H-shaped steel exposed self-resetting seismic column base based on shape memory alloy plate

Abstract

The application discloses an H-shaped steel exposed type self-resetting seismic column foot based on a shape memory alloy plate, which comprises a column foot and a shape memory alloy plate, the lower end of the column foot is fixed to a foundation, and the upper end is connected with an H-shaped steel column through the shape memory alloy plate. The middle section of the shape memory alloy plate is smaller in width than the two end sections, the length of the shape memory alloy plate crosses the connecting interface of the column foot and the steel column, and the two ends are fixedly connected with the column foot and the steel column through bolts respectively; a long circular hole is formed in the lower end of the web of the steel column along the column height direction, and the web is allowed to displace along the length direction of the hole relative to the bolt when the steel column swings. Under the action of an earthquake, the H-shaped steel column swings relative to the column foot mainly in the strong-axis bending mode, relative vertical displacement is generated between the flanges of the H-shaped steel column and the column foot, the displacement is transmitted to the shape memory alloy plate through the bolts passing through the corresponding circular holes, the shape memory alloy plate is deformed, hysteresis energy is generated, and the steel column is driven to reset by the super-elastic restoring force.

Description

Technical Field

[0001] This invention relates to the field of seismic engineering technology, specifically to an exposed self-resetting seismic-resistant column base for H-beams based on shape memory alloy plates. Background Technology

[0002] In steel frame structures, column bases are critical force transmission nodes between steel columns and foundations. Under strong earthquakes, traditional exposed column bases may experience problems such as base plate yielding, anchor bolt tension or slippage, local buckling at the column ends, and local foundation damage, leading to residual rotation and difficulties in post-earthquake repair.

[0003] To overcome the aforementioned shortcomings, self-resetting column base structures have been developed in recent years, mainly forming three technical paths. The first is the post-tensioned prestressing path, which relies on prestressing tendons to provide restoring force. However, this approach is cumbersome in construction, involves a large number of components, has limited elastic strain capacity of the prestressing tendons, and is prone to prestress loss. Some designs require anchoring the prestressing tendons inside the foundation, making post-earthquake inspection and replacement difficult, and requiring foundation damage for post-earthquake maintenance. The second is the shape memory alloy (SMA) path, which has a relatively simpler construction, but in existing designs, most SMA elements also need to be pre-embedded in the foundation. The third is the disc spring path, which relies on a combination of disc springs and friction devices to achieve restoring and energy dissipation. However, the friction devices suffer from long-term performance problems such as wear and degradation and prestress relaxation.

[0004] Therefore, there is an urgent need for a self-resetting column base scheme that is simple in structure, does not rely on sliding friction, does not have a reset element embedded in the foundation, and keeps the bottom column as elastic as possible under the design seismic load, thereby reducing irreversible damage to the column base and foundation. Summary of the Invention

[0005] The purpose of this invention is to provide an exposed self-resetting seismic-resistant column base for H-beams based on shape memory alloy plates, in order to solve the problems of existing column bases having many components, relying on sliding friction for energy dissipation, and being difficult to maintain after an earthquake, while achieving self-resetting after an earthquake and reducing the risk of irreversible plastic damage to the bottom column.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an exposed self-resetting seismic-resistant H-beam steel column base based on a shape memory alloy plate, comprising a column base, a first shape memory alloy plate, and a second shape memory alloy plate; The column base connects the H-beam steel column to the foundation; the cross-section of the column base is H-shaped, consistent with the cross-sectional shape and size of the H-beam steel column; the upper end of the column base is connected to the H-beam steel column, and the lower end of the column base is fixedly connected to the foundation. The first shape memory alloy plate is disposed on the outer side of the flange of the H-shaped steel column, and its width covers the entire flange width of the H-shaped steel column; the second shape memory alloy plate is disposed on the inner side of the flange of the H-shaped steel column and is located on both sides of the web. Both the first and second shape memory alloy plates are dog-bone shaped, with the width of the middle section being smaller than that of the two end sections. This shape makes the cross-sectional area of ​​the middle section smaller than the effective cross-sectional area after the end bolt holes are weakened, making the weakened middle section the main deformation zone and avoiding damage to the end bolt hole area first. Its length spans the lower end of the H-shaped steel column and the upper end of the column base, and is connected to the H-shaped steel column and the column base by bolts. The H-shaped steel column can swing and rotate relative to the column base (mainly along the strong axis direction); when the H-shaped steel column swings and rotates, the first and second shape memory alloy plates undergo recoverable deformation, and their hyperelastic properties generate a stable hysteresis loop to absorb seismic energy at the same time. After unloading, the restoring force generated by the shape memory alloy plates drives the steel column back to its initial position. Furthermore, the exposed self-resetting seismic-resistant H-beam column base also includes steel plates. These steel plates are categorized by their arrangement and function into constraint steel plates covering the outer sides of the first and second shape memory alloy plates, and connecting steel plates covering both sides of the H-beam column web. The constraint steel plates have elongated holes to accommodate the relative displacement between the bolts and the constraint steel plates during column swaying and to limit the out-of-plane deformation of the shape memory alloy plates. The connecting steel plates have circular holes to facilitate the connection between the H-beam column web and the column base.

[0007] Furthermore, the lower end of the web of the H-shaped steel column is provided with an elongated hole, the length of which is along the height of the steel column, so that the web can be displaced relative to the bolt during swaying and rotation. When the designed swaying displacement does not exceed the allowable slip range of the elongated hole, the shearing effect of the bolt can be significantly reduced.

[0008] Furthermore, circular holes are provided at the lower end of the flange of the H-shaped steel column, the upper end of the column base, and the first and second shape memory alloy plates. Bolts pass through the corresponding circular holes and are pre-tightened to achieve a fast connection between the shape memory alloy plates and the H-shaped steel column and column base.

[0009] Furthermore, a vertical stiffening plate is welded to the lower end of the column base, and the vertical stiffening plate is respectively disposed at the outer end of the flange of the column base and the outer area at the junction of the flange and the web.

[0010] Furthermore, a base plate is welded to the lower end of the column base. The base plate is a flat steel plate with multiple mounting holes. The base plate is fixedly connected to the foundation by anchor bolts or embedded parts. In addition, transverse stiffening ribs can be provided at the lower end of the column base.

[0011] Furthermore, the first shape memory alloy plate and the second shape memory alloy plate are made of nickel-titanium based shape memory alloy, copper-based shape memory alloy, iron-based shape memory alloy or other shape memory alloy materials with recoverable phase transformation capabilities that have superelastic properties.

[0012] The beneficial effects of this invention are: 1. By utilizing the superelastic hysteresis properties of shape memory alloy plates, seismic energy is dissipated during the swaying of steel columns, and restoring force is provided after unloading, thereby reducing residual rotation angle at column bases and residual structural deformation, and improving the post-earthquake functional recovery capability of the structure. 2. The main deformation and energy dissipation are concentrated on the shape memory alloy plate that spans the interface between the steel column and the column base, so that the main body of the H-shaped steel column and the main body of the column base can maintain an elastic state as much as possible under the design earthquake action, and avoid the column base plate, anchor bolts, foundation connection area and other difficult-to-repair parts becoming the main damage areas. 3. The swaying interface, energy-dissipating reset components, and auxiliary connecting components are all located above the foundation, ensuring that key functional components such as the shape memory alloy plate do not physically overlap with the foundation. Post-earthquake maintenance or replacement of the shape memory alloy plate does not require damage to the foundation, allowing for exposed inspection and rapid replacement. 4. This invention achieves deformation guidance and force control through a combination of an elongated hole, a constraint steel plate, and a dog-bone shaped shape memory alloy plate. The elongated hole reduces the bolt shearing requirements, the constraint steel plate restricts the out-of-plane buckling of the shape memory alloy plate, and the dog-bone structure concentrates deformation and energy dissipation in the central weakened section, thereby ensuring that the shape memory alloy plate stably performs its energy dissipation and reset functions. Attached Figure Description

[0013] Figure 1 This is a structural schematic diagram of a specific embodiment of the present invention.

[0014] Figure 2 This is an exploded view of the structure of a specific embodiment of the present invention.

[0015] Figure 3 This is a schematic diagram of the first shape memory alloy plate according to a specific embodiment of the present invention.

[0016] Figure 4 This is a schematic diagram of the second shape memory alloy plate according to a specific embodiment of the present invention.

[0017] In the diagram, 1: column base; 2: foundation; 3: H-shaped steel column; 4: first shape memory alloy plate; 5: second shape memory alloy plate; 6: steel plate; 7: vertical stiffening plate; 8: base plate; 9: oblong hole; 10: bolt; 11: transverse stiffening rib. Detailed Implementation

[0018] The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings.

[0019] like Figure 1 and Figure 2 As shown, this embodiment provides an exposed self-resetting seismic-resistant H-beam steel column base based on shape memory alloy plate, including column base 1, first shape memory alloy plate 4, second shape memory alloy plate 5, steel plate 6, vertical stiffening plate 7 and base plate 8.

[0020] The cross-sectional shape of the column base 1 is consistent with that of the H-shaped steel column 3, being H-shaped, and their dimensions are matched and aligned vertically. Vertical stiffening plates 7 and transverse stiffening ribs 11 are welded to the lower end of the column base 1, and a base plate 8 is welded to the lowest end. The vertical stiffening plates 7 are respectively located at the outer ends of the flanges of the column base 1 and in the outer region where the flanges meet the web, to enhance the local stability of the column base 1; the transverse stiffening ribs 11 are located between the lower flanges of the column base 1 to enhance the connection rigidity between the base plate 8 and the column base 1. The base plate 8 is a flat steel plate with multiple mounting holes, which are fixedly connected to the foundation 2 via anchor bolts or embedded parts.

[0021] The lengths of the first shape memory alloy plate 4 and the second shape memory alloy plate 5 both span the connection interface between the upper end of the column base 1 and the lower end of the H-shaped steel column 3. Circular holes are opened at both ends of the plate, as well as at the lower end of the flange of the steel column 3 and the upper end of the column base 1. Bolts 10 pass through the circular holes at the corresponding positions and apply pre-tightening force to fix the shape memory alloy plates to the flange of the steel column and the column base respectively.

[0022] According to their arrangement and function, the steel plate 6 can be divided into a constraint steel plate covering the outside of the first shape memory alloy plate 4 and the second shape memory alloy plate 5, and a connecting steel plate covering both sides of the web of the H-shaped steel column.

[0023] A steel plate 6, covering the outer sides of the first shape memory alloy plate 4 and the second shape memory alloy plate 5, serves as a constraint steel plate. The constraint steel plate has elongated holes arranged along the length of the steel column to accommodate the relative displacement between the bolts and the constraint steel plate during the column's swaying motion. This constraint steel plate primarily restricts the out-of-plane deformation of the shape memory alloy plates and prevents out-of-plane buckling during compression; it does not function as a primary energy-dissipating and restoring element, nor does it bear the main vertical tensile and compressive deformation.

[0024] The steel plates 6 covering both sides of the web of the H-shaped steel column are connecting steel plates, used to guide the connection between the web of the H-shaped steel column and the column base 1, and to limit lateral misalignment between the steel column and the column base. The connecting steel plates span the connection interface between the lower end of the web of the H-shaped steel column and the upper end of the column base 1. The upper part of the connecting steel plates is connected to the web of the H-shaped steel column by bolts 10, and the lower part is connected to the column base 1 by bolts 10. An elongated hole 9 is provided at the corresponding position at the lower end of the web of the H-shaped steel column, and the length direction of the elongated hole 9 is arranged along the height direction of the steel column; circular holes are provided at the upper and lower parts of the connecting steel plates and at the corresponding positions at the upper end of the column base 1. Bolt 10 passes through the elongated hole 9 on the web of the H-shaped steel column and the round hole at the top of the connecting steel plate, connecting the connecting steel plate and the web. This allows the web to slide vertically relative to the bolt within the allowable range of the elongated hole 9 when the steel column sways, thereby reducing the shearing requirements of the bolt. Bolt 10 passes through the round hole at the bottom of the connecting steel plate and the round hole at the top of the column base 1, fixing the connecting steel plate and the column base 1 together.

[0025] During an earthquake, the steel column sways and rotates along the strong axis, and a relative vertical displacement occurs between the flange of the H-shaped steel column and the column base. This displacement is transmitted to the shape memory alloy plate through bolts passing through the corresponding circular holes, causing the shape memory alloy plate to deform and enter a superelastic hysteresis working state. After unloading, the restoring force generated by the shape memory alloy plate drives the steel column to return to its initial position.

[0026] The main energy-consuming reset components and auxiliary connecting components, including the first shape memory alloy plate 4, the second shape memory alloy plate 5 and the steel plate 6, are all located on the foundation 2 and do not physically overlap with the foundation 2. Damaged shape memory alloy plates can be easily replaced, and damaged plates can be easily replaced without damaging the foundation.

[0027] The first shape memory alloy plate 4 and the second shape memory alloy plate 5 may be made of nickel-titanium based shape memory alloy, copper-based shape memory alloy, iron-based shape memory alloy or other shape memory alloy materials with recoverable phase transformation ability.

[0028] like Figure 3 As shown in Figure 4, a first shape memory alloy plate 4 is arranged on the outer side of the flange of the H-shaped steel column 3, its width covering the entire flange; a second shape memory alloy plate 5 is arranged on the inner side of the flange and on both sides of the web, with at least one on each side. All shape memory alloy plates are dog-bone shaped, meaning the width of the middle section... smaller than the width of both ends The dog-bone-shaped structure makes the central weakened section the main deformation zone, concentrating recoverable phase transformation deformation and hysteresis energy dissipation in the middle section and preventing the end bolt hole area from being damaged first.

[0029] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the technical concept and principle of the present invention, or any substantially similar technical means used to achieve substantially similar functions or effects based on the technical solutions disclosed in the present invention, should be covered within the protection scope of the present invention. The protection scope of the present invention is defined by the claims.

Claims

1. An exposed self-resetting seismic-resistant H-beam steel column base based on shape memory alloy plate, characterized in that: Includes column bases, a first shape memory alloy plate, and a second shape memory alloy plate; The column base connects the H-shaped steel column to the foundation; the column base has an H-shaped cross-section, which is consistent with the cross-sectional shape and size of the H-shaped steel column; the upper end of the column base is connected to the H-shaped steel column, and the lower end is fixed to the foundation. The first shape memory alloy plate is arranged on the outer side of the flange of the H-shaped steel column, and its width covers the entire flange; the second shape memory alloy plate is arranged on the inner side of the flange and is located on both sides of the web plate; both the first shape memory alloy plate and the second shape memory alloy plate are dog bone shaped, with the width of the middle section being smaller than that of the two end sections, and their length spanning the lower end of the H-shaped steel column and the upper end of the column base, and are bolted to the H-shaped steel column and the column base; The H-shaped steel column can swing and rotate relative to the column base. During the swing, the shape memory alloy plate undergoes recoverable deformation, and its superelasticity generates a hysteresis loop to dissipate energy and reset.

2. The exposed self-resetting seismic-resistant H-beam steel column base based on shape memory alloy plate according to claim 1, characterized in that: The exposed self-resetting seismic-resistant H-beam column base also includes steel plates. The steel plates are divided into constraint steel plates covering the outside of the first shape memory alloy plate and the second shape memory alloy plate, and connecting steel plates covering both sides of the web of the H-beam column, according to their arrangement and function. The constraint steel plates are provided with elongated holes. The connecting steel plates are provided with round holes for connecting with the web and column base of the H-beam column.

3. The exposed self-resetting seismic-resistant H-beam steel column base based on shape memory alloy plate according to claim 2, characterized in that: The lower end of the web of the H-shaped steel column is provided with an elongated hole, the length of which is along the height of the steel column, so that the web can be displaced relative to the bolt along the length of the hole when it is swaying and rotating.

4. The exposed self-resetting seismic-resistant H-beam steel base based on shape memory alloy plate according to claim 3, characterized in that: The lower end of the flange of the H-shaped steel column, the upper end of the column base, and the first and second shape memory alloy plates are all provided with round holes. Bolts pass through the corresponding round holes and are pre-tightened to achieve a fast connection between the shape memory alloy plates and the H-shaped steel column and column base.

5. The exposed self-resetting seismic-resistant H-beam steel column base based on shape memory alloy plate according to claim 4, characterized in that: The lower end of the column base is welded with a vertical stiffening plate, which is respectively located at the outer end of the flange of the column base and the outer area at the junction of the flange and the web.

6. The exposed self-resetting seismic-resistant H-beam steel base based on shape memory alloy plate according to claim 5, characterized in that: The lower end of the column base is also welded with a base plate, which is a flat steel plate with multiple mounting holes. The base plate is fixedly connected to the foundation by anchor bolts or embedded parts. The lower end of the column base is also welded with transverse stiffening ribs.

7. The exposed self-resetting seismic-resistant H-beam steel base based on shape memory alloy plate according to claim 6, characterized in that: The first shape memory alloy plate and the second shape memory alloy plate are made of nickel-titanium based shape memory alloy, copper-based shape memory alloy or iron-based shape memory alloy with superelastic properties.

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