CN220413984U - Flexible beam falling prevention device - Google Patents

Abstract

A flexible beam falling prevention device relates to an anti-seismic device for a bridge, which comprises a connecting cable and an anchoring piece; the anchoring parts are respectively connected with two ends of the connecting rope in an anchoring way, and the connecting rope is respectively connected with the side surface of the bridge pier and the bottom of the box girder and adopts a high-strength steel strand inhaul cable or a high-strength steel wire rope; the anchoring piece comprises an anchoring barrel, a fork lug and a universal hinge bracket; the anchoring barrels are respectively connected with two ends of the connecting rope in an anchoring manner; one end of the fork lug is fixedly connected with the anchoring cylinder, and the other end of the fork lug is rotationally connected with the universal hinge bracket; the universal hinge brackets are respectively arranged on the side surface of the bridge pier and the bottom of the box girder; and a buffer is also arranged between the fork lugs at any end of the bridge pier or the box girder and the anchoring cylinder. The utility model can realize multi-directional beam falling prevention limit at the same time, can meet the requirement of instantaneous impact test, has simple integral structure, definite stress, easy realization, convenient and efficient construction and installation, and is particularly suitable for earthquake-resistant measures of simply supported system beam bridges.

Description

Flexible beam falling prevention device

Technical Field

The utility model relates to an anti-seismic device for a bridge, in particular to a flexible beam falling prevention device.

Background

In order to lighten the earthquake damage of the structure, avoid casualties and reduce economic loss, the bridge is required to take certain anti-seismic measures in both the highway bridge anti-seismic design rule and the urban bridge anti-seismic design rule. The utility model patent with the publication number of CN215104596U discloses a guy cable type grading energy-absorbing type beam falling prevention device, which is provided with a transverse beam falling prevention device arranged between box girders and the box girders and used for realizing a transverse limiting function and a vertical beam falling prevention device arranged between the box girders and piers and used for realizing a vertical limiting function, and also provides an energy-absorbing control assembly capable of grading and absorbing the instantaneous impact energy of a large earthquake, and can effectively avoid the instantaneous impact of the earthquake from damaging a bridge structure. However, the transverse limiting function and the longitudinal limiting function of the device still need to be realized through two sets of beam falling preventing devices respectively, the structure is complex, the structure of the energy absorption control assembly is also complex, the volume is large, and the energy absorption control assembly is only suitable for being arranged in the transverse beam falling preventing device between the box beams and the bridge pier, and is not suitable for being arranged on the vertical beam falling preventing device between the box beams and the bridge pier.

In addition, the utility model patent with the publication number of CN209760004U discloses a multi-directional bridge beam falling prevention limiting device which can realize the transverse and longitudinal beam falling prevention limiting functions at the same time, but still has the following defects: (1) The horizontal deflection and the longitudinal deflection are realized by a horizontal pin shaft and a vertical pin shaft, when the inhaul cable is not stressed in practice in the construction and installation stage, the pin shafts in two directions can respectively realize deflection, but when transverse displacement occurs in the stage after the inhaul cable is stressed, the vertical pin shaft cannot rotate due to the horizontal pulling force, so that the joint of the anchoring piece and the inhaul cable is folded, and the stress of the connecting cable is not facilitated. (2) If the rubber buffer is required to bear the pressure and impact force of the inhaul cable under the stress, the pressure bearing area of the rubber buffer is required to be far larger than the pressure bearing area of the nut, and the displacement spring is required to be designed into a cone shape, so that the beam bottom mounting structure is huge, the bracket baffle is stressed and cantilever is long, and the connection part of the bracket and the beam bottom is stressed with a large bending moment, so that the structure stress of the beam falling device is not facilitated.

Furthermore, since the longitudinal or transverse force generated by an earthquake is an instantaneous impact force, the instantaneous impact performance of the anti-drop beam device should be such that the components of the test device are not destroyed at a maximum impact speed of 1 m/s. Therefore, the beam falling prevention device meets the requirements of a limit load test, a periodic load test and a fatigue test, and also meets the requirements of an instant impact test.

Disclosure of Invention

The utility model aims to solve the technical problems that: the flexible beam falling prevention device is used for solving the defects that the transverse beam falling prevention limit function and the longitudinal beam falling prevention limit function cannot be realized simultaneously in the prior art, the structure is complex, the energy absorption buffer assembly is large in size, and the stress of the structure is not facilitated.

The technical scheme for solving the technical problems is as follows: the flexible girder falling prevention device comprises an anchoring piece and a connecting rope, wherein two ends of the connecting rope are respectively connected between a bridge pier and a box girder through the anchoring piece in an anchoring way; the connecting rope adopts a high-strength steel strand inhaul cable or a high-strength steel wire rope; the anchoring piece comprises an anchoring barrel, a fork lug and a universal hinge bracket; the anchoring barrels are respectively connected with two ends of the connecting rope in an anchoring manner; one end of the fork lug is fixedly connected with the anchoring cylinder, and the other end of the fork lug is rotationally connected with the universal hinge bracket; the universal hinge brackets are respectively arranged on the side surface of the bridge pier and the bottom of the box girder; a buffer is also arranged between the fork lug at any end and the anchoring cylinder; the buffer comprises a control tube, a damping device and a buffer pull rod; one end of the control tube is fixedly connected with the end part of the anchoring cylinder, and the inner hole at the other end of the control tube is provided with the damping device and the damping pull rod; the distance L=5 mm-500 mm is arranged between the end face of the head part of the buffer pull rod and the end face of the anchoring cylinder, and the tail part of the buffer pull rod passes through the damping device and extends out of the control tube to be fixedly connected with the fork lugs.

The utility model further adopts the technical scheme that: the inner hole of the control tube is formed by sequentially connecting a threaded hole, a large unthreaded hole and a small unthreaded hole; the threaded hole is connected with the end part of the anchoring cylinder through threads; the head of the buffer pull rod is a T-shaped rod head which is arranged in a big light hole of the control tube, the distance L is reserved between the end face of one end of the T-shaped rod head and the end face of the anchoring cylinder arranged in the threaded hole, and the damping device is arranged between the end face of the other end of the T-shaped rod head and the bottom of the big light hole; the tail part of the buffer pull rod passes through the damping device and extends out of the control tube to be connected with the fork lugs through screw threads.

The utility model further adopts the technical scheme that: the damping device comprises a butterfly-shaped backing ring, a buffer baffle, a foaming material plate and a toothed damping plate which are sequentially sleeved on the buffer pull rod; the toothed shock absorbing plate is arranged at one end close to the T-shaped club head, and convex teeth are arranged on one side of the toothed shock absorbing plate close to the foaming material plate.

The utility model further adopts the technical scheme that: the foaming material plate is a polyurethane material plate or a rubber material plate.

The utility model further adopts the technical scheme that: the convex teeth on the toothed shock absorbing plate are annular convex teeth or sharp convex teeth; the hardness of the convex teeth is greater than that of the buffer baffle.

The utility model further adopts the technical scheme that: the universal hinge bracket comprises a bracket and a ball joint, and the bracket is respectively and fixedly arranged on the side surface of the bridge pier and the bottom of the box girder; the ball joint comprises a ball joint bearing and a pin shaft, the ball joint bearing is arranged on the bracket, the pin shaft penetrates through the fork lugs and the ball joint bearing to enable the fork lugs to be hinged on the bracket, and deflection within 15 degrees in any direction is achieved between the pin shaft and the ball joint bearing.

The utility model further adopts the technical scheme that: the bracket comprises a fixed plate and a connecting plate, wherein the fixed plate is respectively embedded at the side face of the bridge pier and the bottom of the box girder, and embedded bars for bearing tensile force and shearing force are embedded at the bottom of the fixed plate; the connecting plate is vertically arranged on the fixed plate, and the connecting plate is provided with a mounting through hole for mounting the spherical joint bearing.

By adopting the structure, the flexible beam falling prevention device has the following beneficial effects compared with the prior art:

1. can realize multidirectional roof beam limit function that falls simultaneously

The bridge pier comprises an anchoring piece and a connecting rope, wherein two ends of the connecting rope are respectively connected between a bridge pier and a box girder through the anchoring piece in an anchoring manner; the anchoring piece comprises an anchoring barrel, a fork lug and a universal hinge bracket; the anchoring barrels are respectively connected with two ends of the connecting rope in an anchoring manner; one end of the fork lug is fixedly connected with the anchoring cylinder, and the other end of the fork lug is rotationally connected with the universal hinge bracket; the universal hinge brackets are respectively arranged on the side surface of the bridge pier and the bottom of the box girder; a buffer is also arranged between the fork ear and the anchoring cylinder at any end. The connecting cable adopts the high-strength steel strand inhaul cable or the high-strength steel wire rope with better flexibility, so that the connecting cable can better adapt to the changing requirements of the bridge structure in all directions; and the fork lugs of the anchoring piece are connected with the side surface of the bridge pier and the bottom of the box girder by adopting the universal hinge brackets with flexible structures, so that deflection within 15 degrees in any direction can be realized, and the displacement change requirement in the transverse direction, the longitudinal direction or other any directions can be realized. Under the earthquake condition, when the bridge structure is impacted and displaced, the utility model is in a stress tensioning state, wherein the universal hinging mode at the two ends of the fork lugs can steer under the stress state, deflection can not occur in the stress process of the inhaul cable, shearing damage can not occur to the stress ribs, and the bridge displacement is effectively limited; therefore, the utility model can realize the multi-directional beam falling prevention limiting function at the same time.

2. Reasonable structural stress

When the bridge structure is impacted to displace under the earthquake condition, the device is in a stress tensioning state, wherein the universal hinging modes at the two ends of the fork lugs can turn under the stress state, deflection can not occur in the stress process of the inhaul cable, shearing damage can not occur to the stress rib easily, and the device is reasonable in structural stress and can effectively limit bridge displacement.

In addition, the buffer of the utility model comprises a control tube, a damping device and a buffer pull rod which are respectively arranged in the control tube; the whole structure is simple, the volume is small and exquisite, can be fit for installing on the anchor assembly at arbitrary one end or both ends between case roof beam and pier, solved the beam bottom mounting structure that prior art exists huge, bracket baffle atress cantilever length, bracket and beam bottom junction receive the defect of great moment of flexure, prevent falling beam device's overall structure atress is reasonable.

3. Simple structure and small buffer volume

The connecting cable adopts the high-strength steel strand inhaul cable or the high-strength steel wire rope with better flexibility, so that the connecting cable can better adapt to the changing requirements of the bridge structure in all directions; and the fork lugs of the anchoring piece are connected with the side surface of the bridge pier and the bottom of the box girder by adopting the universal hinge brackets with flexible structures, so that deflection within 15 degrees in any direction can be realized, and the displacement change requirement in the transverse direction, the longitudinal direction or other any directions can be realized. Therefore, the utility model can realize the beam falling prevention limit function in the transverse direction, the longitudinal direction or any other directions by only one beam falling prevention device, has simple structure and effectively reduces the production cost.

In addition, the buffer of the utility model comprises a control tube, a damping device and a buffer pull rod which are respectively arranged in the control tube; the whole structure is simple, the volume is small, and the device can be suitable for being arranged on anchoring parts at any one end or two ends between the box girder and the bridge pier.

4. The buffer has simple integral structure, definite stress and easy realization

The buffer has simple integral structure, one end of the control tube is connected with the end part of the anchoring cylinder, and the inner hole at the other end is provided with the damping device and the damping pull rod; the distance L=5 mm-500 mm is arranged between the end face of the head part of the buffer pull rod and the end face of the anchoring cylinder, and the tail part of the buffer pull rod passes through the damping device and extends out of the control tube to be connected with the fork lugs. When the shock absorber is subjected to an earthquake force, the phenomenon of shell clamping does not occur, the shock absorber does not have multi-stage steps, the shock absorber of the shock absorber directly absorbs energy when the shock absorber is subjected to an axial impact force by utilizing the difference of material strength, and the shock absorber is definite in stress and convenient to design and calculate.

5. Can meet the requirements of instant impact test

The buffer comprises a control tube, a damping device and a buffer pull rod; the damping device comprises a butterfly-shaped backing ring, a buffer baffle, a foaming material plate and a toothed damping plate which are sequentially arranged together; the toothed shock absorbing plate is provided with convex teeth on one side close to the foaming material plate. As the soft foaming material plate is arranged between the toothed shock absorbing plate and the buffer baffle, the soft foaming material is mainly polyurethane material, and rubber material can also be adopted. The convex teeth of the toothed shock absorbing plate can be annular or distributed in sharp protrusions, and the hardness of the convex teeth is higher than that of the shock absorbing baffle. Under normal use state, the tooth-shaped shock-absorbing plate does not act on the buffer baffle, the foaming material only plays a role of filling space, when instant impact force appears, the convex teeth with high hardness are instantly pressed into the buffer baffle with low hardness, the effect of absorbing the impact force is achieved, the impact force on other structural members is reduced, the foaming material is compressed without affecting the impact space, and the buffer structure can meet the requirement of instant impact test.

6. The connecting rope is easy to process and meets the fatigue requirement of the rope for bridge structure

In the prior art, the maximum wire diameter of a high-strength chain commonly used for connecting ropes is only phi 42mm, the pitch is 152mm, the ultimate stress is 1000MPa, and the breaking force is 2770kN, which is equivalent to the stress of 10 steel strands; the upper limit of the fatigue test of the annular chain is 40% of limit stress, but the pulse cycle number is only no less than 30000 times, and the upper limit of the fatigue test required by the bridge is 40% of limit stress, so that the cycle number is far from 2 multiplied by 106. The connecting cable adopted by the utility model is a high-strength steel strand inhaul cable or a high-strength steel wire rope, wherein a single steel strand with the diameter phi of 15.2mm has the lowest tensile strength of 1470MPa and the highest tensile strength of 2160MPa, and is bundled into the steel strand inhaul cable, so that the connecting cable is applied to the inhaul cable of the beam falling prevention device, 1 steel strand to 19 steel strand combinations can be used, and the breaking force can be used at 260-4940 kN. Therefore, the connecting rope adopted by the utility model is easy to process, and the number of steel strands or steel wire ropes can be increased or reduced according to the design requirement so as to meet the fatigue requirement of the rope for the bridge structure.

7. Convenient and efficient construction and installation

The utility model is convenient and efficient in construction and installation, and is particularly suitable for earthquake-proof measures of simply supported system beam bridges.

The technical features of the flexible beam drop prevention device of the present utility model will be further described with reference to the drawings and examples.

Drawings

Fig. 1: embodiment-the flexible beam falling prevention device of the present utility model is a schematic structural view,

fig. 2: embodiment one the fork ear is a schematic structural view,

fig. 3: embodiment-a schematic structural diagram of the buffer,

fig. 4: embodiment-a schematic structural diagram of the control tube,

fig. 5: embodiment-front view of the toothed shock absorbing plate,

fig. 6: the left-hand view of figure 5 is taken,

fig. 7: the utility model is installed in the structure schematic diagram between the bottom of the box girder and the side of the pier;

in the above figures, the reference numerals are as follows:

1-a bridge pier, wherein the bridge pier comprises a bridge pier body,

2-anchoring piece, 21-anchoring barrel, 22-fork ear, 221-side plate, 2211-through hole,

23-universal hinge brackets, 231-brackets, 2311-fixing plates, 2312-connecting plates, 2313-embedded bars,

232-ball joints, 2321-ball joint bearings, 2322-pin shafts,

a 3-connecting rope, wherein the connecting rope is connected with the connecting rope,

4-a box girder of the utility model,

a 5-buffer, which is used for buffering the data,

51-control tube, 512-big light hole, 513-small light hole,

52-a damping device, 521-a butterfly-shaped backing ring, 522-a buffer baffle plate, 523-a foaming material plate,

524-toothed shock absorbing plate, 5241-annular teeth,

53-buffer pull rod, 531-T-shaped rod head, 532-external thread.

C-the center line of the connecting cable under the normal use state,

z-the connecting cable centerline of the present utility model in the seismic state.

Detailed Description

Example 1

The flexible girder falling prevention device comprises an anchoring piece 2 and a connecting rope 3, wherein two ends of the connecting rope 3 are respectively connected between a bridge pier 1 and a box girder 4 through the anchoring piece 2 in an anchoring manner; wherein:

the connecting cable 3 adopts a high-strength steel strand inhaul cable and consists of N steel strands which are arranged in a regular hexagon shape and PE outer protective pipes, N is more than or equal to 1 and less than or equal to 19, the tensile strength of the steel strands is 1670 MPa, 1770 MPa, 1860 MPa and other levels, and the elastic modulus of the steel strands is not less than 1.6X105 MPa.

The anchoring piece 2 comprises an anchoring cylinder 21, a fork lug 22 and a universal hinge bracket 23; the anchoring cylinders 21 are respectively connected with two ends of the connecting rope 3 in an anchoring way, the anchoring cylinders 21 adopt a conventional technology, and the high-strength steel strand inhaul cable is anchored by external force extrusion or cold casting grouting materials; the anchoring cylinder 21 is also provided with external threads connected with the fork lugs 22; one end of the fork lug 22 is provided with a threaded hole, the other end is provided with two parallel opposite side plates 221, and the two side plates 221 are provided with through holes 2211. In the two sets of anchoring pieces 2, one end (threaded hole end) of a fork lug 22 positioned at the box girder end is directly and fixedly connected with external threads of an anchoring cylinder 21, and the other end (side plate end) of the fork lug 22 is rotatably connected with a universal hinge bracket 23 at the bottom of the box girder 4; one end (threaded hole end) of a fork lug 22 positioned at the pier end is fixedly connected with the anchoring cylinder 21 through the buffer 5, and the other end (side plate end) is rotatably connected with a universal hinge bracket 23 on the side surface of the pier 1.

The universal hinge bracket 23 comprises a bracket 231 and a ball joint 232, the bracket 231 comprises a fixing plate 2311 and a connecting plate 2312, the fixing plate 2311 is respectively embedded at the side surface of the pier 1 and the bottom of the box girder 4, and embedded bars 2313 for bearing tensile force and shearing force are embedded at the bottom of the fixing plate 2311; the connection plate 2312 is vertically welded to the fixing plate 2311, and the connection plate 2312 is provided with a mounting through hole for mounting the ball joint 232. The ball joint 232 includes a ball joint bearing 2321 and a pin 2322, the ball joint bearing 2321 is mounted on a mounting through hole of the connection board 2312, the pin 2322 passes through a through hole of a side plate of the fork lug 22 and the ball joint bearing 2321, and the fork lug 22 is clamped and positioned by a baffle and a bolt, so that the fork lug 22 is hinged on the bracket 231, and deflection within 15 degrees in any direction is realized between the pin 2322 and the ball joint bearing 2321.

The buffer 5 comprises a control tube 51, a damping device 52 and a buffer pull rod 53; the inner hole of the control tube 51 is formed by sequentially connecting a threaded hole 511, a large light hole 512 and a small light hole 513; wherein the threaded hole 511 is screwed with the end of the anchor cylinder 21; the head of the buffer pull rod 53 is a T-shaped rod head 531, the T-shaped rod head 531 is installed in the big light hole 512 of the control tube 51, a distance l=5 mm-500 mm is left between one end face of the T-shaped rod head 531 and the end face of the anchor cylinder 21 installed in the threaded hole 511, that is, a distance L is left between one end face of the T-shaped rod head 531 and the end face of the bottom end of the threaded hole 511, the distance is the shock absorption displacement, and the shock absorption device 52 is installed between the other end face of the T-shaped rod head 531 and the bottom of the big light hole 512; the tail part of the buffer pull rod 53 passes through the shock absorbing device 52 and extends out of the control tube 51 to be connected with the fork lug 22 through screw thread fastening.

The damping device 52 comprises a butterfly-shaped backing ring 521, a buffer baffle 522, a foam material plate 523 and a toothed damping plate 524 which are sequentially sleeved on the buffer pull rod 53; the toothed shock absorbing plate 524 is mounted at one end close to the T-shaped club head 531, the toothed shock absorbing plate 524 is provided with a convex tooth 5241 at one side close to the foam material plate 523, the convex tooth 5241 is a ring-shaped convex tooth or a sharp convex tooth, and the hardness of the convex tooth 5241 is greater than that of the buffer baffle 522; the foam material plate 523 is a polyurethane material plate or a rubber material plate.

As an alternative to the first embodiment, the connecting cord 3 may be a high-strength steel wire rope.

As yet another variation of the first embodiment, the damper may also be a damping rubber structure or a hydraulic damping structure.

Embodiment one flexible beam falling prevention device of the present utility model is installed and constructed as follows:

A. processing a bracket, an anchoring cylinder, a buffer and a high-strength steel strand inhaul cable in a factory;

B. two ends of the high-strength steel strand inhaul cable are connected with the anchoring cylinders, and one end of the anchoring cylinder is connected with a fork lug;

C. a disc spring, a buffer baffle, a foaming material plate, a toothed shock-absorbing plate and a buffer pull rod are sequentially arranged in the buffer, one end of the anchor cylinder is screwed into the control tube, and the distance between the T-shaped rod head of the buffer pull rod and the anchor cylinder is the allowable displacement L under the normal use state of design requirements;

D. the external thread of the buffer pull rod is connected with the other fork lug to form a connecting rope with fork lugs at two ends;

E. pre-burying a fixed plate and pre-buried bars of a bracket at the side surface of a bridge pier and the bottom of a box girder; at this time, the ball joint bearing shaft is installed on the bracket before leaving the factory;

F. the fork lugs at two ends of the connecting cable are respectively connected with the bottom of the box girder and the brackets at the bridge pier, and the pin shaft penetrates into the fork lug through holes and the ball joint bearing holes and is fixed by the baffle plate and the screws to prevent the fork lugs from slipping. The upper structural member is typically first installed.

The working principle of the utility model is as follows:

in a normal use state, the connecting cable is in a loose state as shown in fig. 7, and a longitudinal bridge displacement movement space allowed by design is arranged in the buffer so as to meet the displacement, including the influence of temperature, of the bridge in the normal operation process. The ball joint bearings at the two ends of the fork lugs can still play a role in limiting the longitudinal direction and the transverse direction when the box girder moves slightly in any direction such as the left-right direction or the front-back direction of the transverse bridge, but do not allow the box girder to move transversely, and the transverse movement is completely not allowed to limit the transverse displacement of the shock insulation support.

When an earthquake impact occurs, the connecting cable is in a tensioning state, for the initial small impact load, the impact force is firstly eliminated by the two opposite disc springs, when the impact load exceeds the elastic force of the disc springs, the T-shaped rod heads 531 of the buffer pull rods impact the toothed shock absorbing plates 524, the tooth-shaped parts of the shock absorbing plates are harder than the shock absorbing plates 522, the shock absorbing plates are embedded under the action of the impact force, the impact energy is absorbed, and the impact influence of the impact force on other components of the anti-falling beam device is reduced.

Claims (7)

1. The flexible girder falling prevention device comprises an anchor piece (2) and a connecting rope (3), wherein two ends of the connecting rope (3) are respectively connected between a bridge pier (1) and a box girder (4) through the anchor piece (2) in an anchoring manner; the method is characterized in that: the connecting rope (3) adopts a high-strength steel strand inhaul cable or a high-strength steel wire rope; the anchoring piece (2) comprises an anchoring barrel (21), a fork lug (22) and a universal hinge bracket (23); the anchoring barrels (21) are respectively and fixedly connected to the two ends of the connecting rope (3); one end of the fork lug (22) is fixedly connected with the anchoring cylinder (21), and the other end is rotationally connected with the universal hinge bracket (23); the universal hinge brackets (23) are respectively arranged on the side surface of the bridge pier (1) and the bottom of the box girder (4); a buffer (5) is also arranged between the fork lug (22) at any end and the anchoring cylinder (21); the buffer (5) comprises a control tube (51), a damping device (52) and a buffer pull rod (53); one end of the control tube (51) is fixedly connected with the end part of the anchoring cylinder (21), and the damping device (52) and the damping pull rod (53) are arranged in the inner hole at the other end; the end face of the head of the buffer pull rod (53) is provided with a distance L=5 mm-500 mm from the end face of the anchoring cylinder (21), and the tail of the buffer pull rod (53) passes through the damping device (52) to extend out of the control tube (51) to be fixedly connected with the fork lugs (22).

2. The flexible fall prevention device according to claim 1, wherein: the inner hole of the control tube (51) is formed by sequentially connecting a threaded hole (511), a large unthreaded hole (512) and a small unthreaded hole (513); the threaded hole (511) is connected with the end part of the anchoring cylinder (21) through threads; the head of the buffer pull rod (53) is a T-shaped rod head (531), the T-shaped rod head (531) is arranged in a big light hole (512) of the control pipe (51), the distance L is reserved between one end face of the T-shaped rod head (531) and the end face of the anchoring cylinder (21) arranged in the threaded hole (511), and the damping device (52) is arranged between the other end face of the T-shaped rod head (531) and the hole bottom of the big light hole (512); the tail part of the buffer pull rod (53) passes through the shock absorption device (52) to extend out of the control tube (51) and is connected with the fork lug (22) through screw thread fastening.

3. The flexible fall prevention device according to claim 2, wherein: the damping device (52) comprises a butterfly-shaped backing ring (521), a buffer baffle (522), a foaming material plate (523) and a toothed damping plate (524) which are sequentially sleeved on the buffer pull rod (53); the toothed shock absorbing plate (524) is arranged at one end close to the T-shaped rod head (531), and the toothed shock absorbing plate (524) is provided with convex teeth (5241) at one side close to the foaming material plate (523).

4. A flexible fall arrest device according to claim 3, wherein: the foaming material plate (523) is a polyurethane material plate or a rubber material plate.

5. A flexible fall arrest device according to claim 3, wherein: the convex teeth (5241) on the toothed shock absorbing plate (524) are annular convex teeth or sharp convex teeth; the hardness of the teeth (5241) is greater than the hardness of the bumper plate (522).

6. The flexible fall prevention device according to claim 1, wherein: the universal hinge bracket (23) comprises a bracket (231) and a ball joint (232), and the bracket (231) is respectively and fixedly arranged on the side surface of the bridge pier (1) and the bottom of the box girder (4); the ball joint (232) comprises a ball joint bearing (2321) and a pin shaft (2322), the ball joint bearing (2321) is arranged on the bracket (231), the pin shaft (2322) penetrates through the fork lug (22) and the ball joint bearing (2321) to enable the fork lug (22) to be hinged to the bracket (231), and deflection in any direction within 15 degrees is achieved between the pin shaft (2322) and the ball joint bearing (2321).

7. The flexible fall prevention device according to claim 6, wherein: the bracket (231) comprises a fixed plate (2311) and a connecting plate (2312), wherein the fixed plate (2311) is respectively embedded at the side surface of the bridge pier (1) and the bottom of the box girder (4), and embedded bars (2313) for bearing tensile force and shearing force are embedded at the bottom of the fixed plate (2311); the connecting plate (2312) is vertically arranged on the fixing plate (2311), and the connecting plate (2312) is provided with an installation through hole for installing the ball joint bearing (2321).