A bridge head structure used to control bridge head jumping

Abstract

The invention discloses a bridge head structure for controlling bump at bridge head. The bridge head structure comprises a bridge abutment, a beam slab, a subgrade, a pavement structure layer, a bridge head transition slab and a bridge deck layer, wherein the pavement structure layer comprises a subbase layer, a base layer and a surface layer from bottom to top; the bridge head transition slab is arranged between the subgrade and the subbase layer, and one end of the bridge head transition slab is lapped on the bracket of the bridge abutment; a contraction joint is formed between the base layer and the back of the bridge abutment, and an expansion joint is formed between the back of the bridge abutment and the beam slab. The bridge head transition slab of the bridge head structure is arranged underneath so that the subgrade cavity phenomenon under the transition slab of the end near the abutment can be eliminated; as a result, differential settlement between the subgrade and the bridge can be effectively adjusted, bump at the joint of the bridge abutment and the embankment and secondary bump at the far end of the transition slab can be avoided, the reflection crack of the pavement can be prevented and controlled, the integrity of the pavement is good and the construction operation is simple and convenient; the service life of each of the pavement, the bridge head transition slab, the expansion joint and the bridge is prolonged, and therefore, an effective technical scheme for comprehensively controlling bump at bridge head is provided.

Description

technical field [0001] The invention belongs to the technical field of connection between bridge engineering and subgrade engineering, and in particular relates to a bridge head structure for controlling vehicle jumping at the bridge head. Background technique [0002] Vehicle jumping at the bridge head is almost a common phenomenon on highway bridges in all countries in the world. Therefore, the most intuitive standard for evaluating the quality of use and service level of a highway is whether the vehicle is comfortable when driving on it, and whether the problem of vehicle jumping at the bridge head is serious. At present, most of the bridges have significantly reduced the settlement difference of the bridge head and improved the driving conditions after setting the bridge head slab and taking soft foundation reinforcement measures. However, there are also quite a few bridges with different degrees of vehicle jumping disease due to improper treatment of soft foundation, s...

AI Technical Summary

Problems solved by technology

[0007] (1) The bridge head straps are laid under the asphalt concrete surface or on the top of the flat road base, and the vehicle load is quickly transmitted to the road bed. In addition, there are two joints at the connection between the bridge abutment and the straps, such as figure 1 As shown in a and d, there is often a height difference between points a and d, and the pavement layer is easy to crack. Generally, asphalt wadding is filled in joint a as a water barrier, but in actual use, this joint is easy to be damaged by asphalt The aging of the material and the expansion and contraction of the joints make the joints empty, causing the surface water to infiltrate along the joints and directly scour the filling soil on the back of the abutment, resulting in deformation or loss of the filling soil on the back of the abutment, and finally subsidence of the subgrade soil at this place, and the subgrade below the slab Voids appear; if the subsidence of the soft ground at the bridge head is large after construction, the overall subsidence of the roadbed will also cause voids under the strapping board, and the strapping board will become a bending-tension structure, which will seriously crack or break the strapping board

[0008] (2) by figure 1 It can be seen that the two ends of a and b of the board and the fulcrum c constitute a lever. Due to the leverage effect, the settlement of the b end will produce a vertical displacement at the a end. car, which contradicts the original intention of designing the bridgehead

[0009] (3) by figure 1 It can be seen that d is the expansion joint of the bridge, and a is the joint between the board and the abutment. The distance between the two joints is very small. When the car passes by here quickly, there will be two consecutive jumps, which makes driving very uncomfortable. It is also not conducive to the operation of the driver

[0010] (4) There is a layer of bridge deck pavement between the joints d and a. The longitudinal dimension of the pavement along the route is very small. Acceleration, deceleration, braking and other shocks, such as figure 1 As shown, the impact load caused by the jump caused by the joints on both sides can easily damage this small section of concrete, and its destruction will naturally cause damage to the adjacent two joints, resulting in car jumping at the two joints.

[0013] (7) if figure 1 Because the expansion joint d shown in the figure is set at the weak part of the beam end structure, it is difficult to effectively connect with the post-cast bridge deck pavement concrete, and it is set on the surface of the road surface to directly bear the repeated impact of the wheel load. Naturally, expansion joints tend to fail prematurely during operation and are therefore the most vulnerable and difficult to repair part of the bridge structure

Once the bridge telescopic structure is damaged, it will cause a large impact load of the vehicle, further aggravate the jumping of the bridge head, and deteriorate the driving condition. The water leakage of the bridge deck will also cause corrosion and damage to the reinforced concrete structure at the bottom of the bridge, reducing the service life of the bridge.

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