CN113914227A - Construction method for viaduct curved section steel box girder supporting system on existing bridge - Google Patents

Abstract

The invention discloses a construction method of a viaduct curve section steel box girder supporting system on an existing bridge, which comprises the steps of carrying out topographic survey on a to-be-constructed area to obtain related data; carrying out foundation treatment on the area to be constructed; establishing a support system model, carrying out support system modeling checking calculation, calculating the stress influence of the support system on the existing bridge through structural safety, and analyzing and optimizing the support system model until no hidden danger exists if the hidden danger exists; selecting a position of a support system on the existing bridge through a support system model; measuring and paying off; mounting a support system; hoisting the steel box girder; after the construction is finished, dismantling the construction auxiliary parts; the invention can effectively reduce the influence on the existing bridge, and has the characteristics of shortening the construction period, good support integrity, saving the engineering cost, being easy for quality control and safety management, and the like.

Description

Construction method for viaduct curved section steel box girder supporting system on existing bridge

Technical Field

The invention relates to the field of bridge construction, in particular to a construction method of a viaduct curved section steel box girder supporting system on an existing bridge.

Background

The application of the hoisting foundation installed on the existing bridge is less in the hoisting construction of the steel box girder, and the current support system research on the bridge construction at home and abroad is insufficient. The newly-built viaduct steel box girder needs to span the existing bridge in the hoisting process, and supports the space and time limitation of a system, so that the viaduct steel box girder needs to be installed on the existing bridge. At present, urban viaducts and overpasses are designed and constructed on the basis of existing bridges, and are not mature in practical engineering application.

The newly-built steel box girder overlaps more with existing bridge, if set up the support system in existing bridge both sides, the support system middle cross beam leads to the cost too high because the overlength, has the potential safety hazard, considers the hoist and mount demand and erects on existing bridge, practices thrift construction cost.

Disclosure of Invention

The invention aims to solve the technical problem that a hoisting construction method for a steel box girder on an existing bridge is immature, and aims to provide a construction method for a curved section steel box girder supporting system of a viaduct on the existing bridge and solve the construction problem of the curved section steel box girder supporting system of the viaduct on the existing bridge.

The invention is realized by the following technical scheme:

a construction method for a viaduct curved section steel box girder supporting system on an existing bridge comprises the following steps:

carrying out topographic measurement on the area to be constructed to obtain related data;

carrying out foundation treatment on the area to be constructed;

establishing a support system model, carrying out support system modeling checking calculation, calculating the stress influence of the support system on the existing bridge through structural safety, and analyzing and optimizing the support system model until no hidden danger exists if the hidden danger exists;

selecting a position of a support system on the existing bridge through a support system model;

measuring and paying off;

mounting a support system;

hoisting the steel box girder;

and finishing construction, and dismantling the construction auxiliary member.

Specifically, the topographic survey of the area to be constructed and the obtaining of topographic data specifically include the following steps:

carrying out measurement lofting according to topographic survey, construction drawings and cofferdam design, and determining the positions of a construction pavement and a cofferdam;

the terrain data comprises various terrain points, plane positions of the terrain points and elevation data of the terrain points.

Specifically, the step of performing foundation treatment on the area to be constructed specifically includes the following steps:

according to the project schedule, performing control measurement and topographic map field data acquisition, and collecting topographic data and existing bridge data;

constructing a construction pavement and a cofferdam;

measuring and discharging a bottom side line of the construction pavement, digging out soft soil at the bottom of the pavement, and filling and leveling the bottom of the pavement, wherein the construction pavement is pitched according to a ratio of 1:1, and the digging width at the bottom of the pavement is not less than the sum of the width of an embankment and the width of a pitched;

according to the elevation data of the topographic points, the filling materials are transported to a roadbed filling end for layered filling;

in the process of filling in layers, the filler on the water surface is tamped in layers, and after the cofferdam is closed to a preset position and formed, the periphery of the cofferdam is protected and reinforced.

Specifically, the foundation treatment of the area to be constructed further comprises a dredging method, specifically, clean foundation pit water in the foundation pit is pumped out through a clean water pump, then the substrate sludge is flushed and stirred through a pressurized water gun, and meanwhile, a mud pump in the foundation pit pumps out muddy foundation pit water.

Specifically, the establishing of the support system model, the support system modeling checking calculation, the calculation of the stress influence of the support system on the existing bridge through the structural safety, and if the hidden danger exists, the analysis and optimization of the support system model until no hidden danger exists comprise the following steps:

establishing a support system calculation model;

loading a support system load and calculating a counter force;

designing a concrete foundation according to the counter force;

establishing a support architecture calculation geometric model;

setting the width of the bridge deck and the concrete strength of the column beam, and constraining the permanent support according to the support conditions of the structural continuous beam;

calculating according to a part of prestress A type components, wherein the calculation content comprises calculation analysis of box girder structure bridge stress and distribution calculation analysis of automobile load effect and support load effect on pier vertical force;

and judging whether hidden danger exists according to the result of calculation and analysis, and modifying the support system structure calculation geometric model if hidden danger exists.

Specifically, the calculation and analysis of the stress of the box girder structural bridge comprises the following steps:

checking and calculating the normal compressive stress of the concrete of the positive section, the tensile stress of the prestressed reinforcement and the main stress of the concrete of the oblique section of the box girder structure under the lasting condition;

checking and calculating the crack resistance of the normal section and the oblique section of the box girder structure in the extreme state under the normal use condition in the lasting condition;

checking and calculating the bending resistance bearing capacity of the right section of the box girder structure in the ultimate bearing capacity state under the lasting condition;

the distribution calculation analysis of the automobile load effect and the support load effect on the vertical force of the pier comprises the following steps:

checking and calculating the support reaction at the abutment and the middle pier caused by the single effect of the automobile;

and (4) checking and calculating the vertical force distributed to the single pile foundation of the abutment and the single pier of the middle pier.

Preferably, the specific method for surveying and paying off comprises the step of determining the horizontal and vertical coordinates and the elevation of the temporary buttress by using a theodolite or a total station according to the division condition of the central line, the axis and the segment of the bridge.

Specifically, the mounting of the support system specifically includes:

the lower part of the supporting system adopts a concrete foundation and is connected through expansion bolts;

the temporary buttress adopts a steel pipe lattice column, and the size and the structure of the temporary buttress are determined according to the self weight of the steel box girder segment and the geological conditions on site.

Specifically, the steel box girder hoist and mount construction specifically includes:

positioning a crane;

the beam transporting flat car provided with the steel box beam is in place, and two cable ropes are respectively arranged at two ends of the steel box beam;

lifting the steel box girder;

the girder transporting flat car is withdrawn;

after the suspension arm rotates and shifts in the air, the beam falls into place.

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

the invention reduces the influence on the existing bridge structure in the construction stage, the initial hoisting stage and the later hoisting stage by carrying out on-site investigation design and modeling analysis, optimizes the position of the support system on the existing bridge, further hoists and constructs the steel box girder, can effectively reduce the influence on the existing bridge, and has the characteristics of shortening the construction period, good support integrity, saving engineering cost, easy quality control, safe management and the like

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the principles of the invention.

Fig. 1 is a schematic flow chart of a construction method of a curved section steel box girder supporting system of a viaduct bridge according to the present invention.

Fig. 2 is a schematic flow diagram of the basic process according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are for purposes of illustration only and are not to be construed as limitations of the invention.

It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.

In the present invention, the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

The steel box girder for newly building the viaduct has the disadvantages of complex construction natural conditions, large traffic flow, difficult traffic protection and higher difficulty in construction, modeling, analysis and control of the steel box girder on the existing bridge.

According to the analysis of engineering environmental conditions, site topographic survey and water level monitoring are carried out, and the change condition of river water is known, so that the arrangement time of construction of a support system is determined, and construction in a flood season is avoided;

determining the type, the number, the arrangement and other works of the supporting system according to the bidding documents, the actual situation of the site, the site scale, the construction conditions, the schedule and the like, and further determining the selection of the position, the erection method and the equipment selection of the supporting system;

carrying out work on a construction site, determining parameters such as positions of pier columns and web plates of the bridge, positions and topography of support body systems, power of hoisting equipment, quantity of equipment and the like, and determining work efficiency parameters such as finishing time of each process and the like and corresponding quality inspection work;

example one

The embodiment provides a construction method of a viaduct curved section steel box girder supporting system on an existing bridge, which comprises the following steps:

carrying out topographic measurement on the area to be constructed to obtain related data;

carrying out foundation treatment on the area to be constructed;

establishing a support system model, carrying out support system modeling checking calculation, calculating the stress influence of the support system on the existing bridge through structural safety, and analyzing and optimizing the support system model until no hidden danger exists if the hidden danger exists;

selecting a position of a support system on the existing bridge through a support system model;

measuring and paying off;

mounting a support system;

hoisting the steel box girder;

and finishing construction, and dismantling the construction auxiliary member.

Example two

A specific example is provided below to supplement the description of the first example.

Firstly, carrying out topographic survey on an area to be constructed to obtain topographic data.

According to the project schedule, performing control measurement and topographic map field data acquisition, and collecting topographic data and existing bridge data;

preparing various surveying and mapping instruments and equipment, manufacturing measuring marks and the like, and performing control measurement and field data acquisition of topographic maps, wherein the data comprises plane positions and elevation data of various object points and topographic points; and data processing is carried out through an internal computer to finally form a diagram.

The data processing is performed according to the mapping data, and the final mapping is a technology that can be understood and implemented by those skilled in the art, which is not described herein again.

The terrain data comprises various terrain points, plane positions of the terrain points and elevation data of the terrain points.

And secondly, performing foundation treatment on the area to be constructed.

Carrying out measurement lofting according to design requirements of topographic survey, construction drawings, cofferdams and the like, and determining positions of construction sidewalks and cofferdams;

then determining to carry out construction of a construction access and a cofferdam;

measuring and discharging a bottom side line of the construction pavement, digging out soft soil at the bottom of the pavement, and filling and leveling the bottom of the pavement, wherein the construction pavement is pitched according to a ratio of 1:1, and the digging width at the bottom of the pavement is not less than the sum of the width of an embankment and the width of a pitched; and 4 DN100 concrete pipes with the length of 100 meters are arranged during construction of the sidewalk. The soil cutting section is backfilled mechanically, so that the surrounding environment is protected as much as possible, and the greening of the river edge is damaged as little as possible.

Loading and transporting fillers: determining the height of the seasonings according to the construction mechanical performance, adopting a loading mode of a dumper loaded by a loader or an excavator, and transporting the fillers to a roadbed filling end for filling in layers according to the elevation data of the landform points;

in the process of filling in layers, the filler on the water surface is tamped in layers, and after the cofferdam is closed to a preset position and formed, the periphery of the cofferdam is protected and reinforced.

And (4) dredging the base after the cofferdam is closed, wherein the bed bottom of the riverbed is generally silt clay.

After clean foundation pit water in the foundation pit is pumped out through a clean water pump, the substrate sludge is flushed and stirred through a pressurizing water gun, and meanwhile, muddy foundation pit water is pumped out through a mud pump in the foundation pit.

After dredging, clay is filled to the designed elevation, and a road roller of 18t is adopted for tamping in layers, so that the bearing capacity is ensured to reach more than 200 kpa. And (4) carrying the road set according to the on-site hoisting condition of the steel box girder to a waste soil yard by adopting machinery such as an earth moving vehicle and the like after the project is finished.

The construction of the berm is preferably carried out by adopting plain soil backfilling and tamping, and a road roller is adopted for rolling, so that the bridge is prevented from settling and deforming in the processes of hoisting and crane walking, and the difference of the height of the berm construction from the bottom surface of the bridge is not more than 7 meters, so that the smooth hoisting of the steel box girder is ensured.

Thirdly, supporting the system modeling checking calculation

And establishing a support system model, and carrying out support system modeling checking calculation.

And establishing a support system calculation model, loading a support system load, calculating a counter force, and designing a concrete foundation according to the counter force.

In this embodiment, the range of the curve segment of the Longhai road viaduct is K20+ 345.212-K20 +535.212, the curve segment is 36+59+59+36m, the length of the four-span continuous steel box girder is 190m, the bridge is divided into single parts, and the full width is 25.5m

The bridge needs to be provided with a support positioned on the existing Qili river bridge (the existing bridge) during the hoisting construction of the steel box girder. The seven-river bridge (existing bridge) is a four-width separated concrete continuous beam bridge with the span of 30+45+30m, the two outermost bridges are pedestrian bridges 9m in width, and the two inner bridge bridges are full-width bridges 18.5 m. The weight of the steel box girders on two sides is 443 ton +443 ton, the loads are distributed according to the uniform load (the load distribution width is 10 m), then the live load coefficient of 1.4 is considered, the load on the bracket is 443 × 10 × 1.4/(2 × 20) ═ 155kN/m, and a support system calculation model is established:

the reaction force calculation is carried out, the reaction forces of the foundation on the road are 1367kN and 1319kN respectively, and the concrete foundation is designed according to the partial axial force.

The average substrate pressure of 196kPa and the maximum substrate pressure of 392kPa were calculated.

And fourthly, calculating the structural safety of the support system.

And calculating the stress influence of the support system on the existing bridge through the structural safety, and if hidden danger exists, analyzing and optimizing the support system model until no hidden danger exists.

This example is calculated for a 30+45+30 qili river bridge (existing bridge) prestressed concrete continuous box girder.

Building a support structure calculation geometric model, setting the width of a bridge deck and the concrete strength of a column beam, constraining a permanent support according to the support conditions of a structural continuous beam, and calculating according to a part of prestress A-type component.

The bridge is modeled and analyzed by a bridge doctor plane rod system finite element program (V3.2.0), and the bridge deck width is 18.5m by adopting a beam unit for simulation. The main beam is made of C50 strength grade concrete and calculated according to a part of prestress A type component. The permanent support is constrained by the structural continuous beam support conditions.

According to the regulations related to the design specifications of reinforced concrete and prestressed concrete bridges and culverts for highways (JTG D62-2004), the stress of the box girder structure bridge is calculated and analyzed:

(1) checking and calculating the normal compressive stress of the concrete at the front section, the tensile stress of the prestressed reinforcement and the main stress of the concrete at the inclined section of the box girder structure under the lasting condition (in the using stage);

(2) checking and calculating the crack resistance of the normal section and the oblique section of the box girder structure in the extreme state under the normal use condition in the lasting condition;

(3) the bending resistance bearing capacity of the right section of the box girder structure in the limit state of the bearing capacity under the lasting condition;

and carrying out qualitative analysis on the distribution of the vertical force of the pier by aiming at the automobile load effect and the support load effect.

(1) The abutment and middle pier support reaction force caused by the single effect of the automobile is 1700KN and 2700 KN. The vertical forces distributed to the single pilings of the abutment and the single piers of the middle pier are 1700/2KN,2700/2 KN.

(2) The most adverse factor of the support load is that the support load is transversely eccentrically arranged, so that large transverse pier pile unbalanced force can be caused, and the vertical force distributed to the single pile foundation of the abutment and the single pier of the middle pier after the support load is specifically distributed is 1000KN or 1300 KN.

(3) Compared with the effects of an automobile and a support, the vertical force distribution of the middle pier is almost equal, and in addition, the support load cannot cause horizontal factors such as braking force and the like, so that the problem of the vertical bearing capacity of the middle pier and the lower pile foundation of the middle pier can be qualitatively considered. However, the vertical force effect of the side pier and the pile foundation at the abutment close to the side of the support is larger than the load effect of the automobile lane, the situation is qualitatively considered to be larger than the considered maximum vertical force of the original design, the difference value is about 300KN, and certain potential safety hazards exist.

And fifthly, selecting a position of the support system on the existing bridge.

This bridge is calculated vertical counter-force and is confirmed under the prerequisite that existing bridge structure does not have the defect at the support and go on:

(1) in the overall longitudinal calculation of the beam body, although the support load is large, the overall structural effect of the beam part can basically meet various structural requirements for the overall beam part calculation result.

(2) For the local calculation condition of the bridge deck plate part, due to the fact that the load is concentrated and the crack width of the part near the web plate of the bridge deck plate is over-limited, and the bending resistance bearing capacity partially does not meet the specification, further adjustment and optimization are needed.

(3) For a substructure, the qualitative comparison calculation of the middle pier and the foundation can meet the requirements, but the vertical force of the side pile close to the support at the bridge abutment exceeds the original design state, so that certain potential safety hazards exist.

The total load of the support is large, but the overall longitudinal analysis condition of the beam body is still acceptable, for the conditions of the No. 2 and the No. 3, the distribution condition of the support load is mainly caused by the unevenness, the distance between the supports can be adjusted for the No. 2 reason, the center position of each row of supports directly corresponding to the web plate of the beam part can reduce the large concentrated force effect on the bridge deck, and the shearing force and the negative bending moment effect are reduced.

For the factor 3, the factor is mainly caused by that the supports are located at one section in the transverse bridge direction, if the load is integrally and uniformly distributed in the width of the transverse bridge direction, the vertical force distributed on the lower portion of a support load action line can be smaller than the automobile load action, a single support which can be arranged on the bridge is changed into two supports, the arrangement mode enables two rows of supporting columns of each support to be located at the center of the web plate and arranged, and the transverse lifting beam above the steel support continuously extends outwards and is lengthened to exceed the center of the automobile roadway bridge and is distributed and uniformly distributed on the two supports.

Sixthly, mounting the support system.

The specific measurement paying-off method comprises the step of determining the horizontal and vertical coordinates and the elevation of the temporary buttress by using a theodolite or a total station according to the division condition of the central line, the axis and the sections of the temporary buttress.

The lower part of the support system is made of concrete foundation and connected by expansion bolts (taking Z10-Z12 as an example).

The temporary buttress adopts a steel pipe lattice column, and the size and the structure of the temporary buttress are determined according to the self weight of the steel box girder segment and the geological conditions on site.

The Z10-Z12 segmental support system is set up:

according to the self weight of the steel box girder segment and the geological conditions on site, the support system adopts a steel tube lattice column.

The four limbs of the main structure of the temporary buttress adopt Q235 steel pipes with diameter of 426mm multiplied by 8 mm. The cross section of the steel pipe is 3m multiplied by 3m, the top of the steel pipe is welded with double rows of No. 40a I-steel, and the top of the steel pipe is provided with phi 325mm multiplied by 8mm multiplied by 1500mm leveling steel pipes with the distance of 1 m; meanwhile, two 50t hydraulic jacks are arranged at the upper part of each temporary buttress, and the linear adjustment can be carried out on the steel box girder. The cross section and the side surface of each bearing steel pipe are connected by adopting L100 multiplied by 8 angle steel, so that the integral stability of the structure is enhanced. The buttresses of each group of buttresses are transversely and longitudinally connected by L100 multiplied by 8 angle steel, so that the stability of each group of supports is enhanced. And (3) erecting Z12-Z14 segmental scaffolds:

and (3) erecting Z12-Z14 segmental scaffolds:

the four limbs of the main structure of the temporary buttress adopt Q235 steel pipes with the diameter of 273mm multiplied by 8 mm. The cross section of the steel pipe is 2m multiplied by 2m, the top of the steel pipe is welded with double rows of No. 40a I-steel, and the top of the steel pipe is provided with phi 325mm multiplied by 8mm multiplied by 1500mm leveling steel pipes with the distance of 1 m; meanwhile, two 50t hydraulic jacks are arranged at the upper part of each temporary buttress, and the linear adjustment can be carried out on the steel box girder. The longitudinal and transverse sections of each bearing steel pipe are connected by 16# channel steel, and the inclined struts on the side surfaces are connected by L100 multiplied by 8 angle steel, so that the integral stability of the structure is enhanced. The backing plate is made of a steel plate with the thickness of 16mm multiplied by 600 mm.

And seventhly, hoisting the steel box girder.

Positioning a crane; the beam transporting flat car with the steel box beam is in place, two cable ropes are respectively arranged at two ends of the steel box beam to lift the steel box beam, the beam transporting flat car is withdrawn, and the suspension arm rotates and shifts in the air and then falls into place.

Before hoisting, various preparation works on site are well done, in particular, the temporary pier axis line paying-off, the elevation positioning, the side positioning line and the longitudinal limiting device are well done, and temporary cushion blocks and the like are placed on two sides of the support base cushion.

The operation flow of the steel box girder hoisting construction is as follows: the crane is in place → the beam transporting flat car with the beam section is in place → the steel box beam is lifted → the beam transporting flat car is withdrawn → the suspension arm rotates and shifts in the air → the crane slowly falls the beam into place.

Before the steel box girder is hoisted, two hoisting workers are arranged to observe the conditions of peripheral temporary facilities, support legs and hang steel wire ropes. After the crane is in place as designed, the legs are supported and the distribution beam is installed.

The command crane rotates the steel box girder in the air, two cable wind ropes are respectively arranged at two ends of the steel box girder, each rope is provided with 4 cable wind pulling tools, and the cable wind ropes are used for dragging and stabilizing the girder body and rotate to the nearest positions of the pier body support and the support system.

The crane slowly falls to the position, the steel box girder is firstly positioned near the pier end, the gap between the box girder and the pier cap girder is controlled, the axial positioning is adjusted, the size of the expansion joint is ensured, and the accurate plane position of the girder body is ensured.

When the bridge is installed, the change of the existing bridge and the supporting system is observed, and if the change is found, the hoisting is stopped in time; and after the installation is finished, setting a settlement observation point on a building fixed nearby for observing the settlement condition and stability of the whole support. And observing the settlement value at any time to ensure that the foundation is stable and does not sink.

And eighthly, finishing construction and dismantling the construction auxiliary parts.

And (3) dismantling sequence: scaffold board → upper beam → diagonal brace → upright column → bottom parallel connection; before dismantling, the sundries and ground obstacles on the bracket are firstly dismantled; the dismantling operation needs to be dismantled layer by layer from top to bottom, and simultaneous operation from top to bottom is strictly forbidden;

EXAMPLE III

According to the construction method, the embodiment provides other application examples.

(1) The tenth section of the BT project of Zhengzhou Longhai rapid channel project

Overview of the engineering

The rapid channel engineering of the Longhai road is an important component of a rapid system of roads in Zhengzhou city, namely the West four-ring West, east to Jing hong Kong and Australia, the total length is 32.5 kilometers, and the whole line passes through a central urban area in the form of an elevated expressway and a ground auxiliary road. And 4 intercommunicating overpasses are arranged along the line and respectively comprise a Xitetracyclo overpass, a Jingguang overpass, a Zhongzhou large road overpass and a 107 auxiliary road overpass.

The tenth section of the BT project for fast channel construction of Longhai road in Zhengzhou city is built, the construction range is from west to ten miles, the east side of the pavement is paved, the east to the east side of the pavement is covered, the pile number range is K20+ 074.347-K22 +114.081, the length of the main line elevated bridge is 2040m, the whole line construction comprises the elevated bridge and the ground auxiliary channel, and the fourth section of the section is connected with a steel box girder.

Construction conditions

The quick channel engineering of Zhengzhou Longhailu in 2013 is started in 11 months and planned to be completed in 2015 5 months. The highest day of construction of the steel box girder is about 3000 tons, and the highest monthly completion amount of the engineering is 10000 tons.

(2) The ninth section of the BT project of Zhengzhou Longhai rapid channel engineering

Overview of the engineering

The rapid channel engineering of the Longhai road is an important component of a rapid system of roads in Zhengzhou city, namely the West four-ring West, east to Jing hong Kong and Australia, the total length is 32.5 kilometers, and the whole line passes through a central urban area in the form of an elevated expressway and a ground auxiliary road. And 4 intercommunicating overpasses are arranged along the line and respectively comprise a Xitetracyclo overpass, a Jingguang overpass, a Zhongzhou large road overpass and a 107 auxiliary road overpass.

The method comprises the steps of carrying out construction on the ninth section of the quick channel project BT project of the Gangzhou Ganghai road, carrying out construction on the west side of the West Zhongzhou avenue (pile number: K19+124.00), carrying out construction on the east-to-ten-mile pavements (pile number: K20+074.347), and carrying out construction on a main line viaduct with the length of 950.347m, wherein the construction on the whole line comprises an overhead bridge and a ground auxiliary channel, and the fourth section of the main line of the section, the ES05 section, the NE04 section, the NE05 section, the SW05 section, the SW07 section, the WN05 section, the WN07 section, the WS03 section, the ZX03 section and the YX04 section are steel box girders.

Construction conditions

The ninth segment of the Zhengzhou province Longhai road rapid channel project is started in 12 months in 2013 and is planned to be completed in 6 months in 2015. The maximum daily hoisting of the steel box girder construction is 298 tons, and the maximum monthly completion amount of the engineering is 4719 tons.

In the description herein, reference to the description of the terms "one embodiment/mode," "some embodiments/modes," "example," "specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment/mode or example is included in at least one embodiment/mode or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to be the same embodiment/mode or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments/modes or examples. Furthermore, the various embodiments/aspects or examples and features of the various embodiments/aspects or examples described in this specification can be combined and combined by one skilled in the art without conflicting therewith.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

It will be understood by those skilled in the art that the foregoing embodiments are merely for clarity of description and are not intended to limit the scope of the invention. It will be apparent to those skilled in the art that other variations or modifications may be made on the above invention and still be within the scope of the invention.

Claims (9)

1. A construction method for a viaduct curved section steel box girder supporting system on an existing bridge is characterized by comprising the following steps:

carrying out topographic measurement on the area to be constructed to obtain related data;

carrying out foundation treatment on the area to be constructed;

establishing a support system model, carrying out support system modeling checking calculation, calculating the stress influence of the support system on the existing bridge through structural safety, and analyzing and optimizing the support system model until no hidden danger exists if the hidden danger exists;

selecting a position of a support system on the existing bridge through a support system model;

measuring and paying off;

mounting a support system;

hoisting the steel box girder;

and finishing construction, and dismantling the construction auxiliary member.

2. The method for constructing the viaduct curved section steel box girder supporting system on the existing bridge according to claim 1, wherein the step of performing terrain measurement on the area to be constructed to obtain terrain data specifically comprises the following steps:

according to the project schedule, performing control measurement and topographic map field data acquisition, and collecting topographic data and existing bridge data;

the terrain data comprises various terrain points, plane positions of the terrain points and elevation data of the terrain points.

3. The method for constructing the viaduct curved section steel box girder supporting system on the existing bridge according to claim 2, wherein the step of performing foundation treatment on the area to be constructed specifically comprises the following steps:

carrying out measurement lofting according to topographic survey, construction drawings and cofferdam design, and determining the positions of a construction pavement and a cofferdam;

constructing a construction pavement and a cofferdam;

measuring and discharging a bottom side line of the construction pavement, digging out soft soil at the bottom of the pavement, and filling and leveling the bottom of the pavement, wherein the construction pavement is pitched according to a ratio of 1:1, and the digging width at the bottom of the pavement is not less than the sum of the width of an embankment and the width of a pitched;

according to the elevation data of the topographic points, the filling materials are transported to a roadbed filling end for layered filling;

in the process of filling in layers, the filler on the water surface is tamped in layers, and after the cofferdam is closed to a preset position and formed, the periphery of the cofferdam is protected and reinforced.

4. The method for constructing the viaduct curved section steel box girder supporting system on the existing bridge according to claim 3, wherein the foundation treatment of the area to be constructed further comprises a dredging method, specifically, after clean foundation pit water in the foundation pit is pumped out by a clean water pump, the substrate sludge is flushed and mixed by a pressurized water gun, and meanwhile, a slurry pump in the foundation pit pumps out the turbid foundation pit water.

5. The method for constructing the viaduct bridge curve section steel box girder supporting system on the existing bridge according to claim 3, wherein the method comprises the following steps of establishing a supporting system model, carrying out supporting system modeling checking calculation, calculating the stress influence of the supporting system on the existing bridge through structural safety, and if hidden danger exists, analyzing and optimizing the supporting system model until no hidden danger exists:

establishing a support system calculation model;

loading a support system load and calculating a counter force;

designing a concrete foundation according to the counter force;

establishing a support architecture calculation geometric model;

setting the width of the bridge deck and the concrete strength of the column beam, and constraining the permanent support according to the support conditions of the structural continuous beam;

calculating according to a part of prestress A type components, wherein the calculation content comprises calculation analysis of box girder structure bridge stress and distribution calculation analysis of automobile load effect and support load effect on pier vertical force;

and judging whether hidden danger exists according to the result of calculation and analysis, and modifying the support system structure calculation geometric model if hidden danger exists.

6. The method for constructing the viaduct bridge curved section steel box girder supporting system on the existing bridge girder according to claim 5, wherein the calculation and analysis of the stress of the box girder structural bridge comprises:

checking and calculating the normal compressive stress of the concrete of the positive section, the tensile stress of the prestressed reinforcement and the main stress of the concrete of the oblique section of the box girder structure under the lasting condition;

checking and calculating the crack resistance of the normal section and the oblique section of the box girder structure in the extreme state under the normal use condition in the lasting condition;

checking and calculating the bending resistance bearing capacity of the right section of the box girder structure in the ultimate bearing capacity state under the lasting condition;

the distribution calculation analysis of the automobile load effect and the support load effect on the vertical force of the pier comprises the following steps:

checking and calculating the support reaction at the abutment and the middle pier caused by the single effect of the automobile;

and (4) checking and calculating the vertical force distributed to the single pile foundation of the abutment and the single pier of the middle pier.

7. The method for constructing the viaduct curved section steel box girder supporting system on the existing bridge according to claim 6, wherein the specific method for measuring and paying off comprises determining the horizontal and vertical coordinates and elevation of the temporary buttress by using a theodolite or a total station according to the division condition of the bridge center line, the temporary buttress axis and the section.

8. The method for constructing the viaduct curved section steel box girder supporting system on the existing bridge according to claim 7, wherein the installing of the supporting system specifically comprises:

the lower part of the supporting system adopts a concrete foundation and is connected through expansion bolts;

the temporary buttress adopts a steel pipe lattice column, and the size and the structure of the temporary buttress are determined according to the self weight of the steel box girder segment and the geological conditions on site.

9. The method for constructing the viaduct bridge curve section steel box girder supporting system on the existing bridge according to claim 8, wherein the steel box girder hoisting construction specifically comprises:

positioning a crane;

the beam transporting flat car provided with the steel box beam is in place, and two cable ropes are respectively arranged at two ends of the steel box beam;

lifting the steel box girder;

the girder transporting flat car is withdrawn;

after the suspension arm rotates and shifts in the air, the beam falls into place.

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