CN206591438U - A kind of suspension bridge pier-stage type prestressing force anchorage - Google Patents

Abstract

The utility model discloses a prestressed anchorage of a suspension bridge pier platform, which is composed of a steel structure concrete cap, a steel pipe pile group, a prestressed anchor cable group, a main cable, and a main cable anchorage system. The steel pipe pile group consists of vertical piles One end of the vertical pile and the inclined pile extends into the bedrock, and the other end is rigidly connected with the steel structure concrete cap; the inner anchor head of the prestressed anchor cable group is fixed on the bedrock, and the outer anchor head is connected to the steel structure concrete cap. The cap is fixedly connected, and the angle between the overall stress direction of the prestressed anchor cable group and the direction of the main cable is 0‑5°; the anchor system of the main cable is fixed on the top of the steel structure concrete cap. The utility model transmits the huge pulling force of the main cable to the bedrock through the prestressed anchor cable group, changes the traditional force bearing mode of the anchorage structure, greatly improves the load-bearing range of the anchorage structure, and provides a new method for the construction of super-long-span suspension bridges. A new way to save engineering costs.

Description

A platform-type prestressed anchorage for suspension bridge piers

technical field

The utility model belongs to the technical field of bridge engineering, and more specifically relates to a suspension bridge pier platform prestressed anchorage, which is suitable for the construction of suspension bridge anchorages in large rivers, lakes, etc., and is especially suitable for the construction of super long-span suspension bridge anchorages in coastal plains or in the sea.

Background technique

Suspension bridge is currently the bridge form with the largest spanning capacity in the world. According to the anchoring method of the main cable, it can be divided into two types: self-anchored suspension bridge and ground-anchored suspension bridge. Ground-anchored suspension bridges are mainly composed of anchors, cable towers, cable systems, stiffening beams, etc. The anchors are an important component that transmits the cable force to the foundation, and are generally divided into two types: gravity anchors and tunnel anchors.

Tunnel-type anchorage relies on the anchor plug body to mobilize the surrounding rock mass to jointly bear the huge tension of the main cable. Although the cost is low, and it has the unique advantage of not requiring large excavations on the surface and protecting the environment, due to the limitation of topographic and geological conditions, only in Applicable only under suitable conditions.

Gravity anchorage relies on the self-weight of the anchorage to balance the vertical component of the main cable, and relies on the frictional resistance f between the foundation and the foundation to balance the horizontal component of the main cable, and the frictional resistance depends on the self-weight of the anchorage G and the vertical component Nv of the main cable. The difference (i.e. Figure 1, f=G-Nv) is generated, and when there is groundwater or construction in water, it is the difference between the self-weight of the anchorage G, the vertical component force Nv of the main cable and the buoyancy force F (i.e. Figure 1, f=G -Nv-F), so the gravity anchor is bulky, and the efficiency of this kind of anchor is low. As bridge construction moves from inland rivers to bays and open seas, and from medium and large spans to super-long spans, the requirements for the bearing capacity of the anchorage structure of suspension bridges are getting higher and higher, and the construction difficulty of anchorage foundations is also increasing. . In the construction of anchorage foundations for extra-long-span suspension bridges in large rivers, lakes, and seas, gravity anchorages require large excavations and low efficiency, resulting in large anchorage volumes, huge amounts of poured concrete, and large environmental disturbances. The cost is also high. . In addition, cofferdams are required for the construction of gravity anchors in water, and underground diaphragm walls are often required for construction on land, which makes the construction difficult. Therefore, there is an urgent need to improve the existing anchor structure.

Contents of the invention

The purpose of the utility model is to provide a suspension bridge pier platform prestressed anchorage, which is simple in structure and easy to use, and solves the problem of large excavation volume of gravity anchors, great interference to the environment, and difficulty in constructing gravity anchorages in water. The problem of low efficiency.

In order to achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

A suspension bridge pier platform prestressed anchorage, which includes a steel structure concrete cap, steel pipe pile group, prestressed anchor cable group, main cable and main cable anchorage system, one end of the steel pipe pile group extends into the bedrock, and the other end Rigidly connected with the bottom surface of the steel structure concrete cap, the main cable anchor system is set on the upper surface of the steel structure concrete cap, the inner anchor head of the anchor cable of the prestressed anchor cable group is fixed in the bedrock, and the prestressed anchor cable group The outer anchor head of the anchor cable is fixedly connected with the steel structure concrete cap, and the angle between the overall stress direction of the prestressed anchor cable group and the direction of the main cable is 0-5°.

Preferably, the steel pipe pile group is composed of steel pipe vertical piles and steel pipe inclined piles, intersecting vertical piles are arranged between the steel pipe vertical piles, and the steel pipe inclined piles are arranged on the periphery of the steel structure concrete cap and spread outward.

The steel pipe vertical piles are roughly composed of 8-18 steel pipes with a diameter of 2m, and the number is determined according to the tonnage and water depth of the specific project.

The steel pipe inclined piles are roughly composed of 4-8 steel pipes with a diameter of 2m, and the inclination angle of the steel pipe inclined piles is 5-15°, and the specific number thereof shall be determined according to specific engineering design requirements.

The prestressed anchor cable group is composed of a series of prestressed anchor cables with a single tonnage of 200t~500t, the number of which should be determined according to the design cable force and safety margin of the specific project.

As a preference, the rigid frame of the steel structure concrete cap is a section steel, so as to improve the reliability of the cap.

As a preference, the anchor cables of the prestressed anchor cable group should adopt pressure dispersion anchor cables, and special attention should be paid to strict anti-seepage, and geotechnical engineering dense prestress anchor cables that can be freely stretched for many times can also be used. Since the prestressed anchor cable group is the main load-bearing component, its reliability and durability are very important. Therefore, it is necessary to install a corresponding force-measuring device at the outer anchor head of the prestressed anchor cable to monitor the prestressed anchor cable during construction. and the stress during operation, which is convenient for the anchoring and locking of prestressed anchor cables and timely replacement when a single prestressed anchor cable fails.

The design idea of the utility model is: the overall stress direction of the prestressed anchor cable group is approximately the same as the direction of the main cable force, and the tension of the main cable of the suspension bridge is converted into multi-strand prestressed anchor cable force through the main cable anchorage system and transmitted to the bedrock, so that When the bridge is completed, the steel pipe pile group only bears a small part of the pressure; the steel structure concrete cap and the steel pipe pile group form a pier foundation, and the cap provides an anchoring platform for the main cable and the prestressed anchor cable group, so that the main cable and cable The prestressed anchor cable group is effectively transmitted to the bedrock. The top of the steel pipe pile group is a steel structure concrete cap, and the steel pipe pile group is connected as a whole through the cap, so as to enhance the integrity and deformation resistance of the steel pipe pile group. .

Compared with the prior art, the utility model has the following advantages and beneficial effects:

1. The huge tension of the main cable is transmitted to the bedrock through the large-tonnage prestressed anchor cable group, which does not rely on the weight of the anchorage structure itself and the frictional resistance of the foundation and the foundation. It can not only effectively reduce the amount of concrete, reduce the cost of the project, but also expand the The load-bearing range of the anchorage structure;

2. Borrowing the structural form of the pier and abutment, the construction technology of the abutment is mature. Compared with the construction of gravity anchorage, not only the construction difficulty is greatly reduced but also the construction speed is fast;

3. The anchorage of the utility model does not require large excavation, has little interference with the surrounding environment, and achieves the goal of harmonious coexistence between man and nature. In the construction of tunnel anchorage, prestressed anchorage dispersedly anchored in the bedrock can also be used The cable group replaces the poured concrete anchor body to bear the load, which avoids the excavation of the rock mass and saves the engineering cost;

4. In the steel pipe pile group, the vertical pile support connection plays a supporting role between the vertical piles, and the peripheral inclined piles are directly driven to the bedrock, thereby effectively improving the safety and overall stability of the structure.

5. Adopting the utility model can reliably transmit the pulling force of the main cable, and the gravity anchor of the span suspension bridge with a large amount of concrete will be greatly reduced (taking the Hong Kong Tsing Ma Bridge with a main span of 1377m using gravity anchors on both sides as an example, both sides The amount of anchor concrete used is as high as 292,000 m³, and the utility model can greatly reduce the amount of concrete used), effectively reducing the cost of the anchor anchor project and shortening the anchor anchor construction period.

Description of drawings

Fig. 1 is a schematic diagram showing the effectiveness of a gravity anchor.

Among them, N is the tension force of the main cable, Nv is the vertical force component of the main cable, Nh is the horizontal component force of the main cable, F is the buoyancy force on the gravity anchor, G is the self-weight of the gravity anchor, and f is the weight of the gravity anchor foundation and Frictional resistance between bedrocks, f=(GFN _V )*μ.

Fig. 2 is a schematic diagram of a three-dimensional structure of a pier-type prestressed anchorage.

Fig. 3 is a two-dimensional force schematic diagram of a pier-type prestressed anchorage.

The upward arrow indicates the tension of the main cable, and the downward arrow indicates the force of the prestressed anchor cable.

Figure 4-a is a top view of a pier-type prestressed anchorage.

Figure 4-b is a front view of a pier-type prestressed anchorage.

Figure 4-c is a side view of a pier-type prestressed anchorage.

In Figures 2 to 4: 1-steel structure concrete cap; 2-steel pipe pile group; 2A-steel pipe vertical pile, 2B-steel pipe inclined pile, 2C-vertical pile support; 3-prestressed anchor cable group; 4-main cable; 5-main cable anchoring system.

detailed description

Below in conjunction with accompanying drawing, the utility model is described in further detail:

As shown in Figure 1-Figure 4-c, a suspension bridge pier prestressed anchorage, including steel structure concrete cap 1, steel pipe pile group 2, prestressed anchor cable group 3, main cable 4, main cable anchorage system 5. The steel pipe pile group 2 is composed of a steel pipe pile group vertical pile 2A and a steel pipe pile group inclined pile 2B, and the steel pipe pile group vertical pile 2A is composed of 8 or 13 or 18 steel pipes with a diameter of 2m; The inclined steel pipe piles 2B are set on the periphery of the steel structure concrete cap 1 and spread outwards, and the steel pipe pile group inclined piles 2B are composed of 4 or 6 or 8 steel pipes with a diameter of 2m and an inclination angle of 5°, 10° or 15° ; One end of the vertical pile 2A of the steel pipe pile group and the inclined pile 2B of the steel pipe pile group extends into the bedrock, and the other end of the vertical pile 2A of the steel pipe pile group and the inclined pile 2B of the steel pipe pile group is rigidly connected with the steel structure concrete cap 1 . The prestressed anchor cable group 3 is composed of 10 or 12 or 14 prestressed anchor cables with a diameter of 0.6m; the inner anchor head of each single prestressed anchor cable in the prestressed anchor cable group 3 is fixed The end of the anchor head is fixedly connected to the steel structure concrete cap 1, the angle between the overall stress direction of the prestressed anchor cable group 3 and the direction of the main cable 4 is 0° or 2° or 4° or 5°, and the prestressed anchor The inclination angle of the cable group direction is slightly larger than the 4 inclination angles of the main cable (0° or 2° or 4° or 5°), so as to ensure that the overall stress direction of the prestressed anchor cable group is close to the direction of the main cable, so that the steel pipe piles in the bridge state Only bear a small part of the pressure; the strands of the main cable 4 loosened are connected to the main cable anchor system 5, and the main cable anchor system 5 is fixed on the top of the steel structure concrete cap 1.

Example 1:

The steel pipe vertical pile 2A is composed of 15 steel pipes with a diameter of 2m, and the steel pipe inclined pile 2B is composed of 6 steel pipes with a diameter of 2m, and the inclination angle is 10°. Prestressed anchor cable group 3 is composed of a series of prestressed anchor cables with a single tonnage of 500t. The design cable force of the main cable is 7,000 tons, and the number of prestressed anchor cables is 14. For decentralized anchor cables, special attention should be paid to strict anti-seepage, or dense prestressed anchor cables in geotechnical engineering that can be stretched freely for many times.

In the embodiment, in order to improve the reliability of the steel structure concrete cap 1, section steel is selected as the rigid skeleton of the cap.

Example 2:

Using the structure of embodiment 1, the specific quantity and inclination angle are changed. The prestressed anchor cable group 3 is composed of a series of prestressed anchor cables with a single tonnage of 200t or 300t; The included angle of the cable direction is 0°, so as to ensure that the overall force direction of the prestressed anchor cable group is consistent with the direction of the main cable, so that the steel pipe pile only bears a small part of the pressure in the bridge state.

The steel pipe vertical pile 2A is composed of 8 or 18 steel pipes with a diameter of 2m, and the steel pipe inclined pile 2B is composed of 4 or 8 steel pipes with a diameter of 2m, and the inclination angle is 15°. When the prestressed anchor cable group 3 is composed of a series of prestressed anchor cables with a single tonnage of 200t, the design cable force of the main cable is 2,000 tons (in the case of small span and very good rock conditions), the prestressed anchor cable The number of prestressed anchor cables is 10; when the prestressed anchor cable group 3 is composed of a series of prestressed anchor cables with a single tonnage of 300t, the design cable force of the main cable is 20,000 tons, and the number of prestressed anchor cables is at least 67. It should be added according to the specific engineering design requirements. A single prestressed anchor cable should use a pressure dispersion anchor cable, and special attention should be paid to strict anti-seepage, or a compact prestressed anchor cable in geotechnical engineering that can be freely stretched many times.

A construction method for a platform prestressed anchorage of a suspension bridge pier, the steps of which are:

1. Construction of steel pipe pile groups: According to engineering geological conditions, use static pressure piles, hammering, etc. to move the vertical piles and peripheral inclined piles in place according to the pile machine→hanging piles→inserting piles→hammering sinking→connecting piles → Hammering to the design depth → Inner steel pipe pile → The construction sequence of pressure grouting extends into the bedrock to a certain depth, and the steel support is connected between the vertical piles in the form of welding, and 881-X epoxy zinc-rich primer is used for anti-corrosion measure;

2. The construction of the steel structure concrete cap: firstly hang the steel rigid skeleton, and then pour the concrete in layers and blocks;

3. Main cable anchoring system construction and main cable loosening;

4. When the utility model is adopted in water, the installation of the prestressed anchor cable needs to first drive a steel pipe with a diameter greater than 1.5 times the diameter of the prestressed anchor cable into the water, and then pass through the beam to complete the installation of the prestressed anchor cable. The traditional clip-type prestressed anchor is used When cable is installed, it is necessary to adopt the anti-corrosion measures of injecting resin slurry into the PE corrugated pipe;

5. Tension anchoring of prestressed anchor cables and anchorage of main cable strands: In order to ensure the reasonable stress of caps and steel pipe piles during the construction process, tensioning of prestressed anchor cables and anchoring of main cables shall be carried out at intervals. 25% of the design load of the cable → 20% of the loose strands of the anchoring main cable → 50% of the design load of the tensioned prestressed anchor cable → 40% of the loose strands of the anchoring main cable → 75% of the design load of the tensioned prestressed anchor cable → anchorage 60% of the loose strands of the main cable → 100% of the design load of the tensioned prestressed anchor cable → 80% of the loose strands of the anchored main cable → 100% of the loose strands of the anchored main cable.

Claims (6)

1. a kind of suspension bridge pier-stage type prestressing force anchorage, it includes steel structure concrete cushion cap（1）With steel pipe pile group（2）, steel pipe Pile group（2）One end stretch into basement rock, the other end and steel structure concrete cushion cap（1）Bottom surface is rigidly connected, it is characterised in that：Also wrap Include prestress anchorage cable group（3）, main push-towing rope（4）With main push-towing rope anchoring system（5）, described main push-towing rope anchoring system（5）It is arranged on steel construction Concrete bearing platform（1）Upper surface, described prestress anchorage cable group（3）Anchor cable Inner bolt head end be fixed in basement rock, prestressing force Anchor cable group（3）The outer anchor head end of anchor cable and steel structure concrete cushion cap（1）It is fixedly connected, prestress anchorage cable group（3）It is overall by Force direction and main push-towing rope（4）The angle in direction is 0-5 °.

2. a kind of suspension bridge pier-stage type prestressing force anchorage according to claim 1, it is characterised in that:Described steel pipe pile group （2）By steel pipe soldier piles（2A）And inclined steel-pipe pile（2B）Constitute, steel pipe soldier piles（2A）Between set the soldier piles of intersection to support（2C）, steel Pipe taper pile（2B）It is arranged on steel structure concrete cushion cap（1）Periphery and tilted to external diffusion.

3. a kind of suspension bridge pier-stage type prestressing force anchorage according to claim 2, it is characterised in that:Described steel pipe soldier piles （2A）It is made up of a diameter of 2m of 8-18 roots steel pipe.

4. a kind of suspension bridge pier-stage type prestressing force anchorage according to Claims 2 or 3, it is characterised in that:Described steel pipe Taper pile（2B）It is made up of a diameter of 2m of 4-8 roots steel pipe, the inclination angle of inclined steel-pipe pile is 5-15 °.

5. a kind of suspension bridge pier-stage type prestressing force anchorage according to claim 1, it is characterised in that:Described prestressed anchor Suo Qun（3）Anchor cable be pressure dispersing anchorage cable.

6. a kind of suspension bridge pier-stage type prestressing force anchorage according to claim 1, it is characterised in that:Described steel construction Concrete bearing platform（1）Stiff skeleton be shaped steel.