A bridge construction method and external beam device

Abstract

The present invention provides a bridge construction method and an external beam device, comprising the following steps: S1: constructing the cable area and the non-cable area of ​​the segment; S2: constructing the segment in the cable area by the delayed tensioning method of the cable-stayed cable; S3: constructing the segment in the cable-stayed area in parallel and realizing the interval setting of the longitudinal prestress. It includes a reserved groove structure located on the segment and a stress frame structure detachably arranged on the reserved groove structure; adjacent segments are respectively provided with reserved groove structures, and the two ends of the stress frame structure are respectively fixed in the corresponding reserved groove structures to realize the connection of adjacent segments. It solves the problem of long construction period of the existing low-tower cable-stayed bridge. A bridge construction method and an external beam device of the present invention adopt the delayed tensioning construction method of the cable-stayed cable. The construction of the cable-stayed cable in this segment is parallel to the construction of the segment reinforcement and formwork of the next segment, and the construction of the cable-stayed cable is eliminated from the key line of the segment construction. It is conservatively estimated that each segment saves 2 days.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge construction, and in particular relates to a bridge construction method and an external beam device. Background Art

[0002] The low-tower cable-stayed bridge is also called a partial cable-stayed bridge. It has the stress characteristics of both a prestressed concrete cable-stayed bridge and a continuous rigid frame bridge. The height of the main beam of a prestressed concrete low-tower cable-stayed bridge is higher than that of an ordinary cable-stayed bridge, but lower than that of a continuous rigid frame bridge. The bending stiffness of the main beam of a low-tower cable-stayed bridge is generally between that of an ordinary concrete cable-stayed bridge and a continuous rigid frame bridge. During the construction of the cable-stayed section of the upper structure of a low-tower cable-stayed bridge, the main beam is mainly responsible for bearing its own weight and construction load, and the cable-stayed cable will also bear part of the load. The main beam is designed to have sufficient rigidity, and the longitudinal prestress also has some safety reserves.

[0003] According to the traditional hanging basket suspended casting construction method of the superstructure of the low-tower cable-stayed bridge, after the longitudinal prestressing of the beam section is completed, the cable tensioning is carried out, and then the hanging basket moves forward to start the construction of the next section. Under the action of the longitudinal prestressing and the cable, the concrete of the beam section is in a compressive state and has a large compressive stress reserve. There is no need to consider the problem of concrete tensile cracking during the construction process, but the construction period (15 days per section) is relatively long. Summary of the invention

[0004] The invention aims to provide a bridge construction method and an external beam device, which solves the problem of long construction period of existing short-tower cable-stayed bridges.

[0005] The technical solution adopted by the present invention is:

[0006] A bridge construction method comprises the following steps:

[0007] S1: Construction of the cabled and non-cabled areas of the segment;

[0008] S2: Construction of the segments in the cable area by means of the cable-stayed cable post-tensioning method;

[0009] S3: The segments in the cable area are constructed in parallel and the longitudinal prestressing is set at intervals.

[0010] Compared with the existing bridge construction methods, when the longitudinal prestressing is set continuously, the cable-stayed post-tensioning method can be directly implemented because the compressive stress reserve of the segment is large enough, but this cannot achieve the purpose of saving construction time; after the longitudinal prestressing is designed to be intervals, the cable-stayed post-tensioning method can be used to save construction time, but the compressive stress reserve of the segment without longitudinal prestressing is insufficient, and the tensile stress during construction will cause cracks in the segment without longitudinal prestressing, so an external beam device is set to resist the tensile stress to ensure that the segment without longitudinal prestressing meets the design requirements.

[0011] Preferably, the construction of the segments in the cable-free area is carried out in sequence according to the following steps: formwork, pouring, solidification, longitudinal prestressing and cable stressing.

[0012] Preferably, the construction of the segments in the cable area includes the following steps: formwork, pouring, solidification, longitudinal prestressing, cable stress tensioning, installation of an extracorporeal bundle device and removal of the extracorporeal bundle device.

[0013] Preferably, the pouring refers to the pouring of concrete; and the solidification refers to waiting for the concrete to reach construction strength.

[0014] Preferably, in step S2, the cable-stayed cable post-tensioning method comprises the following steps:

[0015] S21: After the longitudinal prestressing of the Nth segment, the hanging basket moves forward to carry out the construction of the N+1th segment;

[0016] S22: The stress tensioning of the cable of the Nth segment is carried out while the N+1th segment is being constructed;

[0017] S23: connect the Nth segment and the N+1th segment through an extracorporeal bundle device;

[0018] S24: The N+1 segment skips the longitudinal prestressing and directly performs the cable stressing. At the same time, the hanging basket moves forward to carry out the construction of the N+2 segment.

[0019] S25: The external restraint device is removed after the cable is stressed in the N+1 segment.

[0020] An external beam device for a bridge construction method comprises a reserved groove structure located on a segment and a stress frame structure detachably arranged on the reserved groove structure;

[0021] Adjacent segments are respectively provided with reserved groove structures, and the two ends of the stress frame structure are respectively fixed in the corresponding reserved groove structures to achieve the connection of adjacent segments.

[0022] The purpose of saving construction period was achieved by using the post-tensioning method of the inclined cables. The use of the external bundle device in conjunction with the post-tensioning method of the inclined cables ensured that the non-longitudinal prestressed segments met the design requirements.

[0023] Preferably, the reserved groove structure includes a reserved groove body, a reserved hole, a reinforcing rib mesh and a plurality of embedded pipes located in the reserved hole, and a force transmission plate is provided on the end surface of one end of the reserved groove body.

[0024] Preferably, the reinforcing rib mesh includes a plurality of transverse ribs and a plurality of vertical ribs, and the transverse ribs and the vertical ribs are staggered and arranged in a grid shape.

[0025] Preferably, the force transmission plate and the vertical ribs are arranged parallel to each other.

[0026] Preferably, the stress rack structure comprises a connecting rod and a stress rack body located at an end of the connecting rod, and the stress rack body comprises a first connecting hole matching the connecting rod and a second connecting hole matching the reserved hole.

[0027] Preferably, the stress rack body comprises a bottom plate, at least two stiffening plates located on the bottom plate, and end plate structures located at both ends of the stiffening plates;

[0028] The end plate structure comprises a tensioning end plate connected to the connecting rod and an end plate abutting against the reserved groove body, and the first connecting hole is provided on the tensioning end plate.

[0029] Preferably, there are four stiffening plates evenly distributed on the bottom plate, three connecting grooves are left between adjacent stiffening plates, the middle connecting groove is connected to the first connecting hole, and second connecting holes are respectively provided on the connecting grooves on both sides.

[0030] The beneficial effects of the present invention are:

[0031] A bridge construction method and an external beam device adopt a cable-stayed cable post-tensioning construction method. The cable-stayed cable construction of this segment is carried out in parallel with the segment reinforcement and formwork construction of the next segment, and the cable-stayed cable construction is removed from the key segment construction line. Each segment is conservatively estimated to save 2 days. At present, with the rapid development of low-tower cable-stayed bridges in China, the span is also gradually increasing. If the main beam cable segment is calculated as 15 segments, the construction period will be shortened by at least one month, and the conservative economic benefit is estimated to be 3.5 million.

[0032] The use of an external beam device to implement the delayed tensioning construction method of the cable-stayed bridge speeds up the construction progress of the main beam while ensuring quality and safety. The key nodes of the project are often concentrated on the super-large bridge, thus ensuring the project schedule. The implementation of this technology has a positive effect on the construction unit to control the project cost, the construction unit to control the bidding price limit, and the design unit to optimize the design, which promotes the development of low-tower cable-stayed bridges. It provides a reference for the construction of similar projects in the future and has good social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 It is a flow chart of a bridge construction method.

[0035] Figure 2 It is a flow chart of the post-tensioning method of the inclined cable.

[0036] Figure 3 It is a structural diagram of the stress rack structure.

[0037] Figure 4 It is a structural schematic diagram of the stress rack body.

[0038] Figure 5 It is a structural schematic diagram of the reserved slot structure.

[0039] Figure 6 It is a schematic diagram of the top view of the reserved groove structure.

[0040] Figure 7 It is a schematic diagram of the coordination of the extracorporeal beam device connecting adjacent bridge segments.

[0041] Figure 8 It is the force analysis diagram of the longitudinal prestressing interval setting.

[0042] In the figure: 1-reserved groove structure; 11-reserved groove body; 12-buried pipe; 13-reinforcement rib mesh; 14-force transmission plate; 2-stress frame structure; 21-connecting rod; 22-stress frame body; 23-first connecting hole; 24-second connecting hole; 221-bottom plate; 222-stiffening plate; 223-end plate structure; 223a-tensioning end plate; 223b-end plate. DETAILED DESCRIPTION

[0043] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0044] Embodiment 1:

[0045] like Figure 1 to Figure 2 As shown, a bridge construction method of this embodiment includes the following steps:

[0046] S1: Construction of the cabled and non-cabled areas of the segment;

[0047] S2: Construction of the segments in the cable area by means of the cable-stayed cable post-tensioning method;

[0048] S3: The segments in the cable area are constructed in parallel and the longitudinal prestressing is set at intervals.

[0049] The construction of existing bridges often takes a long time. For example, during the construction of existing low-tower cable-stayed bridges, the upper structure is often constructed using a hanging basket suspended casting method. After the longitudinal prestressing of the Nth segment is completed, the cable-stayed cable is tensioned, and then the N+1 segment is constructed.

[0050] After the longitudinal prestress, i.e. the internal stress of the segment, and the cable stress, i.e. the external stress of the segment, of the Nth segment are tensioned, the segment is in a compressive state and has a large compressive stress reserve. There is no need to consider the problem of concrete tensile cracking during construction. However, the construction of each segment takes about 15 days. The long construction time of a single segment leads to a longer entire construction period and increased costs.

[0051] In order to shorten the construction period and reduce production costs, this bridge construction method is designed. By utilizing the characteristics of large segment bending stiffness and sufficient compressive stress reserve in the hanging basket suspended casting construction method, the longitudinal prestress of the segment in the cable area is adjusted to discontinuous prestressed tendons, which are tensioned once every other segment, achieving the technical effect of saving prestressed steel tendons and saving prestressing tensioning time.

[0052] Through the application of the delayed tensioning method of the inclined cable, after the longitudinal prestressing of the current segment is completed, the hanging basket moves forward to construct the next segment. While the inclined cable stress is being tensioned in the current segment, the next segment is constructed, and the flow-type construction is changed to partial parallel construction. The construction time of each segment is conservatively estimated to be saved by 2 days, which effectively shortens the construction period of a single segment, achieves the purpose of shortening the entire construction period, and also ensures a reduction in production costs.

[0053] By providing external stress through the setting of the external beam device, combined with the internal stress of the segment itself, the prestress value of the segment is controllable and adjustable, ensuring the realization of the delayed tensioning method of the inclined cable. At the same time, the installation, construction and removal of the external beam device are convenient, saving the setting time of the external beam device; the external beam device also has the characteristics of low investment and high turnover rate, and can be used in different segments without longitudinal prestress.

[0054] The construction quality of the segments is controllable. At the same time, the construction period is shortened by the use of the delayed tensioning method of the inclined cables, achieving a fast and good technical effect.

[0055] Through the application of the delayed tensioning method of the inclined cable, the construction of the inclined cable can be carried out in parallel with the construction of the segmental reinforcement and formwork, which has a positive effect on the cost control of the construction unit, the price control of the construction unit, and the optimization of the design by the design unit.

[0056] The bridge construction method will now be explained in conjunction with its specific implementation methods, wherein, for segments without longitudinal prestress, the structural characteristics of the low-tower cable-stayed bridge, that is, the segment stiffness is large and the tensioned cable-stayed cables can bear part of the load, are utilized. Under the condition of delayed tensioning of the cable-stayed cables, an external beam device is used to offset the tensile stress caused by the forward movement of the hanging basket, so as to avoid cracks in the segment under the action of tensile stress, which would affect the service life of the bridge. Specifically, the tensile stress generated by the deadweight of the segment without longitudinal prestress, the tensile stress provided by the steel bars of the segment, the tensile stress generated by the deadweight of the hanging basket and the tensile stress generated by the deadweight of the steel bars of the next segment are mainly offset, so that the cable force, line shape, etc. of the segment without longitudinal prestress meet the design and specification requirements.

[0057] For the construction in the cable-free area, the existing hanging basket suspended pouring construction method is still used for segment construction.

[0058] For the construction in the cable area, on the basis of the hanging basket suspended pouring implementation method, the inclined cable post-tensioning method is adopted to construct the segments in the cable area, so as to realize the interval setting of the longitudinal prestressing of the segments in the cable area.

[0059] Below, each step is explained in conjunction with the specific steps of the bridge construction method.

[0060] In a specific embodiment provided by the present disclosure, as an option, the construction of the segment in the cable-free area is carried out in sequence according to the following steps: formwork, pouring, solidification, longitudinal prestressing and cable stressing.

[0061] Now, the hanging basket suspended pouring construction method is introduced in combination with the construction of the segments in the cable-free area. Among them, the formwork steps mainly include formwork installation and steel bar binding, which further increases the bearing space and the general shape of the segment for concrete pouring.

[0062] The pouring step and the solidification step are both for the construction of concrete. Specifically, in the pouring step, the concrete is poured on the formwork, and the solidification step is to wait for the concrete to solidify until the strength of the concrete reaches the requirement of the next step of construction.

[0063] The sequential application of longitudinal prestressing and cable-stayed stressing enables the segment to obtain sufficient compressive stress reserve, making the segment safe and reliable in stress bearing.

[0064] In the specific embodiment provided by the present disclosure, as an option, the construction of the segment in the cable area includes the following steps: formwork, pouring, solidification, longitudinal prestressing, cable stress tensioning, installation of an extracorporeal bundle device and removal of the extracorporeal bundle device.

[0065] Now, the steps included in the delayed tensioning method of the inclined cable for the construction of the segments in the cable area will be introduced. Since the segments in the cable area are divided into two types, namely, the segments with longitudinal prestress and the segments without longitudinal prestress, the difference between the two in the construction steps is that the segments without longitudinal prestress are not longitudinally prestressed, which makes the longitudinal prestressing intervals on the segments in the cable area.

[0066] At the same time, the segments in the cable area are partially constructed in parallel. The construction of the next segment with longitudinal prestressing is carried out while the segment without longitudinal prestressing is under construction. Since there is no longitudinal prestressing in the segment without longitudinal prestressing, the forces brought about during the construction of the next segment with longitudinal prestressing, namely the tensile stress generated by the deadweight of the segment without longitudinal prestressing, the tensile stress provided by the steel bars of this segment, the tensile stress generated by the deadweight of the hanging basket and the tensile stress generated by the deadweight of the steel bars of the next segment, act on the segment without longitudinal prestressing, which can easily cause cracks in the segment without longitudinal prestressing and result in the need to apply longitudinal prestressing to the segment without longitudinal prestressing.

[0067] Therefore, before the construction of the next longitudinal prestressed segment, the segment without longitudinal prestressing is connected to the previous segment with longitudinal prestressing by an external beam device, and then the external beam device is used to offset the effect of the force on the segment without longitudinal prestressing during the construction of the next longitudinal prestressed segment, ensuring that the cable tension and line shape of the segment without longitudinal prestressing meet the design and specification requirements.

[0068] In the specific implementation provided by the present disclosure, as an option, the pouring refers to the pouring of concrete; the solidification refers to waiting for the concrete to reach the construction strength. The pouring and solidification have been explained in the construction of the cable-free zone segment, and will not be repeated here.

[0069] In a specific embodiment provided by the present disclosure, as an option, in step S2, the cable-stayed cable post-tensioning method includes the following steps:

[0070] S21: After the longitudinal prestressing of the Nth segment, the hanging basket moves forward to carry out the construction of the N+1th segment;

[0071] S22: The stress tensioning of the cable of the Nth segment is carried out while the N+1th segment is being constructed;

[0072] S23: connect the Nth segment and the N+1th segment through an extracorporeal bundle device;

[0073] S24: The N+1 segment skips the longitudinal prestressing and directly performs the cable stressing. At the same time, the hanging basket moves forward to carry out the construction of the N+2 segment.

[0074] S25: The external restraint device is removed after the cable is stressed in the N+1 segment.

[0075] The post-tensioning method of the inclined-stayed cable will now be explained in combination with its specific steps, wherein after the longitudinal prestressing construction of the Nth segment is completed, the hanging basket moves forward to construct the N+1 segment and simultaneously construct the inclined-stayed cable of the Nth segment, and the concrete of the N+1 segment is constructed after the construction of the inclined-stayed cable of the Nth segment is completed; after the concrete strength of the N+1 segment is reached, the external beam device is installed to temporarily anchor the Nth segment and the N+1 segment, and then the hanging basket moves forward to construct the N+2 segment and simultaneously construct the inclined-stayed cable of the N+1 segment, and after the construction of the inclined-stayed cable of the N+1 segment is completed, the temporary external prestressing is released, and the concrete of the N+2 segment is constructed after the construction of the inclined-stayed cable of the N+1 segment is completed.

[0076] Combined with Figure 8 The longitudinal prestress of the segment is optimized. Longitudinal prestress is set in the cable-free area, and the longitudinal prestress of the segment in the cable area is discontinuous prestress, which is tensioned once every other segment.

[0077] Embodiment 2:

[0078] This embodiment supplements the specific structure of the extracorporeal beam device on the basis of the embodiment 1.

[0079] like Figures 1 to 8 As shown, an external beam device for a bridge construction method of this embodiment includes a reserved groove structure 1 located on a segment and a stress frame structure 2 detachably arranged on the reserved groove structure 1;

[0080] Adjacent segments are respectively provided with reserved groove structures 1, and both ends of the stress rack structure 2 are respectively fixed in the corresponding reserved groove structures 1 to achieve the connection between adjacent segments.

[0081] When the delayed-tensioning method of the inclined cable is used, in order to avoid defects such as deformation of the non-longitudinal prestressed segment under the action of tensile stress, an external bundle device is set to offset the tensile stress. Now, the use of the external bundle device is explained in combination with the specific structure of the external bundle device. While the segments in the cable area are being constructed, a reserved groove structure 1 is set on the segments. When the external bundle device needs to be installed, the stress frame structure 2 is fixed in the reserved groove structure 1 to connect the adjacent segments.

[0082] For example, the Nth segment and the N+2th segment are both segments with longitudinal prestress, and the N+1th segment is a segment without longitudinal prestress.

[0083] When the Nth section is cast, a reserved groove structure 1 is preset at the same time. After the longitudinal prestressing construction of the Nth section is completed, the hanging basket moves forward to construct the N+1 section and simultaneously construct the Nth section inclined cable. The concrete of the N+1 section is cast after the construction of the Nth section inclined cable is completed. When the N+1 section is cast, a reserved groove structure 1 is also preset; after the concrete strength of the N+1 section is reached, the stress frame structure 2 is installed to temporarily anchor the Nth section and the N+1 section, and then the hanging basket moves forward to construct the N+2 section and simultaneously construct the N+1 section inclined cable. After the construction of the N+1 section inclined cable is completed, the temporary external prestressing is released, and the concrete of the N+2 section is cast after the construction of the N+1 section inclined cable is completed.

[0084] After the hanging basket moves forward and before the construction of the inclined cable is completed, the external cable force value should be adjusted in real time according to the measured data of the internal stress element. According to the calculated working conditions, the external cable is released after the construction of the inclined cable is completed.

[0085] Since the external cable force value does not take into account the concrete deadweight of the N+1th segment, the concrete pouring of the N+1th segment should be carried out after the construction of the Nth segment cable is completed.

[0086] At the same time, before using the external beam device to implement the cable-stayed cable post-tensioning method, communication should be carried out with the design and monitoring units to ensure the line shape and cable tension of the completed bridge.

[0087] The setting of the external bedding device ensures the interval setting of the longitudinal prestress in the cable area, ensures the realization of the delayed tensioning method of the inclined cable, avoids the occurrence of cracks in the segment without longitudinal prestress, and ensures that the segment quality meets the design and specification requirements.

[0088] The use of the external beam device is described below in conjunction with the specific structures of the various components of the external beam device.

[0089] In the specific embodiment provided by the present disclosure, the reserved groove structure 1 can be constructed as any suitable structure. As an option, the reserved groove structure 1 includes a reserved groove body 11, a reserved hole, a reinforcing rib mesh 13 and a plurality of embedded pipes 12 located in the reserved hole, and a force transmission plate 14 is provided on the end surface of one end of the reserved groove body 11.

[0090] The use of the reserved groove structure 1 is now explained in combination with the specific structure of the reserved groove structure 1, wherein the reserved groove body 11 is used for placing the stress frame structure 2, the reserved hole is used for fixing the stress frame structure 2 in the reserved groove body 11, and the arrangement of the reinforcing rib net 13 ensures the load-bearing capacity of the reserved groove structure 1, thereby effectively offsetting the tensile stress.

[0091] At the same time, combined with the specific structure of the segment, there are requirements for the setting of the reserved groove structure 1. Specifically, because the force transfer plate 14 of the segment is relatively thin, the reserved groove structure 1, that is, the external cable anchorage point, should be selected near the web and diaphragm, where the concrete is thicker to facilitate stress transfer.

[0092] The size of the embedded groove body is slightly larger than the reaction frame body to facilitate the installation and removal of the reaction frame body, and gaps are left in the transverse direction and the longitudinal direction of the bridge.

[0093] Control the embedding accuracy of the reserved groove body 11 and the embedded pipe 12. The bottom of the reserved groove body 11 should be cast flat, and the embedded pipe 12 should be embedded vertically to ensure the vertical locking of the reaction frame body and the top plate of the segment.

[0094] A force transmission plate 14 is provided on the contact surface between the end of the reserved groove body 11 and the reaction frame body to prevent the concrete at the end of the reserved groove body 11 from being uneven and causing the concrete to be locally crushed by force.

[0095] Specifically, as an option, the reinforcing rib mesh 13 includes a plurality of transverse ribs and a plurality of vertical ribs, and the transverse ribs and the vertical ribs are staggered and arranged in a grid shape.

[0096] When pouring the top slab concrete of the segment, the slurry thickness should be controlled to avoid insufficient strength and thus breakage and cracking when the external cable stress is applied. To ensure the transmission of stress, reinforcing steel meshes are respectively provided on the bottom plate 221 and the end of the reserved groove body 11.

[0097] Specifically, as an option, the force transfer plate 14 and the vertical ribs are arranged parallel to each other, that is, for two adjacent segments that need to use the external beam device, the force transfer plate 14 and the reinforcing rib net 13 are located between the two stress frame bodies 22, thereby improving the segment's ability to withstand tensile stress.

[0098] More specifically, the reinforcing rib mesh 13 is made of finely rolled threaded steel bars. Considering that the reinforcing rib mesh 13 is relatively short, the shrinkage rate of the connecting rod 21 is large, and the prestress loss is relatively large, super-tensioning should be adopted. The reinforcing rib mesh 13 can also be made of steel strands, but super-tensioning should be adopted.

[0099] In the specific embodiment provided by the present disclosure, the stress rack structure 2 can be constructed as any suitable structure. As an option, the stress rack structure 2 includes a connecting rod 21 and a stress rack body 22 located at the end of the connecting rod 21, and the stress rack body 22 includes a first connecting hole 23 matching the connecting rod 21 and a second connecting hole 24 matching the reserved hole.

[0100] Now, the use of the stress rack structure 2 is described in combination with the specific structure of the stress rack structure 2, wherein the stress rack body 22 is placed in the reserved slot body 11 to realize the connection between the stress rack structure 2 and the reserved slot structure 1. At the same time, since adjacent segments are connected, the same stress rack structure 2 includes two stress rack bodies 22 respectively located at the ends of the connecting rod 21. The connecting rod 21 connects the stress rack body 22 to connect the adjacent segments into a whole.

[0101] After the concrete of the N+1 segment is poured, the external tension device is installed during the waiting period, and the external tension device is tensioned after the age is reached. As an option, the connecting rod 21 is made of Φ40 finely rolled threaded steel (1080 grade), and the length is relatively short, 5m. Considering the large loss of prestress after tensioning, the connecting rod 21 is over-tensioned (20% over the calculated tensioning force). When the hanging basket moves forward to construct the N+2 segment, it will be tensioned again according to the data collected by the internal stress element.

[0102] Specifically, the prestress loss is large because the prestress is short-beam prestress. In this regard, the extracorporeal stress applied by the extracorporeal beam device is combined with the real-time monitoring of the extracorporeal stress applied by the stress element, so that the extracorporeal beam device can be flexibly supplemented to ensure that the prestress meets the use requirements.

[0103] More specifically, the connecting rod 21 should be covered with a PVC tube for corrosion protection to ensure multiple turnover uses, and care should be taken to protect it during construction.

[0104] Specifically, as an option, the stress rack body 22 includes a bottom plate 221, at least two stiffening plates 222 located on the bottom plate 221, and end plate structures 223 located at both ends of the stiffening plates 222;

[0105] The end plate structure 223 includes a tensioning end plate 223 a connected to the connecting rod 21 and an end plate 223 b abutting against the reserved slot body 11 , and the tensioning end plate 223 a is provided with the first connecting hole 23 .

[0106] Now the structure of the stress frame body 22 is supplemented, wherein the stress frame body 22 is made of steel plate, a plurality of second connection holes 24 are provided on the bottom plate 221 for connection with the reserved slot body 11; a first connection hole 23 is provided on the tensioning end plate 223a for connection with the connecting rod 21.

[0107] More specifically, as an option, there are four stiffening plates 222 evenly distributed on the bottom plate 221, three connecting grooves are left between adjacent stiffening plates 222, the middle connecting groove is connected to the first connecting hole 23, and second connecting holes 24 are respectively provided on the connecting grooves on both sides.

[0108] Now, a practical and feasible scheme for the stress frame body 22 is introduced. After the concrete strength and elastic modulus meet the design requirements, external prestressing symmetrical tensioning is carried out. The stress frame body 22 and the reserved groove body 11 are connected by bolts. For example, the connection is achieved by using precision-rolled threaded steel nuts, and the matching of the threads is checked one by one during installation to ensure that they can be smoothly screwed together and tightened during the tensioning and anchoring process.

[0109] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0110] The present invention is not limited to the above-mentioned optional implementation modes. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that fall within the scope defined by the claims of the present invention fall within the protection scope of the present invention.

Claims

1. A bridge construction method, characterized in that: The following steps are involved: S1: Construction of the cabled and non-cabled areas of the segment; S2: Construction of the segments in the cable area by means of the cable-stayed cable post-tensioning method; S3: Parallel construction of the segments in the cable area and the spacing of the longitudinal prestressing are achieved; The construction of the segment in the cable area includes the following steps: formwork, pouring, solidification, longitudinal prestressing, cable stress tensioning, external bundle device installation and external bundle device removal; in step S2, the cable delayed tensioning method includes the following steps: S21: After the longitudinal prestressing of the Nth segment, the hanging basket moves forward to carry out the construction of the N+1th segment; S22: The stress tensioning of the cable of the Nth segment is carried out while the N+1th segment is being constructed; S23: connect the Nth segment and the N+1th segment through an extracorporeal bundle device; S24: The N+1 segment skips the longitudinal prestressing and directly performs the cable stressing. At the same time, the hanging basket moves forward to carry out the construction of the N+2 segment. S25: The external tendon device is removed after the cable is stressed in the N+1 segment; The extracorporeal bundle device further comprises a reserved groove structure (1) located on the segment and a stress rack structure (2) detachably arranged on the reserved groove structure (1); Adjacent segments are respectively provided with reserved groove structures (1), and both ends of the stress rack structure (2) are respectively fixed in the corresponding reserved groove structures (1) to achieve the connection between adjacent segments.

2. The bridge construction method according to claim 1, characterized in that: The construction of the segments in the cable-free area is carried out in the following steps: formwork, pouring, solidification, longitudinal prestressing and cable stressing.

3. The bridge construction method according to claim 2, characterized in that: The pouring refers to the pouring of concrete; and the solidification refers to waiting for the concrete to reach construction strength.

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