Construction method of railway composite beam steel-concrete joint section with steel truss

Abstract

The present application belongs to the field of railway bridge construction technology, and particularly relates to a construction method of a railway hybrid girder steel-concrete joint section with steel truss, comprising the following steps: S1, manufacturing steel truss and steel cantilever beam; S2, before pouring the concrete girder, embedding the steel truss to the end of the concrete girder, pouring the concrete girder and curing; S3, after the concrete girder reaches the design strength, hoisting the steel girder to the design height; S4, fixing the steel girder and the concrete girder through the steel truss and the steel cantilever beam; S5, pouring the joint between the concrete girder and the steel girder to form a wet joint section, and completing the construction of the steel-concrete joint section after the wet joint section reaches the design strength. The present application uses the steel cantilever beam and the steel truss as the temporary fixing device for the construction of the steel-concrete joint section, greatly improving the positioning accuracy of the hoisted steel girder, and reducing the height difference between the concrete girder and the steel girder; after pouring the wet joint section concrete, the steel truss remains in the concrete as a permanent device, and the concrete girder and the steel girder are not prone to large deformation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of railway bridge construction, and particularly relates to a railway hybrid beam steel-concrete joint construction method with a steel truss. BACKGROUND

[0002] The current steel-concrete joint construction method of a highway hybrid beam bridge is to set temporary steel members between steel beam segments and concrete segments, and the steel members are not connected and are discretely distributed in space. The steel-concrete joint often has a problem of a slight deviation between the design height and the steel beam hoisted into position during construction, which causes a height difference between the concrete beam and the steel beam, affecting the transmission of internal forces, and thus the steel beam height needs to be adjusted by a hoisting system before pouring the wet joint concrete. This construction method is more likely to cause larger deformation for the steel-concrete joint of a railway bridge with a relatively high beam height. Therefore, a railway hybrid beam steel-concrete joint construction method with a steel truss is needed to solve the problem. SUMMARY

[0003] The present application aims to provide a railway hybrid beam steel-concrete joint construction method with a steel truss to solve the above problems.

[0004] To achieve the above-mentioned purpose, the present application provides the following solutions.

[0005] A railway hybrid beam steel-concrete joint construction method with a steel truss, comprising the following steps:

[0006] S1, making a steel truss and a steel cantilever beam;

[0007] S2, before pouring the concrete beam, embedding the steel truss into the end of the concrete beam, pouring the concrete beam and curing;

[0008] S3, after the concrete beam reaches the design strength, hoisting the steel beam to the design height;

[0009] S4, fixing the steel beam and the concrete beam through the steel truss and the steel cantilever beam;

[0010] S5, pouring the joint between the concrete beam and the steel beam to form a wet joint, and completing the steel-concrete joint construction after the wet joint reaches the design strength.

[0011] Preferably, in the step S1, the steel truss is made of chord members, web members and node plates.

[0012] Preferably, in the step S1, the steel cantilever beam is composed of a plurality of I-beams spliced end to end, and adjacent two I-beams are fixedly connected.

[0013] Preferably, in the step S2, the outer formwork of the concrete beam is erected, the steel truss is placed at the designed position, the steel reinforcement of the concrete beam is bound and ensured to pass through the mounting holes of the steel truss, the prestressed pipe and the prestressed steel beam are installed, the inner formwork is erected, and the concrete is poured and cured.

[0014] Preferably, in the step S3, the steel beam is moved to the position right below the position to be installed, and the steel beam is hoisted by the way of staged loading.

[0015] Preferably, in the process of hoisting the steel beam, the two symmetrical sides of the top of the steel beam are loaded in stages according to the load staged loading of 20%→40%→60%→80%→100%, and whether there is an abnormal condition is observed in the loading process; the load of the two symmetrical sides of the top of the steel beam is kept the same in the hoisting process.

[0016] Preferably, in the step S3, after the steel beam is hoisted to the designed height, the position of the steel beam is finely adjusted, the axis, elevation, transverse slope and longitudinal slope of the steel beam are reviewed and finely adjusted by using the total station and the level, the steel beam after splicing is ensured to be on the same vertical line with the steel beam after hoisting, and after confirming that the design and monitoring requirements are met, the steel truss and the steel beam are fixed, so that the steel beam is supported on the concrete beam only by the steel truss.

[0017] Preferably, in the step S3, the steel cantilever beam is accurately adjusted to the designed position, the tail end of the steel cantilever beam is fixed on the concrete beam through an anchoring device, the middle part of the steel cantilever beam is connected with the ear plate of the pre-buried member on the concrete beam through a hinged support, the front end of the steel cantilever beam is connected with the steel beam through another hinged support, the steel cantilever beam is locked, the steel beam and the concrete beam form a firm and stable structure, and the steel cantilever beam and the steel truss become the stress structure for pouring the wet joint section.

[0018] Preferably, in the step S5, the formwork is erected at the position of the wet joint section, the steel reinforcement is bound, the prestressed pipe and the prestressed steel beam are installed, the concrete is poured and cured, after the concrete of the wet joint section reaches the designed strength, the formwork and the steel cantilever beam are removed, the prestressed steel beam is tensioned, and the construction is completed.

[0019] Compared with the prior art, the present application has the following advantages and technical effects:

[0020] The present application adopts the steel cantilever beam and the steel truss as the temporary fixing device for the steel-concrete joint section construction, greatly improves the positioning accuracy of hoisting the steel beam, and reduces the height difference between the concrete beam and the steel beam; after the concrete of the wet joint section is poured, the steel truss remains in the concrete as a permanent device, and the concrete beam and the steel beam are not easy to produce large deformation. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below only illustrate some of the embodiments of the present application, and all other drawings obtained by those of ordinary skill in the art without creative effort based on these drawings also belong to the protection scope of the present application.

[0022] Figure 1 The schematic diagram for pouring the cantilever concrete beam of the present application;

[0023] Figure 2 The schematic diagram for installing the steel truss before hoisting the steel beam of the present application;

[0024] Figure 3 The schematic diagram for hoisting the steel beam into place of the present application;

[0025] Figure 4 The schematic diagram for installing the steel cantilever beam of the present application;

[0026] Figure 5 The schematic diagram for pouring the wet joint section concrete of the present application;

[0027] Figure 6 The schematic diagram for completing the wet joint section concrete pouring, removing the formwork and the steel cantilever beam of the present application;

[0028] Figure 7 The corresponding cross-sectional view for installing the steel cantilever beam and the steel truss of the present application;

[0029] Among them, 1, hanging basket; 11, hanging basket main truss; 12, hanging basket rear anchoring system; 13, hanging basket slide and walking system; 14, bottom mold platform; 15, inner and outer mold system; 16, hanging system; 2, bridge deck crane; 21, crane main truss; 22, lifting system; 23, crane rear anchoring system; 24, crane slide and walking system; 3, steel truss; 31, chord; 32, web; 33, node plate; 4, steel cantilever beam; 41, anchoring device; 42, hinged support; 5, concrete beam; 6, steel beam; 7, steel-concrete joint section. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, and all other embodiments obtained by those of ordinary skill in the art without creative effort based on these embodiments also belong to the protection scope of the present application.

[0031] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0032] Referring Figures 1 to 7 The application discloses a construction method of a railway hybrid beam steel-concrete joint section with a steel truss, and comprises the following steps:

[0033] S1, manufacturing a steel truss 3 and a steel cantilever beam 4;

[0034] S2, before pouring the concrete beam 5, embedding the steel truss 3 to the end of the concrete beam 5, pouring the concrete beam 5 and curing;

[0035] S3, after the concrete beam 5 reaches the design strength, hoisting the steel beam 6 to the design height;

[0036] S4, fixing the steel beam 6 and the concrete beam 5 through the steel truss 3 and the steel cantilever beam 4;

[0037] S5, pouring the joint between the concrete beam 5 and the steel beam 6 to form a wet joint section, and completing the construction of the steel-concrete joint section after the wet joint section reaches the design strength.

[0038] The application adopts the steel cantilever beam 4 and the steel truss 3 as a temporary fixing device for the construction of the steel-concrete joint section, greatly improves the positioning accuracy of hoisting the steel beam, and reduces the height difference between the concrete beam 5 and the steel beam 6; after pouring the wet joint section concrete, the steel truss 3 is left in the concrete as a permanent device, and the concrete beam 5 and the steel beam 6 are not prone to large deformation.

[0039] In a further optimization scheme, the steel truss 3 is made of chord bars 31, web bars 32 and node plates 33.

[0040] The steel truss 3 is composed of chord bars 31, web bars 32 and node plates 33, the chord bars 31 and the web bars 32 are preferably I20a channel steels, the node plates 33 are rectangular steel plates, the web bars 32 and the chord bars 31 are connected by three-sided welding angle welds, and the node plates 33 are divided into two types of node plates with holes and node plates without holes.

[0041] In a further optimization scheme, the steel cantilever beam 4 is composed of a plurality of I-shaped steels which are spliced at the head and tail and are fixedly connected between two adjacent I-shaped steels.

[0042] The steel cantilever beam 4 is composed of two I80a I-shaped steels which are spliced and connected by butt welds in the length direction of the flanges of the two I-shaped steels.

[0043] In a further optimization scheme, in step S2, an outer formwork of the concrete beam 5 is erected, the steel truss 3 is placed at a designed position, the steel reinforcement of the concrete beam 5 is bound and ensured to pass through the mounting holes of the steel truss 3, a prestressed pipe and a prestressed steel beam are installed, an inner formwork is erected, and the pouring and curing of concrete are started.

[0044] Before the concrete beam 5 is poured, the steel truss 3 is arranged at the end of the concrete beam 5, and then the reinforcement binding and prestressed duct installation of the concrete beam 5 are performed, and the concrete beam 5 is poured by using the hanging basket 1.

[0045] The hanging basket 1 mainly comprises a hanging basket main truss 11, a hanging basket rear anchoring system 12, a hanging basket slide and walking system 13 and a hanging system 16, and the formwork system comprises a bottom formwork platform 14 and an inner and outer formwork system 15, wherein the inner and outer formwork system 15 comprises an outer formwork and an inner formwork.

[0046] The hanging basket slide and walking system 13 is installed on the beam segment that has been poured, the hanging basket main truss 11 is moved to the designated position by the hanging basket slide and walking system 13, is fixed by the hanging basket rear anchoring system 12, the bottom formwork platform 14 is hoisted by the hanging system 16, and the bottom formwork platform 14 is moved to the bottom of the concrete beam 5 to be poured, and the bottom formwork platform 14 is fixed with the beam segment that has been poured during pouring.

[0047] Before pouring the concrete beam 5, the outer formwork is first erected, then the steel truss 3 with the node plate 33 on the side with the opening and the chord 31 and the web 32 connected thereto are pre-buried at the designed position, finally the reinforcement is bound and it is ensured that the reinforcement passes through the holes of the node plate 33 on the side with the opening of the steel truss 3, the prestressed duct and the prestressed steel beam are installed, the inner formwork is erected, and the concrete is poured and cured.

[0048] In a further optimization scheme, in step S3, the steel beam 6 is moved to be directly below the position to be installed, and the steel beam 6 is hoisted by means of staged loading.

[0049] After the concrete beam 5 reaches the strength, the hanging basket 1 is transformed into the bridge deck crane 2, wherein the hanging basket main truss 11 serves as the crane main truss 21, the hanging basket rear anchoring system 12 serves as the crane rear anchoring system 23, the hanging basket slide and walking system 13 serves as the crane slide and walking system 24, and the hanging system 16 serves as the lifting system 22.

[0050] The bottom formwork platform 14 and the inner and outer formwork system 15 are moved away from the steel beam 6, a lifting hanger is installed on the lifting system 22 and is accurately positioned, a beam transport vehicle is used to transport the steel beam 6 of the steel-concrete combined segment to be hoisted to the water platform directly below the position to be installed on the bridge, a lifting lug is arranged directly below the hanger and close to the web of the steel beam 6, the lifting lug is welded and fixed with the top plate of the steel beam 6, a stiffener is arranged at the position of the lifting lug of the web to strengthen the welding with the steel beam 6, the lifting hanger is lowered, the lifting hanger is connected with the lifting lug of the steel beam, and the steel beam is hoisted.

[0051] In a further optimization scheme, during the lifting of the steel beam 6, staged loading is performed on the two symmetrical sides at the top of the steel beam 6, the load is staged according to 20%→40%→60%→80%→100%, and whether there is an abnormal condition is observed during the loading process; during the lifting process, the loads on the two symmetrical sides at the top of the steel beam 6 are kept the same.

[0052] Two continuous jacks are arranged near the position of the lifting system 22 in front of the upper crossbeam of the crane main truss 21 as the lifting device combined with the segment steel beam. During the lifting process, the load should be loaded in stages (symmetrically on both sides) according to the load grading of 20%→40%→60%→80%→100%, and the steel beam 6 and the lifting system 22 should be observed during the loading process. If there is no abnormal condition, the loading can continue. During the lifting process, the same load should be applied to both ends to ensure the smooth lifting of the steel beam 6. The lifting system 22 is composed of a lifting control system, continuous jacks, lifting pressure sensors, steel strands, steel strand reels, and lifting devices. After the steel beam is lifted to the designed height, the lifting system is temporarily locked.

[0053] Further optimization scheme, in step S3, after the steel beam 6 is lifted to the designed height, the position of the steel beam 6 is fine-tuned, and the axis, elevation, transverse slope and longitudinal slope of the steel beam 6 are reviewed and fine-tuned by using a total station and a level, to ensure that the assembled steel beam 6 is on the same vertical line as the lifted steel beam 6, and to confirm that it meets the design and monitoring requirements. After that, the steel truss 3 is fixed with the steel beam 6, so that the steel beam 6 is supported on the concrete beam 5 only by the steel truss 3.

[0054] After the position of the steel beam 6 is fine-tuned and the steel beam 6 reaches the designed position, the steel beam 6 is connected with the steel truss 3. When installing the steel cantilever beam 4, the position of the steel beam is adjusted to ensure that the assembled steel beam 6 is on the same vertical line as the lifted steel beam 6. The axis, elevation, transverse slope and longitudinal slope of the steel beam are reviewed by using a total station and a level. If it does not meet the requirements, the lifting system 22 is used for fine-tuning. After confirming that the review or adjustment meets the design and monitoring requirements, the node plate at one end of the steel truss 3 is welded on the T rib of the web plate of the steel beam 6, and the rigid connection between the steel beam 6 and the concrete beam 5 is completed.

[0055] Further optimization scheme, in step S3, the steel cantilever beam 4 is accurately adjusted to the designed position. The tail end of the steel cantilever beam 4 is fixed on the concrete beam 5 through the anchoring device 41. The middle part of the steel cantilever beam 4 is connected with the pre-embedded lug plate on the concrete beam 5 through the hinged support 42. The front end of the steel cantilever beam 4 is connected with the steel beam 6 through another hinged support 42. The steel cantilever beam 4 is locked, so that the steel beam 6 and the concrete beam 5 form a stable structure, and the steel cantilever beam 4 and the steel truss 3 become the force structure of the wet joint segment pouring.

[0056] The lifting frame of the lifting system 22 is unbuckled at the connection part with the steel beam lug plate, and the lifting frame of the bridge crane 2 is removed, so that the steel beam 6 is supported on the concrete beam 5 only by the steel truss 3.

[0057] The steel cantilever beam 4 is installed and accurately adjusted to the design position during installation. The steel cantilever beam 4 is made of double-spliced I-beams, the rear end is fixed on the concrete beam 5 through the anchoring device 41, the front end is connected with the steel beam 6 through the hinged support 42, the middle is connected with the concrete beam 5 embedded piece lug plate through another hinged support 42, and then the steel cantilever beam 4 is locked to form a more stable whole structure of the steel beam 6 and the concrete beam 5, so that the steel cantilever beam 4 and the steel truss 3 become the stress structure of the subsequent pouring of the wet joint concrete.

[0058] Further optimization scheme, in step S5, the formwork is erected at the wet joint position, the steel bars are bound, the prestressed pipe and the prestressed steel beam are installed, the concrete is poured and the concrete is maintained, after the wet joint concrete reaches the design strength, the formwork and the steel cantilever beam 4 are removed, the prestressed steel beam is tensioned, and the construction is completed.

[0059] The originally retreated bottom mold platform 14 and the inner and outer mold system 15 are moved forward to the wet joint position, and the bottom mold platform 14 and the inner and outer mold system 15 are modified as the formwork system for pouring the wet joint, then the formwork system is locked on the bottom plate of the concrete beam 5 and the steel beam 6, and the formwork system is connected with the bridge crane 2.

[0060] The steel bars are bound, the prestressed pipe and the prestressed steel beam are installed, and the pouring of the wet joint concrete and the maintenance of the concrete are started.

[0061] After the wet joint concrete reaches the design strength, the formwork system and the steel cantilever beam 4 are removed, the prestressed steel beam is tensioned, and the construction of the steel-concrete joint section is completed.

[0062] Compared with the prior art, the present application has the following advantages:

[0063] (1) The steel cantilever beam 4 and the steel truss 3 are used as the temporary fixing device for the construction of the steel-concrete joint section, which greatly improves the positioning accuracy of the hoisted steel beam 6;

[0064] (2) The pouring of the concrete beam 5 is first erected with the outer mold plate, then the steel truss 3 with the side node plate and the connected chord 31 is pre-buried at the designed position, finally the steel bars are bound to ensure that the steel bars pass through the holes of the node plate 33 of the steel truss 3, the prestressed pipe and the steel beam are installed, the inner mold plate is erected, and the pouring of the concrete and the maintenance of the concrete are started.

[0065] (3) The steel truss 3 is composed of chord 31, web 32 and node plate 33. The chord 31 and the web 32 are made of I20a channel steel, which are used as the upper and lower chords and webs of the truss. The node plate 33 is divided into two types of perforated steel plate and non-perforated steel plate.

[0066] (4) The hanging basket 1 used for construction is mainly composed of hanging basket main truss 11, hanging basket rear anchoring system 12, hanging basket slide and walking system 13, bottom mold platform 14, inner and outer mold system 15 and hanging system 16.

[0067] (5) After the completion of the cantilever concrete beam 5, the hanging basket 1 is modified into a bridge deck crane 2. The bridge deck crane 2 mainly consists of a crane main truss 21, a lifting system 22, a crane rear anchoring system 23, a crane slide and walking system 24, a construction operation platform and the like.

[0068] (6) In order to prevent the influence on the hoisting of the steel beam, the inner and outer guide beams, the bottom mold platform 14 and the inner and outer mold system 15 of the hanging basket 1 are moved backward.

[0069] (7) The lifting hanger is connected with the top plate lifting lug of the steel beam 6. The lifting hanger is made of steel plate by welding and is connected as a whole through a pin shaft. The lifting lug is arranged below the hanger and close to the web of the steel beam, and is welded and fixed with the top plate of the steel beam 6 at the joint section. The stiffened plate is arranged at the position of the lifting lug on the top plate of the steel beam 6 at the side web, and is welded with the steel beam 6.

[0070] (8) The whole steel beam 6 is lifted according to the graded loading, and the load at both ends of the steel beam 6 should be kept the same to prevent tilting. After lifting, the steel beam 6 is on the same vertical line as the initial position of the steel beam 6.

[0071] (9) After the steel beam 6 is accurately adjusted to the designed position, the node plate of the steel truss 3 at one end in the steel beam 6 is welded on the corresponding T rib of the web of the steel beam, and the steel cantilever beam 4 is locked, so that the steel beam 6 and the concrete beam 5 form a whole stable structure.

[0072] (10) The rear end of the steel cantilever beam 4 is fixed on the concrete beam 5 through the anchoring device 41, the front end is connected with the steel beam 6 through the hinged support 42, and the middle part is connected with the pre-embedded lug plate of the concrete beam 5 through the hinged support 42.

[0073] (11) The steel cantilever beam 4 adopts double-spliced I-beam section. The steel-concrete joint section construction can be removed and reused after completion.

[0074] (12) The bottom mold and the inner and outer molds for pouring the concrete beam 5 are modified as the mold system of the wet joint concrete.

[0075] (13) After pouring the wet joint concrete, the steel truss 3 is left in the concrete as a permanent device.

[0076] (14) After the wet joint concrete reaches the designed strength, the bottom mold platform 14 is removed first, then the mold system is removed, and finally the steel cantilever beam 4 is removed, and then the prestressed steel tendon is tensioned, to complete the steel-concrete joint section construction.

[0077] In the description of the present application, it needs to be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0078] The above-described embodiments are only to describe the preferred modes of the present application, and not to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A method for constructing a railway composite beam steel-concrete joint segment with a steel truss, characterized in that, The method comprises the following steps: S1, manufacturing a steel truss (3) and a steel cantilever beam (4); S2, before pouring the concrete beam (5), embedding the steel truss (3) into the end of the concrete beam (5), pouring the concrete beam (5) and curing; S3, after the concrete beam (5) reaches the design strength, hoisting the steel beam (6) to the design height; S4, fixing the steel beam (6) and the concrete beam (5) through the steel truss (3) and the steel cantilever beam (4); S5, pouring the joint between the concrete beam (5) and the steel beam (6) to form a wet joint section, and completing the construction of the steel-concrete joint section after the wet joint section reaches the design strength. In the step S1, the steel truss (3) is composed of chord bars (31), web bars (32) and node plates (33).

2. The method of claim 1, wherein: In the step S1, the steel cantilever beam (4) is composed of a plurality of I-shaped steels which are spliced together, and adjacent two I-shaped steels are fixedly connected.

3. The method of claim 1, wherein: In the step S2, the outer formwork of the concrete beam (5) is erected, the steel truss (3) is placed at the designed position, the steel bars of the concrete beam (5) are bound and ensured to pass through the mounting holes of the steel truss (3), the prestressed pipe and the prestressed steel bar are installed, the inner formwork is erected, and the concrete is poured and cured.

4. The method of claim 1, wherein: In the step S3, the steel beam (6) is moved to the position directly below the position to be installed, and the steel beam (6) is hoisted by means of staged loading.

5. The method of claim 4, wherein: During the lifting of the steel beam (6), the top of the steel beam (6) is loaded symmetrically on both sides in stages, and the load is loaded in stages according to 20%→40%→60%→80%→100%, and whether there is an abnormal situation during the loading process is observed; during the lifting process, the loads on the top of the steel beam (6) on both sides are kept the same.

6. The method of claim 1, wherein: In the step S3, after the steel beam (6) is hoisted to the designed height, the position of the steel beam (6) is fine-tuned, the axis, elevation, transverse slope and longitudinal slope of the steel beam (6) are reviewed and fine-tuned by using a total station and a level, it is ensured that the assembled steel beam (6) and the lifted steel beam (6) are on the same vertical line, and after it is confirmed that the design and monitoring requirements are met, the steel truss (3) and the steel beam (6) are fixed, so that the steel beam (6) is supported on the concrete beam (5) only by the steel truss (3).

7. The method of claim 6, wherein: In the step S3, the steel cantilever beam (4) is accurately adjusted to the designed position, the tail end of the steel cantilever beam (4) is fixed on the concrete beam (5) through an anchoring device (41), the middle part of the steel cantilever beam (4) is connected with the pre-embedded lug plate of the concrete beam (5) through a hinged support (42), the front end of the steel cantilever beam (4) is connected with the steel beam (6) through another hinged support (42), the steel cantilever beam (4) is locked, the steel beam (6) and the concrete beam (5) form a firm and stable structure, and the steel cantilever beam (4) and the steel truss (3) become the stress structure for pouring the wet joint section.

8. The method of claim 1, wherein: In the step S5, the formwork is erected at the wet joint section position, the reinforcement is bound, the prestressed pipe and the prestressed steel beam are installed, the concrete is poured and the concrete is maintained, after the concrete of the wet joint section reaches the design strength, the formwork and the steel cantilever beam (4) are removed, the prestressed steel beam is tensioned, and the construction is completed.

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