CN115387228A - A high-stability steel truss girder jacking and floating drag frame construction method - Google Patents

Abstract

The invention discloses a high-stability steel truss girder pushing and floating bracket construction method, and relates to the technical field of steel truss girder floating bracket construction. Preparing a steel truss girder before floating and towing construction: a platform is built on a pier, and a slide way and a sliding device are arranged; manufacturing a bracket on a floating ship; the steel truss girder is assembled and the floating towing bracket is arranged: assembling a steel truss girder with a plurality of sections above the slideway, assembling the steel truss girder by two rounds, moving the steel truss girder to piers at two sides by four-time pushing and floating dragging, and finally dropping the steel truss girder. The invention has the advantages that: by adopting the overall construction method of on-site assembly, slippage and floating, the steel truss beam is integrally assembled by two-time assembly, the problem that the operation site of the floating crane is limited is solved, the construction is not limited by the site, and the operation difficulty is reduced; the cantilever of the steel truss girder is large, the floating drag construction difficulty is reduced by pushing and floating drag for multiple times, the floating drag ship construction is more stable, and the navigation requirement can be ensured in the construction.

Description

A high-stability steel truss girder jacking and floating drag frame construction method

technical field

The invention relates to the technical field of construction of a steel truss girder floating tow frame, in particular to a construction method of a steel truss girder pushing and floating tow frame with high stability.

Background technique

With the rapid development of bridge technology in our country, various forms of bridges across rivers emerge in an endless stream, especially steel truss girders are widely used in railways, highways and urban rail transit due to their advantages of low building height, beautiful style and large span. At present, in the process of building railway bridges and viaducts in coastal cities and cities with many inland rivers, it often happens that large-span steel trusses cross navigable canals.

The construction methods of bridge erection include cantilever erection construction method using girder crane, jacking or dragging construction method. The cantilever construction method has the disadvantages of requiring large-scale lifting equipment or low component positioning and assembly efficiency; while the push or drag construction method needs to set up guide beams to reduce the internal force and overturning moment of the structure at the maximum outstretched state. There are many supporting facilities for construction, and multiple system conversions are required, the operation is cumbersome, and the construction efficiency is low. In addition, the above methods need to be closed to navigation during the construction period, which will affect water traffic.

The floating dragging method has the advantages of short construction period, good economy, and short sailing time. It has obvious advantages when operating on rivers with navigation requirements, so it is widely used. However, in the prior art, the floating and dragging method is to directly assemble the steel truss girder as a whole on the slideway, but in actual construction, the floating crane operation will have limited space, and the direct overall assembly operation is difficult, and the steel truss girder is dragged The cantilever is relatively large, and the jacking can be done directly at one time, so that the front section of the steel truss girder protrudes from the bracket and hangs in the air, which will increase the difficulty of floating towing, and the ship will easily lose stability. It is necessary to provide a construction method of steel truss girder jacking and floating towing frame with high stability, so as to reduce the construction difficulty of steel truss girder floating towing erection, make the construction process more stable, and ensure the navigation requirements.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high-stability steel truss girder jacking and floating trailer construction method, which can solve the situation of limited space for floating crane operations in the prior art, difficulty in direct overall assembly operation, Directly complete the jacking at one time, so that the front section of the steel truss girder protrudes from the bracket and hangs in the air, which will increase the difficulty of floating towing and the problem that the ship is prone to instability.

In order to solve the above-mentioned technical problems, the technical solution of the present invention is: for erecting steel truss girders on two bridge piers on both sides, characterized in that it includes the following steps:

S1. Preparations before construction of steel truss girder floating tow:

S1.1. Set up temporary steel pipe support frames by piling in the water between the bridge piers, and set anchor brackets on the bridge piers erected with steel truss girders for cantilever floating towing; build a platform on the bridge piers, and erect longitudinal beams on the top of the platform, And set the slideway and sliding equipment on the longitudinal beam, and set the pad on the slideway;

S1.2, making the bracket, hoisting the bracket as a whole into the cabin of the floating towing ship, and welding the bracket and the hull of the floating towing ship firmly;

S2. Assembly of steel truss girders and erection of floating tow: Assemble steel truss girders with multiple internodes above the slideway, and place the steel truss girders on pads. The order of assembly is two-wheel assembly from the side of the large pile to the side of the small pile, and then the floating tow erection:

S2.1. The first assembly: assemble from the side of the large pile, except for the last internode component on the side of the small pile, the assembly of other internode components is completed;

S2.2. The first push: After the first assembly, welding and inspection are qualified, the temporary connection with the steel pipe support frame is removed, the sliding equipment is started, and the steel truss girder is subjected to the first round of sliding construction. The front end of the truss girder slides in the direction of floating towing, and a section at the front of the steel truss girder protrudes from the steel pipe support frame to hang in the air, and cantilever 1 section, completing the first round of steel truss girder sliding construction;

S2.3, the second assembly: the steel truss girder is assembled for the second time, the last internode member is assembled, and the overall assembly of the steel truss girder is completed;

S2.4, the second push: the second push pushes the steel truss beam forward by one section, and the steel truss cantilever has two sections;

S2.5. Press water into the cabin of the floating tugboat to sink, the top of the support is lower than the bottom of the steel truss girder, then move the floating tow to the third node of the steel truss beam cantilever, align the support with the third node, and pull it out Ballast the water in the cabin of the floating tugboat, and the front end of the steel truss girder is lifted up by the support, so that the steel truss girder is suspended 10cm in the air, and the fulcrums of the nodes at the rear of the steel truss girder are removed, and the pads on the slideway are removed. The two fulcrums of the fulcrum bear force and support the steel truss girder;

S2.6. The third push: activate the sliding equipment at the tail of the steel truss girder, push the steel truss girder forward for the third time, to the 3 nodes of the steel truss girder cantilever, the fulcrum of the steel truss girder tail is located in the two groups In the middle position of the steel pipe support frame, the floating drag moves forward at the same time;

S2.7, the fourth push: start the sliding equipment at the end of the steel truss girder, slide the steel truss girder forward, the floating tow and the support on it move with the sliding speed of the steel truss girder, and pass through the forward winch and the steel truss girder Move forward together, and monitor the running direction of the steel truss girder and the floating tow, use the direction control cable of the winch to stabilize the running direction of the floating tow, push the tail of the steel truss girder to the top of one side of the pier for the fourth time, and the steel truss girder The front end reaches the top of the pier on the other side;

S2.8. Set up two drop beam jacks on the top of the two piers on both sides. The drop beam jacks are set on the inside of the slideway. Pressurized water sinks in the cabin, releases the constraints of the support of the floating tow and the steel truss girder, removes the floating tow, completes the floating tow operation, and proceeds to the beam drop construction;

S2.9. Remove the Bailey frame support and girder erection equipment between the bridge pier on one side and the steel pipe support frame, and install the support, and then carry out the beam drop construction. The erection of steel truss girders is completed on the piers on both sides.

Further, in the step S1.2, two brackets are provided, and the two brackets are installed on the floating tow ship. The brackets are welded by steel pipe piles and I-beams, and the I-beams are spliced Form the support foundation, two I-beams protrude from the periphery of the support foundation in the horizontal and vertical directions, and are used to connect and fix with the floating towed ship and the support on the other side. The steel pipe piles are welded on the support foundation to serve as The main body of the bracket, the channel steel is used as scissors support between the steel pipe piles, and the double and four-piece I-beams are used as distribution beams on the top of the steel pipe piles to carry the steel truss beams, and finally the whole bracket is hoisted to the floating tow ship In the cabin, it is firmly welded to the hull.

Further, in the step S2.8, before setting the drop beam jacks on the top of the pier, first measure the offset data of the steel truss girder with a total station, and then use four three-dimensional drop beam jacks to be arranged on the inside of the slideway, and the same pier The two drop beam jacks on the top are operated by a pump station, and the deflection correction of the steel truss girder is carried out through the PLC control system.

Further, the sliding equipment in the steps S1 and S2 is a hydraulic crawler, the hydraulic crawler is a combined structure, one end is connected to the slideway by a wedge-shaped clamp block, and the other end is connected to the sliding tire frame in the form of a hinge point Or the components are connected, and the hydraulic cylinder is used to drive the crawling in the middle. The wedge-shaped clamping block of the hydraulic crawler has a one-way self-locking effect. When the oil cylinder is extended, the wedge-shaped clamping block works to achieve clamping and automatically locks the slideway; the oil cylinder When retracting, the clamp block does not work to achieve release, and moves in the same direction as the oil cylinder;

The working process of the hydraulic crawler is as follows:

Step 1: Clamp the wedge and the slideway in the clamping device of the hydraulic crawler, connect the piston rod pin shaft at the front end of the cylinder of the hydraulic crawler to the sliding member, extend the cylinder, and push the sliding member to slide forward;

Step 2: The cylinder of the hydraulic crawler is extended for one stroke, and the component slides forward by 300mm;

Step 3: After the cylinder is extended for one stroke, the sliding member does not move, and the oil cylinder shrinks, so that the wedge in the clamping device and the slideway are released, and the clamping device is dragged to slide forward;

Step 4: After one stroke of the hydraulic crawler is completed shrinking the cylinder, drag the clamping device to slide forward 300mm, and one crawling advance stroke is completed, then perform the process of step 1 again, and reciprocate in this way to slide the component to the final position.

Further, in the step S2, during the floating construction process, all the sliding equipment synchronously push the steel truss girder to slide, and each sliding equipment is evenly loaded, and the computer control system feeds back the distance signal through the banyan grid sensor to control each The error of the sliding equipment is within 20mm, so as to control the synchronous sliding of the entire sliding unit. The sliding unit is equipped with a transverse stopper corresponding to the position of the slideway to ensure the safety and reliability of the entire sliding process.

Further, in the steps S2.8 and S2.9, during the construction of the falling beam, the falling beam jack used for the falling beam has a spherical support pad safety hoop at the top, and the multiple falling beam jacks acting together are selected from the same model, and the oil pipe Parallel connection; in the falling beam, asbestos board anti-skid material is placed between the supporting surface of the bridge pier and each cushion; in order to adapt to the horizontal displacement of the fulcrum, the bottom of the falling beam jack is provided with an MGE plate pedestal, and the center of the pedestal coincides with the central axis of the falling beam jack. Observe and record changes in the top-fall elevation, fulcrum reaction force, fulcrum displacement, and mid-span deflection; when the beam is placed on a temporary support during the fall process, the height difference between the two adjacent truss fulcrums should be measured, and when the height difference is greater than 3mm , adjust the elevation of the two fulcrums.

The advantage of the present invention is that: the overall construction method of on-site assembly plus sliding and floating towing is adopted, and the steel truss girder is assembled as a whole through two assembly, which solves the situation that the floating crane operation site is limited, and the construction is not limited by the site. Reduce the difficulty of operation;

After the steel truss girders are assembled twice, they are respectively pushed twice until the front end of the steel truss girder cantilever two sections, and then the steel truss girder is supported by the support on the floating tow, and the fulcrum is set at the third node. After the fulcrum of the steel truss girder is suspended in the air, withdraw the adjustment block, and only support the steel truss girder through the tail fulcrum and the floating fulcrum, and then carry out the third and fourth push forward and the floating tow until the steel truss girder is moved. to the bridge piers on both sides, and finally drop the steel truss girders on the bridge piers on both sides through the beam drop construction to complete the erection construction of the steel truss girders. The cantilever of the steel truss girders is relatively large. The way of floating towing reduces the difficulty of floating towing construction, and the construction of floating towing ships is more stable, and the navigation requirements can be guaranteed during construction.

Description of drawings

Fig. 1 is the structural representation of the support on the floating towing ship of the present invention;

Fig. 2 is the schematic diagram of steel truss girder assembly of the present invention for the first time;

Fig. 3 is the schematic diagram after the steel truss girder of the present invention pushes for the first time;

Fig. 4 is the schematic diagram of the overall assembly of the steel truss girder of the present invention;

Fig. 5 is the schematic diagram of steel truss girder of the present invention after pushing for the second time;

Fig. 6 is the schematic diagram of the position of the bracket and the steel truss beam on the floating tow ship of the present invention;

Fig. 7 is a schematic diagram of three internodes of the cantilever after the steel truss girder of the present invention is pushed for the third time;

Fig. 8 is a schematic diagram showing that the steel truss girder of the present invention reaches two bridge piers on both sides after being pushed and floated;

Fig. 9 is a schematic diagram of the steel truss girder of the present invention after falling.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The following examples can enable those skilled in the art to understand the present invention more comprehensively, but the present invention is not limited to the scope of the described examples.

The steel truss girder in this embodiment has a span of 90m and a full width of 23m. The main truss adopts a Warren triangular web bar system with vertical bars, the internode length is 7.4m, the main truss height is 11m, and the height-span ratio is 1/8.07 , the distance between the two main trusses is 22.1m, the width-span ratio is 1/4.02, and the bridge deck width is 20.775m.

The substructure of the main bridge adopts frame piers, the pier cover girder is 2.5m high and 3.3m wide, and the material is C40 concrete. The platform adopts a rectangular cap with a thickness of 3.0m. The foundation adopts 10 bored piles with a diameter of 1.5m, and the pile foundation adopts C30 underwater concrete.

The river surface of this project is relatively wide, and the navigation shall not be closed during the construction period, and the navigation requirements must be guaranteed, and the steel truss girders are heavy.

The specific construction method includes the following steps:

Considering the structural characteristics of the bridge, the overall construction idea of "segmented processing in the factory + on-site assembly + sliding and floating towing" was adopted. The steel truss girders were firstly processed in sections in the factory and then assembled on site.

S1. Steel truss girder 3 floating towing preparations before construction:

S1.1. Set up temporary steel pipe support frames by piling in the water between piers 9#~11#, and set anchor brackets on pier 11# where steel truss girder 3 is erected for cantilever floating towing. Steel truss girder 3 will eventually need Erection on the 11# and 12# bridge piers, build a platform on the 9#~11# bridge piers, set up the longitudinal beam on the top of the platform, and set the slideway and sliding equipment on the longitudinal beam, and set the pad on the slideway.

The sliding equipment is a hydraulic crawler. The hydraulic crawler is a combined structure. One end is connected to the slideway with a wedge-shaped clamp, and the other end is connected to the sliding tire frame or component in the form of a hinge point. The hydraulic cylinder is used to drive the crawler in the middle. The wedge-shaped clamping block of the device has a one-way self-locking effect. When the oil cylinder is extended, the wedge-shaped clamping block works to realize clamping and automatically locks the slideway; when the oil cylinder is retracted, the clamping block does not work to realize loosening. direction to move.

The working process of the hydraulic crawler is as follows:

Step 1: Clamp the wedge and the slideway in the clamping device of the hydraulic crawler, connect the piston rod pin shaft at the front end of the cylinder of the hydraulic crawler to the sliding member, extend the cylinder, and push the sliding member to slide forward;

Step 2: The cylinder of the hydraulic crawler is extended for one stroke, and the component slides forward by 300mm;

Step 3: After the cylinder is extended for one stroke, the sliding member does not move, and the oil cylinder shrinks, so that the wedge in the clamping device and the slideway are released, and the clamping device is dragged to slide forward;

Step 4: After one stroke of the hydraulic crawler is completed shrinking the cylinder, drag the clamping device to slide forward 300mm, and one crawling advance stroke is completed, then perform the process of step 1 again, and reciprocate in this way to slide the component to the final position.

S1.2. Make the bracket 2, hoist the bracket 2 as a whole into the cabin of the floating towing vessel 1, and weld the bracket 2 and the hull of the floating towing vessel 1 firmly.

On the site assembly platform, the steel pipe piles of φ529 and the I-beams of I20a and I56 are welded into two brackets 2 as shown in Figure 1. There are two brackets 2 installed on the floating trailer. On the ship 1, the support 2 is welded by steel pipe piles 22 and I-shaped steel, and the I-shaped steel is spliced to form the support foundation 21. There are two I-beams protruding from the surroundings of the support foundation 21 in the horizontal and vertical directions, and are used for and The floating tow ship 1 and the support 2 on the other side are connected and fixed. The steel pipe piles 22 are vertically welded on the support foundation 21 as the main body of the support. Use double and four-piece I-beams as the distribution beam 23 to carry the steel truss girder 3, and finally lift the bracket 2 as a whole into the cabin of the floating towing ship 1, and weld it firmly with the hull.

S2. Steel truss girder 3 assembly and floating towing erection: Assemble steel truss girder 3 with multiple internodes above the slideway, and steel truss girder 3 is placed on pad 4, considering that the floating crane operation site in the back field is limited , the assembly sequence of the steel truss girder 3 is two-wheel assembly from the large pile side to the small pile side, the large pile side is the 11# pier side, and the small pile side is the 9# pier side, and then the floating tow is carried out.

S2.1. The first assembly: assemble from the side of the large pile, except for the last internode component on the side of the small pile, the assembly of the other internode components is completed, as shown in Figure 2.

S2.2. The first push: After the first assembly, welding and inspection are qualified, the temporary connection with the steel pipe support frame is removed, the sliding equipment is started, and the steel truss girder 3 performs the first round of sliding construction. The front end of the steel truss girder 3 slides in the direction of the floating tow. One section at the front of the steel truss girder 3 protrudes from the steel pipe support frame and hangs in the air. There is one section of the cantilever, and the sliding distance is 16 meters. The first round of steel truss girder 3 sliding is completed. Construction, the state after the first push is shown in Figure 3.

During the construction process, all sliding equipment synchronously pushes the steel truss girder 3 to slide, and each sliding equipment is evenly loaded. The entire construction process should be simulated and analyzed to ensure the safety of the structure during the installation process.

During the hydraulic sliding process, pay attention to observe the pressure and load changes of the equipment system, and carefully record the work; pre-set the pump source pressure value according to the design sliding load, thereby controlling the maximum output thrust of the crawler to ensure The safety of the entire sliding facility; the computer control system feeds back the distance signal through the banyan sensor to control the error of each crawler within 20mm, thereby controlling the synchronous sliding of the entire sliding unit.

There is basically no horizontal force in the horizontal direction during sliding, and the force calculation on the glideway under the sliding condition (considering 5% horizontal force) is safe, and the sliding unit is equipped with a lateral stopper corresponding to the position of the slideway, so the entire sliding process is safe and reliable of.

The crawler is a hydraulic system. Through flow control, the acceleration of the crawler's start and stop is almost zero, and the impact on the track is very small; during the sliding process, pay close attention to the sliding track, hydraulic crawler, hydraulic pump source system, and computer. Synchronize the working status of the control system, sensor detection system, etc.

Slip process synchronous monitoring and control scheme:

1) According to the pre-calculated reaction force value of each slip point under slip slip conditions, in the computer synchronous control system, set the maximum slip force of each hydraulic crawler; when encountering slip When the force exceeds the set value, the hydraulic crawler automatically adopts overflow unloading to prevent the serious uneven load distribution of the slip point and cause damage to the structure or temporary facilities.

2) Through the self-locking device and mechanical self-locking system set in the hydraulic circuit, when the hydraulic crawler stops working or encounters a power failure, the sliding track can be automatically locked for a long time to ensure the safety of the sliding truss.

3) Sensor monitoring system:

Obtain the position information of the main oil cylinder through stroke sensing detection; obtain the slip force information of each slip point through oil pressure sensing detection; obtain the operating status of the motor through the feedback of the motor start signal; obtain the electric signal feedback through the solenoid valve , to obtain the working state of the valve; through the proportional valve current signal feedback, to obtain the system flow (slip speed).

4) Computer control system:

The computer network system reflects the above feedback and control signals remotely, in real time and reliably to the man-machine interface in the central control room: display the current system operating status and parameters (such as cylinder status, synchronous displacement, load oil pressure), record historical data and Curves (such as time history curves of propulsion speed, synchronization accuracy, slip point load, etc.);

The operator will click on the computer man-machine interface: set the running state, start the pump source motor, switch the control mode, adjust the propulsion speed, pause the propulsion process; the computer control system will automatically verify the communication data, correct the communication error code, and change the control algorithm , Optimizing control parameters, correcting synchronization accuracy; the sensing and detection information of the hydraulic synchronous control system is redundant with each other, and the operation control signals are interlocked with each other, which constitutes a safe, reliable, efficient and convenient modern practical equipment.

In order to visually monitor the synchronization and slip state during the sliding process, 50mm is used as the minimum sliding unit during the initial sliding, and the track is marked and numbered; each control monitoring is observed at any time during the sliding process Points relative to the deviation of the scale on the track, accurately understand the slip state at any time, and make a record; if a large synchronization deviation is found, adjust it immediately, and adjust by jogging a single crawler and analyzing the initial slip record data , report to the chief engineer of the project and the engineer of the monitoring unit for review, analyze the reasons for the recorded data in detail and make corresponding adjustments in the subsequent sliding construction process; if the initial sliding state is good, the unit of the sliding track scale can be appropriately increased to serve as The basis for synchronous monitoring and control during the shifting process.

Precautions for sliding construction:

(1) When assembling the steel truss girder 3 on the beam frame, in addition to ensuring that the support has sufficient bearing capacity and reserved compression sinkage, special attention should be paid to the assembled camber curve of the steel truss girder 3;

(2) Clarify the steel truss beam 3 structural design drawings, design instructions, block stress, weight table, etc.;

(3) During the installation process of the steel truss girder 3, due to temperature changes and fulcrum lifting jacks, the movable support will move greatly along the direction of the bridge axis. When the beam body falls on the official movable support, its displacement may exceed its design The maximum allowable offset. During construction, avoid moving the beam body when there is pressure between the beam body and the support. When the beam body moves vertically and horizontally, make it move away from the support, adjust it to the correct position, and then fall on the support;

(4) The layout of the top of the bridge pier shall be handled in strict accordance with the construction design drawings, and a comprehensive inspection shall be carried out before erection, and a signature shall be processed; horizontal and midline observation points shall be set on it, and the subsidence and displacement during the girder erection process shall be observed at any time, so as to timely Adjustment;

(5) Asbestos board or three-ply board and other non-slip materials should be padded on the contact surfaces of steel pad beams, steel pads, jacks and other contact surfaces without bolts;

(6) During the process, regularly check whether the sliding equipment is normal and whether the connection of each line is correct;

(7) During the steel girder sliding construction, the surveyors should strengthen the line type measurement, and timely feedback and adjust the deviation when they are found, so as to ensure the accuracy of steel girder erection and effectively control the lateral elevation of each sliding equipment;

(8) The sliding equipment must be installed horizontally;

(9) When the equipment is installed, it is necessary to control the forward direction of the horizontal jack, the longitudinal direction is parallel to the bridge axis, and the designed longitudinal slope is guaranteed;

(10) When the high-pressure hoses are connected, the joints must be cleaned with diesel oil to avoid bringing dust and impurities into the hydraulic circuit system; sharp objects are not allowed in the workplace to prevent scratching the high-pressure hoses; high-pressure hoses and electrical control cables It should be tied up well to avoid obstruction of traffic and construction work, being damaged, broken and blown off by strong winds, so as to ensure safe construction;

(11) Power lines and high-pressure oil pipes in the construction work area shall not hinder the advancement of components;

(12) The sliding system is kept and maintained by special personnel, and the users should be familiar with the system structure and its action procedures;

(13) When disassembling the oil pipe after the work is completed, the oil pressure in the jack should be unloaded first, and it is strictly forbidden to pull out the oil pipe under pressure; after the high-pressure hose is removed, each joint cover should be worn or wrapped in a plastic bag to avoid dust particles and sundries into the hose;

(14) For long-term storage of the equipment, all parts should be cleaned and covered with plastic bags. If it is reused, the air accumulated in the system must be removed first, the wearing parts in the jack must be replaced, and the lifting jack action must be checked.

(15) The equipment must be used in conjunction with the jacks, hydraulic pump stations, and control systems in the products supplied by the manufacturer. It is not allowed to mix other jacks, pump stations, and control systems with this product, otherwise very serious accidents may occur ;

(16) For the safety pressure setting of the relief valve in the hydraulic pump station, the load should be checked for each construction, and the corresponding oil pressure should be calculated according to the load to protect the hydraulic system.

S2.3, the second assembly: the steel truss girder 3 is assembled for the second time, the last internode member is assembled, the overall assembly of the steel truss girder 3 is completed, and the assembled steel truss girder 3 is shown in Figure 4 .

S2.4, the second push: the second push pushes the steel truss girder 3 forward by one section, and advances 12 meters. The state after the first push is shown in Figure 5.

S2.5. Sink under pressure in the cabin 1 of the floating tugboat, the top of the support 2 is lower than the bottom of the steel truss beam 3, and then move the floating tow to the third node of the cantilever of the steel truss beam 3, and the support 2 is aligned with the third node. As shown in Figure 6, the ballast water in the cabin of the floating tugboat is pumped out, the front end of the steel truss beam 3 is floated on the support 2, so that the steel truss beam 3 is suspended by 10 cm, and the fulcrums of each node at the rear of the steel truss beam 3 are removed, as shown in the figure As shown in Fig. 7, the spacer on the slideway is removed, and the steel truss girder 3 is supported only through the two fulcrums of the steel truss girder 3 end fulcrum and the support fulcrum.

S2.6. The third push: activate the sliding equipment at the tail of the steel truss girder 3, and push the steel truss girder 3 forward for the third time until the steel truss girder 3 cantilever 3 sections, and the steel girder slides forward by 12.5 m, as shown in Figure 7, the steel truss girder 3 tail fulcrum is located in the middle position of two groups of steel pipe support frames, and the floating drag moves forward at the same time;

S2.7, the fourth push: activate the sliding equipment at the tail of the steel truss girder 3, slide the steel truss girder 3 forward, the floating drag and the support on it will move forward with the sliding speed of the steel truss girder 3 The winch and the steel truss girder 3 move forward together, and monitor the running direction of the steel truss girder 3 and the floating tow, use the direction control cable of the winch to stabilize the running direction of the floating tow, and push the fourth time until the tail of the steel truss girder 3 reaches one side Above the pier, the front end of the steel truss girder 3 reaches above the pier on the other side, as shown in FIG. 8 .

Use a level gauge to check the stability of the pontoon during the floating towing and pushing operation. If the ship loses stability, use the water pumps at the four corners of the pontoon to control the water storage inside the ship to adjust the stability of the ship.

S2.8. Set up two 400-ton drop beam jacks on the top of the 11# and 12# piers on both sides. The drop beam jacks are set on the inside of the slideway. After the floating tow is in place, pressurize the water in the cabin of the floating tow to sink, release the constraints of the support of the floating tow and the steel truss girder 3, add water to the floating tow and sink to withdraw from the channel, complete the floating tow operation, and use a three-dimensional drop beam jack to replace the floating tow. Carry out beam drop construction, as shown in Figure 9 is the schematic diagram of steel truss girder 3 after beam drop.

Before installing the falling beam jacks on the top of the pier, measure the offset data of the steel truss girder 3 through the total station, and then use four three-dimensional falling beam jacks to arrange inside the slideway, and use one set of two falling beam jacks on the top of the same pier The pump station is operated, and the deviation correction of the steel truss beam 3 is performed through the PLC control system.

S2.9. Remove the Bailey frame support and girder erection equipment between the 11# bridge pier and the steel pipe support frame, install the support, and then carry out the beam drop construction. The erection of the steel truss girder 3 is completed on the piers on both sides.

During the construction of falling beams, the falling beam jacks used for the falling beams have the top spherical support pad safety hoops, and the multiple falling beam jacks working together are selected to the same model and connected in parallel with oil pipes; the lengths of hydraulic jacks, oil pumps, pressure gauges, and oil pipes should be consistent ; In order to accurately grasp the fulcrum reaction force, the jack, oil pump and pressure gauge should be calibrated together.

In the falling beam, the asbestos board anti-slip material is placed between the supporting surface of the pier and each cushion; in order to adapt to the horizontal displacement of the fulcrum, the bottom of the falling beam jack is provided with an MGE plate pedestal, and the center of the pedestal coincides with the central axis of the falling beam jack; Changes in elevation, fulcrum reaction force, fulcrum displacement, and mid-span deflection shall be observed and recorded; safety bearings must be set when jacking up and falling beams, and the upstream and downstream points of the same pier shall be lifted simultaneously except when the elevation is adjusted separately. ; When the beam is placed on the temporary support in the process of falling, the height difference between the adjacent two truss fulcrums should be measured. When the height difference is greater than 3mm, the elevation of the two fulcrums should be adjusted; It should be placed in strict accordance with the design regulations and should not be changed arbitrarily.

The use of drop beam jacks must comply with the following principles:

① The pump should be placed in the middle of the two girders as far as possible so that the length of the oil pipes is approximately equal;

② Use spindle oil as much as possible;

③ When the jack is lifted, the safety hoop must be screwed on at any time, and asbestos boards are placed on the top and bottom of the jack;

④ When jacking up, the safety hoop cannot be hit to the top at one time, nor can it be pushed to death. It is necessary to keep a gap of 5-10mm with the top surface of the cylinder body, and loosen it at any time to prevent the safety hoop from being crushed, and to prevent accidents at any time.

This specific implementation mode adopts the overall construction method of on-site assembly, sliding, and floating towing. The steel truss girder is assembled through two assemblings to complete the overall assembly, which solves the situation that the floating crane operation site is limited, and the construction is not limited by the site, reducing operation. difficulty;

After the steel truss girders are assembled twice, they are respectively pushed twice until the front end of the steel truss girder cantilever two sections, and then the steel truss girder is supported by the support on the floating tow, and the fulcrum is set at the third node. After the fulcrum of the steel truss girder is suspended in the air, withdraw the adjustment block, and only support the steel truss girder through the tail fulcrum and the floating fulcrum, and then carry out the third and fourth push forward and the floating tow until the steel truss girder is moved. to the bridge piers on both sides, and finally drop the steel truss girders on the bridge piers on both sides through the beam drop construction to complete the erection construction of the steel truss girders. The cantilever of the steel truss girders is relatively large. The way of floating towing reduces the difficulty of floating towing construction, and the construction of floating towing ships is more stable, and the navigation requirements can be guaranteed during construction.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (6)

1. A steel truss girder with high stability pushes and adds a floating drag frame construction method, which is used to erect the steel truss girder on two bridge piers on both sides, it is characterized in that: comprise the following steps: S1. Preparations before construction of steel truss girder floating tow: S1.1. Set up temporary steel pipe support frames by piling in the water between the bridge piers, and set anchor brackets on the bridge piers erected with steel truss girders for cantilever floating towing; build a platform on the bridge piers, and erect longitudinal beams on the top of the platform, And set the slideway and sliding equipment on the longitudinal beam, and set the pad on the slideway; S1.2, making the bracket, hoisting the bracket as a whole into the cabin of the floating towing ship, and welding the bracket and the hull of the floating towing ship firmly; S2. Assembly of steel truss girders and erection of floating tow: Assemble steel truss girders with multiple internodes above the slideway, and place the steel truss girders on pads. The order of assembly is two-wheel assembly from the side of the large pile to the side of the small pile, and then the floating tow erection: S2.1. The first assembly: assemble from the side of the large pile, except for the last internode component on the side of the small pile, the assembly of other internode components is completed; S2.2. The first push: After the first assembly, welding and inspection are qualified, the temporary connection with the steel pipe support frame is removed, the sliding equipment is started, and the steel truss girder is subjected to the first round of sliding construction. The front end of the truss girder slides in the direction of floating towing, and a section at the front of the steel truss girder protrudes from the steel pipe support frame to hang in the air, and cantilever 1 section, completing the first round of steel truss girder sliding construction; S2.3, the second assembly: the steel truss girder is assembled for the second time, the last internode member is assembled, and the overall assembly of the steel truss girder is completed; S2.4, the second push: the second push pushes the steel truss beam forward by one section, and the steel truss cantilever has two sections; S2.5. Press water into the cabin of the floating tugboat to sink, the top of the support is lower than the bottom of the steel truss girder, then move the floating tow to the third node of the steel truss beam cantilever, align the support with the third node, and pull it out Ballast the water in the cabin of the floating tugboat, and the front end of the steel truss girder is lifted up by the support, so that the steel truss girder is suspended 10cm in the air, and the fulcrums of the nodes at the rear of the steel truss girder are removed, and the pads on the slideway are removed. The two fulcrums of the fulcrum bear force and support the steel truss girder; S2.6. The third push: activate the sliding equipment at the tail of the steel truss girder, push the steel truss girder forward for the third time, to the 3 nodes of the steel truss girder cantilever, the fulcrum of the steel truss girder tail is located in the two groups In the middle position of the steel pipe support frame, the floating drag moves forward at the same time; S2.7, the fourth push: start the sliding equipment at the end of the steel truss girder, slide the steel truss girder forward, the floating tow and the support on it move with the sliding speed of the steel truss girder, and pass through the forward winch and the steel truss girder Move forward together, and monitor the running direction of the steel truss girder and the floating tow, use the direction control cable of the winch to stabilize the running direction of the floating tow, push the tail of the steel truss girder to the top of one side of the pier for the fourth time, and the steel truss girder The front end reaches the top of the pier on the other side; S2.8. Set up two drop beam jacks on the top of the two piers on both sides. The drop beam jacks are set on the inside of the slideway. Pressurized water sinks in the cabin, releases the constraints of the support of the floating tow and the steel truss girder, removes the floating tow, completes the floating tow operation, and proceeds to the beam drop construction; S2.9. Remove the Bailey frame support and girder erection equipment between the bridge pier on one side and the steel pipe support frame, and install the support, and then carry out the beam drop construction. The erection of steel truss girders is completed on the piers on both sides. 2. The construction method of a high-stability steel truss girder jacking plus floating tow frame construction method according to claim 1, characterized in that: in the step S1.2, two supports are provided, two supports Installed on a floating towing ship, the bracket is welded by steel pipe piles and I-beams, and the I-beams are spliced to form the bracket foundation, and two I-beams protrude from the surroundings of the bracket foundation in the horizontal and vertical directions. It is used for connection and fixation with the floating towing ship and the bracket on the other side. The steel pipe pile is vertically welded on the foundation of the bracket as the main body of the bracket. Channel steel is used as a scissor-like support between the steel pipe piles. The top uses double-joint and four-piece I-beams as distribution beams to carry steel truss beams. Finally, the bracket is hoisted as a whole into the cabin of the floating towing ship and welded firmly with the hull. 3. The construction method of a high-stability steel truss girder jacking plus floating drag frame construction method according to claim 1, characterized in that: in the step S2.8, before setting the drop beam jack on the top of the bridge pier, first The steel truss girder offset data is measured by a total station, and then four three-dimensional drop beam jacks are arranged on the inside of the slideway. The two drop beam jacks on the top of the same pier are operated by a pump station, and the steel truss is carried out through the PLC control system. Correction of the beam. 4. The construction method of a high-stability steel truss girder pushing and floating tow frame construction method according to claim 1, characterized in that: the sliding equipment in the steps S1 and S2 is a hydraulic crawler, and the hydraulic crawler The crawler is a combined structure, one end is connected to the slideway with a wedge-shaped clamp, the other end is connected to the sliding tire frame or member in the form of a hinge point, and the hydraulic cylinder is used to drive the crawl in the middle. The wedge-shaped clamp of the hydraulic crawler has One-way self-locking function, when the oil cylinder is extended, the wedge-shaped clamp block works to clamp and automatically lock the slideway; when the oil cylinder retracts, the clamp block does not work to release, and moves in the same direction as the oil cylinder; The working process of the hydraulic crawler is as follows: Step 1: Clamp the wedge and the slideway in the clamping device of the hydraulic crawler, connect the piston rod pin shaft at the front end of the cylinder of the hydraulic crawler to the sliding member, extend the cylinder, and push the sliding member to slide forward; Step 2: The cylinder of the hydraulic crawler is extended for one stroke, and the component slides forward by 300mm; Step 3: After the cylinder is extended for one stroke, the sliding member does not move, and the oil cylinder shrinks, so that the wedge in the clamping device and the slideway are released, and the clamping device is dragged to slide forward; Step 4: After one stroke of the hydraulic crawler is completed shrinking the cylinder, drag the clamping device to slide forward 300mm, and one crawling advance stroke is completed, then perform the process of step 1 again, and reciprocate in this way to slide the component to the final position. 5. The construction method of a high-stability steel truss girder jacking plus floating tow frame construction method according to claim 1, characterized in that: in the step S2, during the construction process of the floating tow, all the sliding equipment synchronously push the steel truss The truss girder slips, and each sliding device is evenly loaded. The computer control system feeds back the distance signal through the banyan sensor to control the error of each sliding device within 20mm, thereby controlling the synchronous sliding of the entire sliding unit. The sliding unit A horizontal block is set corresponding to the position of the slideway to ensure the safety and reliability of the entire sliding process. 6. The construction method of a high-stability steel truss girder jacking plus floating tow frame construction method according to claim 1, characterized in that: in the steps S2.8 and S2.9, during the falling beam construction, the falling beam The falling beam jacks used are equipped with safety hoops with spherical support pads on the top. The multiple falling beam jacks used together are of the same model and connected in parallel with oil pipes; in the falling beams, asbestos board anti-skid materials are placed between the supporting surfaces of the pier and each cushion; In order to adapt to the horizontal displacement of the fulcrum, the bottom of the drop beam jack is equipped with an MGE plate pedestal, and the center of the pedestal coincides with the central axis of the drop beam jack, and the changes in the top drop elevation, fulcrum reaction force, fulcrum displacement, and mid-span deflection are observed and recorded; When the beam is placed on the temporary support during the falling process, the height difference between the two adjacent truss fulcrums should be measured, and when the height difference is greater than 3mm, the height of the two fulcrums should be adjusted.

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