A method for installing a pre-embedded section of a stiff skeleton arch rib

Abstract

The application discloses a kind of installation methods suitable for stiff skeleton arch rib pre-embedded section, and the operation flow of the application includes the following steps: (1) construction preparation;(2) arch rib 0# section fixed support erection;(3) arch rib 0# section installation;(4) arch rib 0# section four corners tensioning;(5) arch rib 0# section pre-embedded section reinforcement construction;(6) arch rib 0# section pre-embedded section formwork construction;(7) overall check pre-embedded section construction, arch rib 0# section;(8) arch rib 0# section pre-embedded section formwork construction;(9) temporary facilities removal.This patent sets four steel strands at the four foot points of arch rib 0# section, and fixes arch rib 0# section by tensioning steel strand through jack, and the tensioning end of steel strand is located outside pre-embedded section pouring area, to minimize the influence of external factors on arch rib 0# section installation precision.After arch rib 0# section installation is completed, steel strand tensioning can be used to fine-tune arch rib 0# section again, to improve arch rib installation precision, and to ensure that arch rib 0# section installation precision meets the requirements.

Description

Technical Field

[0001] This invention relates to the field of arch rib installation, and more specifically to an installation method applicable to the pre-embedded section of a rigid frame arch rib. Background Technology

[0002] The traditional installation of the 0# segment of the arch rib typically employs a scaffolding method. This method involves fabricating the 0# segment, supporting it with scaffolding, adjusting the angle, and then placing it directly onto the embedded parts of the arch seat, or fixing it using welding or bolts. While this method is simple, it is susceptible to displacement due to external disturbances and is difficult to correct. During the frame installation process, the 0# segment is highly susceptible to displacement due to external factors such as temperature changes and scaffolding deformation. During the pouring of the embedded section, it is easily displaced by concrete disturbances, and once this displacement occurs, it cannot be corrected. Displacement of the 0# segment affects the overall alignment of the arch rib, leading to suboptimal stress distribution. Furthermore, subsequent installation of the arch rib requires gradual adjustments across multiple segments to correct the displacement. This is particularly problematic for hingeless arches, where the resulting displacement is irreversible and severely impacts subsequent construction. Summary of the Invention

[0003] Therefore, to address the aforementioned shortcomings, this invention provides an installation method suitable for embedded sections of rigid frame arch ribs. The technical problem this patent aims to solve is the issue of misalignment of the embedded sections due to factors such as disturbance from post-cast concrete during installation.

[0004] This invention is implemented by constructing an installation method suitable for the pre-embedded section of a rigid frame arch rib, characterized by the following steps in the operation process: (1) Construction preparation; (2) Erection of fixed support for arch rib section 0; (3) Installation of arch rib section 0; (4) Tensioning at the four corners of arch rib segment 0#; (5) Construction of the pre-embedded steel reinforcement in section 0# of the arch rib; (6) Construction of formwork for the pre-embedded section of arch rib #0; (7) Conduct a comprehensive inspection of the construction of the embedded section and the 0# section of the arch rib; (8) Concrete pouring construction of the pre-embedded section of the arch rib 0# segment; (9) Dismantling of temporary facilities.

[0005] According to the present invention, an installation method for embedded sections of rigid frame arch ribs is characterized in that: the construction preparation in step 1 is as follows: Before the installation of arch rib section 0#, the construction site must be cleared of debris, and preparations such as excavation, filling and leveling of the site must be carried out according to the needs of the subsequent installation of arch rib section 0#. After the site preparation work was completed, construction materials and equipment were transferred to the construction site one after another to prepare for construction. At the same time, the installation points of the 0# section of the arch rib were laid out. Based on the plane position and elevation of the laid-out points, the elevation of the placement points on the embedded parts was adjusted to improve the installation accuracy of the 0# section of the arch rib.

[0006] According to the present invention, an installation method for embedded sections of arch ribs in rigid frames is characterized in that: step 2, the arch rib 0# section fixing bracket is erected as follows: Before erecting the fixed support for the 0# section of the arch rib, the foot points of the support columns need to be laid out. The column height is calculated based on the laid-out elevation, and the support columns are then cut and fabricated. The support column is installed first. The support column is installed precisely according to the laid-out points. During installation, a level and a string line are used to ensure that the columns are vertical and that columns in the same row are on the same elevation. The columns are anchored with rebar, and the columns are welded to the rebar. After the columns are installed, the support load-bearing beam is installed, placed at an angle on the inclined surface of the columns. After placement, the inclination angle of the load-bearing beam is measured with an angle gauge, and the elevation of the load-bearing beam is measured with a total station. After the installation angle and elevation of the load-bearing beam are correct, welding is then carried out. After the load-bearing beams are installed, the main body of the support structure is complete. The support structure needs to be reinforced. Diagonal braces are installed on both sides of the load-bearing beams to enhance the longitudinal stability of the support structure; scissor braces are installed in the middle of the columns to enhance the lateral stability of the support structure.

[0007] According to the present invention, an installation method for the embedded section of a rigid frame arch rib is characterized in that: Step 3, the installation of arch rib segment 0#, is as follows: Before installing the arch rib section 0#, the installation points of the arch rib were re-measured and inspected. After the inspection was qualified, the arch rib section 0# was lifted and placed. According to the site environment of the arch rib section 0#, the arrangement of the supports and the positioning requirements of the arch section, a truck crane or cable crane was selected to lift the arch rib. After the arch rib section 0# is lifted, it is initially placed on the embedded parts. The position of the arch rib is roughly adjusted by using the lifting equipment. Then, the center point of the upper edge of the bottom plate of the main chord tube of the arch foot is laid out by using a total station. The deviation of the arch rib section 0# is finely adjusted by using a hand-operated hoist and a hand-cranked jack to assist in the adjustment. After the No. 0 segment of the arch rib is installed in place, the deviation of the No. 0 segment of the arch rib is re-measured every morning, afternoon and evening when the temperature is stable. During the re-measurement, data such as time, weather, temperature and deviation are recorded. After continuous measurement for more than 3 days, the influence of temperature on the deformation of the arch rib is understood based on the measurement data. Then, the deviation of the arch rib is adjusted again at an appropriate time according to the pattern.

[0008] According to the present invention, an installation method for embedded sections of arch ribs in a rigid frame is characterized in that: step 4, tensioning the four corners of arch rib segment 0#, is as follows: Before tensioning the four corners of the arch rib, steel wire ropes must be used to fix the bottom of the main chord tubes at the four corners in pairs to ensure that the main chord tubes of the arch rib will not deform due to the force on the four corners when tensioning the four corners of the 0# section of the arch rib, leading to the inward tilting of the main chord tube openings. The four-corner tensioning facility consists of steel strands, one working anchor, working anchor plate, P anchor, tensioning end anchor beam, and jacks. The tensioning steel strand uses one steel strand, with one end anchored to the fixed end working anchor on the 0# section of the arch rib using the P anchor method, and the other end tensioned and fixed to the working anchor on the anchor beam through the jacks. The anchoring end installation of the steel strand is based on the layout points in the drawings. The installation positions of the working anchors at the anchoring ends are marked on the steel pipe of section 0# of the arch rib. The working anchors are installed according to the direction of the steel strands. Before fixing the anchoring ends, the steel strands are first fixed to the working anchors using P-anchors. Anchor beams are installed at the tensioning end of the steel strands. The anchor beams are made of structural steel and are located outside the pre-embedded section casting area. The anchor beams are installed by installing rebar on a base plate, and then welding the anchor beams to the base plate. The installation must ensure both the correct anchor beam position and the correct angle of inclination. The jack is used to tension the steel strand at the anchor beam. If the tool anchor or working anchor limit plate is too small, the tool anchor or working anchor limit plate pad needs to be prepared in advance. Before tensioning, the tensioning cable force of the steel strands was calculated based on the modeling calculation and the jack test report. The tensioning oil gauge reading was calculated. On-site construction adopted synchronous graded tensioning. During tensioning, the four corner steel strands were tensioned simultaneously, and the tensioning control force was carried out in stages of 20%, 40%, 60%, 80%, 90%, and 100%. After each stage of tensioning was completed, the deviation of the 0# segment of the arch rib was re-measured. The on-site commander could adjust the tensioning progress appropriately based on the measurement results to ensure that the deviation of the arch rib met the requirements. When the tensioning progress reached 90%, the deviation of the arch rib should be the main control point for subsequent tensioning. After the tensioning was completed, the deviation of the arch rib, the structural weld of the 0# segment of the arch rib, and the contact between the 0# segment of the arch rib and the embedded parts were checked. Only after the inspection found no abnormalities could the next stage of construction be carried out.

[0009] According to the present invention, an installation method for embedded sections of arch ribs in a rigid frame is characterized in that: step 5, the construction of the reinforcing steel bars for the embedded section of arch rib #0, is as follows: After the four corners of arch rib segment 0# are tensioned and fixed, and the deviation of arch rib segment 0# and the arch foot anchorage are checked and found to be qualified, the construction of the embedded section is carried out. The construction of the embedded section reinforcement is carried out according to the design drawings. When constructing the embedded section reinforcement, the position of the protective layer is deducted according to the laid-out arch seat edge line, and the binding line of the outer perimeter reinforcement of the arch seat is determined. Then, the bottom plate reinforcement, horizontal reinforcement, side distribution reinforcement and stirrup reinforcement are tied. At the same time, the reinforcement fabrication and installation should meet the corresponding specification requirements. In addition, the reinforcement binding should avoid contact between the reinforcement and the steel strand to ensure that the steel strand has a certain range of movement.

[0010] According to the present invention, the installation method for the embedded section of the arch rib of the rigid frame is characterized in that: the formwork construction of the embedded section of the 0# segment of the arch rib in step 6 is as follows: After the reinforcement is tied and the reinforcement is inspected and accepted, the deviation of the 0# segment of the arch rib is checked and adjusted. After the deviation of the 0# segment of the arch rib meets the requirements, the formwork of the embedded section is installed. The formwork system consists of imported Vesa board, timber, transverse back ribs and special connectors. The formwork installation should meet the requirement of one-time casting of the embedded section, and vibration holes should be reserved and corresponding sealing measures should be prepared. When installing the template, pre-drill holes for the steel strands. After the template is installed, check the misalignment of section 0 of the arch rib. If the misalignment of the arch rib changes, tension the steel strands to adjust the misalignment of the arch rib. After adjusting the misalignment of section 0 of the arch rib to the correct position, seal the pre-drilled holes for the steel strands on the template.

[0011] According to the present invention, an installation method for embedded sections of rigid frame arch ribs is characterized in that: Step 7 involves a comprehensive inspection of the embedded section construction and the 0# segment of the arch rib as follows: Before concrete pouring, a comprehensive inspection and acceptance of the entire embedded section construction and the 0# section of the arch rib is carried out. The inspection and acceptance includes all supports, the deviation of the 0# section of the arch rib and the four corner tensioning system, formwork, steel bars and embedded parts, etc. After the acceptance is qualified, the concrete pouring construction of the embedded section is carried out. If the arch rib section 0# is misaligned, it can be adjusted by tensioning the steel strands. Since the tensioning end is located outside the pre-embedded section pouring area, the arch rib misalignment can be adjusted outside the pouring area without entering the formwork.

[0012] According to the present invention, an installation method for the embedded section of a rigid frame arch rib is characterized in that: step 8, the construction of the formwork for the embedded section of arch rib 0# segment, is as follows: The concrete pouring is done in one go, using a boom pump. The pump pipe injects concrete into the formwork through pre-reserved holes and the top of the pre-embedded section. Pouring is done in layers, progressing from one direction (the middle) to the other (both sides of the long side). The thickness of each layer should be determined based on the concrete mixing capacity, transportation conditions, pouring speed, vibration capacity, and structural requirements, generally 30-50cm is suitable. For each layer, a vibrator is placed in front and then used for compaction. The vibrator is inserted into the concrete through the pre-reserved holes in the formwork, with a vibration interval controlled at 50-60cm. During vibration, the vibrator should be fully inserted into the concrete. When vibrating the upper and lower layers, the vibrator should be inserted 5-10cm into the lower layer. Each vibration point should be inserted quickly and withdrawn slowly, vibrating until the concrete stops descending, air bubbles stop escaping, and a slurry appears on the surface. When the concrete reaches the pre-reserved holes in the formwork, the pre-reserved holes are sealed.

[0013] According to the present invention, the installation method applicable to the pre-embedded section of the rigid frame arch rib is characterized in that: Step 9, the temporary facilities are removed as follows: After the concrete is poured, once the concrete strength meets the requirements, the temporary facilities such as the formwork and steel strands are removed. When removing the steel strands, the tension of the steel strands is first relieved, and then the steel strands are cut and removed flush with the concrete surface using a cutting device. Then the tension end anchor beam is removed. After the formwork is removed, a layer of geotextile is promptly covered on the concrete surface and water is sprinkled for curing.

[0014] The present invention has the following advantages: (1) This patent sets four steel strands at the four foot points of the 0# section of the arch rib. The 0# section of the arch rib is fixed by tensioning the steel strands with jacks. The tensioning end of the steel strands is located outside the pre-embedded section pouring area, so as to minimize the impact of external factors on the installation accuracy of the 0# section of the arch rib.

[0015] (2) After the installation of the 0# section of the arch rib is completed, the 0# section of the arch rib can be finely adjusted again by tensioning the steel strands to improve the installation accuracy of the arch rib and ensure that the installation accuracy of the 0# section of the arch rib meets the requirements.

[0016] (3) Before pouring concrete in section 0 of the arch rib, if the arch rib is affected by the binding of reinforcing bars, installation of formwork, etc., it can be adjusted by tensioning the steel strands. Since the tensioning end is located outside the pre-embedded section pouring area, the arch rib can be adjusted outside the pouring area without entering the formwork, ensuring that the arch rib can be adjusted before the concrete is poured.

[0017] (4) This patent can effectively control the installation deviation of the 0# segment of the arch rib, laying a good foundation for the high-precision and high-efficiency installation of subsequent arch rib segments, shortening the arch rib installation construction time and reducing the risk factor of hoisting.

[0018] (5) This patent makes the segmental shape of the arch foot section of the rigid frame arch more in line with the requirements, making it easier to control the shape and protective layer thickness of the arch foot section when wrapping the concrete later. Attached Figure Description

[0019] Figure 1 This is a flowchart of the installation and construction process for section 0 of the arch rib; Figure 2 Arch rib fixing bracket site layout diagram; Figure 3 Installation diagram of arch rib section 0; Figure 4 Schematic diagram of the arrangement of the interconnecting steel wire ropes of the main chord tube; Figure 5 Installation and tensioning structure diagram of arch rib segment 0; Figure 6 Detailed drawing of the anchoring end of section 0# of the arch rib; Figure 7 Detailed drawing of the anchoring end of section 0# of the arch rib; Figure 8 Side view of the installation and fixing measures for the embedded section of the arch rib; Figure 9 Front view of the installation and fixing measures for the embedded section of the arch rib; Figure 10 Top view of the installation and fixing measures for the embedded section of the arch rib; Figure 11 Construction drawings for the pre-embedded reinforcement of arch rib segment 0#; Figure 12 Construction drawings for the embedded section formwork of arch rib #0; Figure 13 Construction drawings for the pre-embedded section of the arch rib (section 0#); Figure 14 Schematic diagram of the completed casting of the pre-embedded section of arch rib #0. Detailed Implementation

[0020] The following will be combined with the appendix Figures 1-14 This invention will be described in detail, and the technical solutions in the embodiments of this invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] This invention provides an improved installation method for embedded sections of rigid frame arch ribs. The technical problem this patent aims to solve is the issue of misalignment of the embedded sections due to factors such as disturbance from post-cast concrete during installation.

[0022] The specific composition, structure, and operation instructions involved in this patent are as follows; Composition and structure: This patent consists of steel strands, tension end anchor beams, fixed end working anchors, jacks, and interlocking steel wire ropes; Steel strand: The tensioning steel strand uses one set of steel strands. One end is anchored to the fixed end working anchor on the pre-embedded section of the steel pipe of the stiffened frame arch rib using a P-anchor method, and the other end is tensioned and fixed to the working anchor of the anchor beam by a jack.

[0023] Tensioning end anchor beam: The anchor beam is made of steel, and a working anchor is installed on the tensioning side.

[0024] Fixed-end working anchor: The fixed-end working anchor is fixed to the pre-embedded section of steel pipe of the rigid frame arch rib by four baffles. Before fixing the working anchor, the steel strand is first fixed to the working anchor by P anchor. Jacks: If the tool anchor or working anchor limit plate is too small, a tool anchor or working anchor limit plate pad needs to be prepared in advance.

[0025] Interlocking steel wire ropes: Before tensioning the four corners of the arch rib, steel wire ropes must be used to fix the bottom of the main chord pipes at the four corners in pairs to ensure that the main chord pipes of the arch rib will not deform due to the force on the four corners when tensioning the four corners of the 0# section of the arch rib, leading to the inward tilting of the main chord pipe opening.

[0026] The following is a detailed explanation of the operational procedures involved in this application: (1) The operation process of this patent is as follows: Figure 1 As shown. Figure 1 Flowchart of the installation process for section 0 of the arch rib; (2) Construction preparation: Before the installation of arch rib section 0, the construction site must be cleared of debris, and preparations such as excavation, filling and leveling of the site must be carried out according to the needs of the subsequent installation of arch rib section 0.

[0027] After the site preparation work was completed, construction materials and equipment were gradually transferred to the construction site to prepare for construction. At the same time, the installation points of the 0# segment of the arch rib were laid out, and the elevation of the installation points on the embedded parts was adjusted according to the plane position and elevation of the laid-out points to improve the installation accuracy of the 0# segment of the arch rib.

[0028] (3) Erection of fixed support for arch rib section 0#: Before erecting the fixed support for section 0 of the arch rib, the foot points of the support columns need to be laid out. The column height is calculated based on the laid-out elevation, and the support columns are then fabricated. The support column installation begins with the columns themselves. The columns are installed precisely according to the laid-out points. During installation, a level and a string line are used to ensure the columns are vertical and that columns in the same row are on the same elevation. The columns are anchored using rebar, and the columns are welded to the rebar. After the columns are installed, the support load-bearing beams are installed, placed at an angle on the inclined surface of the columns. After placement, the inclination angle of the load-bearing beams is measured using an angle gauge, and the elevation of the load-bearing beams is measured using a total station. Once the installation angle and elevation of the load-bearing beams are confirmed to be correct, welding is then performed to secure them.

[0029] After the load-bearing beams are installed, the main body of the support structure is complete, and reinforcement is required. Diagonal braces are installed on both sides of the load-bearing beams to enhance the longitudinal stability of the support structure; scissor braces are installed in the middle of the columns to enhance the lateral stability of the support structure. Figure 2 Arch rib fixing bracket site layout diagram.

[0030] (4) Installation of arch rib section 0: Before installing arch rib segment 0, the installation points of the arch rib were re-measured and inspected. After passing the inspection, the arch rib segment 0 was lifted and placed. Based on the site environment, pier layout, and arch segment positioning requirements, a truck crane or cable crane was selected to lift the arch rib.

[0031] After the arch rib section 0# is lifted, it is initially placed on the embedded parts. The position of the arch rib is roughly adjusted using the lifting equipment. Then, the center point of the upper edge of the main chord tube bottom plate of the arch foot is laid out using a total station. The deviation of the arch rib section 0# is finely adjusted by using a hand-operated hoist and a hand-cranked jack for auxiliary adjustment.

[0032] After the No. 0 segment of the arch rib is installed in place, the deviation of the No. 0 segment is re-measured every morning, afternoon, and evening when the temperature is stable. During the re-measurement, data such as time, weather, temperature, and deviation are recorded. After continuous measurement for more than 3 days, the influence of temperature on the deformation of the arch rib is determined based on the measurement data. Then, the deviation of the arch rib is readjusted again at an appropriate time according to the pattern. Figure 3 Installation diagram of arch rib segment 0#.

[0033] (5) Tensioning at the four corners of arch rib segment 0#: Before tensioning the four corners of the arch rib, steel wire ropes must be used to fix the bottom of the main chord pipes at the four corners in pairs to ensure that the main chord pipes of the arch rib will not deform due to the force on the four corners when tensioning the four corners of the 0# section of the arch rib, leading to the inward tilting of the main chord pipe opening. Figure 4 Schematic diagram of the arrangement of the steel wire ropes connecting the main chord pipes.

[0034] The four-corner tensioning device consists of steel strands, a single working anchor, a working anchor plate, a P-anchor, a tensioning end anchor beam, and jacks. The tensioning steel strand uses a single strand, with one end anchored to the fixed-end working anchor on the 0# section of the arch rib using a P-anchor, and the other end tensioned and fixed to the working anchor on the anchor beam using jacks.

[0035] The anchoring end of the steel strand is installed according to the layout points on the steel pipe of section 0# of the arch rib. The working anchor position is then marked out. The working anchor is installed according to the direction of the steel strand. Before fixing the anchoring end, the steel strand is first fixed to the working anchor using P-anchors. Anchor beams are installed at the tensioning end of the steel strand. The anchor beams are made of structural steel and are located outside the pre-embedded section casting area. The anchor beams are installed by installing rebar on a base plate, and then welding the anchor beams onto the base plate. The installation must ensure both the anchor beam's position and its inclination angle.

[0036] The jack is used to tension the steel strand at the anchor beam. If the tool anchor or working anchor limit plate is too small, the tool anchor or working anchor limit plate pad needs to be prepared in advance.

[0037] Before tensioning, the tension gauge readings are calculated based on the modeled tension cable force and jack test reports. On-site construction employs synchronous, graded tensioning, with all four corner strands tensioned simultaneously, according to tension control levels of 20%, 40%, 60%, 80%, 90%, and 100%. After each tensioning stage, the deviation of arch rib segment 0# must be re-measured. On-site supervisors can adjust the tensioning schedule appropriately based on the measurement results to ensure the arch rib deviation meets requirements. Once the tensioning progress reaches 90%, subsequent tensioning should focus primarily on arch rib deviation. After tensioning, the arch rib deviation, the structural welds of arch rib segment 0#, and the contact between arch rib segment 0# and embedded parts are inspected. Only after confirming no abnormalities can the next stage of construction proceed.

[0038] (6) Construction of the pre-embedded reinforcement of the 0# segment of the arch rib: After the four corners of arch rib segment 0# are tensioned and fixed, and the deviation of arch rib segment 0# and the anchorage of the arch foot are checked and found to be qualified, the construction of the embedded section is carried out. The reinforcement construction of the embedded section is carried out according to the design drawings. During the reinforcement construction, the outer perimeter reinforcement binding lines of the arch abutment are determined according to the laid-out arch abutment edge lines, deducting the protective layer position. Then, the bottom slab reinforcement, horizontal reinforcement, side distribution reinforcement, and stirrup reinforcement are bound. Simultaneously, the reinforcement fabrication and installation should meet the relevant specifications. Furthermore, the reinforcement binding should avoid contact between the reinforcement and the steel strands, ensuring that the steel strands have a certain range of movement. Figure 11 Construction drawing of the pre-embedded steel reinforcement of arch rib 0# section.

[0039] (7) Construction of formwork for the pre-embedded section of arch rib #0: After the reinforcing bars are tied and inspected and approved, the deviation of arch rib segment 0# is checked and adjusted. Once the deviation of arch rib segment 0# meets the requirements, the formwork for the embedded section is installed. The formwork system consists of imported Vesa board, timber, transverse back bracing, and special connectors. The formwork installation should meet the requirement of one-time casting of the embedded section, and vibration holes should be reserved with corresponding sealing measures.

[0040] When installing the template, pre-drill holes for the steel strands. After the template is installed, check the misalignment of section 0 of the arch rib. If the misalignment of the arch rib changes, tension the steel strands to adjust the misalignment of the arch rib. After adjusting the misalignment of section 0 of the arch rib to the correct position, seal the pre-drilled holes for the steel strands on the template. Figure 12 Construction drawing of the formwork for the pre-embedded section of the arch rib #0.

[0041] (8) Conduct a comprehensive inspection of the construction of the embedded section and the 0# section of the arch rib: Before concrete pouring, a comprehensive inspection and acceptance of the entire embedded section construction and the arch rib 0# section is carried out. The inspection and acceptance includes all supports, the deviation of the arch rib 0# section and the four corner tensioning system, formwork, steel bars and embedded parts, etc. After the acceptance is qualified, the concrete pouring construction of the embedded section is carried out.

[0042] If the arch rib section 0# is misaligned, it can be adjusted by tensioning the steel strands. Since the tensioning end is located outside the pre-embedded section pouring area, the arch rib misalignment can be adjusted outside the pouring area without entering the formwork.

[0043] (9) The concrete pouring construction of the pre-embedded section of the arch rib 0# segment is as follows: The concrete pouring is done in one continuous pour using a boom pump. The pump pipe injects concrete into the formwork through pre-drilled holes and the top of the pre-embedded section. Pouring is done in layers, progressing from one direction (the middle) to the other (both sides of the long side). The thickness of each layer should be determined based on the concrete mixing capacity, transportation conditions, pouring speed, vibration capacity, and structural requirements, generally 30-50cm is suitable. Each layer of concrete is placed in front and then vibrated with a vibrator. The vibrator is inserted into the concrete through the pre-drilled holes in the formwork, with a vibration interval controlled at 50-60cm. During vibration, the vibrator should be fully inserted into the concrete. When vibrating the upper and lower layers, the vibrator should be inserted 5-10cm into the lower layer. Each vibration point should be inserted quickly and withdrawn slowly, vibrating until the concrete stops descending, air bubbles stop escaping, and a slurry layer appears on the surface. The pre-drilled holes in the formwork are then sealed when the concrete reaches them. Figure 13 Construction drawings for the pre-embedded concrete section of arch rib #0.

[0044] (10) Dismantling of temporary facilities: After the concrete pouring is completed and the concrete strength meets the requirements, remove the formwork, steel strands, and other temporary facilities. When removing the steel strands, first unload the tension, then use a cutting device to cut and remove the steel strands flush with the concrete surface. Next, remove the tensioning end anchor beam. After the formwork is removed, promptly cover the concrete surface with a layer of geotextile and water it for curing. Figure 14 Schematic diagram of the completed casting of the pre-embedded section of arch rib #0.

[0045] This patent has the following advantages and beneficial effects: (1) This patent sets four steel strands at the four foot points of the 0# section of the arch rib. The 0# section of the arch rib is fixed by tensioning the steel strands with jacks. The tensioning end of the steel strands is located outside the pre-embedded section pouring area, so as to minimize the impact of external factors on the installation accuracy of the 0# section of the arch rib.

[0046] (2) After the installation of the 0# section of the arch rib is completed, the 0# section of the arch rib can be finely adjusted again by tensioning the steel strands to improve the installation accuracy of the arch rib and ensure that the installation accuracy of the 0# section of the arch rib meets the requirements.

[0047] (3) Before pouring concrete in section 0 of the arch rib, if the arch rib is affected by the binding of reinforcing bars, installation of formwork, etc., it can be adjusted by tensioning the steel strands. Since the tensioning end is located outside the pre-embedded section pouring area, the arch rib can be adjusted outside the pouring area without entering the formwork, ensuring that the arch rib can be adjusted before the concrete is poured.

[0048] (4) This patent can effectively control the installation deviation of the 0# segment of the arch rib, laying a good foundation for the high-precision and high-efficiency installation of subsequent arch rib segments, shortening the arch rib installation construction time and reducing the risk factor of hoisting.

[0049] (5) This patent makes the segmental shape of the arch foot section of the rigid frame arch more in line with the requirements, making it easier to control the shape and protective layer thickness of the arch foot section when wrapping the concrete later.

[0050] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An installation method for embedded sections of rigid frame arch ribs, characterized in that; The operation process includes the following steps: (1) Construction preparation; (2) Erection of fixed support for arch rib section 0; (3) Installation of arch rib section 0; (4) Tensioning of the four corners of arch rib segment 0#, as detailed below: Before tensioning the four corners of the arch rib, steel wire ropes must be used to fix the bottom of the main chord tubes at the four corners in pairs to ensure that the main chord tubes of the arch rib will not deform due to the force on the four corners when tensioning the four corners of the 0# section of the arch rib, leading to the inward tilting of the main chord tube openings. The four-corner tensioning facility consists of steel strands, one working anchor, working anchor plate, P anchor, tensioning end anchor beam, and jacks. The tensioning steel strand uses one steel strand, with one end anchored to the fixed end working anchor on the 0# section of the arch rib using the P anchor method, and the other end tensioned and fixed to the working anchor on the anchor beam through the jacks. The anchoring end installation of the steel strand is based on the layout points in the drawings. The installation positions of the working anchors at the anchoring ends are marked on the steel pipe of section 0# of the arch rib. The working anchors are installed according to the direction of the steel strands. Before fixing the anchoring ends, the steel strands are first fixed to the working anchors using P-anchors. Anchor beams are installed at the tensioning end of the steel strands. The anchor beams are made of structural steel and are located outside the pre-embedded section casting area. The anchor beams are installed by installing rebar on a base plate, and then welding the anchor beams to the base plate. The installation must ensure both the correct anchor beam position and the correct angle of inclination. The jack is used to tension the steel strand at the anchor beam. If the tool anchor or working anchor limit plate is too small, the tool anchor or working anchor limit plate pad needs to be prepared in advance. Before tensioning, the tensioning cable force of the steel strands and the jack test report are calculated based on the modeling calculation and the reading of the tensioning oil gauge. On-site construction adopts synchronous graded tensioning. During tensioning, the four corner steel strands are tensioned simultaneously, and the tensioning is carried out in stages of 20%, 40%, 60%, 80%, 90%, and 100% tension control force. After each stage of tensioning is completed, the deviation of the 0# segment of the arch rib needs to be re-measured. The on-site commander can adjust the tensioning progress appropriately based on the measurement results to ensure that the deviation of the arch rib meets the requirements. When the tensioning progress reaches 90%, the subsequent tensioning should focus on the deviation of the arch rib as the main control point. After the tensioning is completed, the deviation of the arch rib, the structural weld of the 0# segment of the arch rib, and the contact between the 0# segment of the arch rib and the embedded parts are checked. Only after the inspection is completed and no abnormalities are found can the next construction step be carried out. (5) Construction of the pre-embedded steel reinforcement in section 0# of the arch rib; (6) Construction of formwork for the pre-embedded section of arch rib #0; (7) Conduct a comprehensive inspection of the construction of the embedded section and the 0# section of the arch rib; (8) Concrete pouring construction of the pre-embedded section of arch rib 0#; (9) Dismantling of temporary facilities.

2. The installation method for the embedded section of the arch rib of a rigid frame according to claim 1, characterized in that; The construction preparations for step 1 are as follows: Before the installation of arch rib section 0, the construction site must be cleared of debris, and the site must be prepared by excavation, filling and leveling according to the needs of the subsequent installation of arch rib section 0. After the site preparation work was completed, construction materials and equipment were transferred to the construction site one after another to prepare for construction. At the same time, the installation points of the 0# section of the arch rib were laid out. Based on the plane position and elevation of the laid-out points, the elevation of the placement points on the embedded parts was adjusted to improve the installation accuracy of the 0# section of the arch rib.

3. The installation method for the embedded section of the arch rib of the rigid frame according to claim 1, characterized in that; Step 2: The fixed support for arch rib segment 0# is erected as follows: Before erecting the fixed support for the 0# section of the arch rib, the foot points of the support columns need to be laid out. The column height is calculated based on the laid-out elevation, and the support columns are then fabricated. The support column installation begins with the installation of the support columns. The support columns are installed precisely according to the laid-out points. During installation, a level and a string line are used to ensure that the columns are vertical and that columns in the same row are on the same elevation. The columns are anchored with rebar, and the columns are welded to the rebar. After the columns are installed, the support load-bearing beams are installed, placed at an angle on the inclined surface of the columns. After placement, the inclination angle of the load-bearing beams is measured using an angle gauge, and the elevation of the load-bearing beams is measured using a total station. After the installation angle and elevation of the load-bearing beams are confirmed to be correct, welding is then performed to fix them. After the load-bearing beams are installed, the main body of the support structure is complete. The support structure needs to be reinforced. Diagonal braces are installed on both sides of the load-bearing beams to enhance the longitudinal stability of the support structure; scissor braces are installed in the middle of the columns to enhance the lateral stability of the support structure.

4. The installation method for the embedded section of the arch rib of a rigid frame according to claim 1, characterized in that; Step 3: Installation of arch rib segment #0 is as follows: Before installing the arch rib section 0#, the installation points of the arch rib were re-measured and inspected. After the inspection was qualified, the arch rib section 0# was lifted and placed. According to the site environment of the arch rib section 0#, the arrangement of the supports and the positioning requirements of the arch section, a truck crane or cable crane was selected to lift the arch rib. After the arch rib section 0# is lifted, it is initially placed on the embedded parts. The position of the arch rib is roughly adjusted by using the lifting equipment. Then, the center point of the upper edge of the bottom plate of the main chord tube of the arch foot is laid out by using a total station. The deviation of the arch rib section 0# is finely adjusted by using a hand-operated hoist and a hand-cranked jack to assist in the adjustment. After the No. 0 segment of the arch rib is installed in place, the deviation of the No. 0 segment of the arch rib is re-measured every morning, afternoon and evening when the temperature is stable. During the re-measurement, data such as time, weather, temperature and deviation are recorded. After continuous measurement for more than 3 days, the influence of temperature on the deformation of the arch rib is understood based on the measurement data. Then, the deviation of the arch rib is adjusted again at an appropriate time according to the pattern.

5. The installation method for the embedded section of the arch rib of a rigid frame according to claim 1, characterized in that; Step 5, the construction of the pre-embedded steel reinforcement in section 0# of the arch rib, is as follows: After the four corners of arch rib segment 0# are tensioned and fixed, and the deviation of arch rib segment 0# and the arch foot anchorage are checked and found to be qualified, the construction of the embedded section is carried out. The construction of the embedded section reinforcement is carried out according to the design drawings. When constructing the embedded section reinforcement, the position of the protective layer is deducted according to the laid-out arch seat edge line, and the binding line of the outer perimeter reinforcement of the arch seat is determined. Then, the bottom plate reinforcement, horizontal reinforcement, side distribution reinforcement and stirrup reinforcement are tied. At the same time, the reinforcement fabrication and installation should meet the corresponding specification requirements. In addition, the reinforcement binding should avoid contact between the reinforcement and the steel strand to ensure that the steel strand has a certain range of movement.

6. The installation method for the embedded section of the arch rib of a rigid frame according to claim 1, characterized in that; Step 6, the installation of the formwork for the pre-embedded section of arch rib #0, is as follows: After the reinforcement is tied and the reinforcement is inspected and accepted, the deviation of the 0# segment of the arch rib is checked and adjusted. After the deviation of the 0# segment of the arch rib meets the requirements, the formwork of the embedded section is installed. The formwork system consists of imported Vesa board, timber, transverse back ribs and special connectors. The formwork installation should meet the requirement of one-time casting of the embedded section, and vibration holes should be reserved and corresponding sealing measures should be prepared. When installing the template, pre-drill holes for the steel strands. After the template is installed, check the misalignment of section 0 of the arch rib. If the misalignment of the arch rib changes, tension the steel strands to adjust the misalignment of the arch rib. After adjusting the misalignment of section 0 of the arch rib to the correct position, seal the pre-drilled holes for the steel strands on the template.

7. The installation method for the embedded section of the arch rib of a rigid frame according to claim 1, characterized in that; Step 7: Conduct a comprehensive inspection of the pre-embedded section construction and the arch rib #0 section as follows: Before concrete pouring, a comprehensive inspection and acceptance of the entire embedded section construction and the 0# section of the arch rib is carried out. The inspection and acceptance includes all supports, the deviation of the 0# section of the arch rib and the four corner tensioning system, formwork, steel bars and embedded parts, etc. After the acceptance is qualified, the concrete pouring construction of the embedded section is carried out. If the arch rib section 0# is misaligned, it can be adjusted by tensioning the steel strands. Since the tensioning end is located outside the pre-embedded section pouring area, the arch rib misalignment can be adjusted outside the pouring area without entering the formwork.

8. The installation method for the embedded section of the arch rib of a rigid frame according to claim 1, characterized in that; Step 8, the concrete pouring for the pre-embedded section of arch rib #0, is as follows: The concrete pouring is done in one go, using a boom pump. The pump pipe injects concrete into the formwork through pre-reserved holes and the top of the pre-embedded section. Pouring is done in layers, progressing from one direction to another. The thickness of each layer should be determined based on the concrete mixing capacity, transportation conditions, pouring speed, vibration capacity, and structural requirements, generally 30-50cm is suitable. For each layer, a vibrator is placed in front and then used for compaction. The vibrator is inserted into the concrete through the pre-reserved holes in the formwork, with a vibration interval controlled at 50-60cm. During vibration, the vibrator should be fully inserted into the concrete. When vibrating the upper and lower layers, the vibrator should be inserted 5-10cm into the lower layer. Each vibration point should be inserted quickly and withdrawn slowly, vibrating until the concrete stops descending, air bubbles stop escaping, and a slurry appears on the surface. The pre-reserved holes in the formwork are sealed when the concrete reaches them.

9. The installation method for the embedded section of the arch rib of a rigid frame according to claim 1, characterized in that; Step 9: Temporary facility removal is as follows: After the concrete pouring is completed and the concrete strength meets the requirements, temporary facilities such as formwork and steel strands are removed. When removing the steel strands, the tension of the steel strands is first relieved, and then the steel strands are cut and removed with cutting equipment flush with the concrete surface. Then the tension end anchor beam is removed. After the formwork is removed, a layer of geotextile is promptly covered on the concrete surface and water is sprinkled for curing.

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