Construction method for starting arch segment at intersection of column and arch of open-web rigid frame bridge

Abstract

The present application relates to the field of arch beam combination bridge, and discloses a construction method for starting arch section at arch intersection of open-web rigid frame bridge column, comprising the following steps: step one, completing bridge pier construction, reserving a framework connector at the position of the lower chord arch foot on the side of the bridge pier; step two, installing a stiff framework at the position of the lower chord arch foot, connecting the lower end of the stiff framework with the framework connector, the length of the stiff framework being greater than the sum of the lengths of the lower chord arch 1# section and the lower chord arch 2# section, installing a temporary cable on the upper end of the stiff framework, connecting the lower end of the cable with the pier column, pouring the lower chord arch 0# section, embedding the framework connector in the lower chord arch 0# section, and pouring the lower chord arch 1# section with the bottom basket system as support, so that the stiff framework serves as the internal support of the lower chord arch 1# section; step three, removing the lower end of the cable, pouring the lower chord arch 2# section with the bottom basket system as support, and connecting the lower end of the cable with the lower chord arch 2# section. The lower chord arch 1# section is quickly and efficiently supported.

Description

Technical Field

[0001] This invention relates to the field of arch-beam composite bridges, specifically to a construction method for the initial arch segment at the intersection of columns and arches in a hollow rigid frame bridge. Background Technology

[0002] With the continuous construction and extension of expressways in western China, expressway construction has entered areas with towering mountains, deep valleys, rivers, and more complex geological conditions. Long-span bridges spanning V-shaped river valleys have become key projects for expressways in western China, controlling the overall project schedule and cost.

[0003] The arch-beam composite bridge adopts a combination of upper chord beam and lower chord arch, with the lower chord arch providing support for the upper chord beam, which increases the maximum span, reduces the self-weight, and improves economy.

[0004] However, at the starting arch section where the bridge column and arch meet, that is, where the lower chord arch foot connects to the pier, there is a lack of working space, so a temporary support platform needs to be erected to provide sufficient support for pouring the lower chord arch section 1. However, this requires the pier to be used as support to erect a cantilever support platform. During the erection of the platform, there is a lack of footholds, which is very dangerous. In order to ensure the strength of the cantilever support platform, a large amount of materials are needed to stabilize the platform structure, which lengthens the erection period and consumes a lot of time. Summary of the Invention

[0005] The present invention aims to provide a construction method for the starting arch segment at the intersection of the column and arch of a hollow rigid frame bridge, which can quickly and efficiently support the lower chord arch segment 1.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a construction method for the starting arch section at the intersection of the arch and column of a hollow rigid frame bridge, step one: complete the construction of the bridge pier, and reserve the skeleton connector at the arch foot position of the lower chord arch on the side of the bridge pier. Step 2: Install the stiffening frame at the arch foot of the lower chord arch, connecting the lower end of the stiffening frame to the frame connector. The length of the stiffening frame is greater than the sum of the lengths of the lower chord arch segments 1 and 2. Install temporary ties at the upper end of the stiffening frame, connecting the upper end of the lower ties to the pier column. Cast the lower chord arch segment 0, embedding the frame connector inside the lower chord arch segment 0. Cast the lower chord arch segment 1 with the bottom basket system as support, making the stiffening frame the internal support for the lower chord arch segment 1. Step 3: Remove the lower end of the lower cable and cast the lower chord arch section 2 using the basket system as support. Connect the lower end of the lower cable to the lower chord arch section 2.

[0007] The beneficial effects of this plan are: 1. This solution eliminates the need for a dedicated cantilever support platform. The upper and lower ends of the rigid frame are connected to the pier and the lower cable, respectively, forming a stable triangular structure that serves as support for the lower chord arch section 1. This structure not only assists in the formwork erection and support of the lower chord arch section 1, providing workers with footholds and connecting to the construction platform, but also becomes part of the lower chord arch section 1 structure after its casting, serving as internal support and strengthening its strength. Thus, it can quickly and efficiently support the lower chord arch section 1.

[0008] 2. The length of the rigid frame is greater than the sum of the lengths of the lower chord arch segments 1 and 2, which can provide support for the lower chord arch segments 1 and 2, and at the same time strengthen the connection strength of the lower chord arch segments 1 and 2, increasing the overall integrity.

[0009] Furthermore, the rigid frame is formed by connecting structural steel sections; In step two, the rigid frame is first assembled, and then the whole frame is hoisted to the design position and connected to the frame connectors.

[0010] Furthermore, in step one, after the pier construction is completed, the upper chord beam segment 0# is poured on the top of the pier, the upper chord hanging basket is installed on the upper chord beam segment 0#, the upper chord beam segment 1# is poured using the upper chord hanging basket, and the lifting system is installed on the main truss system of the upper chord hanging basket. The lifting system can drive the bottom basket system to move downwards and remove the connection between the upper end of the suspension system and the main truss system. In step two, before installing the rigid frame, the lifting system moves the bottom basket system downward to the arch foot of the lower chord arch, extending the upper end of the suspension system to connect the upper end of the suspension system with the upper chord hanging basket main truss system. In step three, the traveling system of the upper chord hanging basket drives the main truss system, lifting system, suspension system and bottom basket system to move forward together, and the bottom basket system is used as support to pour the lower chord arch section 2. It also includes step four, installing the travel system and main truss system of the lower chord hanging basket on the lower chord arch segments 1 and 2, connecting the upper end of the main truss system of the lower chord hanging basket and the suspension system of the upper chord hanging basket, and converting the suspension system and bottom basket system of the upper chord hanging basket into the suspension system and bottom basket system of the lower chord hanging basket.

[0011] Furthermore, the lifting system includes several electric hoists; In step one, during the construction of the bridge piers, the upper ends of the electric hoists are all connected to the main truss system of the upper chord hanging basket, and the lower ends of the electric hoists are all hung on the bottom basket system. In step two, as the electric hoist moves the basket system downward, the upper end of the suspension system is temporarily fixed to the steel cable of the electric hoist; after the electric hoist moves the basket system downward, the lower chord arch section 0# and the lower chord arch section 1# are poured on the basket system in sequence.

[0012] Furthermore, the suspension system of the upper chord hanging basket includes several suspension units, each of which includes a hanger and an extension rod. The upper and lower ends of the hanger are respectively provided with an upper connector and a lower connector. The upper end of the hanger passes through the main truss system of the upper chord hanging basket and is threadedly connected to the upper connector. The upper connector is supported on the main truss system. In step two, the upper connector is removed, and the boom and the electric hoist's cable are temporarily fixed with wire. The electric hoist drives the bottom basket system to move downward. The upper end of the extension rod passes through the main truss system of the upper chord hanging basket and is threadedly connected to the upper connector. The upper connector is supported on the main truss system. The extension connector is threadedly connected to the lower end of the extension rod. The lower end of the extension connector is threadedly connected to the upper end of the boom. The wires on the boom and the electric hoist's cable are removed.

[0013] Furthermore, the threads of the hanger and the extension rod are in the same direction, and the lower end of the extension connector is welded with a conversion pad, through which the upper end of the hanger can pass; the main truss system of both the upper chord hanging basket and the lower chord hanging basket includes a main truss, on which a front crossbeam and a rear crossbeam are provided. The front crossbeam or the rear crossbeam is composed of two parallel I-beams, and the distance between the two I-beams is less than the width of the conversion pad; the bottom basket system of the upper chord hanging basket includes a front cantilever beam and a rear cantilever beam, and several longitudinal beams are provided between the front cantilever beam and the rear cantilever beam; In step four, the method for converting the suspension system and bottom basket system of the upper-curved basket into the suspension system and bottom basket system of the lower-curved basket is as follows: Step 4.1 During the installation of the main truss system of the lower chord hanging basket, make the hoisting rod of the upper chord hanging basket pass through the front or rear crossbeam of the lower chord hanging basket, and hang the upper end of the electric hoist on the front or rear crossbeam, and hang the lower end of the electric hoist on the front or rear cantilever beam. Step 4.2: Rotate the extension connector so that the conversion pad at the lower end of the extension connector is supported on the main truss system of the lower chord hanging basket. Remove the upper connector at the upper end of the extension rod, rotate the extension rod to separate the lower end of the extension rod from the extension connector, and remove the extension rod and the electric hoist.

[0014] Furthermore, one end of several longitudinal beams is hinged to the front cantilever beam, and several horizontally arranged support tubes are provided on the rear cantilever beam. The other end of each longitudinal beam is supported on the support tubes, and the other end of the longitudinal beam can slide on the support tubes.

[0015] Furthermore, the conversion pad has four strip bolt holes, each of which can accommodate a limit bolt. In step 4.2, the conversion pad is supported on the front or rear crossbeam of the main truss system of the lower chord hanging basket. Four limiting bolts are installed on the conversion pad. The four limiting bolts are evenly distributed and attached to both sides of the front or rear crossbeam, thereby limiting the spacing between the two I-beams that make up the front or rear crossbeam.

[0016] Furthermore, with the center line of the pier as the axis of symmetry, the upper chord beams and lower chord arches on both sides of the pier are constructed synchronously and symmetrically; several lower chord cables are installed on the pier, all of which pass through the pier, and the two ends of the lower chord cables are anchored in the lower chord arches on both sides of the pier. Starting from the second segment of the lower chord arch, one lower chord cable is constructed for each segment being poured. In step three, the two ends of a lower cable are anchored to the lower chord arch segment 2 on both sides of the pier.

[0017] Furthermore, in step one, longitudinal temporary prestress is applied to the upper side of segment 1 of the upper chord beam; After step four is completed, the temporary prestress applied to segment 1 of the upper chord beam is removed.

[0018] This solution also has the following effects: 1. Compared to using jacks to move the boom downwards, this solution uses an electric hoist to move the bottom basket system downwards, which is faster and more efficient; Furthermore, during construction on high bridge piers, the wind load is significant, and the lower end of the gantry is in a free state, resulting in severe swaying. As the basket system moves downward, the wind load on the gantry gradually increases, causing even more severe swaying and making it prone to deformation and damage. In this design, the electric hoist's steel cable is more flexible than the gantry, and it can recover even if deformed under wind load. The upper end of the gantry is no longer fixed, and the gantry sways along with the steel cable, thus reducing its deformation. When the basket system reaches the arch foot of the lower chord and is connected to the template and the lower chord arch segment 0, the basket system tends to stabilize under the support of the lower chord arch segment 0. At this point, the swaying of the lower end of the gantry under wind load decreases, and the use of extension rods to extend the gantry further reduces its deformation.

[0019] 2. In step four, since the boom is the main load-bearing component, if the connection between the boom and the extension rod is suddenly disconnected, the electric hoist's steel cable becomes the main load-bearing component. The steel cable will be under increased stress and become longer, making the electric hoist susceptible to impact and damage. If the main truss system of the boom and the lower chord hanging basket needs to be fixed first, the connection between the boom and the extension rod still needs to be disconnected first so that the upper connector can be connected to the upper end of the boom. In this solution, without disconnecting the hanging rod and the extension rod, the bottom basket system of the upper chord hanging basket is transferred to the lower chord hanging basket. This function is achieved through a specially designed extension connector, which can connect the hanging rod and the extension rod, and also serve as a nut and a pad to support the lower chord hanging basket.

[0020] Specifically, in this solution, since both the front and rear crossbeams are composed of two I-beams, when welding the front crossbeam, the lifting rod is positioned between the two I-beams, allowing it to pass through the front or rear crossbeam without disconnecting the lifting rod and the extension rod. Then, by rotating the extension connector, it is moved downwards until the conversion pad at the lower end of the extension connector supports the front or rear crossbeam of the lower chord hanging basket. At this point, the lifting rod and the extension rod remain connected through the extension connector, achieving the conversion of the load-bearing parts in advance. Disconnecting the lifting rod and the extension rod at this point will prevent significant impact on the electric hoist or other load-bearing parts due to the conversion of the load-bearing parts.

[0021] The extension connector in this design is not simply a combination of a nut and a washer. It needs to be long enough to connect both the boom and the extension rod simultaneously, and also to move downwards to allow the conversion washer to contact the front or rear cantilever beam while maintaining its connection to the extension rod. Finally, by rotating the extension rod, the lower end of the extension rod is disengaged from the extension connector.

[0022] 3. The weight of the lower chord arches on both sides of the pier is balanced by the lower cable, and the load is transferred to the pier through the middle of the lower cable.

[0023] 4. After constructing the upper chord beam segment 1 and installing the upper chord hanging basket on it, the upper chord beam segment 1 is in a cantilever state. Due to gravity, the end of the upper chord beam segment 1 will sink and deform. Therefore, it is necessary to apply longitudinal temporary prestress on the upper side of the upper chord beam segment 1 to reduce this deformation by causing the end of the upper chord beam segment 1 to tilt upward. However, after the support is erected, the upper chord beam segment 1 is no longer in a cantilever state and the end no longer sinks and deforms. Therefore, the temporary prestress is cancelled to prevent the end of the upper chord beam segment 1 from tilting upward.

[0024] 5. In step one, mark the connection position between the upper end of the boom and the front or rear crossbeam of the upper chord hanging basket; In step two, the connection position between the extension rod and the front or rear crossbeam of the upper chord hanging basket is also at the positioning mark. When installing the extension rod, a tower crane is used to fix the upper end of the extension rod. At this time, the extension rod remains vertical under the action of gravity. Only when there is no wind will the hoist also remain vertical, and the lower end of the extension rod can be aligned and connected with the upper end of the hoist. Then, check whether the hoist and the extension rod are on the same straight line and adjust them in time. Since the connection position between the lower end of the hoist and the front or rear cantilever beam of the bottom basket system remains unchanged, it ensures that the extension rod and the hoist always remain vertical in the windless state. The direction of force in the windless state is always the axial direction of the rod, without eccentric force, thereby ensuring the load-bearing capacity of the extension rod and the hoist.

[0025] The higher the pier, the greater the wind load. Since the length of the suspenders plus the extension rods is relatively large, they are more affected by the wind load. The verticality mentioned in this plan can only guarantee verticality in the windless state. It is impossible to be vertical at all times. Therefore, it is not possible to wait until the wind stops to check the verticality. We can only ensure that the upper end of the suspenders is always in a fixed state, so that the verticality remains unchanged.

[0026] In step four of this scheme, before fixing the upper end of the suspender rod and the front crossbeam of the lower hanging basket, the suspender rod and the extended suspender rod are always connected to prevent the upper end of the suspender rod from changing its verticality due to loss of connection. This ensures that the central axis of the upper chord hanging basket and the lower chord hanging basket are vertically aligned, thereby ensuring that the central axis of the cast upper chord beam and the lower chord arch are vertically aligned, and preventing the load of the upper chord beam from generating eccentric force on the lower chord arch.

[0027] 6. In step two, when the lifting system moves the bottom railing system downwards, due to the inclination of the bottom of the lower chord arch, the longitudinal beams in the bottom railing system also need to be inclinated to support the formwork of the lower chord arch on the longitudinal beams. If the two connection points of the longitudinal beam, the front cantilever beam, and the rear cantilever beam are fixed, then after the longitudinal beam tilts, the horizontal distance between the front and rear cantilever beams decreases. This leads to a decrease in the distance between the lower ends of the hangers connected to the front and rear cantilever beams, causing the hangers to tilt. No matter what adjustments the operator makes, it is impossible to keep all the hangers vertical at the same time, which will result in the following adverse effects: a. At this time, the operator cannot judge whether there is wind by whether the boom is vertical, so he cannot adjust the construction progress of the formwork of the lower chord arch on the bottom railing system in a timely manner according to whether there is wind, thus reducing the construction accuracy of the lower chord arch formwork.

[0028] b. In step four, when installing the main truss of the lower chord hanging basket, the two I-beams on the front and rear crossbeams of the main truss clamp the hanger rod to prevent it from swaying. However, when the hanger rod is no longer vertical, the clamping of the hanger rod by the two I-beams will bring the upper end of the hanger rod back to a vertical state, while the lower end of the hanger rod remains tilted, thus deforming the hanger rod and creating a large internal force, which in turn reduces the durability of the hanger rod.

[0029] In this design, one end of the longitudinal beam is hinged to the front cantilever beam, and the other end is slidably connected to the rear cantilever beam (sliding can be ensured by applying lubricating oil to the contact surface), so that the longitudinal beam will not change the horizontal distance between the front and rear cantilever beams when tilted, and the suspension rod can still remain vertical under the action of gravity. Regarding adverse effect a, it allows operators to judge whether there is wind by whether the hanger is vertical, thus ensuring the construction accuracy of the lower chord arch formwork; regarding adverse effect b, it can prevent the hanger from generating internal forces, thus ensuring the durability of the hanger.

[0030] 7. Regarding effect 6, during the adjustment of the longitudinal beam inclination, if insufficient lubrication on the contact surface between the longitudinal beam and the rear cantilever beam leads to increased friction and abnormal sliding, or if rust occurs at the hinge point between the longitudinal beam and the front cantilever beam, leading to increased friction and abnormal rotation, or if concrete falls onto the connection point between the longitudinal beam and the front or rear cantilever beam during previous concrete pouring, the hanger may not be able to maintain verticality. In this case, clamping the hanger with the two I-beams that make up the front or rear cantilever beam provides a reaction force to overcome friction in the longitudinal beam. When the hanger connection point is near the end of the I-beam, the end of the I-beam is prone to deformation due to the cantilever effect. When the hanger is tilted, it can easily widen the gap between the two I-beams, making it impossible for the I-beams to clamp the hanger, thus preventing the hanger from maintaining verticality. This solution uses limiting bolts to restrict the gap between the two I-beams, ensuring that the two I-beams can clamp the hanger while minimizing the widening of the gap. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of Example 1; Figure 2 This is a schematic diagram of step one of Example 1; Figure 3 This is a schematic diagram of the rigid frame after installation in step two of Example 1; Figure 4 This is a schematic diagram of the lower chord arch segment 1 after step two of Example 1; Figure 5 This is a schematic diagram of step three in Example 1; Figure 6 This is a three-dimensional isometric view of the upper-curved hanging basket of Example 2; Figure 7 This is a three-dimensional axonometric view of the suspension system and bottom basket system of the upper chord hanging basket in Example 2 when they are transferred to the lower chord hanging basket; Figure 8 for Figure 7 Enlarged view of point A in the image; Figure 9 This is a perspective view of the extension connector in Example 2; Figure 10 This is a schematic diagram of step one of Example 3; Figure 11 This is a structural schematic diagram of step two in Example 3; Figure 12 This is a schematic diagram of step three in Example 3; Figure 13 This is a schematic diagram of step four in Example 3; Figure 14 This is a structural diagram of step five in Example 3; Figure 15This is a structural schematic diagram of step six in Example 3; Figure 16 This is a schematic diagram of the transition pad in step 4.2 of Example 4; Figure 17 This is a schematic diagram of point P in Example 4. Detailed Implementation

[0032] The following detailed description illustrates the specific implementation method: The reference numerals in the accompanying drawings include: pier 1, skeleton connector 11, stiffened skeleton 12, lower cable 13, upper chord beam 2, upper chord beam segment 0# 20, upper chord beam segment 1# 21, closing segment 22, lower chord arch 3, lower chord arch segment 0# 30, lower chord arch segment 1# 31, lower chord arch segment 2# 32, lower chord arch segment 3# 33, upper chord hanging basket 41, lower chord hanging basket 42, walking system 50, main truss 51, front crossbeam 52, rear crossbeam 53, front cantilever beam 61, rear cantilever beam 62, longitudinal beam 63, connecting block 64, pin 65, electric hoist 7, upper connector 81, upper nut 811, upper pad 812, extension connector 82, conversion pad 83, strip bolt hole 831, limit bolt 832, hanger 84, extension rod 85, bracket 9.

[0033] Example 1 The construction method for the initial arch segment at the intersection of column and arch in a hollow rigid frame bridge includes the following steps: Step 1: Complete the construction of pier 1, such as... Figure 2 As shown, a skeleton connector 11 is reserved at the arch foot of the lower chord arch 3 on the side of pier 1; Step 2: Install the stiffening frame 12 at the arch foot of the lower chord arch 3, as follows. Figure 3 As shown, the stiffening frame 12 is formed by rectangular steel bolts. The stiffening frame 12 is a truss structure with parallelogram-shaped sides. The stiffening frame 12 is first assembled and then hoisted to the design position as a whole, so that the lower left end of the stiffening frame 12 is connected to the frame connector 11. The length of the stiffening frame 12 is greater than the sum of the lengths of the lower chord arch segment 1# 31 and the lower chord arch segment 2# 32. The stiffening frame 12 can serve as an internal support for the lower chord arch segment 1# 31 and the lower chord arch segment 2# 32. That is, when pouring the concrete for the lower chord arch segment 1# 31 and the lower chord arch segment 2# 32, the stiffening frame 12 can be buried. A temporary tie cable is installed at the upper right end of the stiffening frame 12. The upper end of the lower tie cable 13 is connected to the pier column. When pouring the lower chord arch segment 0# 30, the frame connector 11 is buried in the lower chord arch segment 0# 30, thereby fixing the connection position between the stiffening frame 12 and the pier 1. Figure 4 As shown, the lower chord arch section 1# 31 is cast with the bottom basket system as support, and the stiffening frame 12 serves as the internal support of the lower chord arch section 1# 31. Step 3, as follows Figure 5As shown, remove the lower end of the lower cable 13, and cast the lower chord arch section 2# 32 with the bottom basket system as support, connecting the lower end of the lower cable 13 and the lower chord arch section 2# 32.

[0034] Example 2 A hanging basket with lifting function is suitable for arch-beam composite bridges; arch-beam composite bridges such as Figure 1 As shown, with the centerline of pier 1 as the axis of symmetry, the two sides of pier 1 are constructed symmetrically and synchronously. Taking the segment on the right side of pier 1 as an example: the segment includes the upper chord beam 2 and the lower chord arch 3. The left end of the upper chord beam 2 and the left arch foot of the lower chord arch 3 are both connected to pier 1. The right end of the upper chord beam 2 and the arch crown of the lower chord arch 3 are joined together, as shown. Figure 1 As shown, both the upper chord beam 2 and the lower chord arch 3 are cast in 13 segments. The thirteenth segment is the closure segment 22 of the upper chord beam 2 and the lower chord arch 3. The section above pier 1 is the upper chord beam 0# segment 20. From the nearest point to the upper chord beam 0# segment 20, the sections are upper chord beam 1# segment 21, upper chord beam 2# segment, and so on. The lower chord arch 0# segment 30 is cast together with pier 1 on both sides of pier 1. From the nearest point to the lower chord arch 0# segment 30, the sections are lower chord arch 1# segment 31, lower chord arch 2# segment 32, and so on. The purpose of casting the lower chord arch 0# segment 30 together with pier 1 is to reserve space in advance for connection with the lower chord arch 1# segment 31. Several lower cable 13s are installed on pier 1. The lower cable 13s all pass through pier 1, and the two ends of the lower cable 13s are anchored in the lower chord arch 3 on both sides of pier 1. Starting from the lower chord arch 2# segment 32, one lower cable 13 is installed for each segment being cast. The upper chord beam 2 and the lower chord arch 3 are constructed using a formwork with a lifting function, cantilevered from the top of pier 1 to both sides. The formwork with the lifting function includes an upper chord formwork 41 and a lower chord formwork 42. Both the upper chord formwork 41 and the lower chord formwork 42 include a traveling system 50, a main truss system, a suspension system, and a bottom formwork system. The traveling system 50 is installed on the upper surface of the upper chord beam 2 or the lower chord arch 3. The main truss system is installed on the traveling system 50 and extends towards the cantilever end. The upper end of the suspension system is detachably connected to the main truss system, and the lower end of the suspension system is connected to the bottom formwork system. The bottom formwork system serves as a support platform to bear the construction load. In this scheme, the traveling system 50 and the main truss system of the formwork with the lifting function are the same as those in the prior art. The key point of this embodiment is that the upper chord formwork 41 is given a lifting function through the lifting system, so that the bottom formwork system can move downward, so that the upper chord formwork 41 and the lower chord formwork 42 can alternately use the suspension system and the bottom formwork system. like Figure 6 As shown, the main truss systems of both the upper chord hanging basket 41 and the lower chord hanging basket 42 include a rhomboid main truss 51. A front crossbeam 52 is welded to the front end of the main truss 51, and a rear crossbeam 53 is welded to the middle of the main truss 51. Both the front crossbeam 52 and the rear crossbeam 53 are formed by combining two parallel I-beams, with a gap between the two parallel I-beams; as shown Figure 8As shown, the main truss system of the upper chord hanging basket 41 and the lower chord hanging basket 42 differs in that the slope of the bottom of the main truss 51 is different, so as to adapt to the movement on the upper chord beam 2 and the lower chord arch 3 respectively.

[0035] The bottom basket system of the upper chord hanging basket 41 includes a front cantilever beam 61 and a rear cantilever beam 62. The front cantilever beam 61 is located directly below the front crossbeam 52, and the rear cantilever beam 62 is located directly below the rear crossbeam 53. Two longitudinal beams 63 are provided between the front cantilever beam 61 and the rear cantilever beam 62. The longitudinal beams 63 can provide support for the formwork of the lower chord arch 3. Both the front cantilever beam 61 and the rear cantilever beam 62 are formed by combining two parallel I-beams with a gap between them. The front cantilever beam 61 is provided with two hinge units, each of which includes two connecting blocks 64. Both connecting blocks 64 are welded to the front crossbeam 52. The left end of the longitudinal beams 63 is slidably supported on the rear cantilever beam 62. The right end of the longitudinal beam 63 is provided with a pin 65, which passes through the right end of the longitudinal beam 63 and the two connecting blocks 64 and is rotatably connected to all three. The right end of the longitudinal beam 63 is located between the two connecting blocks 64.

[0036] The lifting system includes four lifting devices (not shown in the figure). The lifting devices are winches or electric hoists 7. In this embodiment, the lifting device is an electric hoist 7. The upper ends of the electric hoists 7 are all bolted to the main truss system of the upper chord hanging basket 41, specifically located at both ends of the front crossbeam 52 and the rear crossbeam 53. The lower ends of the steel cables of the electric hoists 7 are respectively hung at both ends of the front cantilever beam 61 and the rear cantilever beam 62. The suspension system of the upper chord hanging basket 41 includes four suspension units, each corresponding to one of the positions of the electric hoist 7. Each suspension unit includes a suspension rod 84 and an extension rod 85. The upper and lower ends of the suspension rod 84 are respectively provided with an upper connector 81 and a lower connector. The upper end of the suspension rod 84 passes through the front crossbeam 52 or the rear crossbeam 53 of the main truss system of the upper chord hanging basket 41. The upper connector 81 includes an upper nut 811 and an upper pad 812. The upper pad 812 is supported on the front crossbeam 52 or the rear crossbeam 53 and allows the suspension rod 84 to pass through. The upper nut 811 is threaded. The upper nut 811 is tightened on the upper end of the boom 84. The upper nut 811, together with the front crossbeam 52 or the rear crossbeam 53, clamps the upper pad 812. Similarly, the lower connector is composed of the same parts as the upper nut 811. The lower connector includes a lower nut and a lower pad. The lower pad is set on the lower side of the front cantilever beam 61 or the rear cantilever beam 62 and allows the lower end of the boom 84 to pass through. The lower nut is threaded to the lower end of the boom 84. When the lower nut is tightened, the lower nut, together with the front cantilever beam 61 or the rear cantilever beam 62, clamps the lower pad, thereby providing support for the front cantilever beam 61 or the rear cantilever beam 62. like Figure 9As shown, when the boom 84 is extended, the boom 84 and the extension rod 85 can be connected by an extension connector 82. The extension connector 82 is a sleeve with internal threads. The lower end of the extension connector 82 is threaded to the upper end of the boom 84. The threads on the boom 84 and the extension rod 85 are in the same direction. A conversion pad 83 is welded to the lower end of the extension connector 82, and the upper end of the boom 84 can pass through the conversion pad 83.

[0037] Example 3 Construction method of the initial arch segment at the intersection of column and arch in a hollow rigid frame bridge, such as Figures 10-15 As shown, construction based on the hanging basket with attached lifting function in Embodiments 1 and 2 includes the following steps: Step 1, such as Figure 10 As shown, the construction of pier 1 is completed. During the construction of pier 1, according to step one of Example 1, the pre-reserved skeleton connector 11 is used to pour the upper chord beam 0# segment 20 on the top of pier 1. The upper chord hanging basket 41 is installed on the upper chord beam 0# segment 20. The upper chord hanging basket 41 is used to pour the upper chord beam 1# segment 21. The upper side of the upper chord beam 1# segment 21 is subjected to longitudinal temporary prestress. The method of applying temporary prestress is as follows: longitudinal steel strands are embedded in the upper part of the upper chord beam 2. The jacks are used along the upper side of the upper chord beam 1# segment 21. Figure 10 The longitudinal steel strands are tensioned in the direction of the middle arrow and the ends of the longitudinal steel strands are anchored with anchors, thereby generating pre-stress on the upper part of the upper chord beam 2 to prevent the ends of the upper chord beam 2 from sinking; a lifting system is installed on the main truss system of the upper chord hanging basket 41. The lifting system can drive the bottom basket system to move downward and remove the connection between the upper end of the suspension system and the main truss system. Step 2: Remove the upper connector 81 at the upper end of the boom 84, and temporarily tie and fix the boom 84 and the electric hoist's steel cable with wire. The four electric hoists 7 jointly drive the bottom basket system to move downward. The lower end of the electric hoist on the rear crossbeam 53 descends at a greater speed than the lower end of the electric hoist 7 on the front crossbeam 52. The right end of the longitudinal beam 63 rotates around the pin 65 on the front crossbeam 52, so that the slope of the longitudinal beam 63 of the bottom basket system is the same as the slope of the bottom of the lower chord arch 1# segment 31. The main truss system, suspension system and bottom basket system are driven to move backward through the traveling mechanism of the upper chord hanging basket 41, and the bottom basket system is moved to the arch foot position of the lower chord arch 3. Install the stiffening frame 12 according to the steps described in Example 1. The templates of the lower chord arch 0# segment 30 and the lower chord arch 1# segment 31 are erected sequentially on the bottom basket system, and the lower chord arch 0# segment 30 and the lower chord arch 1# segment 31 are poured sequentially. like Figure 11As shown, the upper end of the suspension system is extended to connect the upper end of the suspension system with the main truss system of the upper chord hanging basket: the upper end of the extension rod 85 passes through the main truss system of the upper chord hanging basket 41 and is threadedly connected to the upper connector 81. The upper connector 81 is supported on the main truss system. The extension connector 82 is threadedly connected to the lower end of the extension rod 85. The wires on the hoist cable and the suspension rod 84 are removed. The lower chord arch section 1# 31 is poured with the bottom basket system as support. Step 3, as follows Figure 12 As shown, the traveling system 50 of the upper chord hanging basket 41 drives the main truss system, lifting system, suspension system and bottom basket system to move forward together, remove the lower cable 13 connected to the upper end of the stiffening frame 12, and cast the lower chord arch section 2# 32 with the bottom basket system as support, and anchor the two ends of the lower cable 13 to the lower chord arch section 2# 32 on both sides of the pier 1 respectively. Step 4, as follows Figure 13 As shown, the travel system 50 and main truss system of the lower chord hanging basket 42 are installed on the lower chord arch segments 1# 31 and 2#. The main truss system of the lower chord hanging basket 42 and the upper suspension system of the upper chord hanging basket 41 are connected at the upper end. The suspension system and bottom basket system of the upper chord hanging basket 41 are converted into the suspension system and bottom basket system of the lower chord hanging basket 42. The method for converting the suspension system and bottom basket system of the upper-curved hanging basket 41 into the suspension system and bottom basket system of the lower-curved hanging basket 42 is as follows: Step 4.1 During the installation of the main truss system of the lower chord hanging basket 42, the hanger rod 84 of the upper chord hanging basket 41 passes through the front crossbeam 52 or the rear crossbeam 53 of the lower chord hanging basket 42. Since the front crossbeam 52 or the rear crossbeam 53 is composed of two I-beams, when welding the front crossbeam 52, the hanger rod 84 is positioned between the two I-beams, which achieves the effect of the hanger rod 84 passing through the front crossbeam 52 or the rear crossbeam 53 without having to disconnect the hanger rod 84 and the extension rod 85. The upper end of the electric hoist 7 is bolted to the end of the front crossbeam 52 or the rear crossbeam 53 of the lower chord hanging basket 42, and the lower end of the electric hoist 7 is hung on the end of the front cantilever beam 61 or the rear cantilever beam 62 of the upper line hanging basket. Step 4.2, as follows Figure 9 As shown, rotate the extension connector 82 to move it downwards, so that the conversion pad 83 at the lower end of the extension connector 82 is supported on the main truss system of the lower chord hanging basket 42. Remove the upper connector 81 at the upper end of the extension rod 85, rotate the extension rod 85 to separate the lower end of the extension rod 85 from the extension connector 82, and remove the extension rod 85 and the electric hoist 7.

[0038] Step 5, as follows Figure 14As shown, the lower chord arch section 3# 33 is poured, and the two ends of a lower cable 13 are respectively anchored in the lower chord arch section 3# 33 on both sides of the pier 1; the upper chord hanging basket 41 is removed, and the support 9 is erected on the lower chord arch section 1# 31 and the lower chord arch section 2# 32 as the support for the upper chord beam 2. The temporary prestress applied to the upper chord beam section 1# 21 is removed, that is, the anchorage at the end of the longitudinal steel strand is removed, and the upper chord beam section 2# is poured. Step Six, as Figure 15 As shown, repeat step five, with the upper chord beam 2 advancing synchronously with the lower chord arch 32 segments, until the concrete is poured to the required level. Figure 1 The shown section 22 is the closure segment of the upper chord beam 2 and the lower chord arch 3, namely, section 13# of the upper chord beam 2 and the lower chord arch 3.

[0039] Example 4 Example 4 is based on Example 3: The conversion pad 83 has four strip bolt holes 831, and each bolt hole can be fitted with a limit bolt 832; In step 4.2, the transition pad 83 is supported on the front crossbeam 52 or rear crossbeam 53 of the main truss system of the lower chord hanging basket 42. Four limiting bolts 832 are installed on the transition pad 83. Taking the front crossbeam 52 as an example, ... Figure 16 As shown, four limiting bolts 832 are evenly distributed and attached to both sides of the front crossbeam 52, thereby limiting the distance between the two I-beams that make up the front crossbeam 52. The limiting bolts 832 need to be fixed in the strip bolt holes 831 with the nuts. When limiting the distance between the two I-beams by the limiting bolts 832, the size of the nuts needs to be taken into account.

[0040] The effect of Example 4 is as follows Figure 17 As shown: The weight of the formwork, concrete, and various components of the lower chord arch 3 will all be transferred to the longitudinal beam 63. Since the longitudinal beam 63 and the cantilever beam 61 are hinged, most of the load of the longitudinal beam 63 is transferred to the cantilever beam 61 through the pin 65. If only the pin 65 is considered to bear most of the load, the strength of the pin 65 is often insufficient to withstand it. In this embodiment, the direct contact point P between the longitudinal beam 63 and the cantilever beam 61 also needs to be considered. When the longitudinal beam 63 rotates to a certain angle, the load of the longitudinal beam 63 is transmitted to the longitudinal beam 63 through point P. However, at this time, the longitudinal beam 63 exerts pressure on the cantilever beam 61 perpendicular to the length of the longitudinal beam 63 (in the direction of the arrow in the figure). This causes the lower end of the hanger 84 to move to the right through the cantilever beam 61, thereby causing the hanger 84 to tilt. The greater the pressure change, the greater the back-and-forth swaying. In this solution, by setting a limiting bolt 832, the upper end of the hanger 84 is clamped by the front crossbeam 52 of the lower chord hanging basket 42, which restricts the tilting of the hanger 84, reduces this swaying, and ensures construction safety.

[0041] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A construction method for the initial arch segment at the intersection of column and arch in a hollow rigid frame bridge, characterized in that... Includes the following steps: Step 1: Complete the construction of the bridge piers, and reserve the frame connectors at the arch foot position of the lower chord arch on the side of the bridge piers; Step 2: Install the stiffening frame at the arch foot of the lower chord arch, connecting the lower end of the stiffening frame to the frame connector. The length of the stiffening frame is greater than the sum of the lengths of the lower chord arch segments 1 and 2. Install temporary ties at the upper end of the stiffening frame, connecting the upper end of the lower ties to the pier column. Cast the lower chord arch segment 0, embedding the frame connector inside the lower chord arch segment 0. Cast the lower chord arch segment 1 with the bottom basket system as support, making the stiffening frame the internal support for the lower chord arch segment 1. Step 3: Remove the lower end of the lower cable and cast the lower chord arch section 2 using the basket system as support. Connect the lower end of the lower cable to the lower chord arch section 2. In step one, after the pier construction is completed, the upper chord beam section 0# is poured on the top of the pier, the upper chord hanging basket is installed on the upper chord beam section 0#, the upper chord beam section 1# is poured using the upper chord hanging basket, the lifting system is installed on the main truss system of the upper chord hanging basket, the lifting system can drive the bottom basket system to move downwards, and the connection between the upper end of the suspension system and the main truss system is removed. In step two, before installing the rigid frame, the lifting system moves the bottom basket system downward to the arch foot of the lower chord arch, extending the upper end of the suspension system to connect the upper end of the suspension system with the upper chord hanging basket main truss system. In step three, the traveling system of the upper chord hanging basket drives the main truss system, lifting system, suspension system and bottom basket system to move forward together, and the bottom basket system is used as support to pour the lower chord arch section 2. It also includes step four, installing the travel system and main truss system of the lower chord hanging basket on the lower chord arch segments 1 and 2, connecting the upper end of the main truss system of the lower chord hanging basket and the suspension system of the upper chord hanging basket, and converting the suspension system and bottom basket system of the upper chord hanging basket into the suspension system and bottom basket system of the lower chord hanging basket. The lifting system includes several electric hoists; In step one, during the construction of the bridge piers, the upper ends of the electric hoists are all connected to the main truss system of the upper chord hanging basket, and the lower ends of the electric hoists are all hung on the bottom basket system. In step two, as the electric hoist moves the basket system downward, the upper end of the suspension system is temporarily fixed to the steel cable of the electric hoist; after the electric hoist moves the basket system downward, the lower chord arch section 0 and the lower chord arch section 1 are poured on the basket system in sequence. The suspension system of the upper chord hanging basket includes several suspension units, each of which includes a hanger and an extension rod. The upper and lower ends of the hanger are respectively provided with an upper connector and a lower connector. The upper end of the hanger passes through the main truss system of the upper chord hanging basket and is threadedly connected to the upper connector. The upper connector is supported on the main truss system. In step two, the upper connector is removed, and the boom and the electric hoist's cable are temporarily fixed with wire. The electric hoist drives the bottom basket system to move downward. The upper end of the extension rod passes through the main truss system of the upper chord hanging basket and is threadedly connected to the upper connector. The upper connector is supported on the main truss system. The extension connector is threadedly connected to the lower end of the extension rod. The lower end of the extension connector is threadedly connected to the upper end of the boom. The wires on the boom and the electric hoist's cable are removed.

2. The construction method for the starting arch segment at the intersection of the column and arch of a hollow rigid frame bridge according to claim 1, characterized in that: The rigid frame is formed by connecting structural steel sections; In step two, the rigid frame is first assembled, and then the whole frame is hoisted to the design position and connected to the frame connectors.

3. The construction method for the starting arch segment at the intersection of the column and arch of a hollow rigid frame bridge according to claim 1, characterized in that: The threads of the hanger and the extension rod are in the same direction. The lower end of the extension connector is welded with a conversion pad, and the upper end of the hanger can pass through the conversion pad. The main truss system of both the upper chord hanging basket and the lower chord hanging basket includes a main truss. The main truss is equipped with a front crossbeam and a rear crossbeam. The front crossbeam or the rear crossbeam is composed of two parallel I-beams. The distance between the two I-beams is less than the width of the conversion pad. The bottom basket system of the upper chord hanging basket includes a front cantilever beam and a rear cantilever beam. Several longitudinal beams are provided between the front cantilever beam and the rear cantilever beam. In step four, the method for converting the suspension system and bottom basket system of the upper-curved basket into the suspension system and bottom basket system of the lower-curved basket is as follows: Step 4.1 During the installation of the main truss system of the lower chord hanging basket, make the hoisting rod of the upper chord hanging basket pass through the front or rear crossbeam of the lower chord hanging basket, and hang the upper end of the electric hoist on the front or rear crossbeam, and hang the lower end of the electric hoist on the front or rear cantilever beam. Step 4.2: Rotate the extension connector so that the conversion pad at the lower end of the extension connector is supported on the main truss system of the lower chord hanging basket. Remove the upper connector at the upper end of the extension rod, rotate the extension rod to separate the lower end of the extension rod from the extension connector, and remove the extension rod and the electric hoist.

4. The construction method for the starting arch segment at the intersection of the column and arch of a hollow rigid frame bridge according to claim 3, characterized in that: Several longitudinal beams are hinged at one end to the front cantilever beam, and several horizontally arranged support tubes are provided on the rear cantilever beam. The other end of each longitudinal beam is supported on the support tube and can slide on the support tube.

5. The construction method for the starting arch segment at the intersection of the column and arch of a hollow rigid frame bridge according to claim 4, characterized in that: The conversion pad has four strip bolt holes, and a limit bolt can be installed in each bolt hole; In step 4.2, the conversion pad is supported on the front or rear crossbeam of the main truss system of the lower chord hanging basket. Four limiting bolts are installed on the conversion pad. The four limiting bolts are evenly distributed and attached to both sides of the front or rear crossbeam, thereby limiting the spacing between the two I-beams that make up the front or rear crossbeam.

6. The construction method for the starting arch segment at the intersection of the column and arch of a hollow rigid frame bridge according to claim 4, characterized in that: With the center line of the pier as the axis of symmetry, the upper chord beams and lower chord arches on both sides of the pier are constructed synchronously and symmetrically. Several lower chord cables are installed on the pier, and all lower chord cables pass through the pier. The two ends of the lower chord cables are anchored in the lower chord arches on both sides of the pier. Starting from the second segment of the lower chord arch, one lower chord cable is constructed for each segment being poured. In step three, the two ends of a lower cable are anchored to the lower chord arch segment 2 on both sides of the pier.

7. The construction method for the starting arch segment at the intersection of the column and arch of a hollow rigid frame bridge according to claim 6, characterized in that: In step one, longitudinal temporary prestress is applied to the upper side of segment 1 of the upper chord beam; After step four is completed, the temporary prestress applied to segment 1 of the upper chord beam is removed.

Images