Special Adaptive Dynamic Balancing Reinforcement System for Single-Pier Bridges

Abstract

The present invention relates to a special adaptive dynamic balance reinforcement system for single-column pier bridges. On both sides of the beam body of the single-column pier bridge, there are respectively provided first pulley groups. Each first pulley group includes a plurality of pulleys arranged along the length direction of the beam body and a first rope wound around the pulleys. At both ends of the first rope, there are respectively provided a set of counterweight blocks. The counterweight blocks are arranged on the foundation. The first rope is in a tensioned state, but in the natural state, the force exerted by the counterweight blocks on the first rope is less than a preset threshold. The present invention can effectively prevent the single-column pier bridge from overturning and can adaptively dynamically balance the overturning dynamic load or overturning torsional moment received by the bridge deck.

Description

Technical Field

[0001] The invention relates to a special adaptive dynamic balance reinforcement system for a single-column pier bridge, belonging to the technical field of bridge reinforcement. Background Art

[0002] Curved bridges such as urban interchanges and highway ramps mostly adopt a single-column cast-in-place continuous box girder structure. The lower structure of this type of bridge has the advantages of reducing land occupation, alleviating the conflict between the bridge foundation and the underground building, and increasing the field of vision and bridge beauty. However, the lateral support system of the pier is a single-point support. Under the action of eccentric load, the lateral anti-overturning of the structure is very unstable, resulting in insufficient safety reserves for the overall anti-overturning stability of the bridge. Moreover, overloading is common in my country's heavy-duty vehicles, and some vehicles are even overloaded by 200% to 300%, resulting in multiple overturning accidents of bridges with this structure during use.

[0003] In order to ensure the safe operation of single-column pier bridges, it is necessary to carry out anti-overturning reinforcement work on single-column pier bridges. Currently, two methods are usually used for reinforcement: adding steel hoops and connecting rod anti-pullout devices.

[0004] The reinforcement is carried out by adding steel hoops. Please refer to the Chinese patent with publication number CN105421250A and the name "Anti-overturning structure of single-column pier bridge". This reinforcement method has the defects of large engineering volume, many processes and difficult construction. In addition, when the single-column pier is subjected to a large lateral overturning moment of the bridge deck, the reinforced steel hoops will produce a large torsional shear force on the single-column pier. Under the action of eccentric loads, the reinforced steel hoops will produce huge horizontal shear stress and torsional stress on the single-column pier, which will still cause sudden instability of the bridge substructure and affect the safety of the single-column pier. Therefore, this solution cannot completely achieve the effect of treating both the symptoms and the root cause.

[0005] The double-column pier cap beam on both sides of the single-column pier bridge is reinforced by adding connecting rod-type anti-pullout devices on both sides. Due to the defects of the structure itself, the concrete anti-pullout strength of the cap beam is not enough to withstand the overturning load moment of the entire bridge deck. Stress concentration can easily cause concrete tearing and damage, resulting in the concrete anti-pullout failure being insufficient to resist the overturning moment of the bridge deck under the dynamic load, and the bridge deck will still slip and overturn.

[0006] In addition, there are usually main roads or auxiliary roads under single-pier bridges, requiring the bridge piers to fall within a limited range. The applicant has found in practice that when working under the bridge, the working surface of the crane is affected by geological conditions or road traffic. When the single-pier bridge is very high, the above two reinforcement schemes may cause the crane to have insufficient lifting height, or even if the height is barely reached, positioning and safe operation are difficult. Summary of the invention

[0007] The object of the present invention is to provide an adaptive dynamic balance reinforcement system that can effectively prevent the overturning of single-column pier bridges.

[0008] To achieve the above object, the present invention adopts the following solution: A special adaptive dynamic balance reinforcement system for single-column pier bridges. On both sides of the beam body of the single-column pier bridge, there are respectively provided first pulley groups. Each first pulley group includes a plurality of pulleys arranged along the length direction of the beam body and a first rope wound around the pulleys. At both ends of the first rope, there are respectively provided a set of counterweight blocks; the counterweight blocks are arranged on the foundation, and the first rope is in a tensioned state, but in the natural state, the force exerted by the counterweight blocks on the first rope is less than a preset threshold.

[0009] The present invention prevents the overturning of single-column pier bridges by respectively arranging first pulley groups on both sides of the beam body of the single-column pier bridge and arranging two sets of counterweight blocks on each side of the beam body through the first ropes that bypass the first pulley groups. When a large overturning dynamic load or overturning torsional moment acts on one side of the single-column pier bridge in the present invention, the other side of the single-column pier bridge can dynamically adjust the torque in the opposite direction exerted by the counterweight blocks, thereby effectively dynamically balancing the resistance to the overturning dynamic load or overturning torsional moment, making the force on the bridge deck of the single-column pier bridge balanced and preventing the bridge deck from overturning.

[0010] The present invention is similar to a suspension bridge or a cable-stayed bridge in that a rope that bears tension is used as the main load-bearing member. However, in the present invention, the beam body is subjected to the downward pulling force of the rope to achieve the purpose of preventing the bridge deck from overturning, while in a suspension bridge or a cable-stayed bridge, the bridge deck is subjected to the upward pulling force of the rope to support the bridge deck, and the principles of the two are completely different. Moreover, in the present invention, the rope and the beam body are connected through a pulley group, which can dynamically balance the torsional overturning load received by the bridge deck, while in a suspension bridge or a cable-stayed bridge, the rope and the bridge deck are connected by single-point anchoring.

[0011] In addition, the present invention is different from a suspension bridge or a cable-stayed bridge in that: suspension bridges or cable-stayed bridges are mostly newly built bridges, and the positions, installation methods, etc. of the ropes have been determined at the design stage, while the present invention is a reinforcement carried out after the construction of the single-column pier bridge is completed. Therefore, it is necessary to facilitate the reinforcement construction and ensure the stability after reinforcement; of course, the present invention can also be applied to newly built bridges.

[0012] The beneficial effects brought by the present invention are as follows: 1) The construction of the present invention is convenient. The first pulley group can be arranged and anchored on the bridge deck by using a bridge inspection vehicle. The present invention makes the beam body evenly stressed through multiple pulleys of the first pulley group, so that the stress area of the bridge is uniform when subjected to an overturning load, and the local concrete structure is not easily damaged by tensile cracking. 2) The first pulley group can change the stress direction. By reasonably arranging the positions of the pulleys and counterweights, the conflict between the counterweight and the underground building or the position of the road under the bridge can be avoided. 3) When the bridge deck system is subjected to non-linear torsional overturning loads in all directions, the moment of rupture is evenly converted into a linear load and transmitted away through the first pulley group on the beam body of the bridge deck system, which can effectively resist the overturning moment of the bridge deck system and prevent concentrated stress at a certain point of the bridge. Therefore, the present invention can provide a greater effective balancing moment. 4) When resisting the overturning moment of the bridge deck system, the single-column pier is only subjected to the vertical pressure and will not be subjected to the horizontal shear force and torsional force. Therefore, the sudden instability of the lower structure of the bridge is avoided. On the basis of preventing the bridge deck from overturning, the safety of the single-column pier itself is not affected, achieving the reinforcement effect of treating both the symptoms and the root causes. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic structural diagram of Embodiment 1;

[0014] Figure 2 is a schematic diagram of Embodiment 2.

[0015] Reference numerals: 1, single-column pier; 2, beam body; 3, first pulley group; 4, counterweight; 5, bracket; 6, first rope; 7, foundation pit; 8, second rope; 9, support platform; 10, anti-pulling pile; 11, second pulley group. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] Embodiment 1

[0017] As Figure 1 shown, a special adaptive dynamic balance reinforcement system for a single-column pier bridge. On both sides of the beam body 2 of the single-column pier bridge, a first pulley group 3 is respectively provided (the first pulley group 3 on the other side is not shown in the figure). The first pulley group 3 includes a plurality of pulleys arranged along the length direction of the beam body 2 and a first rope 6 wound around the pulleys. A set of counterweights 4 are respectively provided at both ends of the first rope 6. In this embodiment, the first pulley group 3 can be arranged and anchored on the bridge deck by using a bridge inspection vehicle, and is preferably installed on the beam body of the single-column pier bridge by means of multi-point anchoring to improve the connection strength between the pulley and the beam body.

[0018] In addition, the first pulley group 3 is preferably arranged at the flange of the beam body of the single-column pier bridge. By arranging a plurality of pulleys below the flange, the stress area of the beam body can be ensured to be uniform, and the local concrete structure is not easily damaged by tensile cracking.

[0019] As Figure 1 shown, the counterweight 4 is arranged on the foundation, and the first rope 6 is in a tensioned state. However, in the natural state, the force exerted by the counterweight 4 on the first rope 6 is less than the preset threshold. That is to say, it is necessary to make the first rope 6 in a tensioned state, and at the same time, the counterweight 4 should not exert too much force on the beam body. The best state is that the force exerted by the counterweight 4 on the beam body is basically 0. The appropriate weight of the counterweight can be calculated according to some design parameters of the bridge, or the number of counterweights can be increased or removed according to the actual situation to adjust its weight. This is the prior art and will not be elaborated here.

[0020] When a large overturning dynamic load or overturning torsional moment acts on one side of the single-column pier bridge (at this time, the system of this embodiment is in a working state), the two groups of counterweights 4 on the other side of the single-column pier bridge exert a reverse torque through the first rope 6, so that the overturning dynamic load or overturning force torque can be effectively dynamically balanced through the conversion of the first pulley group to resist the overturning dynamic load or overturning force torque, and the destruction torque is evenly converted into a linear load through the first pulley group and transmitted away, so that the stress on the bridge deck of the single-column pier bridge is balanced and the bridge deck is prevented from overturning. When the overturning dynamic load or overturning torsional moment disappears, the first pulley group returns to its natural state. By evenly distributing the received overturning dynamic load through the first pulley group, it can also ensure that the single-column pier 1 only receives vertical pressure, avoiding the horizontal shear force from damaging the structural stability of the single-column pier 1.

[0021] The following improvements can also be made to this embodiment:

[0022] 1) The first rope 6 is an SMA rope. The SMA rope has superelasticity and shape memory performance, which can ensure that it is always in a tensioned state. When an overturning dynamic load or overturning torsional moment acts on one side of the single-column pier bridge, the counterweights on the other side can always be effective.

[0023] 2) A bracket 5 is provided on the foundation, and a second pulley group 11 is installed on the bracket 5. The first rope 6 bypasses the second pulley group 11 and is connected to the counterweight 4.

[0024] 3) Since the temperature difference between winter and summer is relatively large, the first rope may expand and contract thermally, resulting in the first rope becoming slack and no longer being tensioned. Therefore, a tensioning device for tensioning the first rope is added. The tensioning device is the prior art and will not be elaborated here.

[0025] Embodiment Two

[0026] This embodiment is an improvement based on Embodiment One. The improvement lies in: As Figure 2As shown, a foundation pit 7 is provided below the counterweight block. A plurality of first uplift piles 10 are provided in the foundation pit. The counterweight block 4 is connected to the first uplift piles 10 through a second rope 8. The second rope 8 is in a tensioned state, so as to ensure that when the weight of the counterweight block 4 is not sufficient to balance the overturning dynamic load or overturning torsional moment received by the single-column pier bridge, the second rope 8 plays a role in further preventing the bridge deck from overturning.

[0027] All the first uplift piles 10 are connected to the support platform 9. Therefore, connecting the second rope 8 to the support platform 9 can ensure that the second rope 8 is connected to the first uplift piles 10. The setting of the uplift piles is prior art and can refer to relevant literature. Generally, there are the following several ways: 1) Adopting a thick and long single pile; 2) Adopting a group of piles as an uplift system, with a pile cap foundation bottom plate at the pile top to converge the combined tensile force or frictional force of the uplift pile system; as Figure 2 As shown, all the first uplift piles 10 are connected to the support platform 9. Therefore, connecting the second rope 8 to the support platform 9 can ensure that the second rope 8 is connected to the first uplift piles 10; 3) It may be a relatively large caisson system or a large foundation raft anchor system.

[0028] The second rope 8 can adopt a common strong rope, such as: a steel wire rope or a composite material rope. Preferably, the second rope is an SMA rope, a combined braided rope of steel wire and SMA, or a combined braided rope of composite material and SMA. SMA has superelasticity and shape memory performance, which can ensure that it is always in a tensioned state, making the first uplift piles 10 always effective.

[0029] This embodiment can also be improved as follows: A second uplift pile (not shown in the figure) is provided below the bracket 5, and the bracket is connected to the second uplift pile. The setting method of the second uplift pile is similar to that of the first uplift pile and will not be elaborated here.

[0030] Embodiment Three

[0031] This embodiment is another improvement based on Embodiment One. The improvement lies in that: a foundation pit is provided below the counterweight block, and a first uplift pile is provided in the foundation pit. The counterweight block is connected to the first uplift pile through a tension spring, and the resilience of the tension spring ensures that the first uplift pile is always effective when necessary. The setting method of the first uplift pile can refer to Embodiment Two.

Claims

1. An adaptive dynamic balance reinforcement system for a single-column pier bridge, characterized in that: On both sides of the beam body of the single-column pier bridge, a first pulley group is respectively provided. The first pulley group includes a plurality of pulleys arranged along the length direction of the beam body and a first rope wound around the pulleys. A set of counterweight blocks are respectively provided at both ends of the first rope; the counterweight blocks are arranged on the foundation, and the first rope is in a tensioned state, but in the natural state, the force exerted by the counterweight blocks on the first rope is less than a preset threshold value; A foundation pit is provided below the counterweight block, and a first anti-pulling pile is provided in the foundation pit. The counterweight block is connected to the first anti-pulling pile through a second rope, and the second rope is in a tensioned state; A bracket is provided on the foundation, and a second pulley group is installed on the bracket. The first rope is connected to the counterweight block after passing around the second pulley group; The first pulley group is arranged at the flange of the beam body of the single-column pier bridge.

2. The special adaptive dynamic balance reinforcement system for single-column pier bridges according to claim 1, wherein: A second anti-pulling pile is provided below the bracket, and the bracket is connected to the second anti-pulling pile.

3. The special adaptive dynamic balance reinforcement system for single-column pier bridges according to claim 1, wherein: The first rope is a steel wire rope, a composite material rope, an SMA rope, a combined braided rope of steel wire and SMA, or a combined braided rope of composite material and SMA.

4. The special self-adaptive dynamic balance reinforcement system for single-column pier bridges according to claim 1, wherein: The second rope is a steel wire rope, a composite material rope, an SMA rope, a combined braided rope of steel wire and SMA, or a combined braided rope of composite material and SMA.

5. The special adaptive dynamic balance reinforcement system for single-column pier bridges according to claim 1, wherein: The first pulley group is installed on the beam body of the single-column pier bridge by means of multi-point anchoring.

6. The special adaptive dynamic balance reinforcement system for single-column pier bridges according to claim 1, characterized in that: A foundation pit is provided below the counterweight block, and a first anti-pulling pile is provided in the foundation pit. The counterweight block is connected to the first anti-pulling pile through a tension spring.

7. The special adaptive dynamic balance reinforcement system for single-column pier bridges according to claim 1, wherein: It also includes a tensioning device for tensioning the first rope.

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