CN111809530A

CN111809530A - Walking type pushing construction method for steel beam with tower belt cable force

Info

Publication number: CN111809530A
Application number: CN202010624882.4A
Authority: CN
Inventors: 李绪森; 刘双; 史伟鉴; 李明; 徐浩; 张嘉恒; 石振武; 张野; 吕洪福; 刘晓峰; 刘振; 高阳; 武俊刚; 路巍; 陈伟; 周庆文; 付磊; 杜永兴; 郑远坤
Original assignee: Heilongjiang Longjian Road & Bridge First Engineering Co ltd
Current assignee: Heilongjiang Longjian Road & Bridge First Engineering Co ltd
Priority date: 2020-07-02
Filing date: 2020-07-02
Publication date: 2020-10-23

Abstract

A walking type pushing construction method for a steel beam with a tower and a cable force. How to better solve the stress change and the key problem of the large-span steel beam in the walking type pushing construction process is urgent to be researched. The invention comprises the following components: (1) construction preparation; (2) erecting a platform and a temporary pier; (3) installing pushing equipment and debugging; (4) assembling steel beams; (5) assembling the steel tower; (6) hanging a rope and primarily tensioning; (7) walking pushing; (8) cable force monitoring and adjusting; (9) beam falling and system conversion; (10) and (5) removing the temporary structure. The invention relates to a walking type pushing construction method for a steel beam with a tower belt and cable force.

Description

Walking type pushing construction method for steel beam with tower belt cable force

The technical field is as follows:

the invention relates to a walking type pushing construction method for a steel beam with a tower belt and cable force.

Background art:

with the rapid development of bridge construction industry, large-span bridges are continuously emerging, and the pushing construction of large-span steel beams is carried out at the same time, so that how to better solve the stress change and the key problems of the large-span steel beams in the walking type pushing construction process is urgent to be researched, and the main structure is fully utilized to research and develop the tower-beam consolidation system pushing construction technology by relying on actual engineering.

The invention content is as follows:

the invention aims to solve the difficulty of overlarge cantilever flexibility in the pushing process of a large-span steel box girder, reduce the stress borne by a main girder and provide a tower-girder-concreted body-tied tower-belt cable-force pushing construction method which improves the working efficiency of walking type pushing.

The above purpose is realized by the following technical scheme:

a walking type pushing construction method for steel beams with tower and cable force comprises the following steps:

the method comprises the following steps: construction preparation;

preparing temporary structure construction, preparing steel beams and steel towers for processing, manufacturing and mounting construction, preparing pushing construction and preparing a cable force adjusting technology in the pushing process;

step two: erecting a platform and a temporary pier;

a steel beam assembling platform and a temporary pier are built, the temporary pier serves as a pushing equipment arrangement platform, double-assembling I-shaped steel serving as a steel beam section assembling base plate is arranged on the assembling platform, and the temporary pier serves as a pushing pier.

Step three: installing pushing equipment and debugging;

the maximum vertical bearing capacity of the bottom surface of the single box chamber is 800t during pushing construction, the uniform diffusion length of the steel beam along the bridge direction is not less than 2m, a web plate of the steel beam bears force in the pushing construction process, a bottom plate does not bear force, and the vertical adjusting capacity is achieved.

Step four: assembling steel beams;

manufacturing longitudinal beams, cross beams and steel tower block plate units and assembling blocks in a steel beam processing plant, transporting the steel beam processing plant to a site, assembling the blocks, hoisting, transporting each section to the site assembling platform, assembling the sections by using a portal crane, directly hoisting the section beams to the platform by using the portal crane after the steel beam is transported to the site, and installing a main tower by using an automobile crane;

step five: assembling the steel tower;

the lower tower column is installed by adopting a portal crane, and the middle tower column and the tower crown are installed by adopting an automobile crane;

step six: hanging a rope and primarily tensioning;

step seven: walking pushing;

selecting an optimal pushing turn according to the pushing length and the maximum pushing span, wherein the walking type pusher has three functions of vertical jacking, horizontal pushing and lateral deviation rectification, the self-balancing pusher moves forwards for a stroke distance under the action of a horizontal top after jacking the steel beam, then the steel beam falls to fulcrums at two sides of the pusher, and the horizontal top is returned to the initial pushing position after the pusher is relieved, so that the process is repeated until the top is pushed to the design position;

step eight: cable force monitoring and adjusting;

step nine: beam falling and system conversion;

step ten: removing the temporary structure;

and the guide beam is dismantled after the steel beam pushes the top of the last seat pier, the inter-span temporary pier is dismantled after the cable force is adjusted to separate the steel beam from the pushing pier, and the temporary pier is dismantled and completed at the closure section.

The walking type pushing construction method for the steel beam with the tower and the cable force comprises the following specific processes of the second step: before assembling steel beams, a profile steel composite material is adopted, the weight of the profile steel is weighed in advance, then a steel beam bottom cushion block is installed on the top surface of a platform according to the design position of a supporting point when the steel beams are assembled, the profile steel is piled on the steel beam cushion block, upright rods are welded on two sides of the cushion block to prevent the pre-pressed profile steel from falling off, a gantry crane is used for hoisting the profile steel to the cushion block for loading according to the design requirement in multiple times, 3-level pre-pressing loading is respectively carried out on the platform and a temporary pier, loads are sequentially applied to 60%, 80% and 100% of the pre-pressing load value in a unit, and during longitudinal loading, symmetrical load distribution is carried out from midspan; during transverse loading, symmetrically distributing loads from the center line of the structure to two sides, and monitoring the settlement of the foundation steel pipe pile at intervals of 12 hours after each level of loading is finished; when the average value of the settlement difference of the measuring points for 2 times is less than 2mm, the platform can be continuously loaded, and the two sides of the platform are symmetrically, evenly and synchronously unloaded after the prepressing is finished.

The walking type pushing construction method of the steel beam with the tower and the cable force comprises the following specific processes: during pushing construction, the maximum vertical bearing capacity of the bottom surface of the single box chamber is 800t, the uniform diffusion length of the steel beam along the bridge direction is not less than 2m, a web plate of the steel beam bears force in the pushing construction process, a bottom plate does not bear force, and the pushing construction equipment has vertical adjusting capacity and horizontal deviation rectifying capacity;

the pushing equipment is composed of a pushing device and a hydraulic oil pump, the pushing equipment is symmetrically arranged at the upper and lower streams of the pier top, each pier on the temporary pier is divided into a group, after the pushing equipment is installed, an oil circuit and a circuit of the system are connected, debugging is carried out to ensure that an execution element runs according to a set motion mode under the running of a manual mode and an automatic mode, when online debugging is carried out, a pump station is started, the manual mode is selected, the cylinder extending or retracting action of the execution element is controlled on an operation panel of a main control console, whether the action is correct or not is checked, a detection element of a stroke detection device is adjusted to ensure that the contact and detection of the detection device are normal, after the manual trial run of the system is completed, an automatic mode system is selected to check the action harmony and the synchronism of each jack of the system, if the design requirements are not met, the reason should be carefully searched, the fault is eliminated, and after the action of the system, the walking top equipment mainly comprises an upper sliding seat mechanism, a top lifting support oil cylinder, a longitudinal top lifting oil cylinder, a transverse adjusting oil cylinder and a base, and the combination and the sequential action are realized through computer control and hydraulic drive.

The walking type pushing construction method for the steel beam with the tower and the cable force comprises the following specific steps: manufacturing longitudinal beams, cross beams and steel tower block plate units and assembling blocks in a steel beam processing plant, transporting the steel beam processing plant to a site, assembling the blocks, hoisting, transporting each section to the site assembling platform, assembling the sections by using a portal crane, directly hoisting the section beams to the platform by using the portal crane after the steel beam is transported to the site, and installing a main tower by using an automobile crane;

(1) constructing a guide beam, wherein in order to resist negative bending moment of a cantilever state at the front end of a steel beam and prevent the cantilever deflection at the front end of a main beam from being overlarge, a 30m long guide beam is arranged at the front end of the steel beam, the guide beam is a double-I-shaped variable cross-section beam, the height of an end beam is 1.2m, the height of a root beam is 3.3m, the two I-shaped beams are connected in a parallel connection manner to form a double I-shaped beam with the same inclination angle as that of the steel main beam, the end part of the double I-shaped beam is connected with the steel main beam, the guide beam is provided with a truss type transverse connection, the width of an upper flange and a lower flange of the I-shaped beam is 400mm, the thickness of the upper flange and the lower flange of the I-shaped beam is 16mm, the thickness of a web is 12mm, the guide beam is installed on an assembling platform by utilizing a gantry crane, the guide beam, a top plate and a web between a guide beam section and a;

(2) the steel beams are installed in sections, the steel beams are assembled to arrange the shape of a jig frame according to the pushing step sequence, the air nozzle units are assembled by truck cranes, and the longitudinal beam blocks, the cross beam units and the lower tower column blocks are installed by 60t gantry cranes;

hoisting sequence during integral installation: the longitudinal beam blocks → the transverse beam blocks and the units are assembled in sequence and are affected by wind load, the steel beam and the steel tower are pushed without installing air nozzles, and the form of covering steel plates on the transverse beam and the longitudinal beam is adopted.

The walking type pushing construction method for the steel beam with the tower and the cable force comprises the following specific processes:

(1) after the steel strand is transported to a construction site, the cable disc is hung on a pay-off rack, the cable disc is pulled upwards from the lower end of the HDPE pipe during cable hanging, the paying-off direction faces to the beam end embedded pipe, and a paving pad and a guide are arranged between the pay-off rack and the embedded pipe to prevent the PE (polyethylene) of the steel strand from being damaged;

(2) placing the coiled steel strand on a plate, opening a tensioning end, connecting the uncoiled steel strand with a special traction device on a circulating steel wire rope, starting a circulating system to draw the steel strand to an upper end pipe orifice along an HDPE protective pipe, then connecting the steel strand with a traction cable penetrating through an anchorage device hole, removing the traction device on the circulating system, drawing the steel strand out of the anchorage device hole through tools such as a gourd and the like in a tower column, correspondingly assisting operating personnel in the tower until the working length required by single tensioning is met, installing a pair of temporary clamping pieces, removing a strand penetrating device, and preparing to draw the next steel strand;

(3) the drawn steel strand is discharged from the disc, is connected with a drawing cable penetrating through an anchorage device at the lower end, manually penetrates through an anchor hole, is provided with a clamping piece, and is tightened and pressed;

(4) when a single hanging rope is hung, the PE sheath is protected, and twisting and rotation are strictly prevented;

(5) the circulating traction steel wire rope can be used for synchronously drawing two steel strands at a time;

(6) after the steel strands in each stay cable are threaded and hung one by one, a jack is used for tensioning one steel strand, the whole cable design tonnage is subjected to tensioning control according to a monitoring instruction issued by a monitoring unit, the steel strand is tensioned to the design tonnage in a grading, synchronous and symmetrical mode, in order to overcome factors such as retraction, deformation of tensioning equipment and the like, the over-tensioning is the control tonnage plus 1 percent during tensioning, and the cables on the same cable, the river span, the bank span and the same span, the upper stream and the lower stream are required to be synchronously symmetrical and mutually correspond, and the error is less than or equal to 5 percent after the level difference is converted into force;

(7) and (3) cable adjustment, wherein before pushing, if the cable force of one or more stayed cables and the elevation of the bridge floor need to be adjusted, single cable adjustment is needed, the cable adjustment working condition, the cable adjustment frequency, the cable adjustment sequence, the cable force control and the cable adjustment position are informed by a monitoring unit, and the cable adjustment process is consistent with the single tensioning process. After the calculation requirement is rechecked through the cable force test, the pushing can be started.

The walking type pushing construction method for the steel beam with the tower and the cable force comprises the following specific steps: firstly, a manual mode is selected, and whether an oil pump, a jacking top, a deviation rectifying top, a jacking top, a pressure gauge, a sensor and the like are abnormal is checked. Starting the pushing equipment on each pier, converting a pressure value detected by a pressure sensor on the jacking system into a thrust and reaction force value, setting pressure for the pushing oil cylinder according to the conversion value of the value, providing pushing force for the pushing oil cylinder under the required pressure, and controlling the pushing oil cylinders on two sides of the temporary pier to synchronously push. The supporting reaction force of the jacking support oil cylinder is detected in real time, on one hand, the real-time accuracy of the jacking force of the jacking oil cylinder is guaranteed, on the other hand, the stress balance of the steel beam in the advancing process is guaranteed by adjusting the jacking support oil cylinder, the maximum allowable supporting reaction force on the single side of the steel beam is not more than 7000KN, after one stroke of pushing is completed, all the jacking oil cylinders retract to the starting point of the next stroke, then jacking of the next stroke can be carried out, and in the jacking process, the maximum and minimum oil pressures in the jacking process are recorded;

in order to avoid the over-tolerance of the transverse offset of the steel beam in the pushing process, an active central axis monitoring system is structurally integrated with the control system, and the central axis of the steel beam is monitored in real time in the pushing process to adjust the limiting device in time so that the offset of the steel beam is always limited within an error range;

the stress state of the steel beam in the pushing process is completely different from that in the bridge forming process, the whole pushing process is monitored by the principle of mainly controlling the support reaction force and secondarily controlling the elevation, so that the change range of the vertical curve of the pier through which the wheel pushes the steel beam and the change range of the allowable support reaction force of the steel beam are determined according to the monitoring instruction before each wheel pushes. Meanwhile, determining the elevation of the temporary pad pier under each pushing working condition;

when pushing, the guide beam pier-crossing process is particularly noticed, the cable force is adjusted again if necessary, the deflection of the front end of the guide beam is reduced, each buttress of the guide beam pier-crossing process needs to be provided with a vertical jack and a temporary support pad, the front end of the steel guide beam is downwards bent due to the dead weight of the steel beam, when a step at the front end of the guide beam is close to a pushing device, the guide beam needs to be jacked up at the moment, a guide beam pier-crossing measure is adopted, the guide beam is stably placed on the pushing device after being landed, then formal pushing is started, the jack for temporary jacking of the guide beam adopts a 100t screw jack, and the jacking height is possibly large due to the small stroke of the jack, so that multiple support pads and reverse jacking are needed when vertical jacking is implemented;

the guide beam pier passing step comprises the following steps:

(1) removing a section of steel cushion block to enable the front end of the guide beam to cross over the walking type pushing equipment;

(2) jacking the front end of the guide beam upwards by using a 100t jack to eliminate the downward deflection of the guide beam;

(3) a cushion-lifting supporting stack is arranged between the guide beam and the pushing equipment, and a walking jack is used for supporting the guide beam;

(4) and pushing the steel beam by using pushing equipment, and starting normal pushing after the bottom of the guide beam reaches the upper part of the pushing device.

(1) and after the steel beam is pushed in place, the guide beam is disassembled in sections by using the truck crane. Because the construction of the pier top cushion stone and the permanent support is completed in advance, the construction of the cushion stone and the permanent support is not needed at the moment;

(2) accurately positioning the steel beam longitudinally and transversely by using pushing equipment on the temporary pier, and paying attention to that the bottom of the steel beam is 50mm higher than the permanent support during positioning;

(3) after the positioning is finished, temporarily placing the steel beam on bearing supports in front of and behind the pushing equipment, checking whether the positions of the permanent support at the top of each pier and the steel beam are accurate or not, and paying attention to the fact that the bottom of the steel beam is 50mm higher than the permanent support at the moment;

(4) and after the detection is correct, jacking the steel beam by 20mm by using the pushing equipment, detaching the backing plates on the front and rear bearing supports of the pushing equipment, retracting the vertical oil cylinder of the pushing equipment, putting the steel beam on the permanent support, constructing the connection between the steel beam and the permanent support, and completing the beam falling and system conversion process.

Has the advantages that:

1. the invention reduces the stress concentration and the generated deflection of the main beam. The steel main tower is used as a steel beam pushing buckling cable in construction, cable force adjustment is continuously optimized, and the negative bending moment of the root of the main beam at the cantilever section in the pushing process is reduced, so that the maximum cantilever length and the stress and deflection of the main beam are reduced, and construction safety guarantee is provided.

The invention reduces the construction cost investment. Through installing main tower and cable in advance, reduce construction cycle, improve the top and push away the span to reduce temporary buttress etc. and face the structure input greatly, practice thrift construction equipment, reduce construction cost.

The invention improves the construction safety guarantee. Through adjusting main tower cable power and increasing interim aerodynamic facility, reduce the influence of wind-force to the girder, improve the overall stability of top pushing process girder steel.

The invention improves the pushing construction precision. The pushing is synchronously performed by 44 walking pushing devices, and the special software is used for unified regulation and control, so that command lag and delay generated by the traditional manual operation are avoided, the synchronism of the pushing process is improved, and meanwhile, the pushing devices can be adjusted and corrected in three directions, and have an active effect on the aspect of linear control.

The invention reduces the damage to the permanent structure. The walking type multi-point pushing construction can realize self-balance of the structure of the pushing fulcrum, ensure that no horizontal pushing force is generated theoretically after the synchronism of the pushing equipment, and reduce the structural requirement of the temporary buttress, thereby avoiding the derivation problem caused by the fact that the pushing equipment must be located on the finished permanent structure in the past, reducing the section bar input amount of the temporary structure and reducing the damage to the permanent structure.

Description of the drawings:

FIG. 1 is a schematic diagram of a cable force jacking system for a main tower 1 according to the present invention;

FIG. 2 is a schematic diagram of a 2-seat main tower cable force jacking of the present invention;

FIG. 3 is a schematic illustration of the main tower involved in cable force adjustment of the present invention;

FIG. 4 is a flow chart of the construction process of the present invention;

FIG. 5 is a schematic view of the positioning of the side rail blocks;

FIG. 6 is a schematic structural view of the installation of the center beam block and units;

the specific implementation mode is as follows:

example 1:

the method comprises the following steps: construction preparation;

step two: erecting a platform and a temporary pier;

Step three: installing pushing equipment and debugging;

Step four: assembling steel beams;

step five: assembling the steel tower;

step six: hanging a rope and primarily tensioning;

step seven: walking pushing;

step eight: cable force monitoring and adjusting;

step nine: beam falling and system conversion;

step ten: removing the temporary structure;

Example 2:

the walking incremental launching construction method for the steel beam with the tower and the cable force according to the embodiment 1 comprises the following specific steps of: before assembling steel beams, a profile steel composite material is adopted, the weight of the profile steel is weighed in advance, then a steel beam bottom cushion block is installed on the top surface of a platform according to the design position of a supporting point when the steel beams are assembled, the profile steel is piled on the steel beam cushion block, upright rods are welded on two sides of the cushion block to prevent the pre-pressed profile steel from falling off, a gantry crane is used for hoisting the profile steel to the cushion block for loading according to the design requirement in multiple times, 3-level pre-pressing loading is respectively carried out on the platform and a temporary pier, loads are sequentially applied to 60%, 80% and 100% of the pre-pressing load value in a unit, and during longitudinal loading, symmetrical load distribution is carried out from midspan; during transverse loading, symmetrically distributing loads from the center line of the structure to two sides, and monitoring the settlement of the foundation steel pipe pile at intervals of 12 hours after each level of loading is finished; when the average value of the settlement difference of the measuring points for 2 times is less than 2mm, the platform can be continuously loaded, and the two sides of the platform are symmetrically, evenly and synchronously unloaded after the prepressing is finished.

Example 3:

the walking incremental launching construction method for the steel beam with the tower and the cable force according to the embodiment 1 or 2 comprises the following specific steps: during pushing construction, the maximum vertical bearing capacity of the bottom surface of the single box chamber is 800t, the uniform diffusion length of the steel beam along the bridge direction is not less than 2m, a web plate of the steel beam bears force in the pushing construction process, a bottom plate does not bear force, and the pushing construction equipment has vertical adjusting capacity and horizontal deviation rectifying capacity;

Example 4:

the walking incremental launching construction method for the steel beam with the tower and the cable force according to the embodiment 1, 2 or 3, wherein the specific process of the fourth step is as follows: manufacturing longitudinal beams, cross beams and steel tower block plate units and assembling blocks in a steel beam processing plant, transporting the steel beam processing plant to a site, assembling the blocks, hoisting, transporting each section to the site assembling platform, assembling the sections by using a portal crane, directly hoisting the section beams to the platform by using the portal crane after the steel beam is transported to the site, and installing a main tower by using an automobile crane;

The concrete process of the step five is as follows: the lower tower column is installed by adopting a 60t gantry crane, the middle tower column and the tower crown are installed by adopting a 220t truck crane (wherein the tower crown is hoisted to a design position after being welded in a two-in-one mode at the side edge of the pushing platform);

each steel tower is transported to the site by 5 segments and consists of 1 lower tower column block, 2 middle tower columns and 2 tower crowns. The lower tower column is installed by adopting a 60t portal crane, the middle tower column and the tower crown are installed by adopting a 220t truck crane, the tower crown is divided into two parts (half of each of the shore side and the river side) to be transported to the site, and the tower crown is assembled, assembled and welded into a whole on a prefabricated jig frame (the jig frame adopts a Q235 square tube to avoid deformation in the using process to influence the assembling precision of segments) for later use. A pedestrian ladder is arranged along the tower column after one section is assembled, and a manufactured hanging basket is adopted at the joint of the two sections to serve as a section connecting working platform and a winter heat preservation shed working platform.

Example 5:

the walking incremental launching construction method for the steel beam with the tower and cable force as in embodiment 1, 2, 3 or 4 comprises the following specific steps:

Example 6:

the walking incremental launching construction method for the steel beam with the tower and the cable force according to the embodiment 1, 2, 3, 4 or 5 comprises the following specific steps: firstly, a manual mode is selected, and whether an oil pump, a jacking top, a deviation rectifying top, a jacking top, a pressure gauge, a sensor and the like are abnormal is checked. Starting the pushing equipment on each pier, converting a pressure value detected by a pressure sensor on the jacking system into a thrust and reaction force value, setting pressure for the pushing oil cylinder according to the conversion value of the value, providing pushing force for the pushing oil cylinder under the required pressure, and controlling the pushing oil cylinders on two sides of the temporary pier to synchronously push. The supporting reaction force of the jacking support oil cylinder is detected in real time, on one hand, the real-time accuracy of the jacking force of the jacking oil cylinder is guaranteed, on the other hand, the stress balance of the steel beam in the advancing process is guaranteed by adjusting the jacking support oil cylinder, the maximum allowable supporting reaction force on the single side of the steel beam is not more than 7000KN, after one stroke of pushing is completed, all the jacking oil cylinders retract to the starting point of the next stroke, then jacking of the next stroke can be carried out, and in the jacking process, the maximum and minimum oil pressures in the jacking process are recorded;

the guide beam pier passing step comprises the following steps:

The concrete process of the step eight is as follows: the field monitoring contents mainly include: stress of the structure (comprising the steel main beam, the temporary pier and the steel guide beam), deformation of the structure (comprising the steel main beam, the temporary pier, the steel guide beam and the steel main tower) and cable force of a stay cable.

The construction monitoring mainly comprises stress monitoring of the steel box girder and the steel guide girder, beam end deflection monitoring of the steel box girder and the steel guide girder, axis deviation monitoring of the steel box girder, longitudinal displacement monitoring of the permanent pier and the temporary pier, settlement monitoring of the permanent pier and the temporary pier and temperature monitoring; and the stay cable force in the pushing process.

The construction monitoring in the pushing process is the key and difficult point of monitoring, and a control method combining theoretical calculation simulation and field real-time data monitoring is adopted. The monitoring is mainly as follows:

(1) and monitoring the jack synchronism in the pushing process.

(2) And monitoring whether the longitudinal axis of the steel box girder deviates in the pushing process.

(3) The deformation of the guide beam is monitored, and the phenomenon that the guide beam collides with the support to cause the whole vibration of the bridge is prevented from occurring due to the abnormal state.

(4) And monitoring the vertical deflection and the stress value of the steel box girder in the pushing process.

(5) The horizontal displacement and the stress change state of the temporary pier are monitored, a grading early warning mechanism is adopted for monitoring the horizontal displacement of the temporary pier, the safety of the whole supporting system is ensured, and the overall collapse caused by local instability of individual rod pieces is prevented.

(6) And calculating friction force according to the fulcrum counter force and verifying the friction force with an oil pressure gauge.

(7) The key monitoring contents in the pushing construction comprise: settlement of the assembly platform, settlement and horizontal displacement of the temporary pier and the pushing pier, cable tower stress, cable force, deflection of the front end of the steel guide beam, stress and deformation of a local bearing part of the steel beam and a joint of the guide beam and the steel beam and the like. If a large deviation exists between the monitoring value and the calculated value, the construction is suspended, the reason is investigated, a processing scheme is formulated and processed, and the construction can be continued after the requirements are met.

(8) In the pushing construction process, the steel longitudinal beam and the steel guide beam web plate are aligned to the supporting point, and the steel longitudinal beam and the guide beam bottom plate are forbidden to bear vertical force.

(9) In the pushing process, the elongation and the jacking force of the longitudinal jacks of the pushing equipment on the left side and the right side of the same pushing pier are monitored, and the forward displacement of the left side and the right side of the steel beam is ensured to meet the requirement. In the pushing process, the deviation of the central line of the steel beam is monitored in real time and is adjusted in time, so that the excessive deviation accumulation is prevented.

(10) And monitoring the maximum crossing distance in the pushing process, continuously pushing forwards according to the construction steps, raising the pier as early as possible, reducing the time of the front end of the guide beam in a large cantilever state, doing weather forecast work, and selecting weather construction without wind, rain and snow.

(11) In the pushing process, because the stress on the supporting points on the same temporary pier, the pushing pier and the main pier is not uniform due to the deformation of the steel beam, the temporary pier, the pushing pier and the main pier have the unbalance loading phenomenon, and the rubber plate on the supporting points is an important structure for improving the unbalance loading and is set according to the design requirement on site; meanwhile, the observation is enhanced in the construction process, and the gap is supported in advance, so that the supporting stress of the same temporary pier, the pushing pier and the main pier tends to be uniform, the load is reduced, and the structure safety is ensured.

After the pushing is in place, the stay cable is adjusted to a certain extent according to the actual construction condition, the principle of the adjustment is that the cable force of the stay cable is matched with the actual weight of the main beam, the internal force of the structure in the bridge state is realized by controlling the reasonable cable force of the stay cable in the bridge state, the final adjustment and construction of the stay cable are carried out, and an auxiliary structure and an anti-corrosion facility of the stay cable are installed.

Example 7:

according to the walking incremental launching construction method for the steel beam with the tower and the cable force of the tower and the belt of the embodiment 1, 2, 3, 4, 5 or 6, the concrete process of the ninth step is as follows:

The specific process of the step ten is as follows: and the guide beam is dismantled after the steel beam pushes the top of the last seat pier, the inter-span temporary pier is dismantled after the cable force is adjusted to separate the steel beam from the pushing pier, and the temporary pier is dismantled and completed at the closure section.

(1) Dismantling a guide beam: and (4) after the guide beam pushes the top of the last seat pier, dismantling the seat pier. The guide beam is divided into 2 sections, a crawler crane on the barge is used for dismantling the guide beam in sections, and the dismantled guide beam is stored in a barge deck storage area.

(2) Dismantling the span pushing pier: and after the steel beam is pushed in place, adjusting the cable force to enable the main bridge steel beam to reach a state line shape, separating the steel beam from the temporary pier between the midspan of the river and the pier side pushing piers, withdrawing the pushing equipment at the moment, and dismantling the pushing piers. And (3) hoisting the components such as the distribution beam, the pad beam and the like to a barge deck storage area by using the crawler crane on the barge for the removal of the pushing piers, then cutting off and removing the pushing piers in sections, and finally hoisting the pushing piers to the barge after pulling out the pushing piers by using a hydraulic vibrating pile hammer for the removal of the pushing piers.

(3) Dismantling the temporary piers (splicing platforms) of the closure section: and after the steel beam is closed, tensioning the closed cross stay cable, separating the steel beam from the assembling platform, and disassembling the assembling platform. The dismantling method is the same as that of the span pushing pier. And after measurement and positioning, jacking the steel beam by using a jacking jack, withdrawing the cushion block and falling the steel beam back onto the support.

Quality control measures

The quality control of the construction technology needs to implement the guarantee measures of the conventional steel beam installation technology, and also needs to accurately control the temporary structure and the pushing process, so that the quality of the construction process is ensured to be controllable.

Steel beam installation technical guarantee measure

Steel beam installation measurement accuracy control

(1) Elevation control: according to the monitoring line shape data, the height of the pad beam and the height of the pressing plate are correctly arranged;

(2) in the welding process, the position of the top surface of the steel beam (mainly welding shrinkage) is monitored so as to be convenient for timely adjustment;

(3) in the jacking process, the condition of the deformation and deflection of the bridge is measured by observing the elevation changes of a plurality of sections of the steel beam before and after the steel beam is lifted off the pad beam.

When the segments are assembled and assembled on the pushing platform, the construction monitoring party combines the measurement result to evaluate the stress-free manufacturing linear error of the assembled segments, the assembled linear shape of the next segment is corrected in real time by utilizing the self-adaptive configuration and effect comprehensive control, and the quality guarantee of the stress-free manufacturing linear shape is mainly carried out from the following aspects:

a) on the basis of fully understanding the design intention, a special technical conference is held, specific technological processes and implementation schemes of steel plate positioning, segment pre-assembly, segment positioning, welding and the like are formulated, and a business owner, a design, a supervision and approval are submitted and sent to a monitoring unit as basic data of monitoring and analysis;

b) when the steel beam is manufactured in a factory, an obvious measurement mark is required to be arranged at each section top surface linear control point, and the manufacturing and lofting inspection of the steel beam are completed by a construction operation group and supervision;

c) the pre-assembly precision of a factory is strictly controlled, the steel beam segments are pre-assembled at the factory with at least five segments, the pre-assembly precision is strictly controlled, and the part of work is mainly completed by a steel beam prefabrication manufacturer and supervision together.

Key procedure construction process

(1) Welding process

Before construction, distribution equipment, welding equipment, ventilation and dust removal equipment and CO are installed and debugged₂The welding method comprises the steps of welding necessary construction equipment and appliances such as a windproof shed frame, a derusting machine, a gouging tool, a flame cutting tool, waterproof and moistureproof equipment, a welding material drying box, high-strength bolt Shining and the like, and setting up dedicated maintenance and management personnel.

Before welding, the dislocation, the gap and the groove size of the interface are comprehensively checked, and before welding, sand is usedThe wheel removes iron rust on the surface, the removing range is 50mm on each side of the welding line, welding is needed within 24h after rust removal, so that the joint is prevented from rusting again or being polluted, otherwise welding is carried out after rust removal is carried out again. Using CO in the steel box₂When gas shielded welding is carried out, a welder wears a protective mask and must be provided with ventilation protection safety facilities so as to prevent CO generated during welding from influencing the safety of the welder. Welding materials such as welding rods and welding fluxes which are easy to be affected with moisture are strictly stored, dried and used according to the process regulations. When the environment humidity is higher, the external time of the materials such as welding rods, welding flux and the like is reduced, the materials for drying and heat preservation are used in time, and the rest materials are returned for drying and heat preservation again.

(2) Bolt screwing process

General requirements

The connection of the high-strength bolts used meets the requirements of GB/T1228-1231-2006. The high-strength bolt connection pair is fastened by a torque method, and the screwing tool is a fixed-torque wrench or an electric wrench. Before the beam is spliced, the burrs and fins on the component are removed, dirt on the joint surface and in the bolt hole is cleaned by a copper wire brush, and the part with the dirt is cleaned by gasoline or acetone. And (4) retreating the bolted plate surface with serious damage according to the corresponding coating process.

Calibration and correction of construction wrench

Before the use, the fixed torque wrench must be calibrated and corrected, the qualified wrench which is not calibrated cannot be used, and the torque wrench should be numbered for use, so as to prevent confusion. In the use process, the fixed torque wrench needs to be calibrated once before and after each shift of operation, and the torque error of the fixed torque wrench does not exceed 5% of the use torque. When the wrench is retested after being taken out of service, if torque is found to be out of tolerance, the bolt fastened by the wrench is processed as follows: for initial screwing, the wrench can be re-initialized after correction; and for final screwing, under-screwed bolts are compensated, over-screwed bolts are replaced, and final screwing is carried out again.

Screwing method

After the position of the component is adjusted correctly, the bolt hole outside the punching pin and the common bolt is inserted into the high-strength bolt according to the specification required by the drawing, when the bolt is inserted, one washer is respectively arranged on one side of the bolt head and one side of the nut, and the side of the washer with the inner chamfer angle must face the bolt head and the nut bearing surface (both face the outer side of the plate bundle). The threaded bolt can be pre-tightened by a short arm wrench. The bolt is supposed to freely penetrate into the bolt hole, and the bolt hole which cannot freely penetrate is allowed to be rested by a reamer, a grinding head or a file after no clearance exists between layers around the hole diameter, so that the bolt cannot be forcibly knocked in, and the bolt cannot be subjected to gas cutting and hole expansion.

The high-strength bolt fastening is carried out in two steps of initial screwing and final screwing, the initial screwing torque value of the high-strength large hexagon bolt connecting pair is 0.5 times of the final screwing torque value, and all the nodes are symmetrically screwed from the middle to two ends when fastened. And after the initial screwing, the relative positions of the bolt, the nut, the washer and the steel plate are marked by white paint, the bolt, the nut, the washer and the steel plate are screwed up after the initial screwing is checked to be qualified, and after the final screwing is finished, the bolt is marked by red paint in time but the initial screwing mark cannot be covered.

Quality inspection

And (3) initial screwing inspection: and checking whether the specification and the installation of the bolt are correct and the close contact degree of the plate layers (the insertion depth of the 0.3mm plug sheet is not more than 20 mm). And knocking the nut by a small hammer with the mass of 0.3Kg to check whether the bolt is not screwed, wherein the check range is that the bolt is completely and initially screwed.

Final screwing inspection: and (4) checking whether the paint marks after initial screwing are dislocated or not for all the high-strength bolt connection pairs after final screwing so as to judge whether screwing is missed or not during final screwing. The final torque check should be completed within 48 hours after 1 hour of final twist. The method for checking the final torque of the high-strength large hexagon head bolt connection pair is a loose-buckling-back-buckling method, and firstly, the checked bolt pair is scribed

The mark is marked on the surface of the substrate,and releasing the angle of about 30 degrees, returning to the original marking position, and recording the torque value at the moment. If the torque value is within the range of 0.9-1.1 TCh, the torque value is qualified, otherwise, the torque value is unqualified. And (4) extracting 5 percent (no less than two sets) of the total number of the bolts of the interface bolt group by the final screwing torque inspection, wherein the reject ratio of each interface spot check bolt does not exceed 20 percent of the total number of the spot checks, and if the reject ratio exceeds 20 percent, the spot check is continued until the accumulated qualification ratio exceeds 80 percent of the total number of the spot checks.

(3) Coating process

A. Coating for friction surface and bolt head

a. Surface cleaning

The part has more oil stains, and careful attention (especially the high-strength bolt head part) is needed in the cleaning process to ensure that the surface has no oil stains.

Rust removal

The head part of the exposed bolt is polished to St2.5 grade by a special polisher (a steel wire bowl brush and a sand paper disc); and manually polishing the exposed surface of the inorganic zinc-rich antirust anti-slip coating paint film by using 100-mesh sand paper.

Coating of

When the bolt head is constructed, the peripheral coating is protected, then 1 primer is brushed on the bolt head part, care is taken in the brushing process to ensure that coating is not missed, the thickness of a dry film reaches the designed thickness, and the primer layer of the bolt head is checked and cleaned; and after the bolt head is repaired to be qualified, brushing a subsequent coating on the whole bolt exposed surface (containing the bolt head) according to an outer surface system.

Note: if the lap joint seam of the bridge site bolting plate is less than or equal to 0.5mm, adopting paint modulation putty to carry out sealing treatment (the modulation proportion is determined according to the construction condition); if the gap is larger than 0.5mm, adopting polysulfide sealant for sealing treatment.

Weld coating

a. Surface cleaning

Removing oil stains, impurities and the like on the surface.

Surface rust removal

The outer surface is mechanically polished to St2.5 grade by a power tool or is sandblasted and derusted by a portable self-circulation sandblasting machine (special equipment for welding seam treatment) to Sa2.5 grade, and the roughness is 30-75 mu m.

Coating of

After the surface treatment is qualified, coating each coating according to the coating system of the welding seam.

Full-bridge damaged surface repair and final first-degree finish paint coating

a. Gouge surface repair

For areas not damaged to the substrate: protecting the peripheral coating after deoiling, and polishing the damaged area by using a polisher; and (3) polishing the surrounding coating into a slope, polishing the surfaces of different paint layers, and coating the paint of the corresponding coating by a brushing method.

For the site damaged to the substrate: polishing and derusting to St2.5 grade after deoiling, polishing the surrounding coating to slope, polishing the surface of different paint layers, protecting the surrounding coating, and coating the corresponding coating on the outer surface.

Coating of last finish paint of full bridge

In order to ensure that the overall appearance of the bridge is consistent in color and beautiful after the bridge is built, the whole bridge is coated with the final finish after the whole bridge is installed and the processes of exposing friction surfaces, welding seams and breaking are finished.

After the full-bridge repairing coating is finished, the coating on the outer surface of the full-bridge is cleaned and activated.

The method comprises the following steps of cleaning dirt and residues on the surface of a steel structure by using tools such as a brush and the like, scrubbing oil stains on the surface of the steel structure by using a diluent, roughening the surface of a paint film by using abrasive paper, and scrubbing surface dust by using a rag.

Finish coating

After the steel structure is subjected to galling and activation treatment, coating a second finish as soon as possible, firstly pre-coating the finish on small uneven parts such as welding seams, corners and the like by using a hairbrush, and then integrally spraying the finish by using a high-pressure airless sprayer;

preparing a proper amount of paint in due time according to engineering quantity and weather conditions, blending strictly according to the proportion, adding a proper amount of diluent according to conditions such as air temperature and the like, and performing construction after uniform stirring;

pre-coating and spraying finish paint at the corners, spraying the finish paint in a large area after the pre-coating is finished, and detecting the thickness of a wet film at any time by using a wet film card in the spraying process to ensure that the thickness of a dry film meets the requirement, and the dry film has uniform appearance color and is attractive and elegant;

the surface of the steel structure is integrally sprayed with finish paint, so that the thickness of the dry film reaches the designed thickness (the spraying time is set according to the temperature influence).

Temporary structural technical assurance measures

The quality control of construction links of temporary structures such as an assembly platform, a span jacking pier, a closure section temporary pier (assembly platform), a guide beam and the like is particularly important, more personnel and equipment are involved, the working face is wide, the difficulty of construction organization is high, and all the links are strictly controlled.

(1) And each component of the temporary structure is processed, installed, checked and accepted according to the requirements of related drawings, and safety protection facilities are arranged according to the requirements of the current related specifications.

(2) Detailed technical background is required before each temporary structure is constructed, so that workers can master design files and understand design intentions.

(3) During the construction of the temporary structure, technicians need to perform construction tracking operation on key parts and make construction records and image data. And checking and accepting the temporary structure size, the perpendicularity, the welding seam quality and the like after one procedure is finished.

(4) The steel pipe pile foundation with the temporary structure is driven into the ground or a riverbed by adopting a vibration method, so that the enough driving depth is ensured.

(5) In the welding construction of the temporary structure, all welding seams meet the standard requirements, the welding seams are full, and the appearance is qualified.

Pushing construction technology guarantee measure

In order to ensure that the steel beam finally meets the designed linear requirement and stress state after being bridged, various working conditions of the splicing and pushing process under dynamic and static conditions need to be analyzed under the environmental influences of wind power, temperature, sunlight and the like, the adverse state and the maximum deformation value are found out, and detailed observation and effective control are carried out

(1) And calculating friction force according to the fulcrum counter force of the working condition and verifying the friction force with an oil pressure gauge.

(2) And (3) displacement observation: the displacement observation mainly comprises the center line offset of the beam body and the horizontal and vertical displacement of the pier top, and a jack is required to be used for timely adjustment in the pushing process. The pier top displacement observation is very important, the coordinate is converted according to the design allowable deviation as the maximum deviation value, the continuous observation is carried out from the moment of force application to the moment of beam body movement, once the displacement exceeds the design calculation allowable value, the force application is stopped immediately, and the jack thrust of each jack is readjusted.

(3) Applying a jacking force: the magnitude of each pier top thrust is adjusted according to the magnitude of the frictional resistance, and the pier top thrust is reacted through an oil meter, and the oil meter with higher precision is selected. The jack and the oil meter are calibrated before being used.

(4) Before the pushing system is used, debugging and testing are carried out according to the operation flow.

(5) Each pushing, the central line of the pushed beam section must be measured and controlled within an allowable range; if a deviation occurs, immediate adjustment is required.

(6) If the jacking force rises suddenly in the jacking process, the jacking force is stopped in time and the reason is checked.

(7) When pushing, a specially assigned person should be sent to check the guide beam and the steel beam, if the guide beam component has deformation, the screw is loose, the connection part of the guide beam and the steel beam has deformation or the steel beam has local deformation, the pushing should be stopped immediately for analysis.

(8) Attention is paid to the changes of the jacking force, the translation force and the descending force in the pushing process.

(9) When pushing to the final beam section, special attention needs to be paid to whether the beam section reaches the design position, the beam section is pushed to the final position at night when the temperature is stable, and the beam length is carefully calculated and measured according to the temperature.

(10) The last pushing should be performed by small stroke inching to correct the deviation and move longitudinally.

(11) Ensuring the synchronism of multipoint pushing.

(12) The pushing construction should be performed according to the relevant requirements of the technical Specification for construction of bridges and culverts on roads (JTG/T F50-2001).

(13) All pushing equipment and oil pumps are controlled by a computer in a unified way, so that the synchronous operation of the pushing equipment is ensured, and the unbalanced horizontal force generated by the asynchronous equipment is reduced.

(14) The process monitoring needs to be enhanced in the pushing construction, and key monitoring contents comprise: settlement of the assembly platform, settlement and horizontal displacement of the temporary pier and the pushing pier, cable force of the cable tower, deflection of the front end of the steel guide beam, stress and deformation of the local bearing part of the steel beam and the joint of the guide beam and the steel beam and the like. If a large deviation exists between the monitoring value and the calculated value, the construction is suspended, the reason is investigated, a processing scheme is formulated and processed, and the construction can be continued after the requirements are met.

(15) The cable force grading control is mainly used for bridge forming elevation and linear control, and the tension force control is assisted.

(16) The pushing operation group should ensure the stability and effectiveness of the control system in the pushing process, and is equipped with an overrun emergency stop device to ensure the safety of the main structure and the construction facilities under abnormal conditions.

(17) In the pushing construction process, the steel longitudinal beam and the steel guide beam web plate are aligned to the supporting point, and the steel longitudinal beam and the guide beam bottom plate are forbidden to bear vertical force.

(18) In the process of assembling and pushing the steel beam, the elevation, the center line position and the segment corner of the steel beam are adjusted according to the requirements of a main structure design drawing and a monitoring instruction, so that the line shape of the steel beam is ensured to meet the design requirements.

(19) In the pushing process, the elongation and the jacking force of the longitudinal jacks of the pushing equipment on the left side and the right side of the same pushing pier are monitored, and the forward displacement of the left side and the right side of the steel beam is ensured to meet the requirement. In the pushing process, the deviation of the central line of the steel beam is monitored in real time and is adjusted in time, so that the excessive deviation accumulation is prevented.

(20) Synchronous pushing guarantee measure

Although the friction force can not be ensured to be consistent in the pushing process, the jacking force can be ensured to be consistent through the synchronization of the jacks, so that the occurrence of the unfavorable condition of structure deflection is reduced. When the jacking jack piston extends out to jack the steel beam, the jacking jack piston extends out to push the beam to move forwards, and displacement synchronization control, pressure equalization control and transverse adjustment control are required in the process. Besides controlling the unified action of the jacking jacks on all piers, the main control console must also ensure the synchronization of each stroke of all jacking jacks.

(21) Vertical jacking control

According to the jacking wedge block and the beam jacking when the piston of the vertical jacking jack extends out, the main control console controls the unified action of the cluster jacking jacks, and detects the jacking height through installing the displacement sensor, so that the synchronization of the jacking jacks on two sides is ensured. The control strategy is that one side is taken as a reference, the displacement difference between the two sides is controlled within a set range, if the following side jacking height is larger, the flow of the side proportional valve is reduced, and otherwise, the flow of the side proportional valve is increased. The process synchronization precision can be controlled within 4 mm.

When the vertical jacking jack retracts, the jacking wedge block and the beam descend and fall onto the jacking device bracket again. In the process, the main control console controls the unified action of the cluster jacking jacks, and detects the jacking height through a displacement transmitter arranged between the slide way and the slide box, so that the synchronization of the jacking jacks on two sides is ensured. The control strategy is that one side is taken as a reference, the displacement difference of the two sides is controlled within a set range, if the jacking height of the following side is larger, the flow of the side proportional valve is increased, and otherwise, the flow of the side proportional valve is reduced. The synchronous precision of each stroke of the jack can be controlled within 4 mm.

As 1 pressure sensor is arranged on each stress point (4 vertical lifting jacks) for monitoring the load of each stress point. The highest pressure of each stress point and the maximum pressure difference between the stress points on the same temporary pier can be set through a panel on a field controller or a main control console, and the computer accurately coordinates the load distribution of the whole system by monitoring the load change condition of the stress points. If the load of a certain stress point reaches the set highest pressure or the maximum pressure difference between stress points on the same bridge pier is larger than the set value, the system can automatically stop and give an alarm.

(22) Control of the scale

Since 1 inclination angle sensor for detecting the inclination angle of the steel beam in the X-axis and Y-axis directions is installed on the slide box of each temporary pier, the balance of the steel beam can be controlled by setting the maximum inclination angle of each inclination angle sensor in the X-axis and Y-axis directions. If the inclination angle of the inclination angle sensor in the X-axis direction and the Y-axis direction exceeds a set value, the system stops and gives an alarm. The detection and control of the degree of balance is carried out throughout the pushing process.

(23) Deviation correcting measure

Installing 1-2 photoelectric switches at appropriate positions on each temporary pier, and detecting whether the central axis is consistent with the designed central axis or not (the central axis of the steel beam is shown by a full-length black identification line). Through the detection of chromatic aberration, the detection of the central axis of the steel beam is realized. In the horizontal pushing process of the jack extending cylinder and the steel beam translation process, if any photoelectric switch cannot detect the central axis, a signal is sent to drive the corresponding transverse adjusting jack to act until the photoelectric switch detects the central axis and then stops acting, so that transverse deviation correction is realized. The transverse deviation correction can be implemented only gradually during the pushing forward of the beam body, and the beam body is strictly pushed transversely in a longitudinal static state.

(24) Control of accumulated error

In the process of steel beam translation, the main control console calculates the total displacement of each stress point horizontally pushing the jack to move, the maximum displacement is used for reducing the minimum displacement to obtain an accumulated error, if the accumulated error exceeds the requirement, the automatic mode is stopped to enter the manual mode, and the oil cylinder on one side is independently adjusted to correct the error. And if the total station monitors that the accumulated error exceeds the requirement, stopping the 'automatic' mode from entering the 'manual' mode, and independently adjusting the action of the oil cylinder on one side to correct the error.

Claims

1. A walking type pushing construction method for steel beams with tower belts and cable forces is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: construction preparation;

step two: erecting a platform and a temporary pier;

building a steel beam assembling platform and a temporary pier, wherein the temporary pier is used as a pushing equipment arranging platform, double-assembling I-shaped steel is arranged on the assembling platform and used as a steel beam section assembling base plate, and the temporary pier is also used as a pushing pier;

step three: installing pushing equipment and debugging;

the maximum vertical bearing capacity of the bottom surface of the single box chamber is 800t during pushing construction, the uniform diffusion length of the steel beam along the bridge direction is not less than 2m, a web plate of the steel beam bears force during the pushing construction, a bottom plate does not bear force, and the vertical adjusting capacity is realized;

step four: assembling steel beams;

step five: assembling the steel tower;

step six: hanging a rope and primarily tensioning;

step seven: walking pushing;

step eight: cable force monitoring and adjusting;

step nine: beam falling and system conversion;

step ten: removing the temporary structure;

2. The walking incremental launching construction method for the steel beam with the tower and the cable force as claimed in claim 1, which is characterized in that: the specific process of the second step is as follows: before assembling steel beams, a profile steel composite material is adopted, the weight of the profile steel is weighed in advance, then a steel beam bottom cushion block is installed on the top surface of a platform according to the design position of a supporting point when the steel beams are assembled, the profile steel is piled on the steel beam cushion block, upright rods are welded on two sides of the cushion block to prevent the pre-pressed profile steel from falling off, a gantry crane is used for hoisting the profile steel to the cushion block for loading according to the design requirement in multiple times, 3-level pre-pressing loading is respectively carried out on the platform and a temporary pier, loads are sequentially applied to 60%, 80% and 100% of the pre-pressing load value in a unit, and during longitudinal loading, symmetrical load distribution is carried out from midspan; during transverse loading, symmetrically distributing loads from the center line of the structure to two sides, and monitoring the settlement of the foundation steel pipe pile at intervals of 12 hours after each level of loading is finished; when the average value of the settlement difference of the measuring points for 2 times is less than 2mm, the platform can be continuously loaded, and the two sides of the platform are symmetrically, evenly and synchronously unloaded after the prepressing is finished.

3. The walking incremental launching construction method for the steel beam with the tower and the cable force as claimed in claim 1 or 2, which is characterized in that: the third step comprises the following specific processes: during pushing construction, the maximum vertical bearing capacity of the bottom surface of the single box chamber is 800t, the uniform diffusion length of the steel beam along the bridge direction is not less than 2m, a web plate of the steel beam bears force in the pushing construction process, a bottom plate does not bear force, and the pushing construction equipment has vertical adjusting capacity and horizontal deviation rectifying capacity;

4. The walking incremental launching construction method for the steel beam with the tower and cable force as claimed in claim 1, 2 or 3, wherein the construction method comprises the following steps: the specific process of the step four is as follows: manufacturing longitudinal beams, cross beams and steel tower block plate units and assembling blocks in a steel beam processing plant, transporting the steel beam processing plant to a site, assembling the blocks, hoisting, transporting each section to the site assembling platform, assembling the sections by using a portal crane, directly hoisting the section beams to the platform by using the portal crane after the steel beam is transported to the site, and installing a main tower by using an automobile crane;

5. The walking incremental launching construction method for the steel beam with the tower and cable force as claimed in claim 1, 2, 3 or 4, wherein: the concrete process of the sixth step is as follows:

(7) cable adjustment, wherein before pushing, if one or more stayed cables need to be adjusted in terms of cable force and bridge deck elevation, single cable adjustment is needed, cable adjustment working conditions, times, sequence, cable force control and cable adjustment positions are informed by a monitoring unit, and the cable adjustment process is consistent with a single tensioning process; after the calculation requirement is rechecked through the cable force test, the pushing can be started.

6. The walking incremental launching construction method for the steel beam with the tower and cable force as claimed in claim 1, 2, 3, 4 or 5, wherein the construction method comprises the following steps: the concrete process of the seventh step is as follows: firstly, selecting a manual mode, and checking whether an oil pump, a jacking top, a deviation correcting top, a jacking top, a pressure gauge, a sensor and the like are abnormal or not; starting the pushing equipment on each pier, converting a pressure value detected by a pressure sensor on the jacking system into a thrust and reaction force value, setting pressure for the pushing oil cylinder according to the converted value of the value, providing pushing force for the pushing oil cylinder under the required pressure, and controlling the pushing oil cylinders on two sides of the temporary pier to synchronously push; the supporting reaction force of the jacking support oil cylinder is detected in real time, on one hand, the real-time accuracy of the jacking force of the jacking oil cylinder is guaranteed, on the other hand, the stress balance of the steel beam in the advancing process is guaranteed by adjusting the jacking support oil cylinder, the maximum allowable supporting reaction force on the single side of the steel beam is not more than 7000KN, after one stroke of pushing is completed, all the jacking oil cylinders retract to the starting point of the next stroke, then jacking of the next stroke can be carried out, and in the jacking process, the maximum and minimum oil pressures in the jacking process are recorded;

the stress state of the steel beam in the pushing process is completely different from that in the bridge forming process, the whole pushing process is monitored by the principle of mainly supporting reaction force control and secondarily elevation control, so that the variation range of a vertical curve of a pier through which the steel beam is pushed by the wheel top and the variation range of allowable supporting reaction force of the steel beam are determined according to a monitoring instruction before each wheel of pushing;

meanwhile, determining the elevation of the temporary pad pier under each pushing working condition;

the guide beam pier passing step comprises the following steps:

7. The walking incremental launching construction method for steel beam with tower and cable force as claimed in claim 1, 2, 3, 4, 5 or 6, wherein: the concrete process of the ninth step is as follows:

(1) after the steel beam is pushed in place, the guide beam is disassembled in sections by using the truck crane;

because the construction of the pier top cushion stone and the permanent support is completed in advance, the construction of the cushion stone and the permanent support is not needed at the moment;