Stair weak connection device based on negative poisson's ratio structure and installation method thereof

Abstract

A weak connection method for stairs based on a negative Poisson's ratio structure is disclosed. The device includes a negative Poisson's ratio energy-dissipating component, fixing screws, side steel plates for the stair slabs, side steel plates for the stair beams, studs, and protective covers. Two to three circular holes are pre-drilled in the side steel plates for the stair slabs, and corresponding screw holes are pre-drilled in the side steel plates for the studs. Circular holes are pre-drilled in the concrete stair slab above the circular holes in the side steel plates for housing the hollow negative Poisson's ratio energy-dissipating component. The screws pass through the energy-dissipating component and the circular holes in the side steel plates for tightening into the screw holes in the side steel plates for the studs. A protective cover is installed at the top of the studs, and cement mortar is poured onto the cover to seal the holes. Under seismic loading, the relative displacement between the stair slabs and the stair beams causes the negative Poisson's ratio energy-dissipating component to deform and dissipate seismic energy, providing the structure with a certain horizontal stiffness and damping force. Simultaneously, the vertical stiffness of the screws controls the uplift of the stair slabs during earthquakes. The ring-shaped design of the negative Poisson's ratio energy-dissipating component can also adapt to seismic loads at any angle, achieving all-around vibration reduction and energy dissipation.

Description

Technical Field

[0001] This invention relates to a weak connection device for stairs, specifically a weak connection device for stairs based on a negative Poisson's ratio structure and its construction method, belonging to the field of stair structure vibration reduction and disaster prevention technology. Background Technology

[0002] Traditional monolithic staircases suffer severe damage during earthquakes, hindering post-earthquake escape and rescue efforts. In recent years, some scholars have focused on using weak connections—disconnecting staircase components from the frame structure and creating sliding staircases—to reduce damage to the main structure and staircase components. This approach has proven effective in reducing vibration. However, sliding staircases suffer from vertical warping and cantilevered jumps, and under strong earthquakes, the stair slabs may even detach. To address the shortcomings of sliding staircases, new staircase connection methods are emerging, such as incorporating rubber seismic isolation bearings, energy dissipation bearings, friction dampers, and dampers with soft steel. These new weak-connection staircases present new challenges in terms of vibration isolation and energy dissipation.

[0003] In recent years, negative Poisson's ratio materials and structures have seen rapid development. They possess unique mechanical properties, exhibiting lateral contraction (expansion) under uniaxial pressure (tension). Compared to traditional structures, they offer advantages such as increased stiffness, high energy dissipation, and good impact resistance. In particular, negative Poisson's ratio porous materials and structures, due to their special internal structure and deformation characteristics, are superior to traditional bulk and porous materials, significantly improving their impact resistance, large deformation capacity, and energy dissipation capabilities. Currently, negative Poisson's ratio structures are widely used in the automotive, aerospace, and marine industries to leverage their superior vibration reduction and energy dissipation performance. Summary of the Invention

[0004] To address the development needs of novel weakly connected staircases and leverage the performance advantages of negative Poisson's ratio structures, this invention proposes a weakly connected staircase device and construction method based on a negative Poisson's ratio structure. The relative displacement between the stair slabs and beams drives the deformation of the energy-dissipating components of the negative Poisson's ratio structure to dissipate seismic energy, providing the structure with a certain level of horizontal stiffness and damping force. Simultaneously, the vertical stiffness of the bolts controls the warping of the stair slabs during earthquakes. The ring-shaped design of the energy-dissipating components of the negative Poisson's ratio structure can also adapt to seismic loads at any angle, achieving all-around vibration reduction and energy dissipation.

[0005] According to a first embodiment of the present invention, a weak connection device for stairs based on a negative Poisson's ratio structure is provided.

[0006] A staircase weak connection device based on a negative Poisson's ratio structure is characterized by comprising a negative Poisson's ratio energy-dissipating component, a fixing screw, a stair tread side steel plate, a stair beam side steel plate, studs, and a protective cover plate. The stair tread side steel plate and the stair beam side steel plate are pre-embedded in the bottom surface of the stair tread and the top surface of the stair beam respectively by welded studs, with graphite powder laid between the two steel plates; a gap is reserved at the front end of the stair tread and filled with flexible material; 2-3 circular holes are reserved in the stair tread side steel plate, and corresponding screw holes are reserved in the stair beam side steel plate; a circular hole is reserved in the concrete stair tread above the circular hole in the stair tread side steel plate to accommodate the annular negative Poisson's ratio energy-dissipating component; the fixing screw passes through the negative Poisson's ratio energy-dissipating component and the circular hole in the stair tread side steel plate and is screwed into the screw hole in the stair beam side steel plate; a protective cover plate is installed at the upper end of the stud, and cement mortar is poured onto the cover plate to seal the hole.

[0007] Preferably, the negative Poisson's ratio energy-consuming component is a hollow ring, composed of an outer circular wall, an inner circular wall, and 3 to 6 concave triangular thin walls stacked together. The size of the concave triangular thin walls decreases sequentially from the outer circular wall to the inner circular wall. The outer diameter of the negative Poisson's ratio energy-consuming component is 16-25 cm, and the thickness of the outer circular wall, inner circular wall, and concave triangular thin walls is 2-6 mm. The outer diameter of the outer circular wall is the same as the diameter of the pre-reserved circular hole in the concrete stair slab, and the inner diameter of the inner circular wall is the same as the diameter of the fixing screw. The negative Poisson's ratio energy-consuming component is made of low-carbon mild steel.

[0008] Preferably, the fixing screw has a flat nut with a thickness of 3-8mm, and the nut has a slotted or cross-shaped notch. The diameter of the nut is 1-2cm larger than the diameter of the screw.

[0009] Preferably, the protective cover is composed of a circular waterproof cloth and an annular foam board. The annular foam board is at the same height as the nut of the fixing screw, the inner diameter of the annular foam board is the same as the diameter of the nut of the fixing screw, and the outer diameter of the annular foam board is the same as the diameter of the pre-reserved circular hole in the concrete stair slab. The waterproof cloth is attached to the upper end of the annular foam board, and the waterproof cloth is the same as the outer diameter of the annular foam board.

[0010] According to a second embodiment of the present invention, a method for installing a weak connection device for a cast-in-place staircase based on a negative Poisson's ratio structure is provided.

[0011] A method for installing a weak connection device for a cast-in-place staircase based on a negative Poisson's ratio structure, the method comprising the following steps:

[0012] (1) Fill the pre-drilled screw holes in the steel plate on the side of the ladder beam with foam glue, weld 4-8 studs, fix them to the top of the ladder beam formwork, and then pour the ladder beam concrete;

[0013] (2) Weld 4-8 studs on the side steel plate of the ladder slab. After the ladder beam concrete reaches the design strength, lay graphite powder on the side steel plate of the ladder beam and position the side steel plate of the ladder slab at the upper end of the side steel plate of the ladder beam. Use long screws to fix cylindrical foam columns with the same diameter as the negative Poisson ratio energy dissipation component and a height of 25-35cm to the upper end of the side steel plate of the ladder slab through the pre-reserved screw holes on each side steel plate of the ladder beam. Then install the ladder slab template, tie the ladder slab reinforcement and pour the ladder slab concrete.

[0014] (3) After the concrete of the stair slab reaches the design strength, the cylindrical foam column is removed, which means that a pre-reserved circular hole is obtained on the stair slab. The negative Poisson's ratio energy-consuming component is installed in the pre-reserved circular hole of the stair slab and fixed by the fixing screw. Then the protective cover plate is installed, and finally cement mortar is poured on the protective cover plate to seal the hole.

[0015] The present invention has the following beneficial effects:

[0016] The negative Poisson's ratio energy-dissipating component designed in this invention features a ring-shaped design that can adapt to seismic loads at any angle, achieving all-around vibration reduction and energy dissipation. This invention incorporates an energy-dissipating component into an existing sliding staircase. The deformation of the energy-dissipating component under seismic loads provides horizontal damping stiffness and dissipates seismic energy, reducing the K-shaped bracing effect of the stair slabs and preventing staircase damage. Under seismic loads, the relative displacement between the stair slabs and beams drives the deformation of the negative Poisson's ratio energy-dissipating component to dissipate seismic energy, providing the structure with certain horizontal stiffness and damping force. Simultaneously, the vertical stiffness of the screws controls the warping of the stair slabs during earthquakes. This effectively improves the seismic resistance of the structure and significantly enhances the energy dissipation performance of weakly connected staircases. Attached Figure Description

[0017] Figure 1 A structural schematic diagram of a weak connection component for a staircase based on a negative Poisson's ratio structure provided by the present invention.

[0018] Figure 2 A schematic diagram of a negative Poisson's ratio energy-dissipating component provided by the present invention.

[0019] Figure 3 A schematic diagram of the overall structure of a negative Poisson's ratio energy-consuming component provided by the present invention. Detailed Implementation

[0020] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0021] A staircase weak connection device based on a negative Poisson's ratio structure is characterized by comprising a negative Poisson's ratio energy-dissipating component 3, a fixing screw 5, a stair slab side steel plate 6, a stair beam side steel plate 2, studs 7, and a protective cover plate 4. The stair slab side steel plate 6 and the stair beam side steel plate 2 are pre-embedded in the bottom surface of the stair slab and the top surface of the stair beam respectively by welding studs 7, with graphite powder laid between the two steel plates; a gap is reserved at the front end of the stair slab and filled with flexible material 1; 2-3 circular holes are reserved in the stair slab side steel plate 6, and corresponding screw holes are reserved in the stair beam side steel plate 2; a circular hole is reserved in the concrete stair slab above the circular hole of the stair slab side steel plate 6 to accommodate the annular negative Poisson's ratio energy-dissipating component 3; the fixing screw 5 passes through the negative Poisson's ratio energy-dissipating component 3 and the circular hole of the stair slab side steel plate 6 and is screwed into the screw hole of the stair beam side steel plate 2; a protective cover plate 4 is installed at the upper end of the stud, and cement mortar is poured onto the cover plate to seal the hole.

[0022] Preferably, the negative Poisson's ratio energy-consuming component 3 is a hollow ring, composed of an outer circular wall, an inner circular wall, and 3 to 6 concave triangular thin walls stacked together. The size of the concave triangular thin walls decreases sequentially from the outer circular wall to the inner circular wall. The outer diameter of the negative Poisson's ratio energy-consuming component 3 is 16-25 cm, and the thickness of the outer circular wall, the inner circular wall, and the concave triangular thin walls is 2-6 mm. The outer diameter of the outer circular wall is the same as the diameter of the pre-reserved circular hole in the concrete stair slab, and the inner diameter of the inner circular wall is the same as the diameter of the fixing screw 5. The negative Poisson's ratio energy-consuming component 3 is made of low-carbon mild steel.

[0023] Preferably, the fixing screw 5 has a flat nut with a thickness of 3-8mm, and the nut has a slotted or cross-shaped notch. The diameter of the nut is 1-2cm larger than the diameter of the screw.

[0024] Preferably, the protective cover 4 is composed of a circular waterproof cloth and an annular foam board. The annular foam board is at the same height as the nut of the fixing screw 5, the inner diameter of the annular foam board is the same as the diameter of the nut of the fixing screw 5, and the outer diameter of the annular foam board is the same as the diameter of the pre-reserved circular hole in the concrete stair slab. The waterproof cloth is attached to the upper end of the annular foam board, and the waterproof cloth is the same as the outer diameter of the annular foam board.

[0025] According to a second embodiment of the present invention, a method for installing a weak connection device for a cast-in-place staircase based on a negative Poisson's ratio structure is provided.

[0026] A method for installing a weak connection device for a cast-in-place staircase based on a negative Poisson's ratio structure, the method comprising the following steps:

[0027] (1) Fill the pre-reserved screw holes in the steel plate 2 on the side of the ladder beam with foam glue, weld 4-8 studs, fix them to the top of the ladder beam template, and then pour the ladder beam concrete.

[0028] (2) Weld 4-8 studs on the side steel plate 6 of the ladder slab. After the ladder beam concrete reaches the design strength, lay graphite powder on the side steel plate 2 of the ladder beam and position the side steel plate 6 of the ladder slab on the upper end of the side steel plate 2 of the ladder beam. Use long screws to fix cylindrical foam columns with the same diameter as the negative Poisson ratio energy dissipation component 3 and a height of 25-35cm to the upper end of the side steel plate 6 of the ladder slab through the pre-reserved screw holes on each side steel plate 2 of the ladder beam. Then install the ladder slab template, tie the ladder slab reinforcement, and pour the ladder slab concrete.

[0029] (3) After the concrete of the stair slab reaches the design strength, the cylindrical foam column is removed, and a pre-reserved circular hole is obtained on the stair slab. The negative Poisson's ratio energy-consuming component 3 is installed in the pre-reserved circular hole of the concrete stair slab and fixed by the fixing screw 5. Then the protective cover plate 4 is installed, and finally cement mortar is poured on the protective cover plate 4 to seal the hole.

Claims

1. A weak connection device for stairs based on a negative Poisson's ratio structure, comprising a negative Poisson's ratio energy-dissipating component, a fixing screw, steel plates on the side of the stair slab, steel plates on the side of the stair beam, studs, and a protective cover plate; the negative Poisson's ratio energy-dissipating component is a hollow ring, composed of an outer circular wall, an inner circular wall, and 3 to 6 concave triangular thin walls stacked together, the size of the concave triangular thin walls decreasing sequentially from the outer circular wall to the inner circular wall; the steel plates on the side of the stair slab and the steel plates on the side of the stair beam are pre-embedded in the bottom surface of the stair slab and the top surface of the stair beam respectively by studs welded to their respective surfaces, and graphite powder is laid between the two steel plates; the front end of the stair slab is pre-embedded... A gap is left to be filled with flexible material. Two to three round holes are reserved on the steel plate on the side of the ladder slab. Screw holes are reserved on the steel plate on the side of the ladder beam corresponding to the reserved round holes on the steel plate on the side of the ladder slab. A round hole is reserved on the concrete ladder slab above the round hole on the side of the ladder slab to obtain the reserved round hole on the ladder slab. This is used to place the annular negative Poisson's ratio energy-consuming component. The fixing screw passes through the negative Poisson's ratio energy-consuming component and the round hole on the side of the ladder slab and is tightened to fix it in the screw hole on the side of the ladder beam. A protective cover plate is set on the upper end of the fixing screw plate. Cement mortar is poured on the protective cover plate to seal the reserved round hole on the ladder slab.

2. The connection device of claim 1, wherein: The negative Poisson's ratio energy-consuming component has an outer diameter of 16-25cm, and the outer circular wall, inner circular wall, and concave triangular thin wall thickness are 2-6mm. The outer diameter of the outer circular wall is the same as the diameter of the reserved circular hole in the ladder plate, and the inner diameter of the inner circular wall is the same as the diameter of the fixing screw. The negative Poisson's ratio energy-consuming component is made of low-carbon mild steel.

3. The connection device of claim 1, wherein: The fixing screw has a flat nut with a thickness of 3-8mm. The nut has a slotted or cross-shaped notch and its diameter is 1-2cm larger than that of the fixing screw.

4. The connection device of claim 1, wherein: The protective cover consists of a circular waterproof cloth and an annular foam board. The annular foam board is at the same height as the nut of the fixing screw, the inner diameter of the annular foam board is the same as the diameter of the nut of the fixing screw, and the outer diameter of the annular foam board is the same as the diameter of the reserved circular hole in the ladder plate. The waterproof cloth is attached to the upper part of the annular foam board, and the diameter of the waterproof cloth is the same as the outer diameter of the annular foam board.

5. An installation method for a staircase weak connection device based on a negative Poisson's ratio structure according to any one of claims 1-4, the method comprising the following steps: (1) Fill the pre-reserved screw holes in the side steel plate of the ladder beam with foam glue to temporarily seal them. Weld 4-8 studs on the lower surface of the side steel plate of the ladder beam. Fix the side steel plate of the ladder beam after welding the studs to the top of the ladder beam template. Pour the ladder beam concrete. The side steel plate of the ladder beam is fixed to the top surface of the ladder beam by the studs welded on its lower surface. Remove the foam glue from the pre-reserved screw holes in the side steel plate of the ladder beam. (2) Weld 4-8 studs on the upper surface of the side steel plate of the ladder slab. After the concrete of the ladder beam reaches the design strength, lay graphite powder on the upper surface of the side steel plate of the ladder beam. Place the side steel plate of the ladder slab with the studs welded on the upper surface of the side steel plate of the ladder beam. Fix a cylindrical foam column with the same diameter as the negative Poisson ratio energy dissipation component and a height of 25-35cm on the side steel plate of the ladder beam through a long screw at the upper end of the reserved round hole of the side steel plate of the ladder slab. Then install the ladder slab template, tie the ladder slab reinforcement, and pour the ladder slab concrete. The side steel plate of the ladder slab is fixed to the bottom surface of the ladder slab by the studs welded on its upper surface. (3) After the concrete of the ladder slab reaches the design strength, the cylindrical foam column is removed, and the reserved round hole of the ladder slab is obtained. The negative Poisson ratio energy-consuming component is installed in the reserved round hole of the ladder slab and fixed by the fixing screw. Then the protective cover plate is installed, and finally cement mortar is poured on the protective cover plate to seal the reserved round hole of the ladder slab.

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