An anti-falling beam expansion joint device and its working method

Abstract

The present invention discloses a beam-falling prevention expansion joint device, which includes fixed plates arranged oppositely and a cross-gap movable plate. A plurality of first comb teeth are arranged at the inner end of the fixed plate, and a plurality of second comb teeth are arranged at the inner end of the cross-gap movable plate. The first comb teeth and the second comb teeth are arranged alternately and at intervals. The top end of the first comb teeth is provided with a widened first comb tooth head, and the top end of the second comb teeth is provided with a widened second comb tooth head; the width of the second comb tooth head is greater than the gap between two adjacent first comb tooth heads. The beam-falling prevention expansion joint device of the present invention and its working method can limit the displacement of the beam end during an earthquake, the beam end will not separate at the expansion joint position, prevent the beam end from falling, and improve the safety performance.

Description

Technical Field

[0001] The present invention relates to the technical field of building expansion joints, and particularly to a beam-falling prevention expansion joint device and its working method. Background Art

[0002] Bridge expansion joints are provided to meet the requirements of bridge deck deformation. Usually, expansion joints are set between the two beam ends, between the beam end and the abutment, or at the articulated position of the bridge. Bridge expansion joints can adjust the displacement and connection between the superstructures caused by vehicle loads and bridge building materials. At the position where the expansion joint is set, the railing and the bridge deck pavement should be disconnected. There are many types of bridge expansion joints. Among them, the multi-directional displacement comb-type bridge expansion joint device has a relatively wide application. The multi-directional displacement comb-type bridge expansion joint device has the advantages of low structural height, wide application range, smooth driving, anti-slip, etc.

[0003] A large amount of research data on bridge earthquake disasters shows that the falling of bridge beam ends is a common disaster form during earthquakes, causing significant losses of life and property. As the link connecting the bridge beam ends, the bridge expansion joint has not been improved in terms of earthquake prevention and disaster resistance performance, and there is also a lack of research work in this regard.

[0004] Therefore, it is necessary to develop a beam-falling prevention expansion joint device and its working method. Summary of the Invention

[0005] The purpose of the present invention is to provide a beam-falling prevention expansion joint device, which can limit the displacement of the bridge beam end during an earthquake, prevent the beam end from separating at the expansion joint position, prevent the beam end from falling, and improve the safety performance.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A beam-falling prevention expansion joint device of the present invention includes a fixed plate and a cross-gap movable plate arranged oppositely. A plurality of first comb teeth are arranged at the inner end of the fixed plate, and a plurality of second comb teeth are arranged at the inner end of the cross-gap movable plate. The first comb teeth and the second comb teeth are arranged alternately at intervals. The top of the first comb tooth is provided with a widened first comb tooth head, and the top of the second comb tooth is provided with a widened second comb tooth head; the width of the second comb tooth head is greater than the gap between two adjacent first comb tooth heads.

[0008] Furthermore, the horizontal cross-sections of the first comb tooth head and the second comb tooth head are both rectangular. The first comb tooth head coincides with the longitudinal central plane of the first comb tooth, and the second comb tooth head coincides with the longitudinal central plane of the second comb tooth.

[0009] Further, it further includes a first tensile pin shaft and a second tensile pin shaft. A first pin shaft hole is provided at the outer end of the fixed plate, and the first tensile pin shaft is vertically cast in the concrete of the beam end and its top end is pin-connected to the first pin shaft hole; a second pin shaft hole is provided at the outer end of the cross-seam movable plate, and the second tensile pin shaft is vertically cast in the concrete of the beam end and its top end is pin-connected to the second pin shaft hole.

[0010] Further, a plurality of the first tensile pin shafts are arranged at intervals with the L-shaped bolts for fixing the fixed plate; a plurality of the second tensile pin shafts are arranged at equal intervals between the L-shaped bolts for fixing the cross-seam movable plate.

[0011] Further, anti-slip lines are provided on the top surface of the cross-seam movable plate, and the anti-slip lines are recessed and opened between the root of the second comb teeth and the L-shaped bolt mounting holes.

[0012] Further, limiting grooves are opened on both sides of the lower part of the first comb teeth, and side limiting blocks protrude from both sides of the lower part of the second comb tooth head, and the side limiting blocks extend into the limiting grooves.

[0013] Further, there are clearance spaces left on both the top and the side walls outside of the side limiting blocks within the limiting grooves.

[0014] Further, a waist-shaped hole is provided in the middle of the second comb teeth, the waist-shaped hole is opened along the length direction of the second comb teeth, a limiting bolt is arranged in the waist-shaped hole, the head of the limiting bolt is within the waist-shaped hole, and the bottom of the limiting bolt is fixedly connected to the concrete of the beam end.

[0015] Further, convex heads and groove structures that can engage with each other are respectively provided at the left and right ends of the fixed plate and the cross-seam movable plate.

[0016] The present invention also discloses a working method of the anti-falling beam expansion joint device. Using the anti-falling beam expansion joint device described in any one of the above, anti-falling beam is carried out, and the comb teeth heads that engage with each other at the limit positions are used to prevent the beam end from detaching.

[0017] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0018] For the anti-falling beam expansion joint device of the present invention, by respectively providing a first comb tooth head and a second comb tooth head at the top end of the tooth comb plate, and the width of the second comb tooth head is greater than the gap between two adjacent first comb tooth heads. In the case of an earthquake or the like, when the detachment distance of the beam end is greater than the limit design distance of the overlap of the expansion joint tooth comb plate, the second comb tooth head is clamped between two adjacent first comb tooth heads and engages with each other, restricting the continuous detachment of the beam end and preventing the beam end from detaching from the bridge pier. For the anti-falling beam expansion joint device of the present invention, it can limit the displacement of the bridge beam end during an earthquake, the beam end will not separate at the expansion joint position, prevent the beam end from falling, and improve the safety performance.

[0019] In addition, through the symmetrically arranged first and second comb-shaped heads in a rectangular shape, the protruding distances on both sides are the same, which is beneficial for processing and production with good consistency. Moreover, when they bite, the forces on both sides are evenly distributed, and no local plastic deformation will occur, thus extending the service life. Through the arrangement of the first and second tensile pin shafts, the connection strength between the fixed plate and the cross-seam movable plate and the beam end can be increased respectively, avoiding the situation of the fixed plate or the cross-seam movable plate falling off under the impact of seismic waves. Through the anti-slip pattern arrangement of wave patterns or triangular serrated patterns, the aesthetics of the anti-falling beam expansion joint device of the present invention is increased, and at the same time, the anti-slip performance is improved, avoiding the impact on the comb teeth part after the vehicle tires slip on the wet expansion joint surface. Through the side limit block cooperating with the limit groove to form a height-direction anti-falling structure, that is, in extreme situations such as earthquakes, when the beam end under the cross-seam movable plate has an upward lifting trend under the earthquake, the side limit block is restricted in the limit groove, avoiding the cross-seam movable plate from continuing to lift and separating from the fixed plate, thus triggering a dangerous situation of falling beams. By leaving a movable gap outside the top and side walls of the side limit block in the limit groove, the normal expansion and contraction margin of the bridge can be ensured, avoiding jamming and increasing the internal stress of the bridge. Through the arrangement of the displacement hinge shaft mechanism, it is convenient for the angular displacement of the cross-seam movable plate. The setting of the magnet can attract the cross-seam movable plate, avoiding the warping of sundries entering the bottom seam, and reducing the noise. By adding the first-stage limit block composed of waist-shaped holes and limit bolts, and cooperating with the second-stage comb-tooth head biting block, the seismic wave impact is buffered in a two-stage manner, reducing the damage probability of the expansion joint device and extending the service life of the equipment. Through the convex head and groove structures that bite each other between adjacent cross-seam movable plates or adjacent fixed plates, the units in the entire width direction can be connected into one body, avoiding the situation of single detachment of the fixed plate or the cross-seam movable plate under extreme conditions, and improving the safety performance of the anti-falling beam expansion joint device of the present invention.

[0020] The working method of the anti-falling beam expansion joint device of the present invention uses the comb teeth heads that bite each other at the limit positions to prevent the beam end from detaching. Through the height-direction anti-falling structure formed by the side limit block cooperating with the limit groove, the falling of the beam caused by the upward lifting of the beam end under the earthquake can be further prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the drawings.

[0022] Figure 1 It is a top view structural schematic diagram of Embodiment 1 of the anti-falling beam expansion joint device of the present invention;

[0023] Figure 2 It is a front view sectional structural schematic diagram of Embodiment 1 of the anti-falling beam expansion joint device of the present invention;

[0024] Figure 3 It is a partial top view structural schematic diagram of Embodiment 2 of the present invention;

[0025] Figure 4 isFigure 3 Schematic cross-sectional structure diagram of the A-A part

[0026] Figure 5 Top view structure diagram of Embodiment 3 of the present invention

[0027] Figure 6 Schematic cross-sectional structure diagram of multiple cross-seam movable plates in Embodiment 3 of the present invention

[0028] Explanation of reference numerals: 1, fixed plate; 101, first comb tooth; 1011, limit groove; 102, first comb tooth head; 103, first convex head; 2, cross-seam movable plate; 201, second comb tooth; 202, second comb tooth head; 2021, side limit block; 203, anti-slip pattern; 204, waist-shaped hole; 205, second convex head; 206, second groove; 3, first tensile pin shaft; 4, second tensile pin shaft; 5, limit bolt Detailed implementation manners

[0029] The core of the present invention is to provide an anti-falling beam expansion joint device and its working method, which can limit the displacement of the bridge beam end during an earthquake, prevent the beam end from separating at the expansion joint position, prevent the beam end from falling, and improve the safety performance

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention

[0031] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention

[0032] Referring to the accompanying drawings Figure 1 Top view structure diagram of Embodiment 1 of the anti-falling beam expansion joint device of the present invention

[0033] Figure 2 Main view cross-sectional structure diagram of Embodiment 1 of the anti-falling beam expansion joint device of the present invention Figure 3 Partial top view structure diagram of Embodiment 2 of the present invention Figure 4 For Figure 3 Schematic cross-sectional structure diagram of the A-A part; 5 is the top view structure diagram of Embodiment 3 of the present inventionFigure 6 This is a schematic cross-sectional view of a plurality of cross-seam movable plates in Embodiment 3 of the present invention.

[0034] Embodiment 1, as Figure 1 and Figure 2 shown, an anti-falling beam expansion joint device includes fixing plates 1 and cross-seam movable plates 2 oppositely arranged at two ends of bridge girders. A plurality of first comb teeth 101 are arranged at the inner end of the fixing plate 1, and a plurality of second comb teeth 201 are arranged at the inner end of the cross-seam movable plate 2. The first comb teeth 101 and the second comb teeth 201 are arranged alternately at intervals. The top end of the first comb tooth 101 is integrally connected with a first comb tooth head 102 with an increased width, and the top end of the second comb tooth 201 is integrally connected with a second comb tooth head 202 with an increased width. The first comb tooth head 102 and the first comb tooth 101 have the same thickness, and the second comb tooth head 202 and the second comb tooth 201 have the same thickness. The width of the second comb tooth head 202 is greater than the gap between two adjacent first comb tooth heads 102.

[0035] By respectively arranging the first comb tooth head 102 and the second comb tooth head 202 at the top end of the tooth comb plate, and the width of the second comb tooth head 202 is greater than the gap between two adjacent first comb tooth heads 102. In the case of an earthquake or the like, when the separation distance of the beam end is greater than the limit design distance of the overlap of the expansion joint tooth comb plate, the second comb tooth head 202 is clamped between two adjacent first comb tooth heads 102 and engages with each other, restricting the continuous separation of the beam end and preventing the beam end from detaching from the bridge pier. The anti-falling beam expansion joint device of the present invention can limit the displacement of the bridge beam end during an earthquake, the beam end will not separate at the expansion joint position, prevent the beam end from falling, and improve the safety performance.

[0036] In a specific embodiment of this embodiment, as Figure 1 and Figure 2 shown, the horizontal cross-sections of the first comb tooth head 102 and the second comb tooth head 202 are both rectangular. The longitudinal central plane of the first comb tooth head 102 coincides with that of the first comb tooth 101, and the longitudinal central plane of the second comb tooth head 202 coincides with that of the second comb tooth 201. Obviously, the horizontal cross-sections of the first comb tooth head 102 and the second comb tooth head 202 can also be set to trapezoidal, semi-circular or triangular shapes. As long as they can engage with each other to prevent detachment at the limit position, they can play a protective role. Similar deformation methods are all within the protection scope of the present invention.

[0037] By symmetrically arranging the rectangular first comb tooth head 102 and the second comb tooth head 202, the protruding distances on both sides are the same, which is good for processing and production, and the forces on both sides are uniform during engagement, and no local plastic deformation will occur, improving the service life.

[0038] In a specific embodiment of this embodiment, as Figure 1 and Figure 2As shown in the figure, the anti-falling beam expansion joint device of the present invention further includes a first tensile pin shaft 3 and a second tensile pin shaft 4. A first pin shaft hole is provided at the outer end of the fixed plate 1. The first tensile pin shaft 3 is vertically cast in the beam end concrete material, and the top end is pin-connected to the first pin shaft hole. A second pin shaft hole is provided at the outer end of the cross-gap movable plate 2. The second tensile pin shaft 4 is vertically cast in the beam end concrete material, and the top end is pin-connected to the second pin shaft hole. Further, the bottoms of the first tensile pin shaft 3 and the second tensile pin shaft 4 are welded to the steel bar framework at the beam end of the bridge.

[0039] Specifically, as Figure 1 and Figure 2 shown, a plurality of first tensile pin shafts 3 are arranged at intervals with the L-shaped bolts for fixing the fixed plate 1. A plurality of second tensile pin shafts 4 are arranged at equal intervals between the L-shaped bolts for fixing the cross-gap movable plate 2. Obviously, the fixed plate 1 and the cross-gap movable plate 2 can also adopt other anchor bolts or even an installation method of welding to the beam end steel bar framework.

[0040] By providing the first tensile pin shaft 3 and the second tensile pin shaft 4, the connection strength between the fixed plate 1 and the cross-gap movable plate 2 and the beam end can be increased respectively, and the situation that the fixed plate 1 or the cross-gap movable plate 2 falls off under the impact of seismic waves can be avoided.

[0041] In a specific implementation manner of this embodiment, as Figure 1 and Figure 2 shown, an anti-slip pattern 203 is provided on the top surface of the cross-gap movable plate 2. The anti-slip pattern 203 is recessed and opened between the root of the second comb tooth 201 and the L-shaped bolt mounting hole.

[0042] Specifically, as Figure 1 and Figure 2 shown, the anti-slip pattern 203 specifically adopts a wave pattern or a triangular serrated pattern.

[0043] By providing the anti-slip pattern 203 with a wave pattern or a triangular serrated pattern, the aesthetics of the anti-falling beam expansion joint device of the present invention is increased, and at the same time, the anti-slip performance is improved, and the impact on the comb tooth part after the vehicle tire slips on the wet expansion joint surface is avoided.

[0044] Embodiment 2, as Figure 3 and Figure 4 shown, on the basis of the above Embodiment 1, a height-direction anti-detachment structure is added to the anti-falling beam expansion joint device of the present invention to form this embodiment. Limited position grooves 1011 are opened on both sides of the lower part of the first comb tooth 101, and side limited position blocks 2021 protrude from both sides of the lower part of the second comb tooth head 202. The side limited position blocks 2021 penetrate into the limited position grooves 1011.

[0045] The side limiting block 2021 and the limiting groove 1011 cooperate to form a height-direction anti-detachment structure. That is, in extreme cases such as earthquakes, when the beam end under the cross-seam movable plate 2 has an upward lifting trend during the earthquake, the side limiting block 2021 is restricted in the limiting groove 1011, preventing the cross-seam movable plate 2 from continuing to lift and detach from the fixed plate 1, thus avoiding the dangerous situation of beam falling.

[0046] Specifically, as Figure 3 and Figure 4 shown, there are clearance spaces left at the top inside the limiting groove 1011 and outside the side walls of the side limiting block 2021.

[0047] Specifically, a displacement hinge shaft mechanism is provided at the outer end of the cross-seam movable plate 2, and a magnet that attracts and combines is poured into the concrete material below the second comb tooth 201.

[0048] By leaving clearance spaces at the top and outside the side walls of the side limiting block 2021 through the limiting groove 1011, the normal expansion and contraction margin of the bridge can be ensured, and the bridge internal stress caused by jamming can be avoided. Through the setting of the displacement hinge shaft mechanism, the angular displacement of the cross-seam movable plate 2 is facilitated. The setting of the magnet can attract the second comb tooth 201, prevent sundries from entering the bottom seam from warping up, and reduce noise.

[0049] Embodiment 3, as Figure 5 and Figure 6 shown, on the basis of the above Embodiment 1, an auxiliary limiting structure is added to the anti-falling beam expansion joint device of the present invention to form this embodiment. A waist-shaped hole 204 is provided in the middle of the second comb tooth 201. The waist-shaped hole 204 is opened along the length direction of the second comb tooth 201. A limiting bolt 5 is provided in the waist-shaped hole 204. The head of the limiting bolt 5 is in the waist-shaped hole 204, and the bottom of the limiting bolt 5 is fixedly connected to the concrete material at the beam end. The expansion and contraction margin range of the waist-shaped hole 204 is smaller than the expansion and contraction margin range of the comb tooth head limit. In extreme cases such as earthquakes, the head of the limiting bolt 5 first performs limiting and blocking in the waist-shaped hole 204 to form a buffer, and then the comb tooth head bites to prevent the beam from falling, with a better effect. Obviously, the limiting bolt 5 can also be in the form of a limiting stop pin, and similar structural changes all fall within the protection scope of the present invention.

[0050] By adding the first-stage limiting and blocking composed of the waist-shaped hole 204 and the limiting bolt 5, and cooperating with the second-stage comb tooth head biting and blocking, the seismic wave impact is buffered in a two-stage manner, reducing the damage probability of the expansion joint device and improving the service life of the equipment.

[0051] Specifically, as Figure 5 and Figure 6As shown in the figure, the left and right ends of the fixed plate 1 and the cross-seam movable plate 2 are respectively provided with a convex head and a groove structure that can be engaged with each other. The left and right ends of the cross-seam movable plate 2 are respectively provided with a second convex head 205 and a second groove 206. In the bridge width direction, for two adjacent cross-seam movable plates 2, the second convex head 205 and the second groove 206 are engaged together, that is, the whole width direction forms a connected whole. Similarly, the left end of the fixed plate 1 is provided with a first convex head 103, and the right end is provided with a first groove. The connection structures of adjacent fixed plates 1 are the same. Obviously, the cross-section of the convex head and the groove structure in the figure is rectangular, which should not be construed as a limitation on the protection scope of the present invention. The cross-section of the convex head and the groove structure can be set in shapes such as triangles, trapezoids or semi-circles, etc. Similar deformation methods all fall within the protection scope of the present invention.

[0052] By providing a convex head and a groove structure that can be engaged with each other between adjacent cross-seam movable plates 2 or adjacent fixed plates 1, each unit in the whole width direction can be connected into one body, avoiding the situation where a single fixed plate 1 or cross-seam movable plate 2 falls off under extreme conditions, and improving the safety performance of the anti-falling beam expansion joint device of the present invention.

[0053] The present invention also discloses a working method of the anti-falling beam expansion joint device. Using the anti-falling beam expansion joint device in any one of the above embodiments to prevent the falling of the beam, the comb teeth heads that are engaged with each other at the extreme positions are used to prevent the beam end from detaching.

[0054] Furthermore, the anti-falling structure in the height direction formed by the cooperation of the side limit block and the limit groove can further prevent the beam from falling due to the beam end being lifted by vibration.

[0055] The anti-falling beam expansion joint device of the present invention is provided with a first comb tooth head 102 and a second comb tooth head 202 respectively at the top of the comb tooth plate, and the width of the second comb tooth head 202 is greater than the gap between two adjacent first comb tooth heads 102. In the event of an earthquake or the like, when the separation distance of the beam end is greater than the limit design distance of the overlap of the expansion joint comb tooth plate, the second comb tooth head 202 is clamped between two adjacent first comb tooth heads 102 and engages with each other to limit the continuous separation of the beam end and prevent the beam end from detaching from the pier. The anti-falling beam expansion joint device of the present invention can limit the displacement of the beam end of the bridge during an earthquake, and the beam end will not separate at the expansion joint position, preventing the beam end from falling and improving the safety performance. In addition, through the symmetrically arranged rectangular first comb tooth head 102 and second comb tooth head 202, the protruding distances on both sides are the same, which is convenient for processing and production with good consistency. Moreover, when engaging, the forces on both sides are evenly distributed and no local plastic deformation will occur, improving the service life. Through the arrangement of the first tensile pin shaft 3 and the second tensile pin shaft 4, the connection strength between the fixed plate 1 and the cross-gap movable plate 2 and the beam end can be increased respectively, avoiding the situation that the fixed plate 1 or the cross-gap movable plate 2 falls off under the impact of seismic waves. Through the setting of the anti-slip pattern 203 with wave patterns or triangular serrated patterns, the aesthetics of the anti-falling beam expansion joint device of the present invention is increased, and at the same time the anti-slip performance is improved, avoiding the impact on the comb tooth part after the vehicle tire slips on the wet expansion joint surface. Through the side limit block 2021 cooperating with the limit groove 1011 to form a height-direction anti-detachment structure, that is, in the event of an earthquake or other extreme conditions, when the beam end below the cross-gap movable plate 2 has an upward lifting trend under the earthquake, the side limit block 2021 is restricted in the limit groove 1011, avoiding the cross-gap movable plate 2 from continuing to lift and detach from the fixed plate 1 and causing a dangerous situation of beam falling. By leaving an activity gap outside the top and side walls of the side limit block 2021 in the limit groove 1011, the normal expansion margin of the bridge can be ensured, avoiding jamming and increasing the internal stress of the bridge. Through the setting of the displacement hinge shaft mechanism, it is convenient for the angular displacement of the cross-gap movable plate 2. The setting of the magnet can attract the cross-gap movable plate 2, avoid the debris entering the bottom gap from lifting up, and reduce the noise. By adding the first-stage limit block composed of the waist-shaped hole 204 and the limit bolt 5 and cooperating with the second-stage comb tooth head engagement block, the two-stage method buffers the impact of seismic waves, reduces the damage probability of the expansion joint device, and improves the service life of the equipment. By setting the convex head and groove structures that engage with each other between adjacent cross-gap movable plates 2 or adjacent fixed plates 1, the various units in the entire width direction can be connected into one body, avoiding the situation that the fixed plate 1 or the cross-gap movable plate 2 falls off individually under extreme conditions, and improving the safety performance of the anti-falling beam expansion joint device of the present invention.

[0056] The working method of the anti-falling beam expansion joint device of the present invention uses the comb tooth heads that engage with each other at the extreme positions to prevent the beam end from detaching. Through the height-direction anti-detachment structure formed by the cooperation of the side limit block and the limit groove, the beam falling caused by the upward lifting of the beam end under the earthquake can be further prevented.

[0057] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A beam-fall prevention expansion joint device, comprising fixed plates (1) and cross-gap movable plates (2) arranged oppositely. A plurality of first comb teeth (101) are arranged at the inner ends of the fixed plates (1), and a plurality of second comb teeth (201) are arranged at the inner ends of the cross-gap movable plates (2). The first comb teeth (101) and the second comb teeth (201) are arranged alternately at intervals. It is characterized in that, The top of the first comb tooth (101) is provided with a widened first comb tooth head (102), and the top of the second comb tooth (201) is provided with a widened second comb tooth head (202); the width of the second comb tooth head (202) is greater than the gap between two adjacent first comb tooth heads (102). A waist-shaped hole (204) is provided in the middle of the second comb tooth (201). The waist-shaped hole (204) is opened along the length direction of the second comb tooth (201). A limit bolt (5) is arranged in the waist-shaped hole (204). The head of the limit bolt (5) is in the waist-shaped hole (204), and the bottom of the limit bolt (5) is fixedly connected to the beam-end concrete. The telescopic margin range of the waist-shaped hole (204) is smaller than the telescopic margin range of the comb tooth head limit.

2. The beam-fall prevention expansion joint device according to claim 1, characterized in that: The horizontal cross-sections of the first comb tooth head (102) and the second comb tooth head (202) are both rectangular. The longitudinal central plane of the first comb tooth head (102) coincides with that of the first comb tooth (101), and the longitudinal central plane of the second comb tooth head (202) coincides with that of the second comb tooth (201).

3. The beam-fall prevention expansion joint device according to claim 1, characterized in that: It further includes a first tensile pin shaft (3) and a second tensile pin shaft (4). A first pin shaft hole is provided at the outer end of the fixed plate (1). The first tensile pin shaft (3) is vertically cast in the beam-end concrete and its top is pin-connected to the first pin shaft hole; a second pin shaft hole is provided at the outer end of the cross-seam movable plate (2). The second tensile pin shaft (4) is vertically cast in the beam-end concrete and its top is pin-connected to the second pin shaft hole.

4. The beam-fall prevention expansion joint device according to claim 3, characterized in that: The multiple first tensile pin shafts (3) are arranged at intervals with the L-shaped bolts fixing the fixed plate (1); the multiple second tensile pin shafts (4) are arranged at equal intervals between the L-shaped bolts fixing the cross-seam movable plate (2).

5. The beam-fall prevention expansion joint device according to claim 4, characterized in that: The top surface of the cross-seam movable plate (2) is provided with anti-slip lines (203). The anti-slip lines (203) are recessed and opened between the root of the second comb tooth (201) and the L-shaped bolt mounting hole.

6. The beam-fall prevention expansion joint device according to any one of claims 1 to 5, characterized in that: Limit grooves (1011) are opened on both sides of the lower part of the first comb tooth (101). Side limit blocks (2021) are protruded on both sides of the lower part of the second comb tooth head (202), and the side limit blocks (2021) are inserted into the limit grooves (1011).

7. The beam-fall prevention expansion joint device according to claim 6, characterized in that: The side limit blocks (2021) leave a movable gap both at the top and on the side wall outside the limit grooves (1011).

8. The beam-fall prevention expansion joint device according to claim 1, characterized in that: Convex heads and groove structures that can be engaged with each other are respectively provided at the left and right ends of the fixed plate (1) and the cross-seam movable plate (2).

9. A working method of a beam-fall prevention expansion joint device, characterized in that, When using the anti-falling beam expansion joint device described in any one of the above claims 1 to 8 for preventing the falling of the beam, the comb tooth heads that are engaged with each other at the limit positions are used to prevent the beam end from detaching.

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