An exposed steel column foot with replaceable cover and construction method thereof

Abstract

The present invention discloses an exposed steel column foot with a replaceable cover plate and a construction method thereof. The steel column foot comprises a steel column, a cover plate, a base plate, a mortar layer, an anchor rod, a screw rod, and a concrete foundation. The steel column and the base plate are welded together; the cover plate is placed on the base plate and the mortar layer, the base plate is provided with a concrete foundation, the outer periphery of the base plate is provided with a mortar layer, the mortar layer and the base plate are not in contact, and the base plate is provided with a concrete foundation; the anchor rod is pre-buried in the concrete foundation, and the anchor rod connects the concrete foundation, the mortar layer and the cover plate through the reserved holes on the outer side of the cover plate and the mortar layer; the screw rod connects the cover plate and the base plate through the reserved holes on the inner side of the cover plate and the base plate; the anchor rod and the screw rod are both connected and fixed using matching nuts. Compared with the existing technical solutions, the present invention improves the energy consumption capacity of the exposed steel column foot, realizes the control of structural damage and deformation, and achieves the purpose of replaceable components and rapid repair after an earthquake.

Description

Technical Field

[0001] The invention belongs to the field of earthquake resistance of construction engineering, and particularly relates to an exposed steel column foot with a replaceable cover plate and a construction method thereof. Background Art

[0002] Steel column bases are crucial connections between the upper main structure and the foundation of steel structures. They effectively transmit axial forces, bending moments, and shear forces from the upper structure to the foundation, significantly impacting the internal force distribution and displacement of the building structure. Based on their structural form, steel column bases can generally be divided into three categories: exposed, enclosed, and embedded. Exposed column bases are the most widely used type of base in low- and medium-rise buildings due to their ease of installation, short construction periods, and low cost. However, exposed column bases often suffer from insufficient energy dissipation capacity. Under earthquake action, their anchor bolts and base plates are susceptible to plastic deformation, leading to significant slip deformation at the column base. These residual deformations can render earthquake damage to the structure irreversible, complicating post-disaster repair efforts.

[0003] In order to improve the energy dissipation capacity of the exposed steel column base, the thickness of the base plate at the column base can generally be adjusted. However, since the base plate is generally not replaceable, its plastic deformation will continue to accumulate, which will damage the safety of the structure. For example, for the exposed steel column base connected by traditional anchor rods, its deformation under the action of an earthquake is mainly concentrated at the anchor bolts and the base plate. Since the base plate is not replaceable, the plastic deformation of the anchor bolts and the base plate will continue to accumulate and increase, and will eventually cause the anchor bolts to break, which is very unfavorable for post-earthquake reconstruction. Cui Yao et al. disclosed in the invention patent CN108756005A "High-energy-dissipation exposed steel column base that can be quickly repaired after an earthquake and its construction and maintenance method" to improve the seismic performance and energy dissipation capacity of the exposed steel column base. However, the energy-dissipating component (i.e., the outer base plate) in this invention application is fixed by welding, which has a complex structure and high construction difficulty, making it difficult to achieve rapid replacement after an earthquake.

[0004] In summary, existing exposed steel column bases have two obvious limitations: 1) insufficient energy absorption capacity, which makes the anchor bolts and base plate prone to plastic deformation, leading to column base slippage; 2) the non-replaceable (or difficult to replace) energy-absorbing components reduces structural safety and hinders post-earthquake repair of the structure. Summary of the Invention

[0005] In order to solve at least one of the problems existing in the prior art, the present invention provides an exposed steel column base with a replaceable cover plate and a construction method thereof, which can increase the stiffness and energy consumption capacity of the exposed steel column base and improve its seismic performance; at the same time, the earthquake damage of the exposed steel column base can be controlled at the cover plate, and the cover plate is replaceable, thereby realizing replaceable components and rapid repair after an earthquake.

[0006] To achieve the purpose of the present invention, the present invention provides an exposed steel column foot with replaceable cover plates, comprising a concrete foundation, a steel column, a base plate, a mortar layer, multiple cover plates, multiple anchor rods and multiple screw rods.

[0007] The bottom plate is used to be set on the top surface of the concrete foundation and welded to the bottom of the steel column;

[0008] The mortar layer is arranged around the periphery of the base plate, and there is no contact between the mortar layer and the base plate;

[0009] Multiple cover plates are located on the top surface of the mortar layer and the base plate, and are arranged around the periphery of the steel column without contacting the steel column; anchor rods are pre-buried in the concrete foundation; on the side of the cover plate close to the steel column (i.e., the inner side), the cover plate is detachably connected to the base plate through screws; on the side of the cover plate away from the steel column (i.e., the outer side), the cover plate is detachably connected to the mortar layer and the concrete foundation through anchor rods.

[0010] The present invention provides an exposed steel column base with a replaceable cover plate. By providing a cover plate fixed with bolts, it can not only improve the energy consumption capacity of the exposed steel column base and achieve damage control, but also facilitate construction and post-earthquake replacement.

[0011] The cover plate can limit the rotational deformation of the column base, significantly increasing the bending moment required for column base rotation, thereby increasing the rigidity of the steel column base. Compared with traditional exposed steel column bases, the energy-dissipating cover plate of the new steel column base proposed in this invention has greater rigidity, higher yield bearing capacity, and stronger deformation capacity, thus providing better energy dissipation capabilities.

[0012] Specifically, the steel column and the base plate are connected by welding; each cover plate is placed on the mortar layer and the base plate, the side away from the steel column is the outer side, and the lower side of the outer side of the cover plate is the mortar layer, the side close to the steel column is the inner side, and the lower side of the inner side of the cover plate is the base plate; the mortar layer and the base plate are both on the concrete foundation; the mortar layer connects the cover plate and the concrete foundation.

[0013] Furthermore, the mortar layer and the base plate are flush and not in contact.

[0014] Furthermore, the cross-section of the steel column is square, and there are four cover plates, which are respectively located around the steel column.

[0015] Furthermore, each cover plate is provided with a stiffening rib, and the cover plate is welded to the stiffening rib.

[0016] Preferably, the four cover plates have two stiffening ribs welded on one side of each cover plate along the outer side of the reserved holes to enhance the out-of-plane deformation stiffness of the cover plate.

[0017] Furthermore, the cover plate may be in the form of a rectangular cover plate or a trapezoidal cover plate.

[0018] Furthermore, the thickness of the cover plate does not exceed the thickness of the base plate.

[0019] Furthermore, a matching nut for the anchor rod and a matching nut for the screw rod are provided, which are used in conjunction with the anchor rod and the screw rod respectively.

[0020] Furthermore, the cover plate, the concrete foundation, the bottom plate and the mortar layer all contain reserved holes for the anchor rods and screw rods to pass through. The positions of the holes should be arranged symmetrically, and the sizes of the holes should match the diameters of the anchor rods and screw rods.

[0021] Furthermore, four cover plates are provided, the inner side of each cover plate is placed on the base plate, and then the cover plate and the base plate are connected by screws, and the cover plate and the base plate are in close contact by tightening the matching nuts of the screws; the outer side of each cover plate is placed on the mortar layer, and the anchor rods embedded in the concrete foundation will penetrate the mortar layer and the cover plate, and the concrete foundation, mortar layer and cover plate are in close contact by tightening the matching nuts of the anchor rods.

[0022] Furthermore, the cover plate, base plate and mortar layer are all fixed with bolts and can be directly replaced after the earthquake without the need for on-site cutting operations.

[0023] Furthermore, each of the four cover plates does not come into contact with the steel column.

[0024] Furthermore, the thickness of the mortar layer is the same as that of the base plate.

[0025] Furthermore, the steel column and the base plate are prefabricated in the factory in advance, and the two are connected into a whole by welding.

[0026] Furthermore, the thickness of the cover plate does not exceed the thickness of the base plate.

[0027] Furthermore, in order to improve the rigidity of the bottom plate and prevent the bottom plate from being excessively deformed under earthquake action, the thickness of the bottom plate is not less than 30 mm.

[0028] Furthermore, to ensure that deformation of the exposed steel column base during earthquakes is primarily concentrated on the replaceable cover plates, the cover plates are at least 8mm thick. To enhance the rigidity of the cover plates, stiffening ribs are welded to one side of each cover plate. The height, thickness, and length of these ribs must be coordinated, and the thickness must be at least 8mm.

[0029] Furthermore, in order to prevent the outer anchor rods of the four cover plates from slipping, the anchor rods should have a corresponding anchoring length, and the length of the anchor rods embedded in the concrete foundation should not be less than 25d (d is the diameter of the anchor rod).

[0030] The present invention also provides a construction method for the above-mentioned exposed steel column foot with replaceable cover plate, which comprises the following steps:

[0031] After the concrete foundation is cured, the mortar layer is poured, anchor rods are embedded in the concrete foundation, and the mortar layer is set out to form a position for accommodating the bottom plate, and reserved holes are opened in the mortar layer;

[0032] Place the bottom plate and the bottom plate of the steel column, which are welded together in advance in the factory, on the mortar layer at the position where the bottom plate is accommodated, and a reserved hole is opened on the bottom plate;

[0033] After the cover plate and the stiffening rib are welded together, reserved holes are opened on the cover plate. After the mortar layer is cured, multiple cover plates are placed on the mortar layer and the base plate. The multiple cover plates are placed around the steel column, and the reserved holes on the outside of the cover plate are aligned with the reserved holes on the mortar layer, and the reserved holes on the inside of the cover plate are aligned with the reserved holes on the base plate.

[0034] On the outside of the cover plate, the cover plate is connected to the concrete foundation and the mortar layer through anchor rods, and is tightened and fixed with the matching nuts of the anchor rods; on the inside of the cover plate, the cover plate is connected to the base plate through screws, and is tightened and fixed with the matching nuts of the screws.

[0035] Compared with the prior art, the present invention can at least achieve the following beneficial effects:

[0036] 1. Under the action of an earthquake, the deformation of the exposed steel column base provided by the present invention is mainly concentrated on the cover plate, which can achieve the purpose of controlling damage and deformation.

[0037] 2. The setting of the cover plate not only facilitates construction, but also improves the energy dissipation capacity of the exposed steel column base under earthquake action, thereby improving the safety of the building structure.

[0038] 3. When the cover plate undergoes significant deformation, it can be directly replaced, while other components of the exposed steel column base do not need to be replaced, thereby improving the efficiency of post-earthquake repair work and the seismic toughness of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of an exposed steel column foot with a replaceable cover provided by an embodiment of the present invention;

[0040] Figure 2 This is a top view of an exposed steel column foot with a replaceable cover provided by an embodiment of the present invention;

[0041] Figure 3 is a cross-sectional view of a top view AA of an exposed steel column foot with a replaceable cover provided by an embodiment of the present invention;

[0042] Figure 4It is a schematic diagram of other forms of cover plates, which are two forms of rectangular cover plates;

[0043] Figure 5 This is a schematic diagram of the exposed steel column base after removing the anchor rods and cover plates.

[0044] Among them, 1-steel column, 2-cover plate, 3-stiffening rib, 4-base plate, 5-concrete foundation, 6-mortar layer, 7-anchor rod, 8-matching nut of anchor rod, 9-screw, 10-matching nut of screw, 11-reserved hole. DETAILED DESCRIPTION

[0045] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the present applicant belongs.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0047] For the convenience of description, if the words "up", "down", "left" and "right" appear in the present invention, they only indicate that they are consistent with the up, down, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0048] like Figures 1 to 5 As shown, the present invention provides an exposed steel column base with a replaceable cover plate, comprising a steel column 1, a cover plate 2, a stiffening rib 3, a base plate 4, a concrete foundation 5, a mortar layer 6, an anchor rod 7, a matching nut 8 for the anchor rod, a screw rod 9, a matching nut 10 for the screw rod, and a reserved hole 11.

[0049] like Figure 5 The steel column 1 and the base plate 4 are connected as a whole by welding. A mortar layer 6 is provided around the base plate 4. The mortar layer 6 does not contact the base plate 4, and the height of the base plate 4 is the same as that of the mortar layer 6. The mortar layer 6 connects the cover plate 2 and the concrete foundation 5. In some embodiments of the present invention, a space is set out in the center of the mortar layer 6 to form a reserved position for the base plate 4.

[0050] The cover plate 2 and the steel column 1 are not in contact, and the stiffening ribs 3 are welded to the cover plate 2; the cover plate 2 is arranged on the bottom plate 4 and the mortar layer 6, and the bottom of the bottom plate 4 is the concrete foundation 5.

[0051] On one side of each cover plate 2, two stiffening ribs 3 are welded along the outer sides of the reserved holes to enhance the out-of-plane deformation stiffness of the cover plate.

[0052] In some embodiments of the present invention, the cover plate 2 is designed to be trapezoidal. Figure 1 and Figure 2 In other embodiments, the cover plate 2 may also be in other shapes, such as a rectangle, see Figure 4 .in, Figure 4 The stiffening ribs 3 of the cover plate 2 shown in (a) are welded to both sides of the cover plate 2, and the reserved hole 11 is opened between the two stiffening ribs; Figure 4 The reserved hole 11 of the cover plate 2 shown in (b) passes through the stiffening rib 3 and the cover plate 2, and the stiffening rib 3 and the cover plate 2 are welded together.

[0053] See also Figure 5 , a reserved hole 11 is provided on the bottom plate 4, and a reserved hole 11 is also provided on the mortar layer 6, please refer to Figure 4 (a) and Figure 4 (b) Reserved holes 11 are provided on the cover plate 2. The reserved holes 11 on the inner side of the cover plate 2 are aligned with the reserved holes 11 on the base plate 4. The reserved holes 11 on the outer side of the cover plate 2 are aligned with the reserved holes 11 on the mortar layer 6. The cover plate 2 cooperates with the reserved holes on the base plate 4 and the mortar layer 6 through the reserved holes provided thereon so as to facilitate subsequent bolt connection and fixation.

[0054] In some embodiments of the present invention, Figure 1 、 Figure 2 、 Figure 3 and Figure 5 On the outside of the cover plate 2, anchor rods 7 are embedded in the concrete foundation 5. Through the reserved holes, the anchor rods 7 penetrate the cover plate 2 and the mortar layer 6, and are then tightened and fixed with the matching nuts 8 of the anchor rods. On the inside of the cover plate 2, screw rods 9 penetrate the corresponding reserved holes, connecting the cover plate 2 and the base plate 4, and are then tightened and fixed with the matching nuts 10 of the screw rods. The outer anchor rods need to be embedded in the concrete to provide pull-out resistance to embed the energy dissipation cover plate and prevent the outer edge of the energy dissipation cover plate from warping. The inner screw rods only need to connect the steel column base plate and the energy dissipation cover plate, allowing the energy dissipation cover plate and the steel column base plate to deform in coordination, and do not need to be anchored in the concrete foundation.

[0055] The thickness of the replaceable cover plate 2 in the present invention does not exceed the thickness of the base plate 4, which can control the location of damage and deformation, and the cover plate 2 is connected by an inner screw and an outer anchor rod. Such a structure can make the cover plate the main energy-absorbing component of the steel column base, concentrating the earthquake damage on the cover plate, and the cover plate is very convenient to disassemble and replace after the earthquake.

[0056] In some embodiments of the present invention, the cross-section of the steel column 1 is square, and the number of cover plates 2 is four, which are respectively arranged on the four sides of the steel column 1, to ensure that the exposed steel column base has similar high energy consumption capacity in different directions and is easy to install and replace.

[0057] In some embodiments of the present invention, the thickness of the base plate is not less than 30 mm to prevent the base plate from undergoing significant deformation under earthquake action; the thickness of the cover plate is not less than 8 mm, which can effectively increase the stiffness of the steel column base.

[0058] In some embodiments of the present invention, the anchoring depth of the anchor rod 7 is not less than 25d (d is the diameter) to prevent the anchor rod 7 from being pulled out of the concrete foundation 5 under the action of an earthquake.

[0059] In some embodiments of the present invention, a specific construction method for an exposed steel column foot with a replaceable cover plate is also provided, and the steps are as follows:

[0060] 1) After the concrete foundation 5 is cured, a mortar layer 6 is poured. Anchor rods 7 are pre-embedded in the concrete foundation 5. The center of the mortar layer 6 is set out to form a position for setting the base plate 4. The mortar layer 6 includes a reserved hole 11.

[0061] 2) The bottom plate 4 and the steel column 1 are welded in advance in the factory to form a whole, and then the bottom plate 4 is placed in the reserved position in the center of the mortar layer 6 formed in step 1). The bottom plate 4 needs to be provided with a reserved hole;

[0062] 3) Weld the cover plate 2 and the stiffening rib 3 into a whole. The cover plate 2 needs to be provided with reserved holes;

[0063] 4) After the mortar layer 6 is cured, four cover plates 2 are placed on the mortar layer 6 and the base plate 4, and the reserved holes on the outside of each cover plate 2 are aligned with the reserved holes on the mortar layer 6, and the reserved holes on the inside of each cover plate 2 are aligned with the reserved holes on the base plate 4; on the outside of the cover plate 2, use the anchor rod 7 to connect the concrete foundation 5, the mortar layer 6 and the cover plate 2, and tighten and fix them with the matching nut 8 of the anchor rod; on the inside of the cover plate 2, use the screw rod 9 to connect the cover plate 2 and the base plate 4, and tighten and fix them with the matching nut 10 of the screw rod.

[0064] The above construction process adopts the pre-tensioning method to anchor the anchor rods. In some embodiments of the present invention, the post-tensioning method can also be used to anchor the anchor rods.

[0065] The exposed steel column base provided in the embodiment of the present invention adopts a replaceable cover plate, which can firstly increase the stiffness and energy absorption capacity of the exposed steel column base and improve the seismic performance of the exposed column base; secondly, the earthquake damage of the exposed steel column base can be concentrated on the cover plate, thereby achieving the effect of damage control; thirdly, when the cover plate has a large plastic deformation, the exposed steel column base can be repaired by simply replacing the cover plate, thereby realizing rapid recovery of the structure after an earthquake.

[0066] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An exposed steel column base with a replaceable cover, characterized in that: It comprises a concrete foundation (5), a steel column (1), a base plate (4), a mortar layer (6), a plurality of cover plates (2), a plurality of anchor rods (7) and a plurality of screw rods (9); The bottom plate (4) is used to be arranged on the top surface of the concrete foundation (5) and is welded and fixed to the bottom of the steel column (1); The mortar layer (6) is arranged around the periphery of the bottom plate (4), and the mortar layer (6) and the bottom plate (4) are not in contact with each other; The plurality of cover plates (2) are all located on the top surfaces of the mortar layer (6) and the base plate (4), are arranged around the periphery of the steel column (1) and do not contact the steel column (1), and the anchor rods (7) are pre-buried in the concrete foundation (5); on the side of the cover plate (2) close to the steel column (1), the cover plate (2) is detachably connected to the base plate (4) via screw rods (9); and on the side of the cover plate (2) away from the steel column (1), the cover plate (2) is detachably connected to the mortar layer (6) and the concrete foundation (5) via anchor rods (7).

2. The exposed steel column base with replaceable cover according to claim 1, characterized in that: The cross-section of the steel column (1) is square, and four cover plates (2) are provided. The four cover plates (2) are respectively located around the steel column (1).

3. The exposed steel column base with replaceable cover according to claim 1, characterized in that: The mortar layer (6) and the bottom plate (4) are flush with each other.

4. The exposed steel column base with replaceable cover according to claim 1, characterized in that: Each cover plate (2) is provided with a stiffening rib (3), and the cover plate (2) and the stiffening rib (3) are connected by welding.

5. The exposed steel column base with replaceable cover according to claim 1, characterized in that: The thickness of the cover plate (2) does not exceed the thickness of the bottom plate (4).

6. The exposed steel column base with replaceable cover according to claim 5, characterized in that: The thickness of the base plate shall not be less than 30mm, and the thickness of the cover plate shall not be less than 8mm.

7. The exposed steel column base with replaceable cover according to claim 1, characterized in that: The cross-sectional shape of the cover plate (2) is rectangular or trapezoidal.

8. The exposed steel column base with replaceable cover according to any one of claims 1 to 7, characterized in that: A matching nut (8) for the anchor rod and a matching nut (10) for the screw rod are also provided and are used in conjunction with the anchor rod (7) and the screw rod (9) respectively.

9. The exposed steel column base with replaceable cover according to claim 8, characterized in that: Pre-set holes (11) are provided at corresponding positions of the cover plate (2), the concrete foundation (5), the bottom plate (4) and the mortar layer (6).

10. The exposed steel column base with replaceable cover according to claim 9, characterized in that: On the side of the cover plate (2) close to the steel column (1), the screw rod (9) passes through the reserved holes (11) on the cover plate (2) and the base plate (4), and the cover plate (2) and the base plate (4) are tightened and connected by using the matching nut (10) of the screw rod; on the side of the cover plate (2) away from the steel column (1), the anchor rod (7) is pre-buried in the concrete foundation (5), the anchor rod (7) passes through the mortar layer (6) and the reserved holes (11) on the cover plate (2), and the concrete foundation (5), the mortar layer (6) and the cover plate (2) are tightened and connected by using the matching nut (8) of the anchor rod.

11. A construction method for an exposed steel column foot with a replaceable cover plate according to any one of claims 1 to 10, characterized in that: The following steps are involved: After the concrete foundation (5) is cured, a mortar layer (6) is poured, anchor rods (7) are embedded in the concrete foundation (5), a pattern is formed on the mortar layer (6) to form a position for accommodating the bottom plate (4), and reserved holes are opened on the mortar layer (6); The bottom plate (4) and the bottom plate (4) in the steel column (1) that are welded together in advance in the factory are placed at a position on the mortar layer (6) to accommodate the bottom plate (4), and a reserved hole is opened on the bottom plate (4); After welding the stiffening ribs on the cover plate (2), and opening reserved holes on the cover plate (2), after the mortar layer (6) is cured, multiple cover plates (2) are placed on the mortar layer (6) and the base plate (4), and the multiple cover plates (2) are placed around the steel column (1), and the reserved holes on the side of the cover plate (2) away from the steel column (1) are aligned with the reserved holes on the mortar layer (6), and the reserved holes on the side of the cover plate (2) close to the steel column (1) are aligned with the reserved holes on the base plate (4); On the side of the cover plate (2) away from the steel column (1), the cover plate (2) is connected to the concrete foundation (5) and the mortar layer (6) through an anchor rod (7), and is tightened and fixed with a matching nut (8) of the anchor rod; on the side of the cover plate (2) close to the steel column (1), the cover plate (2) is connected to the base plate (4) through a screw rod (9), and is tightened and fixed with a matching nut (10) of the screw rod.

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