CN117431839A - Construction method of cast-in-situ beam of pipeline bridge of south-water and north-water-crossing main channel - Google Patents

Abstract

The invention provides a construction method of a cast-in-situ beam of a cross-south-water north-transfer main canal pipeline bridge, which comprises the steps of treating a foundation and installing a swivel device; secondarily treating the foundation and arranging a water-proof and drainage system; erecting a bracket for supporting the cast-in-situ bridge on the swivel device and prepressing the bracket; erecting a second template for the cast-in-situ bridge on the support, and binding reinforcing steel bars in the second template; pouring and taking crack prevention measures; after the concrete strength reaches the standard, removing the mould, and carrying out maintenance, prestress tensioning and pore canal grouting on the formed bridge; dismantling the bracket; a bridge swivel; dismantling the swivel means; constructing a side span closure section; and constructing the middle span closure section. The bridge is prefabricated beside the channel, the bridge section is turned to the upper side of the channel by adopting the turning device, concrete is effectively prevented from falling into the channel when the bridge is poured, the ecological environments of the south-to-north water quality, river levee and coastal are protected, the influence of construction on the south-to-north water quality of the south-to-north water engineering is reduced, and the safety of a water source is ensured.

Description

Construction method of cast-in-situ beam of pipeline bridge of south-water and north-water-crossing main channel

Technical Field

The invention belongs to the technical field of bridge construction, and particularly relates to a construction method of a cast-in-situ beam of a pipeline bridge of a cross-south-to-north-transfer main channel.

Background

The south-to-north central line canal belongs to a national important drinking water source channel, and is a basic project for promoting regional coordinated development, so that the ecological environment protection requirements on water quality, river levees and coasts are extremely high in the construction process. In bridge construction of China, a river-crossing bridge is generally constructed by adopting a hanging basket cantilever, the hanging basket cantilever is arranged above a river, and when the hanging basket cantilever is used for construction, as the whole bracket is not closed, concrete is poured from two ends of the bracket, slurry is easy to leak in the concrete pouring process, the concrete leaks into a river under the bridge, and water source pollution and the ecological environment along the coast are extremely easy to damage. The basket hanging cantilever frame process has great influence on the ecological environment of the river under the bridge, so that the basket hanging cantilever frame process is not suitable for construction of a main canal bridge crossing south-to-north water, and the south-to-north water project belongs to a national important drinking water source channel and is a basic project for promoting regional coordinated development, and therefore, the ecological environment protection requirements on water quality, river levees and coasts are extremely high in construction; and the average width of the south-to-north-adjustment main canal is about 50 meters, and the span is large, so that the construction of the bridge crossing the south-to-north-adjustment main canal has great difficulty, and the whole construction process is difficult to ensure to be fast, safe and successful by the traditional technology.

Therefore, how to effectively protect the ecological environment of the water quality of south-to-north water regulation, river levees and coasts, reduce the difficulty of construction, and ensure that the bridge is quickly, safely and successfully built is a technical problem to be solved.

Disclosure of Invention

Aiming at the defects in the background technology, the invention provides a construction method of a cast-in-place beam of a cross-south-to-north-transfer main channel pipeline bridge, which solves the problems of serious damage to water quality, river levee and ecological environment along the coast and high bridge construction difficulty in construction.

The technical scheme of the application is as follows:

a construction method of a cast-in-situ beam of a cross-south-water north-adjustment main channel pipeline bridge comprises the following steps:

s1: treating the foundation, and installing a swivel device at a specified position; s2: secondarily treating the foundation and arranging a water-proof and drainage system; s3: erecting a bracket for supporting the cast-in-situ bridge on the swivel device and prepressing the bracket; s4: erecting a second template for the cast-in-situ bridge on the support, and binding reinforcing steel bars in the second template; s5: pouring and taking crack prevention measures; s6: after the concrete strength reaches the standard, removing the second template, and carrying out maintenance, prestress tensioning and pore canal grouting on the formed bridge; s7: dismantling the bracket; s8: turning the bridge; s9: the swivel device is dismantled, and the bridge is connected with the permanent support; s10: constructing the side span closure section; s11: and constructing the middle span closure section.

Further, the specific steps of S1 are as follows:

s1.1: hoisting the spherical hinge lower embedded plate and the support lower embedded plate to the pier body bolster; s1.2: the first templates are arranged around the spherical hinge and the support, and grouting is carried out; s1.3: hoisting the spherical hinge and embedding a plate on the spherical hinge; s1.4: hoisting a slide way of the anti-overturning system, grouting and reinforcing, and welding a stainless steel plate on the top surface of the slide way; s1.5: hoisting supporting feet, a sand box, a steel casing, and installing an anchor and a steel stranded wire; s1.6: hoisting an embedded plate on the anti-overturning system; s1.7: and (5) installing a permanent support and embedding a steel plate on the support.

Further, the first template comprises an inner die, and a plurality of supporting vertical rods are arranged on the inner side of the inner die.

Further, the specific steps of S8 are as follows:

s8.1: weighing experiments are carried out on the rotating bridge; s8.2: balancing weights are adopted for balancing; s8.3: installing swivel construction equipment; s8.4: testing a swivel device; s8.5: cleaning and pre-tightening a traction rope; s8.6: testing; s8.7: and formally turning and synchronously monitoring and setting guarantee measures.

Further, the test content of the weighing experiment comprises the steps of calculating the unbalanced moment of the longitudinal bridge of the rotor part, calculating the eccentric distance of the longitudinal bridge of the rotor part, calculating the friction moment and the static friction coefficient of the spherical hinge of the rotor, and designing the counterweight scheme of the rotor beam.

Further, the specific steps of S9 are as follows: s9.1: removing part of the supporting feet; s9.2: a jacking jack is arranged at the position of the dismantled supporting leg; s9.3: jacking the bridge; s9.4: sequentially removing the spherical hinge support and the rest supporting feet; s9.5: the bridge falls back.

Further, the specific steps of S10 are as follows:

s10.1: setting up a bracket III and a mounting template III at the folding section of the side span; s10.2: binding reinforcing steel bars of the side span closure section, and installing a prestressed pipeline; s10.3: loading a counterweight and closing and locking the side span; s10.4: pouring the side span closure section and simultaneously unloading the counterweight according to the concrete pouring speed; s10.5: curing the concrete; s10.6: and (3) prestress tensioning of the side span closure section, grouting of the pore canal and dismantling of the bracket III.

Further, the specific steps of S11 are as follows:

s11.1: moving the hanging frame provided with the leakage-proof unit from the shore to the junction of the midspan bridge; s11.2: installing a reinforcing steel bar, a template and a prestressed reinforcement, loading a counterweight and closing and locking a midspan; s11.3: pouring concrete on the mid-span closure section; s11.4: curing the concrete; s11.5: prestress tensioning of side span closure sections and grouting of pore canals; s11.6: the hanger is moved to shore and removed.

Further, the leakage-proof unit is arranged below the cast-in-situ bridge, the size of the leakage-proof unit along the cross section of the cast-in-situ bridge is larger than that of the cross section of the cast-in-situ bridge, and the construction of S11 is operated in the leakage-proof unit.

Further, the leak protection unit slope sets up, leak protection unit's below is provided with the water collector who collects waste water.

The invention has the following specific beneficial effects:

1. prefabricating the bridge beside the channel, and turning the bridge section to the upper part of the channel by adopting a turning device, so that concrete is effectively prevented from falling into the channel when the bridge is poured, the ecological environments of the water quality of south-to-north water regulation, river levees and coasts are protected, the influence of construction on the water quality of the south-to-north water regulation engineering is reduced, the pollution of a water source is ensured, the construction difficulty is reduced, and the construction process is accelerated;

2. the middle span closure section adopts hanging bracket cast-in-situ, a leakage-proof unit is arranged under the movable hanging bracket for protection, so that the installation of the steel bars and the templates of the middle span closure section and the pouring of concrete are ensured to be completed on a channel of south-to-north regulation of the whole hanging bracket, the safety of personnel is ensured, the hanging bracket is prevented from moving and falling down the concrete during construction, and the water source is effectively ensured not to be polluted by construction;

3. because the span of the main canal of south-to-north water is large, the bridge weight of the turning body is huge, and the common turning body device cannot ensure the safety and success of the whole process.

Drawings

In order to more clearly illustrate the embodiments of the present invention, the drawings that are required for the description of the embodiments will be briefly described below, it being apparent that the drawings in the following description are only some embodiments of the present invention and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.

FIG. 1 is a schematic view of the position of a rotor apparatus according to the present invention;

FIG. 2 is a schematic diagram of a rotor apparatus according to the present invention;

FIG. 3 is a schematic diagram of the relationship between the swivel device and the cast-in-situ bridge in the present invention;

FIG. 4 is a schematic view of the present invention after rotation;

FIG. 5 is a schematic view of the erection of the stand bars of the present invention;

FIG. 6 is a schematic view of a stent of the present invention;

FIG. 7 is a schematic view of a hanger of the present invention;

FIG. 8 is a schematic view of a leak-proof unit;

FIG. 9 is a schematic illustration of mid-span closure segment construction;

FIG. 10 is a schematic diagram of a construction method of the present invention;

FIG. 11 is a flow chart of a bridge swivel;

FIG. 12 is a schematic view of the temple removal position of the present invention;

FIG. 13 is a schematic view of the installation position of the jack-up jack in the present invention;

FIG. 14 is a flow chart of a construction process of a side span closure segment;

FIG. 15 is a schematic view of an inner mold support of a side closure segment;

FIG. 16 is a flow chart of a mid-span closure segment construction process;

fig. 17 is a schematic diagram of a mid-span closure lock.

Reference numerals illustrate:

1. a swivel means; 2. a hanging bracket; 3. a bracket; 5. an inner mold; 6. supporting the upright rod;

11. a spherical hinge lower embedded plate; 12. a lower embedded plate of the support; 21. a leakage preventing unit; 31. and (3) a steel plate.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without any inventive effort, are intended to be within the scope of the invention.

The construction method of the cast-in-situ beam of the main canal pipeline bridge crossing the south-to-north water, as shown in fig. 8, comprises the following steps:

s1: treating the foundation, and installing the swivel device 1 at a prescribed position; as shown in fig. 1, the stand-up position ensures a level, firm and steady, preventing the crane from capsizing. When in supporting and hanging, a steel plate with the thickness of 2m multiplied by 1.5m is paved on the bottom surface of the supporting leg. And pre-pressing the foundation at the supporting position in advance, wherein the pre-pressing pressure is 180KPa. The crane station has no potential safety hazard to the main channel when capsizing at one side of the edge of the bearing platform, which is far away from the south-to-north main channel.

S2: secondarily treating the foundation and arranging a water-proof and drainage system;

s3: erecting a bracket and a bottom die template for supporting a cast-in-situ bridge on the swivel device, and prepressing; preferably, a disc buckle type bracket is used, as shown in fig. 4, the thickness of a disc buckle type bracket cast steel or steel plate hot section manufacturing connecting disc is not less than 8mm, and the allowable dimensional deviation is +/-0.5 mm; the thickness of the connecting disc manufactured by stamping the steel plate is not less than 10mm, and the allowable deviation is +/-0.5 mm; the rod end buckle joint made of cast steel forms good cambered surface contact with the outer surface of the upright rod steel pipe, and the contact area is not smaller than 500mm < 2 >; the inclination of the wedge-shaped bolt ensures that the wedge-shaped bolt can be self-locked after being wedged into the connecting disc. The thickness of the bolt manufactured by cast steel, steel plate hot section or stamping is not less than 8mm, and the allowable deviation is +/-0.1 mm; the upright rod connecting sleeve can be a cast steel sleeve or a seamless steel tube sleeve. The length of the vertical rod connecting sleeve in the form of cast steel sleeve is not less than 90mm, the insertable length is not less than 75mm, the length of the vertical rod in the form of seamless steel tube sleeve is not less than 160mm, and the insertable length is not less than 110mm. The gap between the inner diameter of the sleeve and the outer diameter of the upright post rigid pipe is not more than 2mm; the upright posts and the upright post connecting sleeve are provided with anti-extraction pin holes for fixing the upright post connection, the aperture of the pin holes is not more than 14mm, and the allowable deviation is +/-0.1 mm; the diameter of the upright rod connecting piece is preferably 12mm, and the allowable deviation is +/-0.1 mm; when the connecting disc is welded and fixed with the vertical rod, the non-coaxiality between the center of the connecting disc and the axis of the vertical rod should not be more than 0.3mm; taking the outer edge of the unilateral connecting disc as a measuring point, wherein the deviation of the perpendicularity of the disc surface and the vertical rod axis is not smaller than 0.3mm; the bottom plate of the adjustable base and the supporting plate of the adjustable bracket are preferably trapezoidal teeth, the A-shaped upright rod is provided with a phi 48 screw rod and an adjusting handle, and the outer diameter of the screw rod is not smaller than 46mm; the bottom plate of the adjustable base and the supporting plate of the adjustable bracket are preferably made of Q235 steel plates, the thickness is not less than 5mm, the allowable deviation is +/-0.2 mm, and the bearing surface steel plates and the width are not less than 150mm; the steel plate of the bearing surface and the screw rod are subjected to ring welding, and stiffening sheets or stiffening arches are arranged; the adjustable bracket supporting plate is provided with an opening baffle, and the height of the baffle is not less than 40mm; the screw and the nut screwing length of the adjustable base and the adjustable bracket are not smaller than 5 buckles, and the thickness of the nut is not smaller than 30mm.

Specifically, the bottom plate templates all adopt δ=15 mm thick bamboo plywood. The secondary edge adopts 100X 100mm square timber, and the center distance is 20cm; the transverse arrangement of the main ridge adopts I-steel with 12.6 diameters, the center distance is 60cm, and the span is 60cm. The bottom of the template is supported and jacked on the main ridge of the bottom plate template by the upright posts of the support frame. The vertical rods are transversely arranged and encrypted according to the size of the axillary angle, and the encrypted rods are connected with the horizontal rods through fasteners.

In order to test the overall stability of the bracket and the actual bearing capacity of the bracket foundation, the uneven settlement of the bracket in the concrete pouring process is overcome, the occurrence of cracks of box girder concrete due to the uneven settlement of the bracket is avoided, meanwhile, the inelastic deformation of the bracket is eliminated, the elastic deformation of the bracket is measured, the inelastic deformation after the bracket pre-pressing is calculated, data are provided for the adjustment of the pre-camber, and a ballast test is carried out after the installation of a full framing bottom die and a support is completed.

The bracket is preloaded by woven bagged sand, the weight of each bag is about 1t, and the preloading load of the bracket is not less than 1.1 times of the sum of the constant load of the concrete structure born by the bracket and the weight of the template. Because the loads of all parts of the box girder are different, the web plate position, the bottom plate position and the flange plate position are respectively loaded according to the weight in the virtual section, 1 technician is specially responsible for loading weight calculation during loading, and 1 technician is specially responsible for commanding the sand bag placing position.

The pre-compaction sand bag can cause load to be bigger because of considering the influence of rainfall on the sand bag, so the sand bag pre-compaction needs to consider waterproof measures, particularly, when the pre-compaction time weather condition is considered, the sand bag is fully covered by using waterproof canvas if the recent rainfall is predicted, phi 5cm water draining holes are arranged at the lower position of the roof of the box girder, 2 water draining holes are arranged at each position, and whether the sand bag is blocked or not is checked in time. And if severe weather such as heavy storm is forecast, the pre-pressing time is adjusted.

After the bottom die is installed, the bracket can be pre-pressed. In order to avoid the increase of load during the prepressing in the raining period, the sand bag can be covered by tarpaulin. When loading longitudinally, symmetrical load distribution is carried out from midspan to the fulcrum; when transversely loaded, the symmetrical load distribution is carried out from the central line of the structure to two sides. The pre-compression loading process of the bracket is preferably carried out in 3 stages, and the load applied in sequence is 60%, 80% and 100% of the pre-compression load value in the unit. After each stage of loading is completed, monitoring the settlement of the bracket at intervals of 12 h; when the average value of the continuous 2 times sedimentation differences of the stent measuring points is smaller than 2mm, the method can continue loading. After loading of each stage, the support is comprehensively checked, problems are found in time, and hidden danger is eliminated. If the phenomena of obvious foundation settlement, foundation cracking, local position and excessive bracket deformation are found in the observation process, the loading and unloading should be stopped immediately, the reasons are searched in time, and remedial measures are taken.

And when the pre-compaction reaches the required weight, starting to enter a sedimentation observation period until the observation data meets the requirement and unloading the sediment. Unloading by adopting a crane after the support prepressing meets the requirements: the unloading adopts one-time unloading, and the unloading is symmetrical, balanced and synchronous on two sides of the bracket.

The monitoring of the bracket pre-compression comprises the following steps:

(1) Monitoring point elevation before loading;

(2) Monitoring point elevation after each stage of loading;

(3) Monitoring point elevation at each interval of 24 hours after loading to 100%;

(4) And (5) unloading for 6 hours, and then monitoring the elevation of the point.

And the precompression monitoring should calculate the settlement amount, the elastic deformation amount and the inelastic deformation amount of the bracket. Before pre-pressing, a monitoring section is arranged along each span in the longitudinal direction of the beam body structure, 5 points are uniformly distributed on the transverse left side and the transverse right side of each monitoring section for observation, elevation of the bottom die and the original ground is observed once before pre-pressing, and the elevation is recorded in a book. Is thoroughly and uniformly arranged on the top plate.

The bracket deformation monitoring and recording work is carried out according to the following sequence:

(1) After all instruments are required to be qualified, the observation work can be started;

(2) Measuring and recording original elevation of measuring points at the top and the bottom of the bracket after the bracket is erected and before the pre-compression load is applied;

(3) After the load of each stage is applied, the elevation of each measuring point is recorded, the sedimentation difference of the front and rear two times is calculated, and when the sedimentation difference of the support of the front and rear two times of each measuring point meets the standard requirement, the load of the next stage can be applied;

(4) After all loads are applied, observing once every 24 hours, and recording elevation of each measuring point; when the pre-compaction of the bracket meets the rule, unloading the bracket;

(5) Observing elevation of each measuring point after unloading for 6 hours, and calculating sedimentation difference of two times before and after unloading, namely elastic deformation;

(6) And calculating the total settlement of the bracket, namely inelastic deformation.

Specifically, in the bracket pre-pressing process after all loads are loaded, when one of the following conditions is met, the bracket pre-pressing is judged to be qualified: firstly, the average value of the settlement amount of each monitoring point for 24 hours is smaller than 1mm; and secondly, the average value of the settlement amount of each monitoring point for 72 hours is smaller than 5mm. According to the measurement result, calculating deformation and drawing a support deformation curve, respectively calculating elastic deformation and inelastic deformation of square timber, a support and a template, and calculating foundation settlement according to the recovery condition after unloading.

Before the frame body is pre-pressed, the support is adjusted according to the calculated elevation, so that each rod piece of the support is ensured to be uniformly stressed. After the pre-pressing, the frame body basically eliminates the plastic deformation of the foundation and the clearance between the rods in the vertical direction of the support, namely the inelastic deformation, under the action of pre-pressing load, and the elastic deformation value of the support is obtained through pre-pressing. And determining and adjusting the elevation of the beam bottom according to the actually measured deformation value of the bracket and combining the designed elevation and the pre-camber value of the beam bottom. The support pre-pressing acceptance is carried out on the basis of the self-inspection qualification of the construction unit, and the construction unit, the supervision unit, the design unit and the construction unit participate in acceptance together. And signing a relevant acceptance file after the bracket is pre-pressed and accepted.

S4: as shown in fig. 5, a second template for the cast-in-situ bridge is erected on the bracket, and steel bars are bound in the second template;

in particular, attention to the installation of the template:

(1) The construction quality of the template engineering meets the requirements of the acceptance Specification of the construction quality of the concrete structure engineering (GB 50204-2015), the correctness of the sizes and the mutual positions of the engineering structure and the components is ensured, and the template and the supporting structure thereof are checked to ensure that the template has enough strength, rigidity and stability, so that the quality safety accidents are avoided;

(2) The template material approach is provided with a qualification certificate and a detection report, the template assembly accurately arranges the templates according to the construction size of the design drawing, and the templates are inspected by a field quality inspector after the template assembly is processed and molded, so that the template assembly is ensured to meet the standard requirements;

(3) When the roof template is constructed, the roof template is arched strictly according to the standard requirement, and the arch height is preferably 1/1000-3/1000 of the span;

(4) The plate seams of the top plate template are arranged on the bottom edges, plastic adhesive tapes are reduced as much as possible, and sponge strips are added to seal the plate seams of the vertical template;

(5) The embedded part and the reserved hole fixed on the template cannot be omitted, the installation is firm, and the deviation meets the regulations;

(6) And detecting the allowable deviation of the template.

TABLE 1 cast-in-place Structure template installation tolerance

TABLE 2 tolerance of embedded parts and reserved holes

Specifically, the template is used for copying and measuring the standard height control points, one control point is arranged every 3m, and the control points should be protected.

Specifically, deformation control of the template:

(1) Before the wall mould is supported, a top mould rod is welded on the vertical ladder bar;

(2) When concrete is poured, a layered ruler rod is made, illumination is matched, layered pouring is carried out, the layer height is controlled within 500, and the template is deformed due to the fact that vibration is prevented from being too tight or excessively vibrated;

(3) After the formwork is erected, horizontal and vertical through lines are pulled, so that the deformation and the running position of the formwork are easy to observe during concrete pouring;

(4) Carefully checking whether the bolts, the top support and the diagonal braces are loosened before pouring;

(5) And after the template is erected, the template is forbidden to be tied with the full framing.

Concretely, when the plate joint is not tight, the joint is blocked by a plastic sealing strip; and when the template is deformed, the template is trimmed in time. And during concrete pouring, special persons are assigned to check the templates in full time, and the problem is found to be solved in time. In order to improve the turnover and installation efficiency of the templates, the templates are numbered according to the positions and the sizes of engineering axes in advance so as to be positioned and used. And (5) sorting and stacking the removed templates according to numbers. The installation operator should take the responsibility of setting the section and the number.

Specifically, the following is the notice during the construction of the template:

(1) And the ink lines are red or black under the plywood strictly according to the drawing size.

(2) And blanking after the elastic wire, wherein the size from edge to edge of the required panel is ensured during cutting, corners are not damaged, the straightness of corners is ensured, and after blanking of the template, the template is classified and coded according to a design drawing and labeled with a mark.

(3) Cleaning the surface of the front template of the bamboo plywood, brushing a release agent, and tightly preventing the release agent from contaminating joints between the reinforcing steel bars and the concrete.

(4) After the templates are assembled and inspected to be qualified, each template is numbered by a wood board at the back of the template, and the templates are hung on a template stacking frame by using a lifting device.

(5) The steel pipe bent is erected horizontally and vertically, vertically and horizontally communicated, the positions of the upper layer support top and the lower layer support top are consistent, the connecting pieces are required to be firmly connected, and the steel pipe bent is horizontally pulled and supported to be communicated.

Specifically, the steel bars with the diameters larger than or equal to 16mm are connected through straight thread sleeves, and other small-diameter steel bars are connected through binding wires. Before processing, the end face of the steel bar is ensured to be flat and vertical to the axis of the steel bar; cutting off by a hot processing method is not needed when the steel bar is fed; it is not necessary to have horseshoe shape or twist; the end part of the steel bar must not be bent; the bending should be straightened when occurring. An aqueous lubricating fluid should be used for the spinneret processing, and an oily lubricating fluid should not be used. When the temperature is lower than 0 ℃, 15-20% of sodium nitrite should be doped, and oily lubricating liquid or no lubricating liquid is strictly forbidden for threading. The pitch diameter, the tooth angle and the effective thread length of the spinneret meet the standard requirements. The thread size of the spinneret is preferably determined according to GB/T196; the effective thread pitch diameter dimensional tolerance preferably meets the requirements specified by class 6f precision in GB/T197. The cylindricity error of the effective thread pitch diameter of the spinneret is not more than 0.20mm. The effective thread length of the standard joint spinneret is required to meet the requirement that the length of the l/2 connecting sleeve is +2P, P is the thread pitch, and other connecting forms are required to meet the requirements of related specifications. After finishing the processing of the wire head and checking the wire head to be qualified, the wire head protective cap should be immediately taken on to prevent the wire head from being polluted and damaged in the processes of loading, unloading, carrying or concrete construction. According to the diameters of the steel bars, plastic protection sleeves with different sizes are selected, the length of each protection sleeve is 10-20 mm longer than the external threads of the steel bars, and one end of each protection sleeve is sealed. In the rolling process, the size of the wire head and the completion condition of the screw threads are checked once every 30 wire heads are processed, and the deviation is found to be timely adjusted. The rib stripping process of the steel bar is only allowed to be carried out once, and the machined wire head is not allowed to be stripped for the second time.

Specifically, after the steel bar is installed and is inspected by the project department, the steel bar is inspected by a supervision engineer after being inspected by the project department, and then the inner side template of the web plate can be installed. The template adopts a 15mm bamboo plywood, and square wood with the spacing of 20cm and the length of 10cm is used as vertical ribs; transverse beam is made of square wood with phi 48 multiplied by 3.5mm, two beams are arranged in total, and the distance is 90cm; and adopting a steel pipe with phi 48 multiplied by 3.5mm as a pair support. The chamfer angles of the web plate and the bottom plate adopt a reinforcing anti-floating measure formed by welding a pull rod, two steel pipes with phi 48 multiplied by 3.5mm and butterfly buckles on the framework steel bars. The top plate template adopts a phi 48 multiplied by 3.5mm fastener type supporting frame, the transverse spacing of the upright posts is 50cm or 60cm, the longitudinal spacing is 90cm, and the step distance of the upright posts is 60cm. The top of the jacking is provided with 10cm multiplied by 10cm square timber as a transverse distribution beam, and 10cm multiplied by 10cm square timber is adopted as a longitudinal distribution beam every 30cm on the transverse square timber.

S5: pouring and taking crack prevention measures; preferably, the cast-in-place concrete is designated as C55 concrete and is a high-designation durable concrete, together with 3436.5m 3. In order to reduce the hydration heat of concrete, improve the concrete performance, control the temperature difference cracks and the shrinkage cracks of concrete, and strictly control the selection of concrete raw materials. The mixing proportion of the concrete is designed by adopting cementing materials such as low hydration heat, uniform heat of hydration, and the like, and meanwhile, the fly ash generates hydration heat through the action of the products of the hydration heat of the cement, so that the complete release time of the hydration heat of the concrete is prolonged, and the temperature rise amplitude and the temperature peak value in the concrete are reduced; after the concrete pouring is finished, a scraping bar is adopted to level the concrete surface, so that shrinkage cracks on the concrete surface are prevented; the temperature should be strictly controlled, the temperature difference between the interior and the surface of the concrete is not more than 25 ℃, and the temperature difference between the surface and the atmosphere is not more than 20 ℃; when in vibration, the vibrating rod should go deep into the concrete of the lower layer which is vibrated for 5 cm to 10cm. The distance between the insertion points of the vibrating bars is 1.5 times of the action radius of the vibrating bars, the moving distance is not more than 1.5 times of the action radius of the vibrator, and the distance between the vibrating bars and the side dies is kept at 5-10cm, so that the leakage vibration is prevented. The vibrating rod is required to be inserted and pulled out quickly and is moved up and down continuously during vibration, so that the concrete surface air bubbles are reduced, and the concrete surface air bubbles are tamped uniformly. The vibration time is adjusted according to the compactness of the concrete, and the two sides are symmetrically vibrated, wherein the vibration is based on that the concrete is not sinking any more, the surface is flat and the grouting starts, and the concrete is not blown out of a large amount of bubbles. And tightly forbidding the tamping rod to collide with the template and the embedded part. The compactness of the chamfer concrete is particularly controlled, and the chamfer template is easy to run and needs to be cared by a special person. The concrete of the bottom plate is required to be smoothed, and the superfluous concrete is required to be shoveled; and (3) preparing a plastic film on site, covering and watering and curing as soon as possible after pouring is finished, and watering and curing in the box.

S6: the concrete strength reaches 2.5Mpa, the die is disassembled under the condition of not damaging the edge angle of the concrete member, and the non-bearing side die is disassembled under the condition of not damaging the edge angle of the concrete member, wherein the concrete strength reaches 2.5 Mpa. The bottom die and the bracket can be removed after the strength reaches the design requirement strength and the tension pressure drop is allowed by a supervision party. After the concrete is poured, the concrete should be covered as soon as possible after the concrete is pulped, and sprayed with water for moisture maintenance, so that the surface of the concrete is not damaged or polluted when the geotextile is covered. The portion covered by the form should be kept wet during curing. The sprinkling and moisture-preserving curing time of the concrete is not less than 14d.

Specifically, the longitudinal prestressed tendons adopt high-strength steel strands with the standard tensile strength value fpk =1860 Mpa and the nominal diameter of 15.2mm, and the technical conditions of the longitudinal prestressed tendons accord with the GB/T5223-2014 standard. The top plate suspension casting beam adopts 19 phi 15.2 steel strands, the midspan top plate beam, the midspan bottom plate beam, the side span top plate beam and the side span bottom plate beam are all 19 phi 15.2 steel strands, the nominal diameter of the steel strands is 15.2mm, the nominal sectional area is 139mm2, and the anchor, the anchor backing plate, the corrugated pipe and the like adopt matched products. And the tensioning adopts symmetrical balance tensioning of two ends of a 500T jack. The longitudinal prestressed pipeline adopts a plastic corrugated pipe, and pipeline grouting adopts a vacuum auxiliary grouting process. The vertical prestressed tendons adopt tensile strength standard values of fpk =1860 Mpa, diameter of phi 15.2 high-strength low-relaxation steel strands, under-anchor tensioning control stress of 1395Mpa, prestressed pipelines adopt high-density polyethylene plastic corrugated pipes with inner diameters of 50mm, the anchors adopt DHM15-3 anchors and DHP15-3 anchors, and 100-ton jacks are used for tensioning.

The transverse and vertical prestressed tendons are designed to be single-ended tension, the corrugated pipe, the sleeve and the prestressed tendons are simultaneously installed in place during construction, and the tension ends of the transverse prestressed cables are staggered; meanwhile, the vent holes are formed at the fixed ends of the horizontal corrugated pipeline and the vertical corrugated pipeline; the longitudinal prestressed tendons are simultaneously tensioned at two ends and tensioned at one end, in order to facilitate construction and prevent pipe blockage caused by slurry leakage of the pipeline, holes are formed in advance by pre-burying corrugated pipes or sleeves during construction, and the method of penetrating steel strands before and after tensioning is finished by concrete pouring; therefore, the prestressed reinforcement pipeline is positioned by adopting phi 12 steel bars before concrete pouring, the linear section of the longitudinal and transverse prestressed reinforcement pipeline positioning steel bar net is arranged at intervals of 50cm, the positioning steel bars and the beams Duan Zhujin are firmly spot-welded, the positioning steel bars are subjected to encryption treatment at the turning control points of the pipeline, and the space encryption is 25cm. For the vertical prestressed reinforcement sleeve, each sleeve is arranged at each of the upper, middle and lower setting positions, if the prestressed pipeline collides with the common steel bar, local adjustment is allowed, the adjustment principle is that the common steel bar is firstly adopted, then the vertical prestressed steel bar is adopted, and the transverse prestressed steel bar keeps the longitudinal prestressed pipeline motionless; if the steel bar is tensioned with prestress, the lap joint length is reserved for temporary bending after cutting, and the steel bar is reset and welded to form a whole when sealing the groove; anchoring the anchored reinforcing steel bar net by adopting phi 12; when the corrugated pipe is lengthened, the folded corners, burrs and the like of the end head are firstly treated, the corrugated pipe with the larger size is used as a sleeve, the sleeve joint length is 80cm, and the sleeve joint length is tightly wrapped by an adhesive tape, so that water seepage and slurry leakage are ensured; in order to prevent the corrugated pipe from being difficult to penetrate steel strands due to flattening, breakage and the like in the construction process, a hard plastic rubber pipe smaller than the corrugated pipe can be penetrated in the corrugated pipe during construction, and the steel strands are penetrated after the concrete is finally solidified and pulled out before tensioning; and the displacement, deformation and damage of the pipeline are prevented in the construction process. The prestress steel beam can be stretched after the concrete strength reaches 90% of the design strength and the age reaches 7 days; the longitudinal prestressed bundles should be stretched symmetrically according to the principle of length first and then length second.

The longitudinal prestressed bundles are symmetrically stretched on the transverse section, and each steel bundle is symmetrically stretched at two ends. The tensioning procedure is as follows: 0 → initial tension → holding for 2 minutes → measuring extension δ0 → tensioning to design tonnage P → holding for 2 minutes → measuring extension δ1 → top wedge fueling → measuring extension δ2. The deviation between the actually measured steel beam extension and the corrected calculated extension meets the standard requirement. Otherwise, the tensioning can be continued after the reason is found and measures are taken for processing. After tensioning is completed, the anchor head or the steel bundle is strictly forbidden to be impacted, and grouting is carried out within 24 hours. The redundant length of the steel beam is cut off by a grinding wheel cutting machine, and 3-5 cm is left during cutting.

Specifically, the grouting adopts a vacuum grouting auxiliary process, and the vacuum pump can reach a negative pressure of 0.1 MPa. The pore canal is vacuumized before grouting, and the vacuum degree is preferably stabilized within the range of-0.06 to-0.1 MPa. Grouting the pair of prestressed pipelines within 24 hours after the prestress tensioning. High-pressure water is used for removing impurities in the pipeline before grouting, the water-cement ratio is 0.29-0.35, the mark is not less than M55, and chlorine salt doping is not allowed. The performance of the post Zhang Kongdao grouting equipment is in accordance with the rotating speed of the stirrer not lower than 1000r/min, the shape of the stirring blade is matched with the rotating speed, the linear speed of the blade is not less than 10m/s, the highest linear speed is not less than 20m/s, and the requirement of uniform stirring in a specified time can be met. The pulp storage tank should be provided with a filter screen with a mesh size not more than 3 mm. The grouting machine adopts a piston type grouting pump capable of continuously operating. The minimum dividing value of the pressure gauge should not be larger than 0.1MPa, and the maximum measuring range should enable the actual working pressure to be within the measuring range of 25% -75%. The air pressure type grouting pump is not adopted for grouting. In the grouting process and 48 hours after grouting, the temperature of the concrete member and the environment is not lower than 5 ℃, otherwise, heat preservation measures are adopted, the concrete member and the environment are treated according to the requirements of winter construction, air entraining agents can be properly mixed into the slurry, and grouting is preferably carried out at night when the environment temperature is higher than 35 ℃. The anchor groove is subjected to roughening treatment before the anchor is sealed, and the steel bars welded on the anchor plate are bound with the anchor sealing steel bars together so as to ensure that the concrete at the anchor sealing end and the concrete of the beam body are connected into a whole, the anchor groove is subjected to waterproof treatment after the anchor is sealed, and the outer side of the anchor groove is coated with waterproof materials.

S7: and (3) dismantling the bracket, wherein the dismantling sequence is as follows: guardrail, scaffold board, scissors support, horizontal rod in longitudinal and transverse directions and vertical rod. The dismantling process should follow the principle of first supporting and then dismantling, then supporting and first dismantling, and the dismantling of the vertical face is not accurate or the dismantling of the frame is carried out in two steps up and down, so that one step and one clearing and one rod and one clearing are realized. The dismantling must be carried out from the midspan symmetry to both sides, preferably in two stages, the first jacking is loosened from the midspan symmetry to both sides, the bottom plate, the web plate and the flange plate are separated from the beam body, and then the brackets are dismantled from the midspan symmetry to both sides. When the flange plate is dismounted, the flange plate is dismounted and then the bottom plate is dismounted; when the scissors support is dismounted, the middle fastener is dismounted firstly, then the middle is supported, and then the end fastener is dismounted; when the vertical rod is detached, the vertical rod is held firstly, and then the last bowl mouth of the connecting cross rod is detached, so that the vertical rod is prevented from falling.

S8: turning the bridge as shown in fig. 3;

s9: dismantling the swivel device, and connecting the bridge with the permanent support;

s10: and (3) constructing the side span folding section, and folding the side span firstly and then folding the middle span according to design requirements. And the construction of the closure section concrete is carried out at the time with the lowest temperature in one day. The concrete adopts C55. The concrete should be strengthened and maintained, and the range of 1m of folding section and two cantilever ends is covered, reduces sunlight temperature difference influence.

The side span closure section is constructed by adopting a full framing method according to design requirements and field practical conditions, the full framing is erected and simultaneously erected with the side span cast-in-situ section frame to form a whole, and the bottom die and the side die are constructed by adopting a wood die. The middle span closure section utilizes a truss to install a bottom die system on the bank, utilizes a chain block to hoist, a bridge deck lays a track and moves in place, and utilizes finish rolling deformed bars to anchor front and rear lower cross beams on a bottom plate and then install side dies, wherein the bottom dies adopt steel dies, and the side dies adopt wood dies. After the side mold and the bottom mold of the folding section are in place, binding the bottom plate and the web steel bars, installing the corrugated pipe and the steel passing beam, and binding the top plate steel bars, installing the corrugated pipe and the steel passing beam by the inner mold in place. And pouring the concrete of the closure section by adopting a balance weight method, removing the counterweight on the top surface of the suspension pouring section while pouring, and unloading the counterweight along with the pouring of the concrete by adopting a water tank weight method. And the weight value of the balance weight is determined according to the monitoring and calculating results of the third-party monitoring unit, and the weight value is provided by the third-party monitoring unit.

S11: the middle span closure section is constructed, and because the lower part of the middle span closure section of the bridge is a south-to-north bridge, the construction is performed by adopting a special middle span closure construction process and a hanger structure thereof, and the bridge is protected by adopting a fully-closed mode under a movable hanger. The anti-leakage unit 21 is arranged at the bottom of the hanging frame, so that the installation of the middle span closure section steel bars and templates and the pouring of concrete are ensured on the canal, the safety of personnel is ensured, and falling objects are prevented from falling during the movement and construction of the hanging frame.

Based on the above embodiment, the specific steps of S1 are as follows:

s1.1: as shown in fig. 2 and 3, the spherical hinge lower embedded plate 11 and the support lower embedded plate 12 are hoisted to the pier body bolster; the lower embedded plate 11 of the spherical hinge and the lower embedded plate 12 of the support are hung on the pier body backing stone by using a crane, so that an anchor rod of the lower embedded plate is inserted into a reserved hole, the central position, the elevation and the levelness of the lower embedded plate are adjusted, the control central position and the design deviation are not more than +/-1 mm in the forward bridge direction and the transverse bridge direction, the control elevation and the design deviation are not more than 5mm, and the overall levelness is not more than 2mm.

S1.2: the first templates are arranged around the spherical hinge and the support, and gaps among the spherical hinge lower embedded plate 11, the support lower embedded plate 12 and the abutment are grouted; the grouting adopts high-quality high-strength non-shrinkage support grouting material, and the strength is not lower than C50. The stirring adopts a handheld high-speed stirrer to stir, so that stirring uniformity is ensured, flowability is good, and grouting is performed after stirring is qualified. In order to ensure that grouting is compact, grouting materials are poured from one side, the other side overflows, and after grouting is finished, the elevation of a grouting surface is 1-2cm higher than the bottom of the embedded steel plate.

S1.3: hoisting the spherical hinge and embedding a plate on the spherical hinge; the spherical hinge is of an integral structure, is integrally hoisted, and is directly arranged on the embedded plate below the spherical hinge through the anchor bolt hole; and hoisting an upper embedded plate of the spherical hinge, and installing the upper embedded plate on the upper spherical hinge through an upper spherical hinge anchor rod hole.

S1.4: hoisting a slide way of the anti-overturning system, grouting and reinforcing, and welding a stainless steel plate on the top surface of the slide way; and hoisting the slideway, and inserting an anchor rod of the slideway into the reserved hole. The central position, the elevation and the overall levelness of the slideway are adjusted, the deviation between the central position and the design value of the slideway is controlled within 5mm, the elevation error of the slideway is controlled within 2mm, and the overall levelness of the top surface of the slideway is controlled to be not more than 2mm; installing a template, and grouting in a reserved notch and a hole of the slideway; and welding a stainless steel plate on the top surface of the slideway by using a discontinuous welding method, and controlling the deviation value between the center of the stainless steel plate and the design to be not more than 5mm.

S1.5: hoisting supporting feet, a sand box, a steel casing, and installing an anchor and a steel stranded wire; and hoisting the supporting feet to a design position, and padding wedge blocks on the bottom surfaces of the supporting feet, wherein the deviation of the position degree of the supporting feet is controlled to be not more than 10mm, and the gap between the bottom surfaces of the supporting feet and the surfaces of the stainless steel plates is 20mm. After the supporting feet are installed in place, foam rubber is used for protecting and sealing the gap between the supporting feet and the stainless steel plate at the periphery of the walking plate; pouring concrete into the supporting leg supporting cylinder; hoisting the sand box to a design position; hoisting a steel pile casing, installing the steel pile casing to a designated position, and welding the steel pile casing and the supporting leg top plate by adopting intermittent welding seams; and setting up a temporary support in the appointed steel casing, and installing an anchor and a steel strand. After the steel strand is installed, the position of the steel tapping pile casing is sealed by using a steel plate or other tools, the installation needs to pay attention to a counter-force pier threading hole, a P anchor end and a steel pile casing outlet, the three points are horizontal, after the agreement of an on-site supervision engineer is solicited, the size of a counter-force pier notch can be properly increased, and the horizontal traction of a spherical hinge during rotation is ensured; and pouring concrete into the steel casing.

S1.6: hoisting an embedded plate on the anti-overturning system; and hoisting an upper embedded plate of the anti-overturning system to a designed position, and welding the upper embedded plate and the steel casing by adopting a discontinuous welding seam after the upper embedded plate is in place.

S1.7: and (5) installing a permanent support and embedding a steel plate on the support. After the support is pre-pressed, the permanent support is installed clockwise, the pre-buried steel plate on the support is welded, the gap between the top surface of the pre-buried plate under the support and the bottom surface of the support plate is controlled to be 30mm, the plane position is the reverse direction of the swivel, and the coordinate is required to be installed after checking.

On the basis of the embodiment, the secondary treatment of the foundation comprises layered backfilling treatment of the bearing platform foundation pit. Firstly, carrying out layered backfill treatment on a bearing platform foundation pit, cleaning the original earth surface, compacting, wherein the compactness index requirement reaches 93%, and the bearing capacity requirement reaches 200Kpa after foundation treatment. According to geological survey data, the support foundation soil layer is the heavy powder loam, the basic allowable value of foundation bearing capacity is 160kpa, and the foundation bearing capacity is low, so that the support foundation soil layer needs to be replaced. The section support area is 9m wide, the isolation belt is 1m wide, the outer side of the isolation belt is provided with a hoisting area with the width of 10m, 50cm broken stone is adopted for treatment, each side in the width direction is larger than 1.5m of the bridge width, and the bridge width is compacted by layering through an Xs261 type vibratory roller; and then a concrete pump truck is used for pouring a C30 concrete cushion layer with the thickness of 30cm, so that the overall uniformity is ensured. If soft foundation is met, broken stone can be used for filling, the filling thickness is 0.5-1m, and concrete data are confirmed by a construction unit, a supervision unit and a construction unit on site according to actual conditions on site. The surface of the cushion layer is provided with 1% of bidirectional transverse slopes to facilitate drainage, concrete drainage ditches are respectively arranged along the bridge at two sides, the structural size is 30 x 30cm, the wall thickness is 15cm, construction is performed simultaneously when the cushion layer is poured, water in the drainage ditches is prevented from penetrating into the foundation, and smooth drainage is ensured.

In accordance with the above embodiment, the water drainage system includes a drain and a sump disposed near the base. Building a drain ditch with the length of 30cm multiplied by 30cm at the position of the base close to the slope toe of the support, and building a water collecting pit every 20 m. And draining rainwater in the water collection pit into a flood discharge ditch at the main ditch of the south-to-north water conditioner by using water pumping equipment, and strictly preventing the drained water from flowing back into the water collection pit. The drainage system of the site should be checked before construction in the rainy period to ensure smooth water flow.

Based on the above embodiment, the specific steps of S8 are as follows:

s8.1: weighing experiments are carried out on the rotating bridge; the rotating process of the bridge is complex, the technical difficulty is high, and the precision requirement is high, so that the method is a key step of bridge construction. Although the principle of the bridge turning technology is the same and the turning technology is mature, for different bridges, reasonable and feasible turning schemes must be made according to the characteristics of the structural form, the construction process, the site, the environmental conditions and the like so as to ensure the stability and the strength requirement of the structure and avoid influencing the normal stress state of the structure due to turning. The ideal rotating system must have two basic conditions of easy rotation and safe and stable. The key component of the swivel construction is a rotating spherical hinge for bearing the weight of the whole swivel, and the friction coefficient of the rotating spherical hinge directly influences the traction torque required by the swivel; in the vertical plane along the beam axis, the swivel bridge may cause different mass distribution and different rigidity of cantilever beam sections at two sides of the bridge pier due to manufacturing and installation errors of the spherical hinge system, differences in beam body mass distribution and differences in prestress tensioning degree, so that unbalanced moment is generated. The problem of unbalanced moment caused by eccentricity must be solved before the rotator, and the rotator needs to work under the self-balancing or counterweight balance after the temporary consolidation and disassembly of the rotating system and during the rotator by the weighing counterweight. The main instrument and equipment table for weighing experiments is shown in table 3:

TABLE 3 Main instruments and gauges

Sequence number

Instrument and device name

Test accuracy

Model specification

Quantity of

Production area

Use of the same

1

Jack (Jack)

200t

2

China

Jacking girder

2

Displacement sensor

0.01mm

Measuring range of 50mm

6

China

Displacement testing

3

Displacement acquisition system

0.01mm

JMZX-3001L

1

China

Displacement data acquisition

4

Pressure sensor

1kN, measuring range 10000kN

JMZX-3360AT

4

China

Weighing test

5

Intelligent comprehensive pressure tester

1KN

JMZX-3006L

4

China

Strain testing

6

Strain gauge

1με

JMZX-3001L

1

China

Strain testing

7

Dial gauge

0.01mm

Measuring range of 50mm

6

China

Displacement testing

8

Notebook computer

--

Association with each other

1

China

Data processing

9

Interphone

6

China

Communication system

S8.2: balancing weights are adopted for balancing; in order to ensure the safety and smooth proceeding of the bridge swivel, a basis is provided for the command and decision of the bridge swivel stage in time, a rotating body weighing test is carried out before the swivel, unbalanced moment, eccentricity, friction moment and static friction coefficient of the rotating body are tested, and reasonable counterweight is carried out according to the technical requirement of the bridge swivel. The counter weight adopts 2X 1 cubic meter standard concrete block, carries out size and weight check to the counter weight before the counter weight, and counter weight position and counter weight are strictly carried out according to weighing test's requirement, and the counter weight is fixed to the counter weight according to the scene actual conditions after the counter weight is bridged.

S8.3: installing swivel construction equipment; the swivel construction equipment comprises 2 swivel control consoles, 2 sets of hydraulic pump stations and 2 ZLD200 continuous pushing jacks, and the swivel control consoles are connected with cables through high-pressure oil pipes to form 2 sets of ZLD swivel traction systems. In addition, 4 YD200-250 boosting jacks are provided as boosting equipment in starting. The rotators on two sides are respectively and independently formed into a set of traction system.

In each set of traction system, 2 ZLD200 continuous pushing jacks are respectively arranged on the counter-force seats on two sides of the turntable horizontally, parallelly and symmetrically, the center line of each jack is coaxial with the axial direction led out by the steel strand of the upper turntable in a tangent way, and the distances from 2 jacks to the upper turntable are equal. The jack is welded on the matched counter-force seat, the slot position and the height of the traction counter-force seat are accurately lofted, and the jack is accurately positioned.

S8.4: testing a swivel device; the hydraulic and electrical equipment in the swivel device should be tested before leaving the factory; after the equipment enters the field, connecting signal wires among the control console, the pump station and the jack, connecting an oil way between the pump station and the jack, connecting power supplies of the control console and the pump station, installing and debugging, and checking whether the equipment operates normally; and (3) carrying out no-load test operation on the equipment, reversely calculating the oil pressure value of each pump station according to the force application value of the jack, adjusting the maximum allowable oil pressure of the pump station according to the oil pressure value, carrying out no-load test operation, and checking whether the equipment is normal.

S8.5: cleaning and pre-tightening a traction rope; the embedded traction rope is cleaned with rust and greasy dirt on the surface of the steel strand, is wound along a given cableway one by one in sequence, and then continuously pushes the jack through ZLD 100; the steel strand of the traction cable cannot be crossed or twisted when being threaded; pretensioning the steel strands one by one with a force of 5-10 KN; the pre-tightening should be performed symmetrically and repeated several times to ensure the even stress of each steel strand. During the pre-tightening process, the steel stranded wires are ensured to be wound on the upper turntable in parallel; scales are marked on the upper turntable, and scale pointers are buried on the lower turntable for monitoring the rotating distance.

S8.6: testing; before turning, the key stress parts of the turning structure should be comprehensively checked for deformation, cracking and other abnormal conditions, if the key stress parts are abnormal, the reasons should be found out, and corresponding measures should be taken to correct the key stress parts and then the key stress parts can be turned on trial; checking whether barriers for blocking the rotator exist on and around the slideway, and determining that the rear part of the barriers for blocking the rotator can be rotated in a trial mode; starting the swivel device, and controlling 2 continuous pushing jacks by using a control console while applying force to test rotation. If the bridge can not rotate, 2 boosting jacks prepared in advance are applied to simultaneously exert force so as to overcome the friction resistance and enable the bridge to rotate.

S8.7: and formally turning and synchronously monitoring and setting guarantee measures. In order to ensure stable and safe turning process, the bridge turning is controlled in the turning process, such as turning weight, turning speed, turning angle, turning time, power reserve coefficient and steel strand safety coefficient; and after the trial rotation is finished, analyzing all the collected data, correcting the rotation scheme and performing formal rotation. And collecting data in the swivel process, wherein a set of strict monitoring system is adopted, and commander coordinates and commands through data information reflected by the monitoring system. The project department establishes a turning construction leader group, personnel division is needed before the turning structure rotates, field personnel are carefully deployed according to each key part and construction links, the personnel division cooperates, and the personnel division is uniformly arranged by a field general command. The wind speed is not more than 6 stages when rotating. The front circle of the rotator is communicated with the meteorological part in time, so that the rotator is ensured not to be operated in heavy rain and strong wind weather. When the beam is turned, 1 anemometer is respectively arranged on two sides of the T-shaped beam of the field turning body, a special person measures wind power, and an interphone is used for reporting wind speed values to the field turning body command.

Specifically, a series of safeguards are also required for the swivel:

1. and an anti-over rotation limiting device is arranged in front of the rotator. Once the overrun happens, the anti-overrun device is used for pushing the supporting feet in the direction so as to enable the bridge to be in place;

2. an anti-eccentric measure is arranged, the weight is balanced according to the procedures of structural theory weight balancing, weighing and weight balancing before trial rotation, and the T-shaped structure after weight balancing can be allowed to deviate from the center of the spherical hinge by 3 cm-5 cm along the bridge to the center of gravity;

3. setting a rotation preventing limiting measure, and before rotation, finishing dismantling the bracket and the sand box, finishing temporarily solidifying and dismantling the wedge blocks at the supporting feet;

4. the whole process of the swivel is monitored, the manual monitoring and the automatic monitoring are respectively carried out, mutual verification of the manual monitoring and the automatic monitoring is carried out, the conditions of swivel speed, external wind load and the like in the swivel process are ensured to meet the design requirements, and the safety of the bridge swivel is ensured. The observer notices the rotation condition of the bridge deck at any moment, reports to the command length once every 1m of rotation of the beam end, and reports to the command length once every 2cm of rotation within 300cm of the end point; and (3) ending the continuous working state of the jack within 100cm, positioning in a 'inching' mode, and controlling the center line within the design requirement range after positioning the rotator. The manual monitoring comprises the steps of using a total station, placing a bridge longitudinal axis on a bearing platform and a steel pile casing by using the total station, pasting a turning angle mark on the steel pile casing, installing a pointer on the bearing platform, and monitoring the turning angle according to the mark angle; and discharging the longitudinal axis of the box girder at the top end part of the box girder by using a total station in advance, pasting an axis scale, calculating the difference value between the longitudinal axis of the box girder and the longitudinal axis of an actual bridge by measuring in the turning process, and providing accurate data for fine adjustment. The manual monitoring also comprises using a level gauge, making elevation observation sections at 2 ends of the cantilever and the pier top, making 3 elevation observation points for each section, monitoring the whole rotation process, wherein 2 tower scales are respectively placed by taking four corners of a beam body as main control points, and observing by using 2 level gauges. The automatic monitoring is to use a BIM informatization system, combine equipment such as automatic total powerstation, sensors, anemometers and the like, establish a real bridge swivel system model, monitor parameters such as wind load, rotation angle of a bridge, swivel speed of the bridge, stress at a spherical hinge, beam end vibration and the like in the swivel process in real time, give out an alarm in time when a problem occurs, and protect the swivel operation.

On the basis of the embodiment, the test content of the weighing experiment comprises the steps of calculating the unbalanced moment of the longitudinal bridge of the rotating body part, calculating the longitudinal bridge eccentric distance of the rotating body part, calculating the friction moment and the static friction coefficient of the spherical hinge of the rotating body, and designing the counterweight scheme of the rotating body beam. The rotating process of the bridge is complex, the technical difficulty is high, and the precision requirement is high, so that the method is a key step of bridge construction. Although the principle of the bridge turning technology is the same and the turning technology is mature, for different bridges, reasonable and feasible turning schemes must be made according to the characteristics of the structural form, the construction process, the site, the environmental conditions and the like so as to ensure the stability and the strength requirement of the structure and avoid influencing the normal stress state of the structure due to turning.

Specifically, the weighing test principle is as follows:

the weighing test assumes that the beam body can rotate around the spherical hinge in a rigid body, and the tangential rotational displacement of the spherical hinge is tested by applying a rotational moment to the beam body to obtain a relation curve between the beam body and the spherical hinge, wherein when the displacement is suddenly changed, the corresponding state is a critical state of static friction and dynamic friction. Because the rotation moment and the vertical top force have a fixed proportional relation between the tangential rotation displacement and the vertical displacement, a top force-displacement curve can be directly drawn, and a critical point can be found out.

Based on the above embodiment, the specific steps of S9 are as follows:

s9.1: removing a portion of the temple, as shown in fig. 12;

s9.2: mounting a jacking jack at the position of the dismantled supporting leg, as shown in fig. 13;

s9.3: jacking the bridge, wherein the jacking height is 20mm, and self-locking the jack after the jacking is completed;

s9.4: sequentially removing the spherical hinge support and the rest supporting feet;

s9.5: opening the jack self-locking device, and allowing the bridge to fall back onto the permanent support;

s9.6: and (3) welding and fixing the upper support plate and the upper embedded plate of the permanent support, and dismantling the jack and the steel casing to finish system conversion.

Based on the above embodiment, the specific steps of S10 are as follows:

s10.1: setting up a third bracket and a third mounting template at the folding section of the side span, and pre-pressing a third bottom template in the third bracket and the third template; the construction of the side span closure section bracket is carried out by adopting the same parameters as those of the side span cast-in-situ section and simultaneously carrying out erection, the box Liang Ligan is made of Q345-level steel, the outer diameter is 48.3mm, the wall thickness is 3.2mm, the longitudinal distance is 90cm, the transverse distance is 60cm, and the transverse rod step distance is 150cm. The transverse distance of the upright posts at the bottom of the wing plate is 60cm, the longitudinal distance is consistent with the bottom plate, and the step distance of the cross rod is 150cm. And the step distance at the top of the vertical rod is reduced by 50cm by adjusting the step distance of the cross rod, so that the free length of the jacking is ensured not to be more than 650cm, and the length of the jacking inserted into the vertical rod is not less than 150mm. The top support upper transverse bridge is provided with double rows of I12.6I-steel as a main ridge, the longitudinal bridge is provided with square timber with the length of 10cm multiplied by 10cm as a longitudinal beam, the distance is 20cm, the web plate is provided with I10I-steel with the distance of 15cm, and the template is a bamboo plywood with the thickness of 15 mm. The periphery of the full framing is protected by steel pipes. The guard rail is 1.2 m high, a cross rod is respectively fixed at 0.6 m and 1.2 m, and the guard rail is firmly and orderly installed by using a fastener; the periphery of the guardrail is sealed by a dense mesh net which is arranged at the inner side of the guardrail and is firmly bound with the guardrail; the steel pipe is painted with red and white warning color and is suspended with safety warning board.

I12.6I-beams are transversely paved on the support jacking along the bridge, square timber with the length of 10cm multiplied by 10cm is longitudinally paved on the I12.6I-beams along the bridge, the spacing is 20cm, the spacing between the I10I-beams is 15cm, and bamboo plywood with the thickness of 15mm is paved on the longitudinal square timber.

Before the bottom die is installed, the bottom plate edge line of the box girder is discharged by the total station, and the two end point stay wires determine the installation edge line of the bottom die. When in installation, the bottom die is placed on the longitudinal square timber, the joint of the transverse plate and the plate is required to be on the same square timber, and the joint is filled with sealant if gaps exist. The line width of two sides of the bottom die is 5 cm-10 cm larger than that of the side of the bottom plate of the box girder so as to fix the side die, and carrying out elevation retest after the installation is completed, and then installing the side die after retest is free.

After the bottom die is installed, the support can be pre-pressed, the pre-pressing weight is 1.1 times of the structural dead weight and the weight of the template, and the pre-pressing weight of the side span cast-in-situ section of the main bridge is 40.92T. When loading longitudinally, carrying out cloth loading from the middle to two ends; when transversely loaded, the symmetrical load distribution is carried out from the central line of the structure to two sides. The preloading process of the loading support is preferably carried out in 3 stages, and the loads applied by the side span cast-in-situ section of the main bridge in sequence are 60% (24.55T), 80% (32.74T) and 100% (40.92T) of the pre-load value in the unit.

After each stage of loading is completed, monitoring the settlement of the bracket at intervals of 12 h; when the average value of the continuous 2 times sedimentation differences of the stent measuring points is smaller than 2mm, the method can continue loading. After loading of each stage, the support is comprehensively checked, problems are found in time, and hidden danger is eliminated. If the phenomena of obvious foundation settlement, foundation cracking, local position and excessive bracket deformation are found in the observation process, the loading and unloading should be stopped immediately, the reasons are searched in time, and remedial measures are taken. And when the pre-compaction reaches the required weight, starting to enter a sedimentation observation period until the observation data meets the requirement and unloading the sediment. Unloading after the support prepressing meets the requirements: the unloading adopts one-time unloading, and the unloading is symmetrical, balanced and synchronous on two sides of the bracket.

The support pre-compaction monitoring includes the following:

(1) Monitoring point elevation before loading;

(2) Monitoring point elevation after each stage of loading;

(3) Monitoring point elevation at intervals of 24 hours after loading to 110%;

(4) Carrying out unloading for 6 hours, and then monitoring elevation of the point;

(5) The precompression monitoring should calculate settlement, elastic deformation and inelastic deformation.

In the support pre-pressing process after all loads are loaded, the support pre-pressing is qualified when one of the following conditions is met: firstly, the average value of the settlement amount of each monitoring point for 24 hours is smaller than 1mm; and secondly, the average value of the settlement amount of each monitoring point for 72 hours is smaller than 5mm.

The outer side mould adopts a 15mm thick bamboo plywood, and steel pipes are used on the wing plate brackets and inserted into jacking supports to be used as supports during reinforcement, wherein the support spacing is the same as the longitudinal spacing of the vertical rods of the full framing. The side mold stiffening ribs are arranged by using 10cm multiplied by 10cm wood Fang Shuxiang, and the spacing is 20cm. The upper surface of the bracket upper support is provided with a through length transverse double-row phi 48.3 common steel pipe. In order to prevent the lateral mold from expanding due to the outward inclination of the wing plate support during concrete pouring, the upright rod of each outermost wing plate support is obliquely and fixedly arranged on the lower support of the bottom plate by 8m steel pipes.

The internal mold 5 can be installed after binding the bottom plate and the web steel bars and checking to be qualified. As shown in FIG. 15, the side wall, chamfer and top plate of the inner mold 5 are made of 15mm thick bamboo plywood, and are made of 10cm×10cm square timber arranged at intervals of 40cm as back ribs, and are processed together with the template. The steel pipe frame is a fastener type steel pipe frame supported by an inner mold 5, vertical rods 6 are spaced at 90cm multiplied by 90cm, horizontal rods are spaced at 150cm, the bottoms of the vertical rods 6 are directly supported on a bottom plate, jacking height adjustment is arranged on the tops of the vertical rods 6, I12.6I-shaped steel is arranged on the upper parts of the jacking, and square timber of 10cm multiplied by 10cm is paved on the tops of the I-shaped steel at 40cm intervals. The template joint adopts double-sided adhesive tape joint, and the position that the template meets with the web adopts foam rubber plug joint.

S10.2: binding reinforcing steel bars of the side span closure section, and installing a prestressed pipeline; the steel bars are processed in a steel bar processing field strictly according to the shape and the size shown in the design drawing, and are directly bound and formed on the bottom die. The steel bar connection adopts straight thread connection, the steel bar framework has enough strength, rigidity and stability, and the structural size, the number of steel bars, the specification, the spacing and the like of each part of the steel bar framework meet the design and specification requirements. The prestressed beam and the pipeline are installed with the same 1# beam section. The corrugated pipe is penetrated into the plastic pipe to ensure the smoothness of the bottom plate bundle pipe after the concrete of the folding section is poured.

S10.3: loading a counterweight; the two T-shaped cantilever ends are provided with the balance weights by adopting a water tank weight method, and the balance weights are loaded simultaneously, so that the balance increase of the balance weights is ensured.

S10.4: pouring the side span closure section and simultaneously unloading the counterweight according to the concrete pouring speed; before the expected folding, the cantilever end is observed for 48 hours continuously, the temperature and the elevation change of the folding section are observed, the length of the folding section is changed, the body temperature is changed, and the optimal folding time is determined according to the recent air temperature and elevation change rule. Gradually removing the counterweight along with concrete pouring.

The mixing ratio of the concrete at the folding section is C55, the casting of the concrete at the folding section is carried out when the air temperature is low in one day, the casting is generally carried out at night, the initial setting is completed in the early morning, the newly cast concrete at the folding section can be ensured to be in an environment with the rising air temperature, and the final setting is achieved in a pressed state, so that the concrete is prevented from cracking. And (5) equivalently unloading the balance weight during concrete pouring. Other matters during concrete pouring are the same as those of the box girder cantilever pouring beam section construction. The concrete should be strengthened and maintained, and the range of 1m of folding section and two cantilever ends is covered, reduces sunlight temperature difference influence. And when the strength of the concrete reaches 75% of the design strength, the inner mold is removed.

S10.5: curing the concrete;

s10.6: and (3) prestress tensioning of the side span closure section, grouting of a pore canal, and dismantling of a bracket III, wherein prestress tensioning can be performed after the concrete strength of the closure section reaches 90% of a design value, and grouting of the pipeline is completed within 48 hours after tensioning is completed. The concrete prestress construction process flow is the same as other beam sections. And after the tensioning is completed, the temporary locking and temporary support are removed. Firstly, the support jacking is lowered, the bottom die and the side dies are separated from contact with the beam body, the bottom die and the side dies are removed, and finally the support is removed layer by layer.

On the basis of the above embodiment, the specific steps of S11 are as follows:

s11.1: as shown in fig. 6 and 7, the hanger 2 provided with the leakage preventing unit 21 is moved from the shore to the bridge closure in the midspan; specifically, the hanger comprises a truss system, a suspension system, a protection system and a traveling system. The truss system is connected through jib and chain block by last truss, lower truss, goes up the truss and places on the steel bolster, and lower truss is connected through finish rolling screw thread steel under and is protected the platform, adopts angle steel and bamboo glued board to form the side protection in gallows both sides. The upper and lower cross beams are made of double-spliced 28a I-steel, the length of a single beam is 7m, and the two ends of the beam are overhanging for 0.5m. And the position 0.5m away from the cross section of the No. 1 beam end is provided with a corresponding penetrating hanging hole on the top plate of the bottom plate, and the upper beam is welded with a limiting bracket up and down to prevent the hanging bracket from sliding and overturning left and right. The midspan closure section is cast in situ by a hanging bracket method. The hanging bracket is installed on the north-south water shore, slides to the midspan and locks the device after accurate measurement. And a hanging bracket and an anti-falling closed platform are arranged at the position of the 10m midspan side of the P1 pier, a bottom die system and a protection system are integrally hung by adopting a chain block, the bottom die system and the protection system are temporarily fixed under an upper cross beam, and the hanging bracket is integrally lifted at the position 1m away from the bottom of the bottom plate. After the installation, the platform is wholly displaced to a midspan folding position by adopting a 5t forklift to carry out supervision and business owner test, and the height of the cross beam from the bridge deck should be ensured not to exceed 30cm in the moving process, so that the platform is specially commanded by a person.

S11.2: installing a reinforcing steel bar, a template and a prestressed reinforcement, loading a counterweight and closing and locking a midspan; after moving to the folding position, the upper cross beam is anchored by a ground anchor, the whole lower truss is lifted to the beam bottom through a chain block and is temporarily locked, and the suspender screw is screwed down. The worker enters the hanging bracket, positions the side die and pulls the side die firmly. The bottom plate is arranged on the pull rod. According to the design drawing, steel plates 31 are embedded in the upper part of the bottom plate chamfer and the top plate of the two adjacent beam sections in the folding section, as shown in fig. 17. The "locking" of the closure follows the principle of pulling back again, i.e. "locking" consists of welding a stiff skeleton or pulling a temporary pre-stressing mass. The folding and locking adopts a stiff steel framework. The supporting stiffness steel skeleton adopts a three-section structure of a pre-buried steel plate, connecting channel steel and a pre-buried steel plate. If the folding section supporting embedded part collides with the common steel bars of the box girder, the common steel bars of the box girder can be slightly moved, connecting channel steel is arranged between the two embedded steel parts, the connecting channel steel and the embedded steel plates are welded into a whole, and the height of a welding seam is not less than 8mm. The pre-buried steel plate and the connecting channel steel are in locking welding and are ensured to be symmetrical and simultaneously carried out so as to prevent temperature difference stress between the connecting pieces.

S11.3: pouring concrete on the mid-span closure section;

S11.4: curing the concrete;

s11.5: prestress tensioning of side span closure sections and grouting of pore canals;

s11.6: the spreader 2 is moved to shore and removed.

On the basis of the above embodiment, as shown in fig. 9, the hanger 2 includes a leakage preventing unit 21 disposed below the cast-in-situ bridge, as shown in fig. 8, the size of the leakage preventing unit 21 along the cross section of the cast-in-situ bridge is larger than that of the cross section of the cast-in-situ bridge, and the construction of S11 is operated in the leakage preventing unit 21. Because the lower part of the middle span closure section of the bridge is south-to-north transferred, a special middle span closure construction process and a hanger structure thereof are required to be adopted for construction, a leakage-proof unit is arranged under the movable hanger for protection, the installation of the steel bars and the templates of the middle span closure section and the pouring of concrete are ensured to be completed on the canal by the whole hanger, the safety of personnel is ensured, and falling objects during the hanger movement and construction are prevented. The leakage prevention unit 21 is obliquely arranged, and a water collecting device for collecting wastewater is arranged below the leakage prevention unit 21. The leakage preventing unit 21 has an angle in one direction, so that water leaked from maintenance can flow to one side better and can be directly collected in the water collecting device.

Folding is a key procedure for controlling the stress condition and the line shape of the structure, so that the folding sequence, the folding temperature and the process are strictly controlled. The elevation is checked before closure, and the form of the closure section temporarily connected with the stiffness framework can be confirmed by a construction unit according to specific conditions and then by a design unit. Before formal construction, the temperature change in one day is observed, a period with lower temperature and relatively stability is selected, and after the stiff framework between the folding sections is welded, concrete is poured once. The whole process is completed in a short time as much as possible, the weight of the water tank can be adopted before the stiff framework is welded, the concrete is unloaded in an equivalent way at the same time, and the steel bundles are pulled after the concrete is poured and meets the design requirement. When the bridge is closed, all temporary construction loads arranged on the bridge deck should meet the requirements of construction control, and after the bridge is closed, the pier beam temporary consolidation device should be removed as soon as possible within a specified time, so that system conversion and support counter force adjustment are completed in time. And simultaneously dismantling the counterforce piers, the heightening platform, the steel pile casings and other rotating auxiliary facilities, crushing the concrete structure after being cut by adopting a rope saw, transporting the crushed concrete structure to a designated stacking place, and dismantling the steel pile casings after the welding seams are cut by adopting gas cutting.

The construction method performs prefabrication on the bridge beside the channel, and then turns the bridge section to the upper part of the channel by adopting the turning device, thereby effectively preventing concrete from falling into the channel when the bridge is poured, protecting the ecological environment of the south-to-north water quality, river levees and coasts, reducing the influence of construction on the south-to-north water quality of the south-to-north water engineering and ensuring the safety of water sources; the middle span closure section is cast in situ by adopting a hanging frame method, a leakage-proof unit is arranged under the movable hanging frame for protection, so that the installation of the steel bars and the templates of the middle span closure section and the pouring of concrete are ensured to be finished on a channel of south-to-north regulation of the whole hanging frame, the safety of personnel is ensured, the concrete is prevented from falling during the movement and construction of the hanging frame, and the water source is effectively prevented from being polluted by the construction; the stability and balance stress conditions of the whole bridge swivel process are simulated, so that the construction safety is ensured; the whole engineering of the swivel is monitored and measured, the position information and the control parameters of the swivel are displayed in real time, data reference is provided for swivel commanders, and the success of the swivel is improved.

The present invention is not limited to the conventional technical means known to those skilled in the art.

The foregoing has shown and described the basic principles, main features and advantages of the present invention. The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.

Claims (10)

1. A construction method of a cast-in-situ beam of a cross-south-water north-adjustment main channel pipeline bridge is characterized by comprising the following steps: the method comprises the following steps:

s1: treating the foundation, and installing a swivel device (1) at a prescribed position;

s2: secondarily treating the foundation and arranging a water-proof and drainage system;

s3: erecting a bracket (3) for supporting a cast-in-situ bridge on the swivel device (1) and pre-pressing the bracket (3);

s4: erecting a second template for the cast-in-situ bridge on the bracket (3), and binding reinforcing steel bars in the second template;

s5: pouring and taking crack prevention measures;

s6: after the concrete strength reaches the standard, removing the second template, and carrying out maintenance, prestress tensioning and pore canal grouting on the formed bridge;

s7: -dismantling the support (3);

s8: a bridge swivel;

s9: dismantling the swivel device (1), wherein the bridge is connected with a permanent support;

s10: constructing a side span closure section;

s11: and constructing the middle span closure section.

2. The construction method of the cast-in-situ beam of the canal pipe bridge crossing the south-to-north water diversion, as set forth in claim 1, is characterized in that: the specific steps of S1 are as follows:

s1.1: hoisting the spherical hinge lower embedded plate (11) and the support lower embedded plate (12) to the abutment;

s1.2: the first templates are arranged around the spherical hinge and the support, and gaps among the spherical hinge lower embedded plate (11), the support lower embedded plate (12) and the abutment are grouted;

S1.3: hoisting the spherical hinge and embedding a plate on the spherical hinge;

s1.4: hoisting a slide way of the anti-overturning system, grouting and reinforcing, and welding a stainless steel plate on the top surface of the slide way;

s1.5: hoisting supporting feet, a sand box, a steel casing, and installing an anchor and a steel stranded wire;

s1.6: hoisting an embedded plate on the anti-overturning system;

s1.7: and (5) installing a permanent support and embedding a steel plate on the support.

3. The construction method of the cast-in-situ beam of the canal pipe bridge crossing the south-to-north water diversion, as set forth in claim 1, is characterized in that: the first template comprises an inner mold (5), and a plurality of supporting vertical rods (6) are arranged on the inner side of the inner mold (5).

4. The construction method of the cast-in-situ beam of the canal pipe bridge crossing the south-to-north water diversion, as set forth in claim 1, is characterized in that: the specific steps of S8 are as follows:

s8.1: weighing experiments are carried out on the rotating bridge;

s8.2: balancing weights are adopted for balancing;

s8.3: installing swivel construction equipment;

s8.4: testing a swivel device;

s8.5: cleaning and pre-tightening a traction rope;

s8.6: performing bridge trial rotation;

s8.7: and formally turning the bridge, synchronously monitoring and setting guarantee measures.

5. The construction method of the cast-in-situ beam of the canal pipe bridge crossing the south-to-north water diversion, as set forth in claim 4, is characterized in that: the test content of the weighing experiment comprises the steps of calculating the unbalanced moment of the longitudinal bridge of the rotating body part, calculating the eccentric distance of the longitudinal bridge of the rotating body part, calculating the friction moment and the static friction coefficient of the spherical hinge of the rotating body, and designing the counterweight scheme of the rotating body beam.

6. The construction method of the cast-in-situ beam of the canal pipe bridge crossing the south-to-north water diversion, as set forth in claim 1, is characterized in that: the specific steps of S9 are as follows:

s9.1: removing part of the supporting feet;

s9.2: a jacking jack is arranged at the position of the dismantled supporting leg;

s9.3: jacking the bridge;

s9.4: sequentially removing the spherical hinge support and the rest supporting feet;

s9.5: the bridge falls back.

7. The construction method of the cast-in-situ beam of the canal pipe bridge crossing the south-to-north water diversion, as set forth in claim 1, is characterized in that: the specific steps of S10 are as follows:

s10.1: setting up a bracket III and a mounting template III at the folding section of the side span;

s10.2: binding reinforcing steel bars of the side span closure section, and installing a prestressed pipeline;

s10.3: loading a counterweight and closing and locking the side span;

s10.4: pouring the side span closure section and simultaneously unloading the counterweight according to the concrete pouring speed;

s10.5: curing the concrete;

s10.6: and (3) prestress tensioning of the side span closure section, grouting of the pore canal and dismantling of the bracket III.

8. The construction method of the cast-in-situ beam of the canal pipe bridge crossing the south-to-north water diversion, as set forth in claim 1, is characterized in that: the specific steps of S11 are as follows:

s11.1: the hanging frame (2) provided with the leakage-proof unit (21) is moved to the junction of the midspan bridge from the shore;

S11.2: installing a reinforcing steel bar, a template and a prestressed reinforcement, loading a counterweight and closing and locking a midspan;

s11.3: pouring concrete on the mid-span closure section;

s11.4: curing the concrete;

s11.5: prestress tensioning of side span closure sections and grouting of pore canals;

s11.6: the hanger (2) is moved to shore and removed.

9. The construction method of the cast-in-situ beam of the canal pipe bridge crossing the south-water and north-water regulation, which is characterized by comprising the following steps of: the anti-leakage unit (21) is arranged below the cast-in-situ bridge, the size of the anti-leakage unit (21) along the cross section of the cast-in-situ bridge is larger than that of the cross section of the cast-in-situ bridge, and S11 construction is operated in the anti-leakage unit (21).

10. The construction method of the cast-in-situ beam of the canal pipe bridge crossing the south-water and north-water regulation, which is characterized by comprising the following steps of: the leakage-proof unit (21) is obliquely arranged, and a water collecting device for collecting wastewater is arranged below the leakage-proof unit (21).