cable (1, 2) is attached at its respective end to a respective lever (6, 7).

5. The building structure damper (9, 12, 13, 17) according to claim 4 as dependent on claim 3, wherein the shorter levers (7) on the respective teeter elements (3) are interconnected by one of the cables (1, 2), and the longer levers (6) on the respective teeter elements (3) are interconnected by the other cable (1, 2).

6. The building structure damper (9, 12, 13, 17) according to any of the preceding claims, wherein the cables (1, 2) comprise mutually different materials.

7. The building structure damper (9, 12, 13, 17) according to claim 6, wherein the cables (1, 2) have mutually different moduli of elasticity.

8. The building structure damper (9, 12, 13, 17) according to any of the preceding claims, wherein the cables (1, 2) have mutually different stiffness.

9. The building structure damper (9, 12, 13, 17) according to any of the preceding claims, wherein the cables (1, 2) have mutually different cross sections (4, 5). 10.The building structure damper (9, 12, 13, 17) according to any of the preceding claims, wherein the surface of at least one cable (1, 2) has an outer layer comprising a different material than the core of the cable (1, 2). 11.A building assembly (16), comprising the building structure damper (9, 12, 13, 17) according to any of the preceding claims. 12.The building assembly (16) according to claim 11, wherein at least two building structure dampers (9, 12, 13, 17) are arranged in an intersecting manner between opposing elements of the building assembly (16).

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