WO2022116394A1

WO2022116394A1 - Construction method for continuous beam having asymmetrical cross section stiffened by large-span arch

Info

Publication number: WO2022116394A1
Application number: PCT/CN2021/076553
Authority: WO
Inventors: 刘文生; 李凤成; 冯超; 梁鹏; 尚亚新; 苏力; 闵坤; 谢磊; 陈云明
Original assignee: 中铁北京工程局集团第二工程有限公司
Priority date: 2020-12-04
Filing date: 2021-02-10
Publication date: 2022-06-09
Also published as: JP2022089733A; CN112482248A

Abstract

A construction method for a continuous beam having an asymmetrical cross section stiffened by a large-span arch, comprising the following steps: S1: designing a counterweight balance load by using a preset method to balance the bending moment of an arch-stiffened continuous beam; and S2: using a preset scheme to complete unbalanced counterweight construction on the large-span arch-stiffened continuous beam. The beneficial effects comprise: under large-span asymmetric cross section load and mobile protection construction conditions, a large unbalanced moment generated at one end is prevented by means of balancing counterweights in sections and moving the counterweights, so as to prevent a large deviation in main beam linearity from occurring during the construction process, ensure the smooth closing of an entire bridge, and achieve the expected linearity of the main beam formed into the bridge; and the tensile stress of a cross section roof caused by the counterweights may be effectively reduced, thereby preventing the generation of cracks.

Description

A construction method for a continuous beam with asymmetrical section stiffened by a large-span arch

technical field

The invention relates to the technical field of large-span continuous beams, in particular to a construction method for a large-span arch stiffening asymmetric section continuous beam.

Background technique

At present, the construction methods of continuous beams mainly include: bracket method, jacking method, swivel method, and cantilever pouring method. The bracket method needs to set up temporary support below the continuous beam pouring position, and when there are many long sections of the pouring beam, this construction method is greatly affected by the geographical environment and the bracket construction time is long; when the jacking method and the swivel method are constructed, the stiffening of the large-span arch is not enough. During the construction of continuous beam with balanced load, due to the large additional load, the unbalanced load of the middle span and side span, the longer the cantilever pouring causes the greater the unbalanced load, the construction linearity is difficult to control, and the unbalanced moment at both ends is difficult to balance, resulting in high safety risks. The above methods have great defects in terms of cost, construction period, and on-site construction, and cannot meet the needs of on-site construction. It is difficult to achieve low-risk and high-efficiency construction for large-span unbalanced load continuous beams.

Cantilever method construction is one of the most commonly used construction methods for continuous girder bridges. It has great advantages for high altitude, large span, deep valleys and special conditions. Cantilever method construction generally adopts a pair of cantilever hanging baskets for symmetrical pouring. Due to the complexity of force requirements or site construction conditions, there will inevitably be a problem of weight symmetry of cantilever cast beams. In addition, the existing large-span arch stiffened unbalanced load continuous beam has disadvantages such as large material consumption, long construction time, high risk, and low efficiency in the construction process.

The existing double-line large-span arch-reinforced continuous beam is designed to span the expressway by using the arch-reinforced continuous beam. Due to the safety consideration of the middle-span cantilever hanging basket construction above the expressway, it is necessary to carry out all-inclusive protection construction on the construction work surface; at the same time, due to the uneven distribution of the tooth blocks in the designed beam section, the suspender beam and the box girder, the side and middle span The load deviation at both ends is large, resulting in an unbalanced load of the continuous beam cantilever construction segment.

In addition, during the construction of long-span arch-stiffened continuous beam bridges, the unbalanced forces on both sides are mainly reflected in two aspects: one is due to structural design reasons; The design structure is different, there are stiffening beams and anchor blocks on the side of the arch-stiffened continuous beam; 2) Due to the design of the arch foot of the designed arch-stiffened continuous beam on the top surface of the 0# block, there is a small eccentric load on both sides; the second is the construction reason, in many In the construction process, complete symmetry is only an ideal state. Even if the construction blocks poured at both ends of the main pier are the same, because one side of the construction site needs to cross the expressway, the hanging basket needs to be designed with a safety protection scaffolding, resulting in different construction loads. balance.

For the problems in the related technologies, no effective solutions have been proposed so far.

SUMMARY OF THE INVENTION

In view of the problems in the related art, the present invention proposes a construction method for a continuous beam with a large-span arch stiffening asymmetrical section, so as to overcome the above-mentioned technical problems existing in the related art.

For this reason, the concrete technical scheme that the present invention adopts is as follows:

A construction method for a large-span arch stiffening asymmetric section continuous beam, the method comprising the following steps:

S1. Use the preset method to design the counterweight balance load to realize the bending moment balance of the arch-stiffened continuous beam;

S2. Use the preset scheme to complete the unbalanced counterweight construction of the large-span arch stiffened continuous beam.

Further, the preset method is to use a pre-compression block to pre-press the counterweight on the previous section before pouring, and move the counterweight block of the corresponding weight of the previous section before the tension is completed after the current section is poured. to the current segment.

Further, the pre-compression block adopts standard pre-compression block and the weight is 3 tons, and the calculation process of the weight of the counterweight block is: using each beam section as a unit to calculate the weight difference of the pouring symmetrical section, using the 0# block. The midpoint is the moment zero point, and the accumulated moment on both sides is made zero by the counterweight, and the theoretical counterweight is calculated.

Further, the formula for the moment balance of the arch-stiffened continuous beam is:

ΣM1+ΣM2+M3+M4=M5+ΣM6+M7;

Among them, ΣM1 is the sum of the counterweight moments of each segment of the side span;

ΣM2 is the pouring moment sum of each segment of the side span;

M3 is the hanging basket and construction load moment;

M4 is the counterweight moment of the hanging basket;

M5 is the moment of 0# segment arch stiffening arch foot;

ΣM6 is the casting moment of the mid-span segment (including the boom beam);

M7 is the moment of hanging basket with protective shed.

Further, the use of the preset scheme to complete the unbalanced counterweight construction of the large-span arch-reinforced continuous beam also includes the following steps:

S21, start segment construction;

S22. Standard segment construction;

S23. Construction of side span closure section;

S24, Zhonghelong section counterweight;

S25, dismantling the temporary structure and counterweight.

Further, the construction of the starting section also includes the following steps:

S211, carry out the installation of temporary buttresses, temporary anchoring and scaffolding and preload the scaffolding;

S212. After the permanent support of the pier top is in place, pour the 0# beam section and the arch stiffening and continuous upper arch foot on the support, and grouting with equal tension;

S213. Change the hanging baskets in turn, and complete the construction of the A1 or B1 beam section;

S214. Install hanging baskets on No. 0 block and A1 or B1 beam sections and preload them, and take temporary anchoring measures for the middle pier at the same time;

S215, cantilever symmetrically pouring A2 or B2 beam sections on the hanging basket;

S216, tension and anchor the longitudinal prestressed steel bundles and the vertical and transverse prestressed tendons of A1 or B1 beam sections;

S217. During the pouring process, the A1 side span beam section is close to the A2 side span beam section, and the weights are pressed one by one according to the symmetrical balance.

Further, the standard segment construction also includes the following steps:

S221. After the longitudinal prestressing construction of this section is completed, move the hanging basket to the next section;

S221. The An or Bn beam segments are cantilevered symmetrically on the hanging basket, and the longitudinal prestressed steel bundles of the An or Bn beam segments and the vertical and transverse prestressed tendons of the An-1 or Bn-1 beam segments are tensioned and anchored;

S223. According to the moment difference of the symmetrical segments, the unbalanced weight of each segment is eliminated by arranging pre-compressed blocks on the beam surface of the corresponding beam segment on site;

S224. During the pouring process, the side span An-1 beam section is next to the side span An beam section according to the symmetrical balance and the corresponding counterweight is gradually added;

S225 , repeating S221 , S222 , S223 and S224 in sequence until the side-span closing section.

Further, the construction of the side span closed section adopts the form of spiral steel pipe + section steel for support, and uses 5 steel pipes with a diameter of 630mm and a wall thickness of 8mm to form a bracket, and the horizontal spacing of the steel pipes is 3.1m, and the top of the steel pipe is placed with double I56a I-shaped. Steel is used as the load-bearing beam, the I25a distribution beam is arranged longitudinally on the load-bearing beam, and the bottom formwork system is installed on the distribution beam.

Further, the described Zhonghelong section counterweight also includes the following steps:

S241. Remove the temporary bracket beside the side pier, and release the temporary locking of the side pier support;

S242. Move the middle-hole hanging basket and pour the concrete of the B19 beam section;

S243, carry out the joint measurement of the bridge alignment, and determine the elevation and position deviation of both ends of the closing section.

Further, the dismantling of the temporary structure and the counterweight also includes the following steps:

S251. Remove the temporary buttress on the middle pier, complete the system conversion, and remove the hanging basket;

S252, stretching and anchoring the remaining prestressed steel bundles of the bottom plate;

S253, performing symmetrical simultaneous tensioning of symmetrical span steel bundles, and alternate tensioning of side span and main span steel bundles;

S254, tensioning the steel bundle of the top plate;

S255. Remove the symmetrical weight of the beam at the lifting point.

The beneficial effects of the present invention are:

The present invention mainly introduces that under the condition of large-span asymmetric section load and moving protection construction, by balancing the counterweight in sections and moving the load, a large unbalanced moment at one end is avoided, so as to prevent the large linearity of the main beam during the construction process. The deviation can ensure the smooth closing of the whole bridge and achieve the expected linearity of the main girder into the bridge; it can effectively reduce the tensile stress of the section roof caused by the counterweight, thereby preventing the occurrence of cracks.

The present invention adopts the construction method of "symmetric pouring + segmental loading" for cantilever pouring of continuous beams with asymmetrical cross-sections of large-span arch stiffening and unbalanced load continuous beam pouring, so as to solve the construction method of unbalanced loading of continuous beams with arch stiffening due to design or construction reasons. This method needs to consider the unbalanced load of the arch foot of the top arch reinforcement when pouring the 0# block during the construction of the 0# block and the 1# block, and set up a temporary support and a temporary anchoring system for balance. After the pouring is completed, use the 0#, 1 #The cantilever hanging basket is installed on the top beam surface, and the segment cantilever construction is carried out through the moment balance calculation. At the same time, the preload block is arranged on the beam surface of the corresponding beam segment to offset the unbalanced moment of each segment. The counterweight loading is mainly divided into two types: one is the additional counterweight, which offsets the unbalanced load caused by the displacement of the cantilever hanging basket during the construction of the closing section; the other is the balance counterweight, which is located at the hanging rod of the structural arch on one side of the arch stiffening. The design of suspender beams results in the difference in the cross-section of the side and mid-span. It is necessary to use counterweights to achieve moment balance in the side and mid-spans. The balance counterweight is not unloaded during the concrete pouring of the closed section. When the concrete strength reaches 100%, the prestressed tension is fully Uninstall when done. This method can prevent the large deviation of the main beam linearity during the construction process. During the construction process, the construction monitoring and the increase of the counterweight are mainly carried out to ensure that the structure is in a balanced state and does not cause instability.

In addition, the invention also has the following advantages: the cantilever method generally adopts a pair of cantilever hanging baskets for symmetrical pouring, which has great advantages for some special terrain and special conditions; by adjusting the counterweight blocks, the height difference on both sides of the closing section can be realized The precise adjustment, that is, the adjustment accuracy is high, the operation is easy, and the construction accuracy can be improved; the centralized counterweight, with the larger the counterweight, the stress of the continuous beam section roof gradually increases; the segmented counterweight can be compared with the concentrated counterweight. Effectively reduce the tensile stress of the top plate of the section and prevent the occurrence of cracks; the problem of large unbalanced bending moment at one end during continuous asymmetric construction is solved by segmental balancing weights, preventing the large linearity of the main beam during construction. To ensure the smooth closing of the whole bridge and achieve the expected linearity of the main girder into the bridge; this construction process solves the low-energy consumption, high-precision, fast and low-risk cantilever pouring construction of large-span unbalanced continuous girder bridges.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a flow chart of a construction method for a continuous beam with a large-span arch stiffening asymmetric section according to an embodiment of the present invention;

Fig. 2 is a pre-compression block configuration diagram in a construction method for a large-span arch stiffening asymmetric section continuous beam according to an embodiment of the present invention;

3 is one of the layout diagrams of the 0# block supports in a construction method for a large-span arch stiffened asymmetric section continuous beam according to an embodiment of the present invention;

Fig. 4 is the second arrangement diagram of the 0# block support in a construction method of a large-span arch stiffening asymmetric section continuous beam according to an embodiment of the present invention;

5 is a construction drawing of a standard section in a construction method for a continuous beam with a large-span arch stiffening asymmetric section according to an embodiment of the present invention;

6 is one of the schematic diagrams of the cast-in-place section of the side span in a construction method for a continuous beam with a large-span arch stiffening asymmetric section according to an embodiment of the present invention;

7 is the second schematic diagram of the cast-in-place section of the side span in the construction method for a continuous beam with a large-span arch stiffening asymmetric section according to an embodiment of the present invention;

8 is a schematic diagram of a side span closure in a construction method for a large-span arch stiffened asymmetric section continuous beam according to an embodiment of the present invention;

9 is one of the schematic diagrams of the balance counterweight in a construction method for a continuous beam with a large-span arch stiffening asymmetric section according to an embodiment of the present invention;

10 is the second schematic diagram of the balance counterweight in the construction method of a large-span arch stiffening asymmetric section continuous beam according to an embodiment of the present invention;

11 is a schematic diagram of the closing of a mid-span hanging basket in a construction method for a large-span arch stiffened asymmetric section continuous beam according to an embodiment of the present invention;

12 is a schematic diagram of a mid-span counterweight in a construction method for a large-span arch stiffened asymmetric section continuous beam according to an embodiment of the present invention.

Detailed ways

In order to further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention, and are mainly used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operation principles of the embodiments. For these, those of ordinary skill in the art will understand other possible implementations and the advantages of the present invention. Components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

According to an embodiment of the present invention, a construction method for a continuous beam with a large-span arch stiffening asymmetric section is provided.

The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. As shown in FIG. 1 , according to the construction method of a large-span arch stiffened asymmetric section continuous beam according to an embodiment of the present invention, the method includes the following steps:

Among them, it is very important to control the unbalanced moment in the continuous beam cantilever symmetrical pouring construction. How to effectively control the unbalance of the cantilever beam pouring moment in the actual construction is the construction focus of the cantilever construction. Generally, the balance can be achieved by adjusting the counterweight at the bottom of the hanging basket and the synchronous construction of the side and mid-span of the corresponding segment during construction. However, it is difficult to achieve a continuous asymmetric section for large-span arch stiffening, and the control difficulty also increases with the length of the cantilever construction segment. However, with the increase of segment length, the sensitivity to unbalanced moment and eccentric load also increases. Therefore, what we need to solve is to ensure that the sides and mid-spans always maintain moment balance when each symmetrical section is finished and moved to the next section. Therefore, the present invention adopts a preset method, so that the balanced construction at both ends can be achieved during the construction of each symmetrical beam section.

In one embodiment, as shown in FIG. 1 , the preset method is to use pre-compressed blocks to pre-press and counterweight the previous section before pouring, and the previous section is stretched after the pouring of the current section is completed. The corresponding weight of the segment is moved to the current segment.

In one embodiment, the pre-compression block is a standard pre-compression block and the weight is 3 tons, and the calculation process of the weight of the counterweight block is as follows: using each beam section as a unit to calculate the weight difference of the pouring symmetrical section, with The midpoint of block 0# is the moment zero point, and the accumulated moment on both sides is zero through the counterweight, and the theoretical counterweight is calculated.

In one embodiment, the formula for the moment balance of the arch-stiffened continuous beam is:

ΣM1+ΣM2+M3+M4=M5+ΣM6+M7;

ΣM2 is the pouring moment sum of each segment of the side span;

M3 is the hanging basket and construction load moment;

M4 is the counterweight moment of the hanging basket;

M5 is the moment of 0# segment arch stiffening arch foot;

ΣM6 is the casting moment of the mid-span segment;

M7 is the moment of hanging basket with protective shed.

In one embodiment, the use of the preset scheme to complete the unbalanced counterweight construction of the large-span arch-reinforced continuous beam further includes the following steps:

S21, start segment construction;

S22. Standard segment construction;

S23. Construction of side span closure section;

S24, Zhonghelong section counterweight;

S25, dismantling the temporary structure and counterweight.

In one embodiment, as shown in Figures 3-4, the construction of the starting section further includes the following steps:

Among them, the 0# block and the 1# block support are composed of upper longitudinal beams, beams, and columns, of which the 0# support column is also used as a temporary pier. During construction, three temporary support piers are placed 2m down from the top of each row of temporary support piers. Fight I56a steel as a corbel to form a bracket system. When the 0# beam section is poured, the formal support and the temporary support pier are in place first, and the movable support is locked.

In one embodiment, as shown in Figure 5, the standard segment construction further includes the following steps:

S221. The An or Bn beam segments are cantilevered symmetrically cast on the hanging basket, and the longitudinal prestressed steel bundles of the An or Bn beam segments and the vertical and transverse prestressed tendons of the An-1 or Bn-1 beam segments are tensioned and anchored;

Among them, during the installation of the steel bar, the pre-compression block of 1/2 weight that needs to be configured is first configured in the previous section. During the concrete pouring process, the weight of the pre-compression block is added one by one in the configuration table of the center of gravity of the previous section, and the counterweight of the corresponding weight of the previous section is moved to the current section before the tension is completed after the pouring of the current section. . The pre-compression block should be placed in the center of the segment as much as possible, and ensure symmetry to avoid eccentric load.

In one embodiment, as shown in Figures 6-10, the construction of the side span closure section adopts the form of spiral steel pipe + section steel for support, and uses 5 steel pipes with a diameter of 630 mm and a wall thickness of 8 mm to form a bracket, and the horizontal spacing of the steel pipes is 3.1m, double I56a I-beam is placed on the top of the steel pipe as the load-bearing beam, the I25a distribution beam is longitudinally arranged on the load-bearing beam, and the bottom mold system is installed on the distribution beam.

Among them, there are two main types of side-span closure weight loading, one is the additional weight, and the other is the balance weight. Standard pre-compression blocks are used for counterweight loading. The additional counterweight of the side span is unloaded according to the pouring volume during the concrete pouring process, and the balance weight is not unloaded during the concrete pouring of the side span closed section, and the unloading is carried out after the concrete strength reaches 100%, and the prestress tension starts.

During the period of counterweight and unloading of the closing section, the two ends should be kept symmetrical, that is, the balance weight should be loaded at the same time on the upper section of the middle-span closing section. When the concrete is poured, the balance weights on the side spans are unloaded synchronously:

(1) If it is within the allowable range (±2cm), no additional counterweight loading is performed;

(2) If the height difference exceeds the allowable range and the beam bottom at the end of the previous section is higher than the theoretical value, additional counterweights should be applied to the previous section, and the specific amount is determined according to the measured height difference combined with the simulation calculation of the monitoring unit;

(3) If the height difference exceeds the allowable range and the bottom of the beam at the end of the previous section is lower than the theoretical value, it should be realized by reducing the balance weight in the previous section, and the balance weight of the side span closing section should be implemented in advance. The form of loading is used to offset the deformation of the beam body caused by the increase of the load during the concrete pouring of the Helong section. Before the construction of the side-span closures, the beams of the upper section of the middle and side-span closures are equipped with pre-compressed blocks equivalent to 1/2 the weight of the side-span closures. The balance weight is unloaded during the concrete pouring process. The speed and the pouring speed are basically synchronized. When the side span is closed, only the balance weight on the side span is unloaded, and the balance weight on the middle span side is retained.

In one embodiment, as shown in Figures 11-12, the Zhonghelong section counterweight further includes the following steps:

Among them, the large-mileage side hanging basket moves back section by section from the end, and the overall lowering of the hanging basket is 0.8 meters before the back. The small mileage side hanging basket is moved forward by meters and the dragon section, the bottom mold is anchored with the reserved holes of the bottom plate of the adjacent sections on both sides with 32mm fine-rolled rebar, and the side mold is made of 32mm fine-rolled rebar and the top plate of the adjacent sections on both sides. Reserve holes for anchoring.

Among them, the mid-span Helong counterweight loading is mainly divided into two types, one is the additional counterweight, and the other is the balance counterweight. The balance weight has been loaded in the middle-span project segment during the construction of the side-span closure. It is necessary to move the counterweight to the adjacent segment of the closure and increase or decrease the counterweight according to the measured data. The additional counterweight should be determined according to the bottom height difference of the mid-span beams in the adjacent segments of the closing section after the side span prestress tension. Additional configuration values for the side. When the height difference between the two ends is less than 2cm, the dragon can be directly closed without additional counterweight. The main factors that cause the height difference between the two ends of the closing section to exceed the limit are: the construction deviation of the adjacent sections of the closing section, and the change of the height difference caused by the forward and backward movement of the hanging baskets on both sides.

The additional counterweight is unloaded during the concrete pouring process, and the unloading speed is basically synchronized with the pouring speed.

In one embodiment, the dismantling of the temporary structure and the counterweight further includes the following steps:

S254, tensioning the steel bundle of the top plate;

S255. Remove the symmetrical weight of the beam at the lifting point.

To sum up, with the help of the above technical solutions of the present invention, the present invention mainly introduces how to balance the counterweight in sections and move the stowage under the conditions of large-span asymmetric section loads and mobile protection construction to avoid large inconsistencies at one end. Balance the moment to prevent the large deviation of the main girder linearity during the construction process, ensure the smooth closing of the whole bridge and achieve the expected linearity of the main girder into the bridge; it can effectively reduce the tensile stress of the section roof caused by the counterweight, thereby preventing the occurrence of cracks . The present invention adopts the construction method of "symmetric pouring + segmental loading" for cantilever pouring of continuous beams with asymmetrical cross-sections of large-span arch stiffening and unbalanced load continuous beam pouring, so as to solve the construction method of unbalanced loading of continuous beams with arch stiffening due to design or construction reasons. This method needs to consider the unbalanced load of the arch foot of the top arch stiffening when pouring the 0# block during the construction of the 0# block and the 1# block, and set up a temporary support and a temporary anchoring system for balance. After the pouring is completed, use the 0#, 1 #The cantilever hanging basket is installed on the top beam surface, and the segment cantilever construction is carried out through the moment balance calculation. At the same time, the preload block is arranged on the beam surface of the corresponding beam segment to offset the unbalanced moment of each segment. The counterweight loading is mainly divided into two types: one is additional counterweight, which offsets the unbalanced load caused by the displacement of the cantilever hanging basket during the construction of the closing section; The design of suspender beams results in the difference in the cross-section of the side and mid-span. It is necessary to use counterweights to achieve moment balance in the side and mid-spans. The balance counterweight is not unloaded during the concrete pouring of the closed section. When the concrete strength reaches 100%, the prestressed tension is fully Uninstall when done. This method can prevent the large deviation of the main beam linearity during the construction process. During the construction process, the construction monitoring and the increase of the counterweight are mainly carried out to ensure that the structure is in a balanced state and no instability occurs.

In addition, the invention also has the following advantages: the cantilever method generally adopts a pair of cantilever hanging baskets for symmetrical pouring, which has great advantages for some special terrain and special conditions; by adjusting the counterweight blocks, the height difference on both sides of the closing section can be realized The precise adjustment, that is, the adjustment accuracy is high, the operation is easy, and the construction accuracy can be improved; the centralized counterweight, with the increase of the counterweight, the roof stress of the continuous beam section gradually increases; the segmented counterweight can be compared with the concentrated counterweight. Effectively reduce the tensile stress of the top plate of the section and prevent the occurrence of cracks; the problem of large unbalanced bending moment at one end during continuous asymmetric construction is solved by segmental balancing weights, preventing the large linearity of the main beam during construction. To ensure the smooth closing of the whole bridge and achieve the expected linearity of the main girder into the bridge; this construction process solves the low-energy consumption, high-precision, rapid and low-risk cantilever pouring construction of large-span unbalanced continuous girder bridges.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims

A construction method for a large-span arch stiffening asymmetric section continuous beam, characterized in that the method comprises the following steps:

S1. Use the preset method to design the counterweight balance load to realize the bending moment balance of the arch-stiffened continuous beam;

S2. Use the preset scheme to complete the unbalanced counterweight construction of the large-span arch stiffened continuous beam.
The construction method of a large-span arch stiffening asymmetric section continuous beam according to claim 1, wherein the preset method is to use pre-compressed blocks to pre-compress the upper section before pouring, and the current After the segment is poured and before tensioning, move the counterweight of the corresponding weight of the previous segment to the current segment.
A construction method for a continuous beam with a large-span arch stiffening asymmetric cross-section according to claim 2, wherein the pre-compression block is a standard pre-compression block and the weight is 3 tons, and the calculation of the weight of the counterweight block The process is: take each beam section as a unit to calculate the weight difference of the pouring symmetrical section, take the midpoint of the 0# block as the moment zero point, and use the counterweight to make the accumulated moment on both sides zero to calculate the theoretical counterweight.
A construction method for a large-span arch-stiffened asymmetric cross-section continuous beam according to claim 3, wherein the formula for the moment balance of the arch-stiffened continuous beam is:

ΣM1+ΣM2+M3+M4=M5+ΣM6+M7;

Among them, ΣM1 is the sum of the counterweight moments of each segment of the side span;

ΣM2 is the pouring moment sum of each segment of the side span;

M3 is the hanging basket and construction load moment;

M4 is the counterweight moment of the hanging basket;

M5 is the moment of 0# segment arch stiffening arch foot;

ΣM6 is the casting moment of the mid-span segment;

M7 is the moment of hanging basket with protective shed.
The method for constructing a continuous beam with asymmetrical cross-sections for long-span arch stiffening according to claim 1, wherein said adopting a preset scheme to complete the unbalanced counterweight construction of the long-span arch stiffening continuous beam with continuous beams further comprises the following steps:

S21, start segment construction;

S22. Standard segment construction;

S23. Construction of side span closure section;

S24, Zhonghelong section counterweight;

S25, dismantling the temporary structure and counterweight.
The construction method of a large-span arch stiffened asymmetric section continuous beam according to claim 5, wherein the construction of the starting segment further comprises the following steps:

S211, carry out the installation of temporary buttresses, temporary anchoring and scaffolding and preload the scaffolding;

S212. After the permanent support of the pier top is in place, pour the 0# beam section and the arch stiffening and continuous upper arch foot on the support, and grouting it with equal tension;

S213. Change the hanging baskets in turn, and complete the construction of the A1 or B1 beam section;

S214. Install hanging baskets on No. 0 block and A1 or B1 beam sections and preload them, and take temporary anchoring measures for the middle pier at the same time;

S215, cantilever symmetrically pouring A2 or B2 beam sections on the hanging basket;

S216, tension and anchor the longitudinal prestressed steel bundles and the vertical and transverse prestressed tendons of A1 or B1 beam sections;

S217. During the pouring process, the A1 side span beam section is close to the A2 side span beam section, and the weights are pressed one by one according to the symmetrical balance.
The construction method of a large-span arch stiffening asymmetric section continuous beam according to claim 5, wherein the standard segment construction further comprises the following steps:

S221. After the longitudinal prestressing construction of this section is completed, move the hanging basket to the next section;

S221. The An or Bn beam segments are cantilevered symmetrically cast on the hanging basket, and the longitudinal prestressed steel bundles of the An or Bn beam segments and the vertical and transverse prestressed tendons of the An-1 or Bn-1 beam segments are tensioned and anchored;

S223. According to the moment difference of the symmetrical segments, the unbalanced weight of each segment is eliminated by arranging pre-compressed blocks on the beam surface of the corresponding beam segment on site;

S224. During the pouring process, the side span An-1 beam section is next to the side span An beam section according to the symmetrical balance and the corresponding counterweight is gradually added;

S225 , repeating S221 , S222 , S223 and S224 in sequence until the side-span closing section.
The construction method of a large-span arch stiffening asymmetric section continuous beam according to claim 5, characterized in that, the construction of the side-span closing section adopts the form of spiral steel pipe + section steel for support, and adopts 5 diameters 630mm, wall thickness The 8mm steel pipe forms the bracket, and the horizontal spacing of the steel pipe is 3.1m. The double I56a I-beam is placed on the top of the steel pipe as the load-bearing beam, the I25a distribution beam is arranged longitudinally on the load-bearing beam, and the bottom mold system is installed on the distribution beam.
The method for constructing a continuous beam with a large-span arch stiffening asymmetric section according to claim 5, wherein the counterweight of the mid-helix section further comprises the following steps:

S241. Remove the temporary bracket beside the side pier, and release the temporary locking of the side pier support;

S242. Move the middle-hole hanging basket and pour the concrete of the B19 beam section;

S243, carry out the joint measurement of the bridge alignment, and determine the elevation and position deviation of both ends of the closing section.
A construction method for a large-span arch stiffening asymmetric section continuous beam according to claim 5, wherein the dismantling of the temporary structure and the counterweight further comprises the following steps:

S251. Remove the temporary buttress on the middle pier, complete the system conversion, and remove the hanging basket;

S252, stretching and anchoring the remaining prestressed steel bundles of the bottom plate;

S253, performing symmetrical simultaneous tensioning of symmetrical span steel bundles, and alternate tensioning of side span and main span steel bundles;

S254, tensioning the steel bundle of the top plate;

S255. Remove the symmetrical weight of the beam at the lifting point.