Construction method for segmental assembly of portal pier cap beam

Abstract

This invention discloses a construction method for assembling portal pier cap beam segments, comprising: 1) prefabricating cast-in-place segments on the top of the pier column, and sequentially installing outriggers, two sets of adjacent main trusses, and two winch cranes on the upper side of the prefabricated cast-in-place segments; 2) fixing the suspension beams to the portal pier cap beam segments respectively; 3) using inverted T-shaped special lifting tools, the winch cranes lift the portal pier cap beam segments one by one through the suspension beams, suspending them under the main trusses after they are close to the prefabricated cast-in-place segments; 4) completing the lifting and suspension of each portal pier cap beam segment segment by segment; 5) completing the temporary prestressing tensioning of several portal pier cap beam segments; 6) completing the construction of wet joints between portal pier cap beam segments; and 7) completing the permanent prestressing tensioning of the steel strands of the assembled portal pier cap beam. This invention solves the problem of constructing portal pier cap beams in road sections with short construction windows, shortens on-site construction time, significantly improves construction efficiency, and yields significant social and economic benefits.

Description

Technical Field

[0001] This invention relates to a bridge construction method, and more particularly to a method for constructing bridge pier cap beams on existing roads without affecting existing road traffic, belonging to the field of bridge construction technology. Background Technology

[0002] When constructing municipal bridges on busy urban roads, road closures are often necessary late at night when traffic is relatively light to avoid disrupting traffic. This results in short construction windows, limited construction areas due to various municipal facilities along the roadsides. If the construction of portal pier cap beams for municipal bridges were to continue using cast-in-place methods, the short road closure time would prevent it from being carried out. New construction methods are needed to solve this problem. Summary of the Invention

[0003] The purpose of this invention is to provide a construction method for assembling portal pier cap beam segments, solving the problem of constructing portal pier cap beams in road sections with short construction windows and high safety standards.

[0004] This invention is achieved through the following technical solution:

[0005] A construction method for assembling portal pier cap beam segments includes the following steps:

[0006] 1) Cast a central portal pier cap beam section on the top of the central pier column of the main road, and cast a ramp portal pier cap beam section on the top of the ramp pier columns on the left and right sides of the main road. Then, install a set of main truss middle legs on both sides of the top surface of the central portal pier cap beam section after maintenance, and install a main truss side legs on both sides of the top surface of the ramp portal pier column section.

[0007] 2) Install one set of main trusses with a load-bearing capacity of 3500kN on the leg hinge seats on the upper side of the main truss legs and the leg hinge seats on the upper side of the main truss side legs respectively. The main trusses are adjacent at one end and cantilevered at the other end. Each set of main trusses includes two truss beams arranged side by side. The top of the truss beam is a straight steel structure beam, the bottom is a welded rectangular frame, and the sides are multiple trusses arranged at inclined intervals. The upper and lower ends of the multiple trusses arranged in a triangle are respectively hinged to the straight steel structure beam and the sides of the welded rectangular frame to form a transversely triangular truss beam. The straight steel structure beams and the welded rectangular frames are connected to each other. The main truss is welded together to form an integral structure via upper and lower horizontal connecting rods. The lower side of the welded rectangular frame is fixedly connected to the upper side of the leg hinge seat via four sets of precision-rolled threaded steel tie rods and nuts. The lower side of the leg hinge seat is fixed to the upper side of the central portal pier cap beam and the upper side of the ramp portal pier column via the leg support beam and leveling device, respectively. The top surface of the I-shaped steel structure beam is equipped with hoisting crane rails. The top surface of the hoisting crane rails is leveled by the leveling device. A hoisting crane is installed on the hoisting crane rail at the top of each main truss, thereby completing the installation of the main truss and hoisting cranes.

[0008] 3) In the following steps, two winch cranes are used to hoist and assemble two portal pier cap beam segments simultaneously. The portal pier cap beam segments are located at the designated positions under the main truss. The middle part of the connecting steel bars is vertically fixed to the four corners of the middle part of the hanging beam. Then, the hanging beam is hoisted to the upper side of the portal pier cap beam segment to be hoisted, and the lower end of the connecting steel bars passes through the corresponding prefabricated through holes of the portal pier cap beam segment. The hanging beam is fixed to the top surface of the portal pier cap beam segment by tightening the nuts on the lower end of the connecting steel bars.

[0009] 4) Using the remote control, the inverted T-shaped special lifting device of the hoisting crane is lowered to the upper side of the suspension beam. The lower hinge pins are inserted into the hinge seats of the central box beam on both sides of the lower side of the inverted T-shaped special lifting device and the ear plates on both sides of the middle of the suspension beam, so that the inverted T-shaped special lifting device and the suspension beam are connected as one unit. Then, the inverted T-shaped special lifting device is raised, and the portal pier cap beam segment is pulled up by the suspension beam. The hoisting crane moves along the hoisting crane track to adjust the position of the inverted T-shaped special lifting device so that the top surface of the portal pier cap beam segment is flush with the top surface of the adjacent central portal pier cap beam cast-in-place segment, and the distance between the two adjacent surfaces is minimized.

[0010] 5) The upper ends of the precision-rolled threaded steel lifting rods pass through the welded rectangular frame, and the lower ends pass through the upper sides of both ends of the hanging beam, and are locked with nuts, thereby suspending the portal pier cap beam segment on the lower side of the main truss and adjacent to the central portal pier cap beam cast-in-place segment, completing the hoisting and positioning of the first portal pier cap beam segment; after removing the lower hinge pins, the inverted T-shaped special lifting tool is instructed to rise and detach from the hanging beam;

[0011] 6) Using two winch cranes, repeat steps 3) to 5) simultaneously to make the top surfaces of two adjacent portal pier cap beam segments flush with each other and minimize the distance between their adjacent surfaces; repeat this process to complete the splicing of portal pier cap beam segments between the central portal pier cap beam cast-in-place segment and the ramp portal pier cap beam cast-in-place segment, as well as the portal pier cap beam segments with cantilevered outer ends at the ramp portal pier cap beam cast-in-place segment.

[0012] 7) After assembling the portal pier cap beam segments, fix the tensioning modules to both sides of the top surface of the portal pier cap beam and the lower side of the rectangular through-hole of the portal pier cap beam. Then, pass the fine-rolled threaded steel horizontal tensioning rods through the hanging beams fixed to the top surface of several portal pier cap beam segments and the tensioning modules fixed at intervals in the rectangular through-hole of several portal pier cap beam segments. The fine-rolled threaded steel horizontal tensioning rods are fixedly connected to each other to form temporary prestressed tensioning rods by connecting bolts. Apply tension to the temporary prestressed tensioning rods by using hydraulic jacks supported on one end of the tensioning module through the base frame, and lock them with nuts. In this way, the temporary prestressing tensioning between the central portal pier cap beam cast-in-place segment and the portal pier cap beam segments, between several portal pier cap beam segments, and between the portal pier cap beam segments and the ramp portal pier column cast-in-place segment is completed segment by segment.

[0013] 8) Install wet joint templates at the joints between the central portal pier cap beam cast-in-place section and the portal pier cap beam segment, the joints between the portal pier cap beam segments, and the joints between the portal pier cap beam segment and the ramp portal pier column cast-in-place section, and use early-strength micro-expansion concrete to fill the joints.

[0014] 9) After the early-strength micro-expansion concrete reaches the required strength, the permanent prestressing tensioning of the portal pier cap beam is prepared. The tensioning platform is suspended under the truss beam by a hoist, located outside the cantilever ends of both ends of the portal pier cap beam. Corrugated pipes are respectively fitted into the reserved holes of the portal pier cap beam. One end of multiple steel strands passes through the conical sleeve at the end of the corrugated pipe and the corrugated pipe inside the portal pier cap beam from one cantilever end of the portal pier cap beam. The conical sleeve passes through the pre-embedded spiral reinforcement in the countersunk hole at the end of the portal pier cap beam, and then exits from the conical sleeve inside the other end of the portal pier cap beam. A steel strand tensioning fixture consisting of an inner anchor plate, a perforated pad, a tensioning cylinder, and an outer anchor plate is installed on the multiple steel strands extending from both ends of the portal pier cap beam. The inner anchor plate is equipped with multiple conical locking sleeves, and the outer anchor plate is equipped with multiple working conical sleeves. High-pressure oil is injected into the... The corresponding tensioning cylinders extend their piston rods to push the outer anchor plates outward. After the multiple working conical sleeves on the outer anchor plates move relative to the outer anchor plates, they clamp the corresponding steel strands. As the piston rods of the tensioning cylinders extend further outward, the steel strands undergo elastic deformation. The elastic restoring force of the steel strands applies a negative bending moment to the portal pier cap beam, partially offsetting the positive bending moment that the portal pier cap beam will experience during service. Then, the piston rods of the tensioning cylinders retract, the tensioning cylinders are unloaded, and the multiple conical locking sleeves move relative to the inner anchor plates, causing the conical locking sleeves to lock the corresponding steel strands. After removing the multiple working conical sleeves, the outer anchor plates, tensioning cylinders, and perforated pads are removed in sequence. Then, the steel strands on the outside of the conical locking sleeves are cut one by one. Finally, concrete is poured to seal the ends of multiple steel strands in the countersunk holes at the ends of the portal pier cap beam, completing the permanent prestressing tensioning of the portal pier cap beam.

[0015] The objectives of this invention can also be further achieved through the following technical measures.

[0016] Furthermore, in step 3), the hanging beam is a composite box girder structure, including a central box girder, two connecting beams, two vertical end beams, and four ear plates. The connecting beams are box girders with rectangular cross-sections. The symmetrically arranged connecting beams are fixed to the lower middle part of the central box girder and intersect the central box girder perpendicularly. One end of the threaded steel hanger rod passes vertically through the outer end of the connecting beam, and the other end of the threaded steel hanger rod passes downward through the prefabricated through hole corresponding to the top surface of the portal pier cap beam segment. The horizontally placed hanging beam is fixed to the portal pier cap beam segment by nuts screwed onto both ends of the threaded steel hanger rod. The four ear plates, which are used to hinge with the inverted T-shaped special hanger, are vertically welded and fixed to the two sides of the middle part of the central box girder in groups of two. The vertical end beams are vertically fixed to both ends of the central box girder, and the lower end of the threaded steel upper tie rod passes through the top of the vertical end beam.

[0017] Furthermore, the vertical end beam is also a composite box girder structure, including a Π-shaped box girder, a pair of upper hinge lugs and a pair of upper hinge seats, the lower ends of which are welded and fixed to the two ends of the central box girder respectively. The upper ends of the Π-shaped box girder are respectively welded to the lower ends of the upper hinge lugs, and the upper hinge seats are respectively hinged to the upper hinge lugs. The lower end of the fine-rolled threaded steel upper tie rod passes through the top of the upper hinge seat and is then fastened by a nut.

[0018] Furthermore, the inverted T-shaped special lifting device includes an upper hinged box girder, a lower hinged box girder, a lower crossbeam, a lower crossbeam support cylinder, and paired side beams, side beam hinge seats, and side beam angle adjustment cylinders. The upper end of the upper hinged box girder is hinged to the lower end of the pulley block of the winch crane, the lower end of the upper hinged box girder is hinged to the upper end of the lower hinged box girder, and the lower end of the lower hinged box girder is hinged to the center of the lower crossbeam to form an inverted T-shaped structure. The side beams intersect perpendicularly with both ends of the lower crossbeam, and the middle parts of the side beams are respectively hinged to the side beam hinge seats fixed on the lower sides of both ends of the lower crossbeam. The lower crossbeam hinge seats are respectively fixed on both ends of the lower crossbeam. The upper ends of the side beam angle adjusting cylinders are respectively hinged to the upper ends of the lower crossbeam hinge seats, and the lower ends of the side beam angle adjusting cylinders are respectively hinged to the side beam hinge seats fixed at one end of the side beam; the upper ends of the lower crossbeam support cylinders are hinged to the upper hinge seats of the lower crossbeam support cylinders on one side of the upper end of the lower hinge box beam, and the lower ends of the lower crossbeam support cylinders are hinged to the lower hinge seats of the lower crossbeam support cylinders, and the lower hinge seats of the lower crossbeam support cylinders are fixed on one end of the lower crossbeam; the four central box beam hinge seats are respectively vertically welded and fixed to the lower side of the middle and rear ends of the side beams, and are respectively hinged to the ear plates on both sides of the middle of the central box beams.

[0019] This invention employs precast cast-in-place sections of portal pier cap beams at the top of the central pier and ramp piers. Two adjacent truss beams are then supported on each cast-in-place pier cap beam section by outriggers. A winch crane is installed on each truss beam, and each winch crane lifts a segment of the portal pier cap beam, splicing it to both ends of the precast cast-in-place pier cap beam. This process completes the assembly of the portal pier cap beam segment by segment. The construction of the portal pier cap beam is then completed through temporary prestressing tensioning between the segments, wet joint construction, and permanent prestressing tensioning of the entire portal pier cap beam. This invention only requires the use of two lanes of the multi-lane road beneath the portal pier cap beam, without interrupting traffic during construction, thus solving the problem of constructing portal pier cap beams on road sections with short construction windows. Compared to the method of constructing a single precast portal pier cap beam, this invention eliminates the need for a complete set of cast-in-place formwork and support systems, shortening on-site construction time, significantly improving construction efficiency, and yielding substantial social and economic benefits.

[0020] The advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments, which are given by way of example only with reference to the accompanying drawings. Attached Figure Description

[0021] Figure 1This is a step diagram of the assembly process for portal pier cap beam segments using the present invention;

[0022] Figure 2 yes Figure 1 AA section enlarged view;

[0023] Figure 3 yes Figure 2 A magnified view from direction B;

[0024] Figure 4 This is a schematic diagram of temporary prestressing tensioning;

[0025] Figure 5 This is a schematic diagram of permanent prestressing tensioning;

[0026] Figure 6 yes Figure 4 Enlarged view of Part I;

[0027] Figure 7 yes Figure 5 Enlarged view of Part II;

[0028] Figure 8 This is an enlarged left view of the suspended beam. Detailed Implementation

[0029] The invention will be further explained below with reference to the accompanying drawings and an example of municipal bridge construction in a certain area.

[0030] The municipal bridge in this embodiment spans a 12-lane dual carriageway with heavy traffic both day and night. Road closures are required from 11:00 PM to 4:00 AM the following day, leaving limited construction time. Various municipal facilities also exist on both sides of the road, restricting the construction area. The total span of the portal pier cap beams to be constructed ranges from 37.6 to 64 meters.

[0031] In the description of this invention, terms such as "upper," "lower," "left," "right," "inner," and "outer" that indicate orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and do not indicate or imply that the device referred to must have a specific orientation.

[0032] like Figures 1-3 As shown, this embodiment includes the following steps:

[0033] 1) Cast the central portal pier cap beam section 101 on the top of the central pier column 10 of the main road, and cast the ramp portal pier cap beam section 201 on the top of the ramp pier columns 20 on the left and right sides of the main road. Then, after the maintenance is completed, install one set of main truss middle support leg 1 on each of the longitudinal sides of the top surface of the central portal pier cap beam section 101, and install one main truss side support leg 2 on each of the transverse sides of the top surface of the ramp portal pier column section 201.

[0034] 2) A set of main trusses 3 with a bearing capacity of 3500kN is installed on the leg hinge seat 11 on the upper side of the main truss leg 1 and the leg hinge seat 21 on the upper side of the main truss side leg 2. The main trusses 3 are adjacent at one end and the other end is cantilevered out as the main truss side leg 2. Each set of main trusses 3 includes two truss beams 31 arranged side by side. The top of the truss beam 31 is a straight steel structure beam 311, the bottom is a welded rectangular frame 312, and the sides are multiple truss members 313 arranged at an inclined interval. The upper and lower ends of the multiple truss members 313 arranged in a triangle are respectively hinged to the straight steel structure beam 311 and the sides of the welded rectangular frame 312 to form a transversely triangular truss beam 31. The straight steel structure beams 311 and the welded rectangular frames 312 are respectively welded together by upper horizontal connecting rods 314 and lower horizontal connecting rods 315 made of steel sections to form an integral main truss 3. The lower side of the welded rectangular frame 312 and the upper side of the support leg hinge seat 21 are fixedly connected by a group of four precision-rolled threaded steel tie rod nuts 4. The lower side of the support leg hinge seat 21 is fixed to the upper side of the central portal pier cap beam cast-in-place section 101 and the upper side of the ramp portal pier column cast-in-place section 201 respectively through the support leg support beam 22 and the leveling device 23. The top surface of the straight steel structure beam 311 is respectively installed with a hoisting crane rail 51. The top surface of the hoisting crane rail 51 is leveled by the leveling device 23. A hoisting crane 5 is installed on the hoisting crane rail 51 at the top of each main truss 3, thereby completing the installation of the main truss 3 and the hoisting crane 5.

[0035] 3) In the following steps, two winch cranes 5 are used simultaneously to lift and assemble two sections of the portal pier cap beam, improving installation efficiency. For example... Figure 1 Work step a and Figure 3 As shown, the portal pier cap beam segment 30 is located at the designated position under the main truss 3. The middle part of the connecting steel bar 6 is vertically fixed to the four corners of the middle part of the hanging beam 7. Then, the hanging beam 7 is hoisted to the upper side of the portal pier cap beam segment 30 to be hoisted, and the lower end of the connecting steel bar 6 passes through the corresponding prefabricated through hole 301 of the portal pier cap beam segment 30. The hanging beam 7 is fixed to the top surface of the portal pier cap beam segment 30 by tightening the nuts 61 on the lower end of the connecting steel bar 6.

[0036] 4) Using a remote control, the inverted T-shaped special lifting device 52 of the hoisting crane 5 is lowered to the upper side of the suspension beam 7. The lower hinge pins 533 are inserted into the center box beam hinge seats 532 on both sides of the lower end of the inverted T-shaped special lifting device 52 and the ear plates 74 on both sides of the middle of the suspension beam 7, so that the inverted T-shaped special lifting device 52 and the suspension beam 7 are connected as one unit. Then, the inverted T-shaped special lifting device 52 is raised, and the portal pier cap beam segment 30 is pulled up by the suspension beam 7. The hoisting crane 5 moves along the hoisting crane track 51 to adjust the position of the inverted T-shaped special lifting device 52, so that the top surface of the portal pier cap beam segment 30 is flush with the top surface of the adjacent central portal pier cap beam cast-in-place segment 101, minimizing the distance between the two adjacent surfaces and improving the accuracy of the splicing of the portal pier cap beam segment 30.

[0037] 5) The upper ends of the precision-rolled threaded steel lifting rods 75 pass through the welded rectangular frames 312, and the lower ends pass through the upper sides of both ends of the hanging beam 7, and are locked with nuts 61, thereby suspending the portal pier cap beam segment 30 on the lower side of the main truss 3 and adjacent to the central portal pier cap beam cast-in-place segment 101, completing the hoisting and positioning of the first portal pier cap beam segment 30. After removing the lower hinge pins 533, the inverted T-shaped special lifting tool 52 is instructed to rise and detach from the hanging beam 7.

[0038] 6) such as Figure 1 As shown in steps b and c, two winch cranes 5 are used to synchronously repeat steps 3) to 5) to make the top surfaces of two adjacent portal pier cap beam segments 30 flush with each other and minimize the distance between their adjacent surfaces. This process is repeated one by one to complete the splicing of the portal pier cap beam segments 30 between the central portal pier cap beam cast-in-place segment 101 and the ramp portal pier cap beam cast-in-place segment 201, as well as the splicing of the portal pier cap beam segments 30 that are cantilevered at the outer end of the ramp portal pier cap beam cast-in-place segment.

[0039] 7) such as Figure 4 and Figure 6 As shown, after the assembly of the portal pier cap beam segment 30 is completed, the tensioning modules 8 are fixed on both sides of the top surface of the portal pier cap beam 300 and the lower side of the rectangular through hole 301 of the portal pier cap beam. Then, the fine-rolled threaded steel horizontal tensioning rods 81 are sequentially passed through the hanging beams 7 fixed on the top surface of several portal pier cap beam segments 30 and the tensioning modules 8 fixed at intervals in the rectangular through holes 301 of several portal pier cap beams. The fine-rolled threaded steel horizontal tensioning rods 81 are fixedly connected to each other by connecting bolts 82 to form temporary prestressed tensioning rods 810. Using hydraulic jacks 83 supported on one end of the tensioning module 8 via the base frame 82, tension force is applied to the temporary prestressed tensioning rods 810 respectively, and they are locked with nuts 61, thereby completing the temporary prestressed tensioning between the central portal pier cap beam cast-in-place section 101 and the portal pier cap beam segment 30, between several portal pier cap beam segments 30, and between the portal pier cap beam segment 30 and the ramp portal pier column cast-in-place section 201 respectively;

[0040] 8) For example Figure 4 As shown, wet joint templates 303 are installed at the joints 302 between the central portal pier cap beam cast-in-place section 101 and the portal pier cap beam segment 30, the joints 302 between the portal pier cap beam segments 30, and the joints 302 between the portal pier cap beam segment 30 and the ramp portal pier column cast-in-place section 20. Early-strength micro-expansion concrete is used to fill the joints 302.

[0041] 9) For example Figure 5 and Figure 7 As shown, after the early-strength micro-expansion concrete reaches the required strength, the permanent prestressing tension of the portal pier cap beam 300 is prepared. The tensioning platform 40 is suspended under the truss beam 31 by a hoist and is located outside the cantilever ends 304 at both ends of the portal pier cap beam 300. Corrugated pipes 305 are respectively fitted into the reserved holes 306 of the portal pier cap beam. The right ends of multiple steel strands 307 pass through the conical sleeves 308 at the ends of the corrugated pipes 305 and the corrugated pipes 305 inside the portal pier cap beam 300 from the cantilever end 304 of the portal pier cap beam 300. The conical sleeves 308 pass through the embedded spiral reinforcements 309 in the countersunk holes 310 at the ends of the portal pier cap beam and then exit from the conical sleeves 308 inside the right end of the portal pier cap beam 300. A steel strand tensioning fixture 9, consisting of an inner anchor plate 91, a perforated pad 92, a tensioning cylinder 93, and an outer anchor plate 94, is installed on the multiple steel strands 307 extending from both ends of the portal pier cap beam 300. The inner anchor plate 91 is equipped with multiple conical locking sleeves 911, and the outer anchor plate 94 is equipped with multiple working conical sleeves 941. High-pressure oil is input into the corresponding tensioning cylinders 93, and the piston rods 931 of the tensioning cylinders extend outward to push the outer anchor plates 94 outward. After the multiple working conical sleeves 941 on the outer anchor plates 94 and the outer anchor plates 94 move relative to each other, they clamp the corresponding steel strands 307. As the piston rods 931 of the tensioning cylinders extend further outward, the steel strands 307 undergo elastic deformation. The elastic restoring force of the steel strands 307 applies a negative bending moment to the portal pier cap beam 300, partially offsetting the positive bending moment that the portal pier cap beam 300 will experience during service. Next, the piston rods 931 of the tensioning cylinders retract, the tensioning cylinders 93 are unloaded, and when the multiple conical locking sleeves 911 move relative to the inner anchor plate 91, the conical locking sleeves 911 lock the corresponding steel strands 307. After removing the multiple working conical sleeves 941, the outer anchor plate 94, the tensioning cylinder 93, and the perforated pad 92 are removed in sequence. Then, the steel strands 307 on the outside of the conical locking sleeves 911 are cut off one by one. Then, concrete is poured to seal the ends of the multiple steel strands 307 in the countersunk holes 310 at the ends of the portal pier cap beam, thus completing the permanent prestressing tensioning of the portal pier cap beam 300.

[0042] like Figure 2 and Figure 8As shown, the hanging beam 7 in step 3) is a composite box girder structure, including a central box girder 71, two connecting beams 72, two vertical end beams 73, and four ear plates 74. The connecting beams 72 are box girders with rectangular cross sections. The symmetrically arranged connecting beams 72 are fixed to the lower middle part of the central box girder 71 and intersect the central box girder 71 perpendicularly. The upper ends of the threaded steel rods 75 pass vertically through the outer ends of the connecting beams 72, and the lower ends pass downward through the prefabricated through holes 301 corresponding to the top surface of the portal pier cap beam segment 30. The horizontally placed hanging beams 7 are fixed to the portal pier cap beam segment 30 by nuts 61 screwed onto both ends of the connecting steel bars 75. The four ear plates 74, which are used to hinge with the inverted T-shaped special lifting tool, are divided into two groups and vertically welded and fixed to both sides of the middle part of the central box girder 71. The vertical end beams 73 are vertically fixed to both ends of the central box girder 71, and the lower ends of the threaded steel upper tie rods 75 pass through the top of the vertical end beams 73. The vertical end beam 73 is also a composite box girder structure, including a Π-shaped box girder 731, a pair of upper hinge lugs 732, and a pair of upper hinge seats 733. The lower ends of the Π-shaped box girder 731 are welded and fixed to both ends of the central box girder 71, and the upper ends of the Π-shaped box girder 731 are welded to the lower ends of the upper hinge lugs 732, respectively. The upper hinge seats 733 are hinged to the upper hinge lugs 732. The lower end of the high-strength threaded steel upper tie rod 75 passes through the top of the upper hinge seat and is fastened by a nut 61.

[0043] like Figure 2 and Figure 3As shown, the inverted T-shaped special lifting device 52 includes an upper hinged box girder 521, a lower hinged box girder 522, a lower crossbeam 523, a lower crossbeam support cylinder 524, and paired side beams 525, side beam hinge seats 526, and side beam angle adjustment cylinders 527. The upper end of the upper hinged box girder 521 is hinged to the lower end of the pulley block 53 of the winch crane 5, and the lower end of the upper hinged box girder 521 is hinged to the upper end of the lower hinged box girder 522. The lower end of the lower hinged box girder 522 is hinged to the center of the lower crossbeam 523 to form an inverted T-shaped structure. The side beams 525 intersect perpendicularly with both ends of the lower crossbeam 523, and the middle parts of the side beams 525 are hinged to the side beam hinge seats 526 fixed to the lower sides of both ends of the lower crossbeam 523. The lower crossbeam hinge seats 528 are fixed to the upper sides of both ends of the lower crossbeam 523. The upper ends of the side beam angle adjusting cylinders 527 are hinged to the upper ends of the lower crossbeam hinge seats 528, and the lower ends of the side beam angle adjusting cylinders 527 are hinged to the side beam hinge seats 529 fixed to one end of the side beam 525. The upper end of the lower crossbeam support cylinder 524 is hinged to the upper hinge seat 530 of the lower crossbeam support cylinder on one side of the upper end of the lower hinged box girder 522, and the lower end of the lower crossbeam support cylinder 524 is hinged to the lower hinge seat 531 of the lower crossbeam support cylinder. The lower hinge seat 531 of the lower crossbeam support cylinder is fixed to the right end of the lower crossbeam 523. The four center box girder hinge seats 532 are divided into two groups and vertically welded and fixed to the lower side of the middle and rear ends of the side beam 525, respectively, and are hinged to the ear plates 74 on both sides of the middle of the center box girder 71. The lower crossbeam support cylinder 524 can be used to adjust the deflection angle of the connecting crossbeam 72 of the hanging crossbeam 7 to adapt to the slope of the portal pier cap beam 300, making the connection between the hanging crossbeam 7 and the portal pier cap beam segment 300 more reliable and ensuring the safe lifting of the portal pier cap beam segment 30.

[0044] In addition to the above embodiments, the present invention may have other implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A construction method for assembling portal pier cap beam segments, characterized in that: Includes the following steps: 1) Cast a central portal pier cap beam section on the top of the central pier column of the main road, and cast a ramp portal pier cap beam section on the top of the ramp pier columns on the left and right sides of the main road. Then, install a set of main truss middle legs on both sides of the top surface of the central portal pier cap beam section after maintenance, and install a main truss side legs on both sides of the top surface of the ramp portal pier column section. 2) Install one set of main trusses with a load-bearing capacity of 3500kN on the leg hinge seats on the upper side of the main truss legs and the leg hinge seats on the upper side of the main truss side legs respectively. The main trusses are adjacent at one end and cantilevered at the other end. Each set of main trusses includes two truss beams arranged side by side. The top of the truss beam is a straight steel structure beam, the bottom is a welded rectangular frame, and the sides are multiple trusses arranged at inclined intervals. The upper and lower ends of the multiple trusses arranged in a triangle are respectively hinged to the straight steel structure beam and the sides of the welded rectangular frame to form a transversely triangular truss beam. The straight steel structure beams and the welded rectangular frames are connected to each other. The main truss is welded together to form an integral structure via upper and lower horizontal connecting rods. The lower side of the welded rectangular frame is fixedly connected to the upper side of the leg hinge seat via four sets of precision-rolled threaded steel tie rods and nuts. The lower side of the leg hinge seat is fixed to the upper side of the central portal pier cap beam and the upper side of the ramp portal pier column via the leg support beam and leveling device, respectively. The top surface of the I-shaped steel structure beam is equipped with hoisting crane rails. The top surface of the hoisting crane rails is leveled by the leveling device. A hoisting crane is installed on the hoisting crane rail at the top of each main truss, thereby completing the installation of the main truss and hoisting cranes. 3) In the following steps, two winch cranes are used to hoist and assemble two portal pier cap beam segments simultaneously. The portal pier cap beam segments are located at the designated positions under the main truss. The middle part of the connecting steel bars is vertically fixed to the four corners of the middle part of the hanging beam. Then, the hanging beam is hoisted to the upper side of the portal pier cap beam segment to be hoisted, and the lower end of the connecting steel bars passes through the corresponding prefabricated through holes of the portal pier cap beam segment. The hanging beam is fixed to the top surface of the portal pier cap beam segment by tightening the nuts on the lower end of the connecting steel bars. 4) Using the remote control, the inverted T-shaped special lifting device of the hoisting crane is lowered to the upper side of the suspension beam. The lower hinge pins are inserted into the hinge seats of the central box beam on both sides of the lower side of the inverted T-shaped special lifting device and the ear plates on both sides of the middle of the suspension beam, so that the inverted T-shaped special lifting device and the suspension beam are connected as one unit. Then, the inverted T-shaped special lifting device is raised, and the portal pier cap beam segment is pulled up by the suspension beam. The hoisting crane moves along the hoisting crane track to adjust the position of the inverted T-shaped special lifting device so that the top surface of the portal pier cap beam segment is flush with the top surface of the adjacent central portal pier cap beam cast-in-place segment, and the distance between the two adjacent surfaces is minimized. 5) The upper ends of the precision-rolled threaded steel lifting rods pass through the welded rectangular frame, and the lower ends pass through the upper sides of both ends of the hanging beam, and are locked with nuts, thereby suspending the portal pier cap beam segment on the lower side of the main truss and adjacent to the central portal pier cap beam cast-in-place segment, completing the hoisting and positioning of the first portal pier cap beam segment; after removing the lower hinge pins, the inverted T-shaped special lifting tool is instructed to rise and detach from the hanging beam; 6) Using two winch cranes, repeat steps 3) to 5) simultaneously to make the top surfaces of two adjacent portal pier cap beam segments flush with each other and minimize the distance between their adjacent surfaces; repeat this process to complete the splicing of portal pier cap beam segments between the central portal pier cap beam cast-in-place segment and the ramp portal pier cap beam cast-in-place segment, as well as the portal pier cap beam segments with cantilevered outer ends at the ramp portal pier cap beam cast-in-place segment. 7) After assembling the portal pier cap beam segments, fix the tensioning modules to both sides of the top surface of the portal pier cap beam and the lower side of the rectangular through-hole of the portal pier cap beam. Then, pass the fine-rolled threaded steel horizontal tensioning rods through the hanging beams fixed to the top surface of several portal pier cap beam segments and the tensioning modules fixed at intervals in the rectangular through-hole of several portal pier cap beam segments. The fine-rolled threaded steel horizontal tensioning rods are fixedly connected to each other to form temporary prestressed tensioning rods by connecting bolts. Apply tension to the temporary prestressed tensioning rods by using hydraulic jacks supported on one end of the tensioning module through the base frame, and lock them with nuts. In this way, the temporary prestressing tensioning between the central portal pier cap beam cast-in-place segment and the portal pier cap beam segment, between several portal pier cap beam segments, and between the portal pier cap beam segment and the ramp portal pier column cast-in-place segment is completed segment by segment. 8) Install wet joint templates at the joints between the central portal pier cap beam cast-in-place section and the portal pier cap beam segment, the joints between the portal pier cap beam segments, and the joints between the portal pier cap beam segment and the ramp portal pier column cast-in-place section, and use early-strength micro-expansion concrete to fill the joints. 9) After the early-strength micro-expansion concrete reaches the required strength, the permanent prestressing tensioning of the portal pier cap beam is prepared. The tensioning platform is suspended under the truss beam by a hoist, located outside the cantilever ends of both ends of the portal pier cap beam. Corrugated pipes are respectively fitted into the reserved holes of the portal pier cap beam. One end of multiple steel strands passes through the conical sleeve at the end of the corrugated pipe and the corrugated pipe inside the portal pier cap beam from one cantilever end of the portal pier cap beam. The conical sleeve passes through the pre-embedded spiral reinforcement in the countersunk hole at the end of the portal pier cap beam, and then exits from the conical sleeve inside the other end of the portal pier cap beam. A steel strand tensioning fixture consisting of an inner anchor plate, a perforated pad, a tensioning cylinder, and an outer anchor plate is installed on the multiple steel strands extending from both ends of the portal pier cap beam. The inner anchor plate is equipped with multiple conical locking sleeves, and the outer anchor plate is equipped with multiple working conical sleeves. High-pressure oil is injected into the... The corresponding tensioning cylinders extend their piston rods to push the outer anchor plates outward. After the multiple working conical sleeves on the outer anchor plates move relative to the outer anchor plates, they clamp the corresponding steel strands. As the piston rods of the tensioning cylinders extend further outward, the steel strands undergo elastic deformation. The elastic restoring force of the steel strands applies a negative bending moment to the portal pier cap beam, partially offsetting the positive bending moment that the portal pier cap beam will experience during service. Then, the piston rods of the tensioning cylinders retract, the tensioning cylinders are unloaded, and the multiple conical locking sleeves move relative to the inner anchor plates, causing the conical locking sleeves to lock the corresponding steel strands. After removing the multiple working conical sleeves, the outer anchor plates, tensioning cylinders, and perforated pads are removed in sequence. Then, the steel strands on the outside of the conical locking sleeves are cut one by one. Finally, concrete is poured to seal the ends of multiple steel strands in the countersunk holes at the ends of the portal pier cap beam, completing the permanent prestressing tensioning of the portal pier cap beam.

2. The construction method for assembling portal pier cap beam segments as described in claim 1, characterized in that: The suspension beam in step 3) is a composite box girder structure, including a central box girder, two connecting beams, two vertical end beams, and four ear plates. The connecting beams are box girders with rectangular cross sections. The symmetrically arranged connecting beams are fixed to the lower middle part of the central box girder and intersect the central box girder perpendicularly. One end of the threaded steel rod passes vertically through the outer end of the connecting beam, and the other end of the threaded steel rod passes downward through the prefabricated through hole corresponding to the top surface of the portal pier cap beam segment. The horizontally placed suspension beam is fixed to the portal pier cap beam segment by nuts screwed onto both ends of the threaded steel rod. The four ear plates, which are used to hinge with the inverted T-shaped special lifting tool, are vertically welded and fixed to the two sides of the middle part of the central box girder in groups of two. The vertical end beams are vertically fixed to both ends of the central box girder. The lower end of the threaded steel upper tie rod passes through the top of the vertical end beam.

3. The construction method for assembling portal pier cap beam segments as described in claim 2, characterized in that: The vertical end beam is also a composite box girder structure, including a Π-shaped box girder, a pair of upper hinge lugs and a pair of upper hinge seats. The lower ends of the Π-shaped box girder are welded and fixed to both ends of the central box girder. The upper ends of the Π-shaped box girder are welded to the lower ends of the upper hinge lugs. The upper hinge seats are hinged to the upper hinge lugs. The lower end of the fine-rolled threaded steel upper tie rod passes through the top of the upper hinge seat and is fastened by a nut.

4. The construction method for assembling portal pier cap beam segments as described in claim 2, characterized in that: The inverted T-shaped special lifting device includes an upper hinged box girder, a lower hinged box girder, a lower crossbeam, a lower crossbeam support cylinder, and paired side beams, side beam hinge seats, and side beam angle adjustment cylinders. The upper end of the upper hinged box girder is hinged to the lower end of the pulley block of the winch crane, the lower end of the upper hinged box girder is hinged to the upper end of the lower hinged box girder, and the lower end of the lower hinged box girder is hinged to the center of the lower crossbeam to form an inverted T-shaped structure. The side beams intersect perpendicularly with both ends of the lower crossbeam, and the middle parts of the side beams are respectively hinged to the side beam hinge seats fixed on the lower sides of both ends of the lower crossbeam. The lower crossbeam hinge seats are respectively fixed on the upper sides of both ends of the lower crossbeam. The upper ends of the beam angle adjusting cylinders are respectively hinged to the upper ends of the lower crossbeam hinge seats, and the lower ends of the side beam angle adjusting cylinders are respectively hinged to the side beam hinge seats fixed at one end of the side beam; the upper ends of the lower crossbeam support cylinders are hinged to the upper hinge seats of the lower crossbeam support cylinders on one side of the upper end of the lower hinge box beam, and the lower ends of the lower crossbeam support cylinders are hinged to the lower hinge seats of the lower crossbeam support cylinders. The lower hinge seats of the lower crossbeam support cylinders are fixed on one end of the lower crossbeam; the four central box beam hinge seats are respectively vertically welded and fixed to the lower side of the middle and rear ends of the side beams, and are respectively hinged to the ear plates on both sides of the middle of the central box beam.

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