Anti-drawing device

Abstract

The invention belongs to the field of building earthquake resistance, and particularly relates to an anti-drawing device which comprises a first anti-drawing module, a second anti-drawing module and an anti-drawing energy consumption module. Wherein the first anti-drawing module comprises a first cross beam, a first connecting frame arranged on the first cross beam and used for being connected with a building, and a first limiting assembly fixedly arranged on one side of the first cross beam, and the inner side of the first limiting assembly is a first limiting area. The anti-drawing energy consumption module is limited in a certain area by the first limiting assembly and the second limiting assembly, and the first anti-drawing module and the second anti-drawing module intersect with each other relative to the sliding direction of the anti-drawing energy consumption module. The first limiting assembly and the second limiting assembly can collide with the anti-drawing energy consumption module in different directions, earthquake energy is consumed by shearing off the anti-shear pin, and the overall structure of the anti-drawing device is protected against failure while a building is protected.

Description

Technical Field

[0001] The present application belongs to the field of building earthquake resistance, and specifically relates to an anti-pullout device. Background Art

[0002] Pullout devices are devices used to resist external pulling or lifting forces, ensuring structural stability. These devices are crucial in construction, particularly when dealing with wind, earthquakes, or other forces that could cause a building to lift upward. For example, in areas with challenging geology or at risk of severe storms and earthquakes, pullout devices may be incorporated into the foundation design of a building to increase safety.

[0003] Existing pullout-resistant devices have upper and lower structures that can move laterally within a certain range to offset damage to the structure caused by lateral building movement. However, if the building moves too much laterally, exceeding the upper and lower structure's displacement limits, the pullout-resistant device can easily be damaged and fail. Summary of the Invention

[0004] The technical problem to be solved by the present application is to provide an anti-pullout device that resists lateral force and limits displacement through a shear energy-dissipating structure, can be sheared off to consume energy under extreme conditions, and protect the overall structure of the anti-pullout device from failure.

[0005] The present application provides an anti-pullout device, comprising: The first anti-pullout module includes a first crossbeam, a first connecting frame provided on the first crossbeam for connecting to the building, and a first limiting assembly fixedly provided on one side of the first crossbeam, wherein the inner side of the first limiting assembly is a first limiting area; The second pull-out resistant module includes a second crossbeam, a second connecting frame provided on the second crossbeam for connecting to the building, and a second limiting assembly fixedly provided on one side of the second crossbeam, wherein the inner side of the second limiting assembly is a second limiting area, the second crossbeam is arranged to intersect with the first crossbeam, and the first limiting assembly and the second limiting assembly are arranged opposite each other; The anti-pullout energy dissipation module includes a first sliding member that is slidably set on the first limiting component and located in the first limiting area, a second sliding member that is slidably set on the second limiting component and located in the second limiting area, and a plurality of shear pins whose ends are respectively inserted into the first sliding member and the second sliding member, and the sliding direction of the first sliding member intersects with the sliding direction of the second sliding member.

[0006] Optionally, a sliding direction of the first sliding member is perpendicular to a sliding direction of the second sliding member.

[0007] Optionally, the second crossbeam is distributed crosswise with the first crossbeam, and the second crossbeam is located below the first crossbeam. When in use, the first connecting frame and the second connecting frame are respectively connected to the lower structure and the upper structure of the building.

[0008] Optionally, the first limiting assembly includes two first guide members arranged in parallel, and two first blocking members arranged between the two first guide members. The two first guide members and the two first blocking members together form a rectangular first limiting area, and the first sliding member slides in cooperation with the two first guide members.

[0009] Optionally, the second limiting assembly includes two second guide members arranged in parallel, two second blocking members arranged between the two second guide members, the two second guide members and the two second blocking members together form a rectangular second limiting area, and the second sliding member slides in cooperation with the two second guide members.

[0010] Optionally, the first blocking member includes one or more staggered first blocking blocks and first energy-dissipating bolts for fixing the first blocking blocks, and the first blocking blocks are fixed to the first crossbeam via the first energy-dissipating bolts.

[0011] Optionally, the second blocking member includes one or more staggered second blocks and second energy-dissipating bolts for fixing the second blocks, and the second blocks are fixed to the second crossbeam via the second energy-dissipating bolts.

[0012] Optionally, there is a gap between the first sliding member and the second sliding member, and opposite surfaces of the first sliding member and the second sliding member have a mounting groove, and a pressure sensor is arranged in the mounting groove.

[0013] Optionally, a wear-resistant plate is provided on the opposite sides of the first sliding member and the second sliding member, and a first mirror stainless steel plate and a second mirror stainless steel plate matching the wear-resistant plate are provided on the first beam and the second beam respectively.

[0014] Optionally, the first limiting assembly is provided with first wear-resistant strips on both sides along the sliding direction of the first sliding member, and the first sliding member is provided with first stainless steel strips matching the first wear-resistant strips on both sides along its own sliding direction; the second limiting assembly is provided with second wear-resistant strips on both sides along the sliding direction of the second sliding member, and the second sliding member is provided with second stainless steel strips matching the second wear-resistant strips on both sides along its own sliding direction.

[0015] Optionally, the two first connecting frames are respectively connected to the two ends close to the first beam and form a U-shaped structure, and the two second connecting frames are respectively connected to the two ends close to the second beam and form a U-shaped structure. The first connecting frame and the second connecting frame both have multiple bolt holes for connecting to the building by bolts.

[0016] The beneficial effect of the present application is that, in the anti-pullout device provided herein, the anti-pullout energy dissipation module is restrained within a specific area by a first limiting assembly and a second limiting assembly, respectively. The sliding directions of the first and second anti-pullout modules intersect with the anti-pullout energy dissipation module. When the building moves laterally beyond the limited displacement (e.g., during an earthquake), the first and second limiting assemblies collide with the anti-pullout energy dissipation module in different directions, shearing the shear pins and consuming the earthquake energy, thereby protecting the building while also preventing failure of the overall anti-pullout device structure. The anti-pullout energy dissipation module can be removed and the shear pins replaced by removing the first and second limiting assemblies. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the three-dimensional structure of the anti-pullout device provided in an embodiment of the present application; Figure 2 A schematic diagram of the longitudinal cross-section structure of the anti-pullout device provided in an embodiment of the present application; Figure 3 for Figure 2 A magnified view of area A in ; Figure 4 A schematic diagram of the three-dimensional structure of another anti-pullout device provided in an embodiment of the present application.

[0018] In the figure: 110, first crossbeam; 120, first connecting frame; 130, first limiting assembly; 131, first guide member; 132, first stop block; 133, first energy-absorbing bolt; 134, first stainless steel bar; 140, first mirror stainless steel plate; 210, second crossbeam; 220, second connecting frame; 230, second limiting assembly; 231, second guide member; 232, second stop block; 233, second energy-absorbing bolt; 234, second stainless steel bar; 240, second mirror stainless steel plate; 310, first sliding member; 320, second sliding member; 330, shear pin; 340, wear-resistant plate; 350, second wear-resistant strip; 400, pressure sensor. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0020] like Figure 1-4 As shown, the present application provides an anti-pullout device, comprising: a first anti-pullout module, a second anti-pullout module and an anti-pullout energy dissipation module; wherein the first anti-pullout module comprises a first crossbeam 110, a first connecting frame 120 provided on the first crossbeam 110 for connecting to a building, a first limiting component 130 fixedly provided on one side of the first crossbeam 110, and the inner side of the first limiting component 130 is a first limiting area; the second anti-pullout module comprises a second crossbeam 210, a second connecting frame 220 provided on the second crossbeam 210 for connecting to a building, a second limiting component 230 fixedly provided on one side of the second crossbeam 210, and the first limiting area is provided on the inner side of the first limiting component 130. The inner side of the second limiting component 230 is the second limiting area, the second crossbeam 210 and the first crossbeam 110 are cross-distributed, and the first limiting component 130 and the second limiting component 230 are relatively distributed; the anti-pullout energy-absorbing module includes a first sliding member 310 that is slidably arranged on the first limiting component 130 and located in the first limiting area, a second sliding member 320 that is slidably arranged on the second limiting component 230 and located in the second limiting area, and a plurality of shear pins 330 respectively inserted into the first sliding member 310 and the second sliding member 320 at both ends, and the first anti-pullout module and the second anti-pullout module intersect with respect to the sliding direction of the anti-pullout energy-absorbing module.

[0021] Compared to the prior art, the pull-out resistance device provided herein features a pull-out resistance energy dissipation module constrained to a specific area by a first limiting assembly 130 and a second limiting assembly 230, respectively. The sliding directions of the first and second pull-out resistance modules intersect with each other. When the building moves laterally beyond the specified displacement (e.g., during an earthquake), the first and second limiting assemblies 130, 230 collide with the pull-out resistance energy dissipation module in different directions, shearing off the shear pins 330 and dissipating the seismic energy. This protects the building while also preventing the overall structure of the pull-out resistance device from failing. The pull-out resistance energy dissipation module can be removed and the shear pins 330 replaced by removing the first and second limiting assemblies 130, 230.

[0022] In one possible implementation, the first and second pullout modules are perpendicular to the sliding direction of the pullout energy dissipation module. Specifically, the first pullout module constrains one direction (for example, the X-axis), while the second pullout module constrains a direction perpendicular to it (for example, the Y-axis). Together, these two constrains displacement in two orthogonal directions within the structure. In practical applications (such as earthquakes and wind-induced vibrations), loads are complex and variable, potentially originating from any horizontal direction. This vertical arrangement of pullout modules effectively prevents unexpected, excessive relative sliding or disengagement of the energy dissipation module in any horizontal direction, significantly improving the stiffness and stability of the entire connection node or energy dissipation device within the plane.

[0023] In one possible implementation, the second crossbeam 210 is arranged crosswise with the first crossbeam 110, and the second crossbeam 210 is located below the first crossbeam 110. When in use, the first connecting frame 120 and the second connecting frame 220 are connected to the lower structure and the upper structure of the building, respectively. Specifically, the cross arrangement of the first crossbeam 110 (usually representing one direction, such as the X direction) and the second crossbeam 210 (perpendicular thereto, such as the Y direction) enables the entire device to provide constraints, guide sliding, or trigger energy dissipation mechanisms in all directions (360°) within the horizontal plane. The device can work effectively regardless of the horizontal direction from which the earthquake wave comes. Providing omnidirectional earthquake protection overcomes the limitation of unidirectional devices that can only resist earthquake forces in a specific direction, significantly improving the safety of the structure. Construct a stable, controllable and multi-directional energy-absorbing sliding / rotating interface to flexibly connect or dissipate energy in the horizontal direction the upper and lower structures of the building, allowing them to undergo controllable relative displacement under the action of horizontal forces (such as earthquake forces and wind loads), while effectively transmitting vertical loads and dissipating seismic energy, thereby protecting the main structure.

[0024] In one possible implementation, the first limiting assembly 130 includes two first guide members 131 arranged in parallel, two first blocking members arranged between the two first guide members 131, the two first guide members 131 and the two first blocking members together form a rectangular first limiting area, and the first sliding member 310 slides in cooperation with the two first guide members 131. Specifically, the two first guide members 131 can be rectangular columnar structures, which are detachably fixed to the first beam 110 by bolts. The two first blocking members can be rectangular block structures, which are detachably fixed to the first beam 110 by bolts. The first guide member 131 and the first blocking member are perpendicular to each other, and the two sides of the first sliding member 310 slide in cooperation with the two first guide members 131 respectively. The two detachable first guide members 131 and the two first blocking members facilitate the replacement of the shear pin 330 in the anti-pullout energy dissipation module.

[0025] In one possible implementation, the second limiting assembly 230 includes two second guide members 231 arranged in parallel, two second blocking members arranged between the two second guide members 231, the two second guide members 231 and the two second blocking members enclose a rectangular second limiting area, and the second sliding member 320 slides with the two second guide members 231. Specifically, the two second guide members 231 can be rectangular columnar structures, which are detachably fixed to the second beam 210 by bolts. The two second blocking members can be rectangular block structures, which are detachably fixed to the second beam 210 by bolts. The second guide member 231 and the second blocking member are perpendicular to each other, and the two sides of the second sliding member 320 slide with the two second guide members 231 respectively. The two detachable second guide members 231 and the two second blocking members facilitate the replacement of the shear pin 330 in the anti-pullout energy dissipation module.

[0026] In one possible implementation, the first blocking member includes a first block 132 and a first energy-absorbing bolt 133 for fixing the first block 132. The first block 132 is fixed to the first beam 110 by the first energy-absorbing bolt 133. The first energy-absorbing bolt 133 cuts off and dissipates seismic energy, thereby protecting the main structure.

[0027] In another possible implementation, Figure 4As shown, the first blocking member includes a plurality of staggered first blocks 132, a first energy-absorbing bolt 133 for fixing the first block 132, and the first block 132 is fixed to the first beam 110 by the first energy-absorbing bolt 133, thereby forming a multi-stage energy-absorbing structure; the second blocking member includes one or more staggered second blocks 232, a second energy-absorbing bolt 233 for fixing the second block 232, and the second block 232 is fixed to the second beam 210 by the second energy-absorbing bolt 233. Specifically, the multiple first stoppers 132 are not arranged in a straight line perpendicular to the sliding direction, but are staggered along the length of the first beam 110 (i.e., the direction of the expected sliding path). Each first stopper 132 is secured to the first beam 110 with a separate first energy-absorbing bolt 133. The multiple second stoppers 232 are not arranged in a straight line perpendicular to the sliding direction, but are staggered along the length of the second beam 210 (i.e., the direction of the expected sliding path). Each second stopper 232 is secured to the second beam 210 with a separate second energy-absorbing bolt 233. Energy-absorbing bolts (referred to as the first and second energy-absorbing bolts 133 and 233) are sacrificial / yielding elements. Their core function is not to provide infinitely strong rigid constraints, but to undergo controlled plastic deformation (yielding) or fracture when subjected to loads exceeding their design threshold. This deformation or fracture process absorbs and dissipates a significant amount of seismic energy. The system has a multi-stage triggering mechanism: Initially, during small earthquakes or wind-induced vibrations, the relative displacement is small. At this point, all the stops and energy-absorbing bolts work together to provide initial stiffness and a small restraining force, allowing the structure to maintain its elasticity. First-stage energy dissipation: When the relative displacement (for example, the second crossbeam 210 drives the pullout-resistant energy-absorbing module to slide relative to the first crossbeam 110) increases to the design displacement threshold of the first stopper, the shear or tensile force on the first energy-absorbing bolt corresponding to that stopper reaches its yield strength. This bolt begins to undergo significant plastic deformation, dissipating a significant amount of energy. Simultaneously, the restraining force provided by the stopper reaches its peak and then begins to "soften" (i.e., the restraining stiffness decreases). Second-stage energy dissipation: The relative displacement continues to increase, reaching the design displacement threshold of the second stopper (offset by a certain distance). At this point, the first energy-absorbing bolt may be severely deformed or close to failure, and the second energy-absorbing bolt begins to enter the yield energy dissipation stage. This continues in a step-by-step manner: As the relative displacement continues to increase, the energy-absorbing bolts corresponding to the stoppers, in the order of their offset distances, reach their yield points and begin dissipating energy. This creates a stepped, hierarchical energy dissipation sequence to cope with earthquakes of varying magnitudes. The stopper itself is relatively rigid. Even if the corresponding energy-dissipating bolt yields or breaks, its physical presence acts as a mechanical limiter, preventing the relative displacement from increasing indefinitely and protecting the main structure and the device from destructive displacement. The energy dissipation of the bolt occurs when the displacement reaches the stopper and attempts to push against it.

[0028] In one possible implementation, Figure 2 As shown, there is a gap between the first sliding member 310 and the second sliding member 320, and the opposite surfaces of the first sliding member 310 and the second sliding member 320 have installation grooves, and a pressure sensor 400 is provided in the installation groove. The tension is converted into pressure, and a pressure sensor 400 is provided in the middle of the anti-pullout energy-absorbing module to monitor the tension borne by the anti-pullout device in real time. The tension of the building structure is monitored during an earthquake. Through these monitoring data, the seismic isolation design of the building can be reversed. For example, the current tensile stress is usually designed according to 1.5MPa based on the results of finite element simulation analysis, but the actual working conditions may not be like this. Through monitoring, actual data can be obtained to reversely optimize the seismic isolation design of the building. Compared with the tension sensor, the pressure sensor 400 has a lower cost and a larger range. Converting tension into pressure can reduce costs.

[0029] In one possible implementation, Figure 3 As shown, the first and second sliding members 310 and 320 are each provided with a wear-resistant plate 340 on their opposing sides. The first and second crossbeams 110 and 210 are respectively provided with a first mirror-finished stainless steel plate 140 and a second mirror-finished stainless steel plate 240 that mate with the wear-resistant plates 340. Specifically, the wear-resistant plates 340 can be made of polytetrafluoroethylene (PTFE), its composite materials, ultra-high molecular weight polyethylene (UHMWPE), etc. The first and second mirror-finished stainless steel plates 140 and 240 can be made of austenitic stainless steel (e.g., 304 or 316L), with their surfaces precision-polished to a mirror-grade finish. The wear-resistant plates 340 directly contact the first and second mirror-finished stainless steel plates 140 and 240, forming a sliding interface. When the first and second crossbeams 110 and 210 undergo relative displacement (e.g., under earthquake conditions), the wear-resistant plates 340 slide on the surfaces of the mirror-finished stainless steel plates. This significantly reduces the force required to initiate and maintain sliding of the device. It makes the structural system more "sensitive" and can activate the isolation / energy dissipation mechanism under the action of a smaller earthquake; at the same time, it reduces the resistance during the sliding process, which is conducive to achieving a larger design displacement and improving the isolation / energy dissipation effect.

[0030] In one possible implementation, Figure 3As shown, first stop assembly 130 is provided with first wear strips on both sides of the first slider 310 along its sliding direction. First stainless steel strips 134 are provided on both sides of the first slider 310 along its sliding direction, cooperating with the first wear strips. Second stop assembly 230 is provided with second wear strips 350 on both sides of the second slider 320 along its sliding direction. Second stainless steel strips 234 are provided on both sides of the second slider 320 along its sliding direction, cooperating with the second wear strips 350. Specifically, the first and second wear strips 350 can be made of polytetrafluoroethylene (PTFE), its composite materials, ultra-high molecular weight polyethylene (UHMWPE), etc., while the first and second stainless steel strips 134 and 234 can be made of austenitic stainless steel (e.g., 304 or 316L), with their surfaces precision-polished to a mirror-grade finish. The first wear strips are in direct contact with the first stainless steel strip 134, while the second wear strips 350 and 234 are in direct contact, forming a sliding interface. When the first crossbeam 110 and the second crossbeam 210 experience relative displacement (e.g., during an earthquake), the wear strips slide on the stainless steel strips. This significantly reduces the force required to initiate and maintain sliding. This makes the structural system more "responsive," enabling the isolation and energy dissipation mechanisms to activate even with relatively minor earthquakes. Furthermore, the reduced resistance during sliding facilitates achieving greater design displacements and enhances isolation and energy dissipation effectiveness.

[0031] In one possible implementation, two first connecting frames 120 are connected to the ends of the first crossbeam 110 to form a U-shaped structure. Two second connecting frames 220 are connected to the ends of the second crossbeam 210 to form a U-shaped structure. Each of the first connecting frames 120 and the second connecting frames 220 has multiple bolt holes for bolting to the building. The material's compressive strength is higher than its tensile strength, which can reduce the size of the intermediate connecting portion and improve the tensile strength of the device.

[0032] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0033] The one or more embodiments of this application are intended to encompass all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this application should be included in the scope of protection of this application.

Claims

1. An anti-pullout device, characterized in that: include: The first pull-out resistant module comprises a first crossbeam (110), a first connecting frame (120) arranged on the first crossbeam (110) for connecting to a building, and a first limiting assembly (130) fixedly arranged on one side of the first crossbeam (110), wherein the inner side of the first limiting assembly (130) is a first limiting area; The second pull-out resistant module comprises a second crossbeam (210), a second connecting frame (220) arranged on the second crossbeam (210) for connecting to a building, and a second position-limiting component (230) fixedly arranged on one side of the second crossbeam (210), wherein the inner side of the second position-limiting component (230) is a second position-limiting area, the second crossbeam (210) and the first crossbeam (110) are arranged crosswise, and the first position-limiting component (130) and the second position-limiting component (230) are arranged relative to each other; The anti-pullout energy dissipation module comprises a first sliding member (310) slidably arranged on the first limiting component (130) and located in the first limiting area, a second sliding member (320) slidably arranged on the second limiting component (230) and located in the second limiting area, and a plurality of shear pins (330) respectively inserted into the first sliding member (310) and the second sliding member (320) at both ends, wherein the sliding directions of the first anti-pullout module and the second anti-pullout module intersect with each other relative to the anti-pullout energy dissipation module.

2. The anti-pullout device according to claim 1, characterized in that: The sliding direction of the first sliding member (310) is perpendicular to the sliding direction of the second sliding member (320).

3. The anti-pullout device according to claim 2, characterized in that: The second crossbeam (210) and the first crossbeam (110) are arranged in a cross-shaped manner, and the second crossbeam (210) is located below the first crossbeam (110). When in use, the first connecting frame (120) and the second connecting frame (220) are respectively connected to the lower structure and the upper structure of the building.

4. The anti-pullout device according to any one of claims 1 to 3, characterized in that: The first limiting assembly (130) comprises two first guide members (131) arranged in parallel, and two first blocking members arranged between the two first guide members (131); the two first guide members (131) and the two first blocking members together form a rectangular first limiting area; the first sliding member (310) is in sliding engagement with the two first guide members (131).

5. The anti-pullout device according to claim 4, characterized in that: The second limiting assembly (230) comprises two second guide members (231) arranged in parallel, and two second blocking members arranged between the two second guide members (231); the two second guide members (231) and the two second blocking members together form a rectangular second limiting area; and the second sliding member (320) is in sliding engagement with the two second guide members (231).

6. The anti-pullout device according to claim 5, characterized in that: The first blocking member comprises one or more staggered first blocking blocks (132) and a first energy-dissipating bolt (133) for fixing the first blocking block (132), wherein the first blocking block (132) is fixed to the first crossbeam (110) via the first energy-dissipating bolt (133); And / or, the second blocking member includes one or more staggered second blocking blocks (232), and a second energy-dissipating bolt (233) for fixing the second blocking block (232), and the second blocking block (232) is fixed to the second crossbeam (210) via the second energy-dissipating bolt (233).

7. The anti-pullout device according to any one of claims 1-3, 5 and 6, characterized in that: There is a gap between the first sliding member (310) and the second sliding member (320), and opposite surfaces of the first sliding member (310) and the second sliding member (320) have a mounting groove, in which a pressure sensor (400) is arranged.

8. The anti-pullout device according to any one of claims 1-3, 5 and 6, characterized in that: A wear-resistant plate (340) is provided on the opposite sides of the first sliding member (310) and the second sliding member (320), and a first mirror stainless steel plate (140) and a second mirror stainless steel plate (240) are provided on the first crossbeam (110) and the second crossbeam (210), respectively, to match the wear-resistant plate (340).

9. The anti-pullout device according to claim 8, characterized in that: The first limiting assembly (130) is provided with first wear-resistant strips on both sides along the sliding direction of the first sliding member (310), and the first sliding member (310) is provided with first stainless steel strips (134) that match the first wear-resistant strips on both sides along its own sliding direction; the second limiting assembly (230) is provided with second wear-resistant strips (350) on both sides along the sliding direction of the second sliding member (320), and the second sliding member (320) is provided with second stainless steel strips (234) that match the second wear-resistant strips (350) on both sides along its own sliding direction.

10. The anti-pullout device according to any one of claims 1-3, 5 and 6, characterized in that: The two first connecting frames (120) are respectively connected to the two ends of the first crossbeam (110) to form a U-shaped structure, and the two second connecting frames (220) are respectively connected to the two ends of the second crossbeam (210) to form a U-shaped structure. The first connecting frame (120) and the second connecting frame (220) are each provided with a plurality of bolt holes for being connected to a building by bolts.

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