CN116024904A - A method of installation and construction of a long-span basket arch bridge - Google Patents

Abstract

The invention relates to the technical field of basket arch bridges, in particular to a method for installing and constructing large-span basket arch bridges. It has the following steps: S1, constructing the pier support; S2, installing the main beam support; S3, hoisting the main beam; S4, positioning and installing the main arch support; S5, hoisting the main arch; S6, removing the main arch support; S7, bridge deck Full laying of prefabricated slabs; S8, installation of suspenders, and initial tensioning of suspenders; S9, removal of main girder supports; S10, repair welding and painting of bridge body; S11, joint pouring of bridge deck prefabricated slabs; S12 , The last tensioning of the boom. The installation and construction method provided by the present invention can be preferably implemented based on the bracket hoisting method, and the installation and construction of the long-span basket arch bridge can be preferably realized by adopting the construction scheme of the beam first and the arch later.

Description

A method of installation and construction of a long-span basket arch bridge

technical field

The invention relates to the technical field of basket arch bridges, in particular to a method for installing and constructing large-span basket arch bridges.

Background technique

In the construction of long-span basket arch bridges, the existing common methods are support method, swivel construction method and cable-stayed buckle-hanging method. The engineering construction unit generally adopts the corresponding construction method or improves the existing construction method according to the specific needs of the engineering construction project and the geographical environment where the project is located.

At present, there is no better solution for the construction of long-span prefabricated basket arch bridges.

Contents of the invention

The invention provides a method for installing and constructing a large-span basket arch bridge, which can overcome some or some defects of the prior art.

According to a kind of large-span basket arch bridge installation and construction method of the present invention, it has the following steps:

S1, build the pier support;

S2, install the main beam bracket;

S3. Hoisting of main girder;

S4, positioning and installation of the main arch bracket;

S5. Hoisting of the main arch;

S6, remove the main arch support;

S7. Comprehensive laying of bridge deck prefabricated slabs;

S8, install the suspender, and carry out the initial tensioning of the suspender;

S9, remove the main beam support;

S10, bridge repair welding and paint repair;

S11. Joint pouring of bridge deck prefabricated panels;

S12. The suspender is stretched for the last time.

Preferably, in S1, after the construction of the pier support is completed, the elevation of the top of the pier support and the bridge axis are remeasured.

As a preference, in S2, the main girder support is installed from the middle of the bridge body to both sides.

As a preference, in S3, the middle section of the main girder is hoisted sequentially to both sides. During the hoisting process, the assembly between the beam and the longitudinal girder of the main girder is completed, and the bridge deck prefabricated slab is simultaneously installed.

Preferably, in S4, the positioning installation of the arch foot bracket is completed first, and then the positioning installation of the main arch bracket is performed.

Preferably, in S5, the main arch is hoisted symmetrically from the arch foot section to the vault section, and the adjacent main arch sections are hoisted and positioned for assembly.

The beneficial effect of the present invention is that: the installation and construction method provided by the present invention can be preferably implemented based on the bracket hoisting method, and the installation and construction of the long-span basket arch bridge can be preferably realized by adopting the construction scheme of the beam first and then the arch .

Description of drawings

Fig. 1 is the flow chart of the construction method of boom installation in embodiment 1.

FIG. 2 is a schematic structural view of the sling cage in Embodiment 1.

FIG. 3 is a layout diagram of the winch in Embodiment 1. FIG.

Fig. 4 is the arrangement diagram of the automobile crane in embodiment 1.

Fig. 5 is the arrangement diagram of the automobile crane in embodiment 1.

Fig. 6 is a schematic diagram of hoisting with slings in Embodiment 1.

Fig. 7 is a schematic diagram of the hoisting sequence of the slings in Embodiment 1.

FIG. 8 is a structural diagram of the tensioning equipment in Embodiment 1.

Detailed ways

In order to further understand the contents of the present invention, the present invention will be described in detail in conjunction with examples. It should be understood that the examples are only for explaining the present invention and not for limiting it.

Example 1

The present embodiment provides a method for installing and constructing a large-span basket arch bridge, which has the following steps:

S1, build the pier support;

S2, install the main beam bracket;

S3. Hoisting of main girder;

S4, positioning and installation of the main arch bracket;

S5. Hoisting of the main arch;

S6, remove the main arch support;

S7. Comprehensive laying of bridge deck prefabricated slabs;

S8, install the suspender, and carry out the initial tensioning of the suspender;

S9, remove the main beam support;

S10, bridge repair welding and paint repair;

S11. Joint pouring of bridge deck prefabricated panels;

S12. The suspender is stretched for the last time.

In S1 of this embodiment, after the construction of the pier support is completed, the elevation of the top of the pier support and the bridge axis are remeasured.

In S2 of this embodiment, the main girder support is installed from the middle of the bridge body to both sides.

In S3 of this embodiment, the middle section of the main girder is hoisted sequentially to both sides. During the hoisting process, the assembly between the beam and the longitudinal girder of the main girder is completed, and the bridge deck prefabricated slab is simultaneously installed.

In S4 of this embodiment, the positioning and installation of the arch foot support is completed first, and then the positioning and installation of the main arch support is performed.

In S5 of this embodiment, the main arch is hoisted symmetrically from the arch foot section to the vault top section, and the adjacent main arch sections are hoisted and positioned for assembly.

The installation and construction method provided by this embodiment can be preferably implemented based on the bracket hoisting method, and the installation and construction of the long-span basket arch bridge can be preferably realized by adopting the construction scheme of the beam first and the arch later.

In this embodiment, the bridge deck system can be installed first, and then the main arch rib can be installed. After the arch rib support is removed, the prefabricated plate can be installed, and then the sling can be installed. After the cable force and line shape are accurately adjusted, the bridge deck system support can be removed.

As shown in Figure 1, S8 of the present embodiment has the following steps:

Step S81, preparatory work before construction, which includes reviewing the angle of the embedded pipe and the distance between the ear plates, and producing matching suspenders according to the specifications of the arch bridge;

Step S82, installing the boom, which mainly includes the following steps:

Step S821, lifting the boom to the corresponding position of the arch rib;

Step S822, pass the hoist through the preset hole at the arch rib, pass the suspender through the pre-buried pipe at the tower end, and install the tower end nut;

Step S823, installing a pin shaft at the lower end of the boom;

Step S83, install the tensioning equipment at the arch end, debug and check, then symmetrically tension in batches according to the requirements, and tighten the set nuts after the tension reaches the design cable force;

Step S84, repeating step S83 until the tensioning of all suspenders is completed;

Step S85, performing protective treatment on the anchorage according to design requirements.

In this embodiment, hoisting the boom by using a winch is not only more convenient in installation and setting than the way of hoisting by a crane, but also can be more convenient to fix the winch on the bridge deck. It is larger in size, takes up less space on the bridge deck, and is more convenient to use, and will not interfere with the construction of the bridge deck due to its large size; thus it is convenient for the construction personnel to carry out the construction of the bridge deck. At the same time, through The hoisting method of the winch is also used to reduce the cost and save the economy.

The specific operation steps are as follows:

(1) Determine the duration of the main line:

Construction preparation-boom installation-tensioning-rope adjustment-boom protection-construction finishing.

(2) Other processes such as: construction platform, suspension of booms, installation of booms, tensioning, and transportation of tensioning equipment.

(3) Strengthen the horizontal connection, do a good job in coordination with the construction units of the main bridge, and rationally use the construction land, construction passages, construction platforms and large-scale handling equipment.

The steel structure team checks the angle of the embedded pipe and the distance between the ear plates, and cuts the material according to the actual length to produce the suspender.

Arch end construction platform

Set the hoisting points and safety ropes of the hoisting cage on the vault. Figure 2 is a schematic diagram of the sling hoisting cage, and the construction hoisting cage under the arch required for construction is ready to be put in place. The main body is made of two 70-meter-long and six 70-centimeter 5# angle steels as the bottom.

The main equipment arranged on the bridge deck includes: car cranes (the layout of the car cranes is shown in Figure 4 and Figure 5), winches, hoists and guiding systems, tension jacks, oil pumps and components.

In order to ensure the convenient operation and accurate control of the procedures such as boom arching and beam end hanging, hoists as important construction equipment should be selected in good condition, and each hoist should be equipped with a block. According to the weight of the cable body in this project, the installation and arrangement of the hoist must be within the safety guarantee factor.

The sling hoisting equipment includes hoists, wire ropes, beam end guide points, arch end guide points, etc. Two 3T hoists are arranged on the abutments on both sides. The welding angle of each diaphragm is oriented, and temporary lifting points are set in the arch, and the wire rope is passed through the cable guide, and the wire rope traction system is arranged, as shown in Figure 3:

Z1. The hoisting point is arranged in the anchor box at the arch end. Use the anchor box to set the hoisting reaction point of the hoist wire rope directly above the anchor pad at the arch end. The wire rope adopts a Φ15.6mm wire rope, and the maximum lifting load can bear 4 tons;

Z2 and 3T winches are installed at the abutments on both sides of the bank, and are temporarily fixed to avoid accidents during the lifting operation;

Z3, hoist, after releasing the steel wire rope, bypass the temporary lifting point on the arch, put the steel wire rope through the cable guide directly below to the exit of the cable guide at the arch end, and add two 2-ton chain hoists beside it;

Z4. The lifting equipment has been installed.

Through the above steps, the hoisting performance of the hoist for the boom is better enhanced, thereby better improving the stability of the hoist when hoisting the boom.

According to the requirements of the design drawings for the cable force of the boom, the jack is YCW200 jack, which meets the requirement of a maximum cable force of 170 tons. The tension is controlled according to the principle of symmetry. The structure of the double boom is symmetrical and synchronous at 4 points, and 8 sets are used. Jack + 8 sets of oil pumps + 8 sets of tensioning tools. The oil pump can use ZB4-500 type. The oil pump is arranged on the bridge deck during the tensioning process. The oil pipe enters the arch rib through the temporary manhole and connects with the jack. Communicate with bridge deck operators through walkie-talkies. When jacks and tensioning tools are moved in the arch rib, they are mainly coordinated with hand chain hoists. The space for moving jacks and tooling in the arch rib is small, and there are great potential safety hazards. Requires extra attention.

The heaviest piece of tensioning tooling and equipment is the jack. When moving from the arch foot to the vault, it is necessary to use a chain hoist for auxiliary traction. At the manhole position of the arch rib partition, use a chain hoist to lift the weight to assist manual passage; Equipment and tooling can be put into the arch rib in advance when the arch rib is hoisting, reducing one-time handling.

The main construction method of the boom

Cable Catheter Handling

The difference between the outer diameter of the anchor head of the boom and the inner diameter of the cable casing is small, and the position deviation is very likely to occur during the installation of the boom, which will cause damage to the outer thread of the anchor head and the PE protective sleeve of the boom. Conduct a comprehensive inspection of the cable casing at the end, and smooth and polish the welding slag and burrs in the cable casing.

Beam end lug treatment

Check the position, angle and hole diameter of the lug plate at the beam end.

Hoisting of the anchor head at the upper end of the sling (the schematic diagram of the sling hoisting is shown in Figure 6)

G1. Slowly lower the connecting device of the hoisting hoisting system of the hoist, connect firmly with the anchor head at the upper end of the sling, and release the hoop on the sling;

G2. Turn on the hoist and slowly pull the upper anchor head to the position of the embedded pipe in the anchor box under the arch. The staff on the construction platform adjust the direction of the anchor head at the upper end of the sling and center it so that it can pass through the embedded pipe to reach the arch Rib diaphragm;

G3. Continue to lift, lift the upper anchor head to the design position and tighten the upper nut, and temporarily anchor the upper anchor head of the sling.

G4. The installation sequence of the suspenders. The suspenders should be installed from the abutment to the mid-span side (the schematic diagram of the sling hoisting sequence is shown in Figure 7).

Through the construction process in this embodiment, the hoisting of the anchor head at the upper end of the sling can be better realized.

Anchor head installation at the lower end of the sling

(1) Arrange the hoist and block according to the position of the boom.

(2) Install an auxiliary fixture at the end of the boom, and use a hoist to pull the fork ear of the boom closer to the ear plate. The staff on the beam surface adjust the position and angle of the fork ear through the hand chain hoist, and insert the pin shaft when the position is appropriate.

Boom tension arrangement

According to the requirements of the design drawings for the cable force of the boom, the jack is YCW100 jack, which meets the requirement of a maximum cable force of 170 tons. The tension control is carried out according to the principle of symmetry. The structure of the double boom is symmetrical and synchronous at 4 points, and 16 sets are used. Jack + 8 sets of oil pumps + 8 sets of tensioning tooling. The oil pump can use ZB4-500 type. The oil pump is arranged on the bridge deck during the tensioning process, and the tensioning tooling is installed and transferred on the bridge deck. The tensioning tooling and The heaviest piece of equipment is the jack, which can be installed by a crane or manually.

tensioning system

In order to ensure that the stress of the suspender meets the design requirements, the tension error of each suspender during construction shall not exceed ±2%, and after the completion of the bridge, the error of each suspender shall not exceed ±1%. The following items:

1. The boom installation controls the tension, which is provided by the monitoring unit to the installation and construction unit in the form of monitoring instructions;

2. Under the tension force of the boom installation control, the relative displacement (or deformation) of the anchor point of the boom is calculated, which is the vertical displacement of the lower anchor point and the vertical displacement of the upper anchor point in the vertical plane where the boom is located. temporarily given by the unit;

3. The relevant physical parameters of the corresponding section of the main beam, which are generally determined according to the design;

4. The geometric and physical parameters of the boom cable body shall be provided by the supplier of the boom product.

Tension process

Explanation of the boom tensioning process: According to the structure of the boom, the adjustment device of the boom is set between the lower fork lug and the lower anchor head, so it is necessary to adopt the tensioning method of the pole, and use two jacks to pull the pull rod synchronously, and the pull rod The jack is set parallel to the axial center line of the boom. During the loading process, the jack "presses loose" the adjustment connection device of the boom through the upper and lower shoulder beams (shown in structural diagram 8), and then connects the boom adjustment device. The tightening and screwing of the sleeve realize the tensioning and releasing of the tension of the boom cable, (rotate and adjust the sleeve while pulling to adjust the length of the boom), so that the tensioning of the boom can be realized more conveniently.

The above device consists of the following components:

Lower pole beam: temporarily connected and fixed with the lower fork lug of the boom. Upper pole beam: temporarily connected and fixed with the lower anchor head of the suspender. Temporary pull rod: full thread, both ends pass through the lower shoulder beam and the upper shoulder beam respectively, and are temporarily fixed with nuts. Jack: Load the load, pull the boom down to the design position through the pull rod, or relax it to the design position.

tensioning procedure

During the tensioning process, symmetrical and synchronous tensioning is performed according to the tensioning sequence given by the monitoring unit, and the difference between synchronous tensioning and asynchronous tensions does not exceed the design value. The synchronous difference of each jack is not greater than the minimum division of the oil gauge reading, and the error of the median value of the cable force is less than ±2%.

1. The suspenders are stretched twice, the first is the pre-tensioning of the cable body when the cables are hung and the formal start of tensioning, and the last is the linear and measured cable force after the completion of the second phase of constant load loading. Dragline fills up sheet or releases sheet. In this embodiment, by stretching the suspender twice, the tension degree of the suspender can be better improved, thereby better ensuring the lifting ability of the suspender to the bridge deck, and further improving the stability of the arch bridge .

2. After receiving the design tensioning instruction, according to the regression equation on the jack calibration book, convert the tension value on the instruction into the oil pressure reading value on each group of tensioning equipment, and submit the tensioning operation instruction in written form To the person in charge of each group of tensioning equipment, and explain the relevant precautions;

3. The tension sequence should be stretched from the middle to both sides.

In this embodiment, by setting the stretching sequence as stretching from the middle to both sides, each suspender can better stretch the bridge deck, thereby better improving the suspender's effect on the bridge deck. At the same time, the tensioning sequence is set to stretch from the middle to both sides, which also enables the construction personnel to construct from the center to both ends of the arch bridge at the same time, avoiding interference during construction, and improving the construction efficiency of the arch bridge .

tensioning process

① Connect the oil pipe of the oil pump and the jack, and check whether the precision pressure gauge is consistent with the jack. Before tensioning, two strokes can be moved under no-load conditions to ensure that the jack has no problems when tensioning;

②The tensioning jack and oil pressure gauge must be calibrated before tensioning;

③Start the oil pump, load the symmetrical suspender synchronously and in stages according to the tensioning command, and load slowly. At the same time follow up to tighten the suspender cable nut;

④ When the design and monitoring requirements are met, the oil pressure should be stabilized, and then the nut should be tightened to fully combine the nut with the anchor backing plate. Finally, remove the oil pressure, return the oil, shut down, and cut off the power to complete the tensioning work;

⑤Cooperate with the inspection unit to measure the cable force of each cable during the tensioning process.

4. After the suspender tensioning of a cable number is completed, carefully check the records, and the tensioning equipment can be disassembled only after confirmation is correct, and the installation and tensioning of the next cable number can be carried out.

Boom Adjustment Construction

After the boom is installed, it may be necessary to adjust the rope in stages and parts. The cable adjustment position and the control cable force are provided by the monitoring unit, and the overstretched cable is released, and the insufficient cable force is supplemented.

Anti-corrosion work

After the tensioning is finished, apply 250-300um of slow-release ointment to the inner surface of the anchor cup; first apply 250-300um of slow-release ointment to the surface of the exposed steel parts at the end of the anchor cup, anchor ring, and anchor backing plate, and then wrap the slow-release tape, overlapping The rate is 50%, and finally apply 2 coats of external protective agent.

Through the anticorrosion work in this embodiment, the anchorage can be effectively treated with anticorrosion, so that the service life of the anchorage can be better improved.

Shock absorber installation

Built-in shock absorbers generally include shock absorbers, metal rings, wedges, pull rods, nuts, spring washers and other components. When installing the shock absorber, first push the shock absorber flat into the embedded pipe, install the movable wedge on the fixed wedge, and press the shock absorber wedge to expand the vibration-absorbing rubber in the radial direction, so that the boom The wedge is tight, and the shock absorber also achieves a fixed effect at the same time.

The self-made hanging cage is used as the installation platform of the shock absorber, and the hanging cage is welded with 5# angle steel. Weld a temporary lifting point above the cable number to be installed, and then use Ф16 steel wire rope and hoist to hang the cage. The chain hoist is used to adjust the height of the cage to facilitate construction operations. A Ф16 steel wire rope is put down at the temporary welding lifting point to tie the cage to prevent accidents.

The cage platform considers using a car crane for installation and suspension.

It is easy to understand that, on the basis of one or several embodiments provided by this application, those skilled in the art can combine, split, recombine, etc., the embodiments of this application to obtain other embodiments, and these embodiments do not exceed the scope of this application. The scope of protection applied for.

The above schematically describes the present invention and its implementation, but the description is not restrictive, and the examples show only part of the implementation of the present invention, and the actual structure is not limited thereto. Therefore, if a person of ordinary skill in the art is inspired by it, without departing from the inventive concept of the present invention, without creatively designing a structural mode and embodiment similar to the technical solution, it shall all belong to the protection scope of the present invention .

Claims (6)

1. a large-span basket arch bridge installation and construction method, it has the following steps: S1, build the pier support; S2, install the main beam bracket; S3. Hoisting of main girder; S4, positioning and installation of the main arch bracket; S5. Hoisting of the main arch; S6, remove the main arch support; S7. Comprehensive laying of bridge deck prefabricated slabs; S8, install the suspender, and carry out the initial tensioning of the suspender; S9, remove the main beam support; S10, bridge repair welding and paint repair; S11. Joint pouring of bridge deck prefabricated panels; S12. The suspender is stretched for the last time. 2. The installation and construction method of a long-span basket arch bridge according to claim 1, characterized in that in S1, after the construction of the pier support is completed, the elevation of the top of the pier support and the bridge axis are remeasured. 3. The installation and construction method of a long-span basket arch bridge according to claim 1, characterized in that: in S2, the main girder supports are installed from the middle of the bridge body to both sides. 4. The installation and construction method of a long-span basket arch bridge according to claim 1, characterized in that: in S3, the middle section of the main girder is hoisted sequentially to both sides, and during the hoisting process, the crossbeam and longitudinal beam of the main girder are completed The assembly between the bridge deck and the synchronous installation of bridge deck prefabricated panels. 5. The installation and construction method of a long-span basket arch bridge according to claim 1, characterized in that: in S4, the positioning and installation of the arch foot support is first completed, and then the positioning and installation of the main arch support is performed. 6. The installation and construction method of a long-span basket arch bridge according to claim 1, characterized in that: in S5, the main arch is hoisted symmetrically from the arch foot section to the arch top section, and the adjacent main arch sections are hoisted and positioned for assembly.

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