Bracket-free mounting method for continuous-span segmented prefabricated steel beam

Abstract

The invention relates to a continuous span subsection prefabricated steel beam support-free installation method which comprises the following steps: firstly, installing a steel beam subsection positioned at a middle joint, secondly, installing a tensioning stability maintaining device, and finally, installing the remaining steel beam subsections at two ends; the tensioning stability maintaining device comprises four pieces of double-spliced steel channels, four pieces of finish rolling deformed steel bars and a plurality of matched nuts. The top and the bottom of the steel beam section are each provided with two pieces of double-spliced channel steel in a criss-cross mode, and four pieces of finish rolling deformed steel bars and matched nuts are installed on the side face of the steel beam section to connect the double-spliced channel steel on the top and the double-spliced channel steel on the bottom to form a tensioning system. The method is suitable for the installation environment with dense traffic and limited space, and has the advantages in the aspects of operation difficulty coefficient, cost and construction period.

Description

Technical Field

[0001] The invention relates to the field of bridge installation, in particular to a method for installing a continuous span segmented prefabricated steel beam without a support. Background Art

[0002] Continuous-span steel beams have a large span and are lighter than concrete structural beams. They are often designed above ground traffic intersections. Considering the impact of construction occupying the road and the constraints of over-limit transportation, they are often transported and installed in sections by prefabrication. When installing in sections, the sections need to be aligned and welded. The traditional method is to set up a ground support platform at the connection between the sections, or to install temporary support and stability devices on the side walls of the bridge columns. The former has ground supports occupying the road, affecting traffic and safety; although the latter has no landing supports, installation holes or embedded steel plates must be reserved when the columns are prefabricated or cast-in-place, and consent for design changes must be obtained. Therefore, both traditional support installation and existing support-free installation have their own shortcomings. Summary of the invention

[0003] The present invention aims to overcome the defects of the prior art and provides a method for installing continuous span segmented prefabricated steel beams without a bracket, which solves the problems that the traditional bracket construction method occupies the road and affects traffic, and the bracket-free construction method requires pre-buried steel plates.

[0004] In order to solve the above-mentioned technical problems, the present invention is achieved as follows: A method for installing continuous-span segmented prefabricated steel beams without a support, characterized in that: first, the steel beam segment located at the middle connection is installed, then a tensioning and stabilization device is installed, and finally the remaining steel beam segments are installed at both ends; the tensioning and stabilization device includes four double-jointed channel steels, four fine-rolled threaded steels and a number of matching nuts; two double-jointed channel steels are arranged at the top and the bottom of the steel beam segment, which are criss-crossed, and four fine-rolled threaded steels and matching nuts are installed on the side of the steel beam segment to connect the double-jointed channel steels at the top and the bottom to form a tensioning system.

[0005] The method for installing a continuous span segmented prefabricated steel beam without a support is characterized in that the specific installation steps are as follows: Step 1: Lifting of steel beams in sections; Step 2: Place the temporary support; Step 3: Measure and adjust to determine the position; Step 4: Adjust the temporary support and fix it by spot welding; Step 5: Install the top double channel steel; Step 6: Finishing rolling of threaded steel and nut assembly; Step 7: Install the bottom double channel steel; Step 8: Tighten the bottom nut; Step 9: The lifting machinery slowly unloads step by step; Step 10: Local welding of the welds between sections and welding of the limit connection code plates.

[0006] The described method for installing a continuous span segmented prefabricated steel beam without a support is characterized in that: in step 2, the placement position of the temporary support should be 1 / 4 and 2 / 4 of the bottom surface of the steel beam segment, and the connection between the bottom plate and the cross partition is the best; the steel beam segment at the connection should be on both sides of the cap beam, and no less than 2 temporary supports are placed; in step 3, the measurement and positioning adopts the prefabricated measurement control points of the steel beam segment, and each segment is set with no less than 4 measurement control points; the elevation and coordinates of each measurement control point need to be measured; the measurement accuracy is controlled at ±5mm; in step 4, the elevation and slope of the upper surface of the temporary support need to be repeatedly adjusted until the measurement data results meet the installation quality requirements after the steel beam segment is in place; after the temporary support is adjusted, in order to prevent the temporary support from settling when the pre-tightening force is applied to the tensioning and stabilization device, the upper and lower cylinders of the temporary support need to be locally welded and fixed, the welding parts should be symmetrically arranged, and only the temporary support on the offset side of the center of the steel beam segment is welded and fixed.

[0007] The method for installing a continuous span segmented prefabricated steel beam without a support is characterized in that a jack replaces the temporary support to improve the installation accuracy.

[0008] The method for installing a continuous span segmented prefabricated steel beam without a bracket is characterized in that: in step five, in addition to the installation direction of the top double-jointed channel steel being consistent with the direction of the cap beam, its length should be greater than the width of the steel beam segment, and the length of the steel beam segment protruding from both ends should be no less than 40 cm; the width of the middle gap of the double-jointed channel steel should be slightly larger than the diameter of the fine-rolled threaded steel and smaller than the outer diameter of the matching nut, preferably the diameter of the fine-rolled threaded steel plus 2-5 mm. When installing the two double-jointed channel steels at the top, they should maintain a parallel relationship and be perpendicular to the side plates of the steel beam sections; the top double-jointed channel steel should be installed before the steel beam sections are hoisted, and should be hoisted to the top surface of the steel beam and placed and securely fixed to prevent falling; in step six, the high-precision rolled threaded steel should be installed along with the top double-jointed channel steel before the steel beam sections are hoisted, and should be hoisted to the top surface of the steel beam or directly installed with the top double-jointed channel steel, and the top nut should be installed before installation; both the nuts on the top surface of the top double-jointed channel steel and the nuts on the bottom surface of the bottom double-jointed channel steel use double nuts to achieve self-locking; the high-precision rolled threaded steel connecting the top and bottom double-jointed channel steels should be kept vertical and parallel to each other; the installation position of the high-precision rolled threaded steel should not be too large or small from the side plates of the steel beam sections and the side end faces of the cap beam, and 5 to 10 cm is appropriate.

[0009] The described method for installing a continuous span segmented prefabricated steel beam without a support is characterized in that: in step seven, the width of the middle gap of the bottom double-jointed channel steel is consistent with the requirement of the top double-jointed channel steel, but the length dimension is based on the width of the cap beam, which is greater than the width of the cap beam, and the length protruding from the cap beam overlaps with the top double-jointed channel steel on the horizontal projection plane; the installation of the bottom double-jointed channel steel should be carried out manually with the aid of a climbing vehicle, which can not only meet the needs of the high-altitude working platform, but also facilitate the maintenance of the bottom double-jointed channel steel when installing the bottom nut; when the two double-jointed channel steels at the bottom are installed, they are also required to maintain a parallel relationship and be perpendicular to the side end face of the cap beam; in step eight, the tightening of the bottom nut should be carried out in multiple times, first perform the initial tightening, and then tighten again as the lifting machinery unloads step by step; the initial tightening is based on eliminating the gap between the contact surface of the top double-jointed channel steel and the steel beam segment, and the gap between the bottom double-jointed channel steel and the cap beam; the final tightening is based on continuing to tighten until the elevation of the steel beam segment measurement control point shows a reverse change trend after the lifting machinery is completely unloaded, and tools must be used for the final tightening.

[0010] The described method for installing a continuous span segmented prefabricated steel beam without a support is characterized in that: in step nine, the unloading of the lifting machinery must be carried out after the bottom nut of the tensioning and stabilizing device is initially tightened, and it is advisable to unload step by step with a gradient of 20%; after the lifting machinery is completely unloaded, the bottom nut of the tensioning and stabilizing device is finally tightened, and the sling can be unhooked.

[0011] The described method for installing a continuous span segmented prefabricated steel beam without a bracket is characterized in that: in step ten, after the steel beam segments at both ends are hoisted into place, code plates must first be used to limit the welding of the steel beam segments at the connection and the end side steel beam segments to keep the two aligned and the weld width controlled; code plates should be set for welding of the side plates, top plates, and bottom plates of the segments; after the code plates are welded, local welding is performed on the welds between the segments to enhance the segment connection strength.

[0012] The beneficial effects of the present invention are as follows: It can be seen from the above technical scheme that the present application provides a method for installing continuous-span segmented prefabricated steel beams without a bracket, which adopts a simpler tensioning and stabilization method and can directly utilize the cap beam body without pre-embedding to achieve the combined fixation of the designated segment of the steel beam and the lower structure of the bridge; and integrates the adjustment of the installation method of the steel beam segments before and after the tensioning and stabilization process to form a method for installing continuous-span segmented prefabricated steel beams without a bracket.

[0013] Compared with traditional bracket installation and existing bracket-free installation, the present invention uses tensioning and stabilization to achieve bracket-free installation of continuous span segmented prefabricated steel beams. There is no landing bracket and no need for pre-design and embedding in advance, which minimizes the negative impact on ground traffic and fits the steel beam installation environment with dense traffic and limited space. In addition, the implementation measures involved in the present invention have a low operating difficulty coefficient and a simple device structure. The manufacturing materials, cost, and construction period are all more advantageous than traditional bracket installation and existing bracket-free installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments: Figure 1 The installation sequence of the bracket-free installation method for continuous span segmental prefabricated steel beams; Figure 2 This is a cross-sectional schematic diagram of the installation of the tensioning and stabilizing device; Figure 3 This is a schematic diagram of the longitudinal section of the installation of the tensioning and stabilizing device; Figure 4 This is a schematic diagram of the temporary sand box layout; Figure 5 The overall installation process flow chart for the unsupported installation of continuous span segmented prefabricated steel beams. DETAILED DESCRIPTION

[0015] The technical solutions of the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments in the embodiments of the present application are within the scope of protection requested by the present application.

[0016] like Figure 1 Shown: A method for installing continuous span segmented prefabricated steel beams without brackets. The overall installation process is as follows: The overall installation sequence of the continuous span segmental prefabricated steel beam without support installation is as follows: Figure 5 As shown in the figure, the steel beam segment located at the middle connection should be installed first, then the tensioning and stabilization device should be installed, and then the remaining steel beam segments should be installed at both ends. During the process, in order to ensure the quality of installation, a series of safeguard measures were taken, including measurement and positioning, setting up temporary supports, adjusting the elevation of temporary supports and welding them, and unloading and unhooking the lifting machinery after partial welding of the welds between segments.

[0017] Process principle: When installing the continuous span segmented prefabricated steel beams, first install and fix the steel beam segments at the continuous span connection, then use the steel beam segments at the connection to replace the support brackets, and install the remaining segments at both ends. Figure 1 The steel beam segments at the continuous span connection are fixed by directly tying and fixing them to the cap beam as a whole using a stable and simple tensioning device. The center of gravity distribution of the steel beam segments and the tension provided by the tensioning device are used to balance the overturning moment generated during the installation of the steel beam segments. Figure 2 , Figure 3 Use a temporary sand box or jack to adjust the installation accuracy. The placement is as follows: Figure 4 shown.

[0018] The specific steps are as follows: Step 1: Segmental lifting of steel beams The lifting of steel beam sections should be based on the lifting site and the weight of the steel beam sections, and appropriate lifting machinery, slings and lifting methods should be selected. For steel beam sections with larger spans, a double-machine lifting method should be adopted.

[0019] The designed hoisting conditions should meet the requirements of the hoisting specifications. The system load rate should not exceed 75% when two cranes are lifting, and the load rate of any one of the cranes should not exceed 80%; (3) Before lifting, determine the crane position based on the designed lifting conditions and leave a channel for transporting beams.

[0020] Step 2: Temporary support placement (1) The temporary support should be placed at the 1 / 4 and 2 / 4 positions of the bottom surface of the steel beam segment, and the connection between the bottom plate and the diaphragm is the best; (2) At the joints of the steel beam sections, at least two temporary supports should be placed on both sides of the cap beam.

[0021] Step 3: Measure and adjust to determine the position (1) The measurement and positioning adopts prefabricated measurement control points in steel beam sections, and each section is set with no less than 4 measurement control points; (2) The elevation and coordinates of each measurement control point must be measured; (3) The measurement accuracy is controlled within ±5mm.

[0022] Step 4: Adjust the temporary support and fix it with spot welding The elevation and slope of the temporary support surface need to be adjusted repeatedly until the measured data results after the steel beam is in place in sections meet the installation quality requirements; After the temporary support is adjusted, in order to prevent the temporary support from settling when the pre-tightening force is applied to the tensioning and stabilization device, the upper and lower cylinders of the temporary support need to be locally welded and fixed. The welding parts should be set symmetrically, and only the temporary support on the offset side of the center of the steel beam segment should be welded and fixed.

[0023] When materials are sufficient, it is advisable to use a jack instead of a temporary support, which is more helpful for adjusting installation accuracy.

[0024] Step 5: Top double channel steel installation The installation direction of the top double-jointed channel steel should be consistent with the direction of the cap beam. Its length should be greater than the width of the steel beam segment, and the length of both ends protruding from the steel beam segment should be no less than 40cm; The width of the middle gap of the double-jointed channel steel should be slightly larger than the diameter of the fine-rolled threaded steel and smaller than the outer diameter of the matching nut, and should be the diameter of the fine-rolled threaded steel plus 2~5mm.

[0025] The two double-jointed channel steels at the top should be installed in parallel and perpendicular to the segmented side plates of the steel beam; The top double-jointed channel steel should be installed before the steel beam is hoisted in sections, and it should be hoisted to the top surface of the steel beam and securely fixed to prevent it from falling.

[0026] Step 6: Finished rolling of rebar and nut threading The fine-rolled threaded steel should be installed with the top double-jointed channel steel before the steel beam is hoisted in sections, and should be hoisted to the top surface of the steel beam or directly installed with the top double-jointed channel steel. The top nut should be installed before installation. Whether it is the nut on the top of the double-jointed channel steel or the nut on the bottom of the double-jointed channel steel, double nuts should be used to achieve self-locking; The top and bottom double-jointed channel steels connected by fine-rolled threaded steel should be kept vertical and parallel to each other; The installation position of the fine-rolled threaded steel bar should not be too large or too small from the side plate of the steel beam segment and the side end surface of the cap beam, and 5~10cm is appropriate.

[0027] Step 7: Installation of double channel steel at the bottom The width of the gap between the bottom double-jointed channel steel is consistent with the requirements for the top double-jointed channel steel, but the length should be based on the width of the cap beam, which should be greater than the width of the cap beam, and the length protruding from the cap beam should overlap with the top double-jointed channel steel on the horizontal projection plane; The installation of the bottom double-jointed channel steel should be carried out manually with the help of a climbing vehicle, which can not only meet the needs of the high-altitude working platform, but also facilitate the maintenance and support of the bottom double-jointed channel steel when installing the bottom nut; When installing the two double-jointed channel steels at the bottom, they are also required to maintain a parallel relationship and be perpendicular to the side end faces of the cap beam.

[0028] Step 8: Tighten the bottom nut The bottom nut should be tightened in multiple steps, first tightened initially, then tightened again as the lifting machinery is unloaded step by step; The initial tightening is based on eliminating the gap between the contact surface of the top double-jointed channel steel and the steel beam segment, and the bottom double-jointed channel steel and the cap beam; The final tightening is determined by continuing to tighten the steel beam until the elevation of the control points measured in sections shows a reverse trend after the lifting machinery is completely unloaded, and tools must be used for the final tightening.

[0029] Step 9: The lifting machinery slowly unloads step by step The unloading of the lifting machinery must be carried out after the initial tightening of the bottom nut of the tensioning and stabilizing device is completed, and it is advisable to unload step by step with a gradient of 20%; After the lifting machinery is completely unloaded, the bottom nut with the tensioning and stabilizing device is finally tightened before the sling can be unhooked.

[0030] Step 10: Local welding of the welds between sections and welding of the limit connection code plate After the steel beam sections at both ends are hoisted into place, the steel beam sections at the connection and the end side steel beam sections must be welded and limited using the yard plates to keep the two aligned and the weld width controlled; the side plates, top plates, and bottom plates of the sections should all be welded with yard plates; (2) After the code plates are welded, local welding is performed on the welds between the segments to enhance the segment connection strength.

[0031] No bracket required for installation The present invention relies on a tensioning and stabilizing device assembled from double-jointed channel steel, precision-rolled threaded steel and nuts to achieve the installation of continuous span segmented prefabricated steel beams without brackets. There are requirements on the strength of the prefabricated segments and the device: Prefabricated segments: The center of gravity of the steel beam segments at the continuous span connection is required to be close to the connection, so as to reduce the overturning moment and improve the safety of installation. Due to the bracket-free installation method of the continuous span segmented prefabricated steel beams in the present invention, the installation sequence requires that the steel beam segments at the connection be installed first, and then the remaining steel beam segments are installed at both ends. Therefore, the stepped joints at both ends of the steel beam segments at the connection are required to be straight stepped, with the top short and the bottom long.

[0032] Device strength: The device is mainly composed of double-jointed channel steel, precision-rolled threaded steel and nuts. It relies on the tensile strength of precision-rolled threaded steel and the bending resistance of double-jointed channel steel to offset the overturning moment. The specifications of the two key components must pass the strength test, and reinforcement measures must be taken to improve the strength of the device. For example, double-jointed channel steel adopts the addition of multiple ribs to improve the bending strength, and precision-rolled threaded steel adopts a size specification larger than the diameter that meets the bending strength requirements.

[0033] Installation precision control The key and difficulty of installing continuous span segmented prefabricated steel beams without brackets lies in the control of installation accuracy, which is also the key control point of installation quality, including the positioning accuracy of the steel beam segments when they are hoisted into place at the connection and the accuracy correction after the installation of the tensioning and stabilization device. It is required to be carried out according to the following procedures: Step 1: Collect and organize design data and steel beam prefabrication measurement control point data; Step 2: Re-measure the height of the cap beam pad stone; Step 3: Calculate the installation position coordinates and elevation of the steel beam segment measurement control points; Step 4: Measure and locate during hoisting to determine the position of the steel beam sections; Step 5: After the temporary support is placed and adjusted, it is welded to prevent the temporary support from settling and causing the steel beam to deviate in sections, or a jack is used; Step 6: After the bottom nut of the tensioning and stabilizing device is tightened for the first time, the lifting machinery is slowly unloaded step by step, and the bottom nut is tightened again step by step, applying prestress to offset the additional overturning moment caused by the segmented installation of the steel beams at both ends, reducing the change in the elongation of the fine-rolled rebar, thereby weakening the segment deviation.

[0034] Step 7: When installing the steel beams at both ends in sections, after the middle section is aligned with the end sections, use the limit code plate to limit and prevent misalignment. At this time, the limit code plate is only welded to the middle section and not to the end sections.

[0035] Step 8: After all the limit code plates are set, the truck crane at the farthest end of the hoisting end side segment will slowly unload first until the end side segment is stably placed on the support, and then the truck crane on the side close to the middle segment of the hoisting end side segment will slowly unload step by step until the load is displayed as zero. During this period, the hooks of the two truck cranes will not be removed.

[0036] Step 9: Measure the elevation change at the connection between the middle section and the end section, and operate two truck cranes to lift the end section again until it is slightly separated from the middle section and remains stable; Step 10: Use a jack to slowly lift the middle segment near the temporary sand box at the bottom of the middle segment, close to the side of the end segment being installed. During the process, loosen the nut on the side of the end segment being installed appropriately with the tensioning device, and tighten the nut on the other side, until the elevation of the connection between the middle segment and the end segment is the sum of the design elevation and the previously measured change value.

[0037] Step 11: Repeat step 8 and measure the elevation value again to see if it meets the design elevation. If not, continue to adjust. If yes, remove the hook of the farthest truck crane, and do not remove the hook of the truck crane near the middle section for the time being. After the welding of the limit code plate and the end section and the partial connection of the weld are completed, remove the hook near the middle section.

[0038] The present invention is a new method for installing continuous span segmented prefabricated steel beams without brackets. It directly realizes the combination and fixation of the designated steel beam segments and the bridge substructure through a simple device, and uses the fixed designated steel beam segments as a support platform to complete the installation of the remaining steel beam segments at both ends. This technology does not require pre-embedded design or landing brackets. The required materials are simple and easy to find, and the implementation difficulty is small. The negative impact on ground traffic is minimized, and it has significant advantages in places with dense traffic and limited space.

[0039] The above are only embodiments provided for the present application and are not intended to limit the present application. Although the present application is described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for installing a continuous span segmented prefabricated steel beam without a support, characterized in that: First, install the steel beam segment located at the middle connection, then install the tensioning and stabilizing device, and finally install the remaining steel beam segments at both ends; the tensioning and stabilizing device includes four double-jointed channel steels, four precision-rolled threaded steels and a number of matching nuts; two double-jointed channel steels are arranged at the top and bottom of the steel beam segment, which are criss-crossed, and four precision-rolled threaded steels and matching nuts are installed on the side of the steel beam segment to connect the double-jointed channel steels at the top and bottom to form a tensioning system.

2. The method for installing a continuous span segmented prefabricated steel beam without a support according to claim 1, characterized in that The specific installation steps are as follows: Step 1: Lifting of steel beams in sections; Step 2: Place the temporary support; Step 3: Measure and adjust to determine the position; Step 4: Adjust the temporary support and fix it by spot welding; Step 5: Install the double-jointed channel steel on the top; Step 6: Finishing rolling of threaded steel and nut assembly; Step 7: Install the bottom double channel steel; Step 8: Tighten the bottom nut; Step 9: The lifting machinery slowly unloads step by step; Step 10: Local welding of the welds between sections and welding of the limit connection code plates.

3. The method for installing a continuous span segmented prefabricated steel beam without a support according to claim 2, characterized in that: In step 2, the temporary support should be placed at 1 / 4 and 2 / 4 of the bottom surface of the steel beam segment, and the connection between the bottom plate and the diaphragm is the best; the steel beam segment at the connection should be on both sides of the cap beam, and at least 2 temporary supports should be placed; in step 3, the measurement and positioning adopts the prefabricated measurement control points of the steel beam segment, and each segment is set with no less than 4 measurement control points; the elevation and coordinates of each measurement control point need to be measured; the measurement accuracy is controlled within ±5mm; in step 4, the elevation and slope of the upper surface of the temporary support need to be adjusted repeatedly until the measurement data results meet the installation quality requirements after the steel beam segment is in place; After the temporary support is adjusted, in order to prevent the temporary support from settling when the pre-tightening force is applied to the tensioning and stabilization device, the upper and lower cylinders of the temporary support need to be locally welded and fixed. The welding parts should be set symmetrically, and only the temporary support on the offset side of the center of the steel beam segment should be welded and fixed.

4. The method for installing a continuous span segmented prefabricated steel beam without a support according to claim 3, characterized in that: The jack replaces the above-mentioned temporary support to improve the installation accuracy.

5. The method for installing a continuous span segmented prefabricated steel beam without a support according to claim 3, characterized in that: In step five, the installation direction of the top double-jointed channel steel should be consistent with the direction of the cap beam. Its length should be greater than the width of the steel beam segment, and the length of the steel beam segment protruding from both ends should be no less than 40cm; the width of the middle gap of the double-jointed channel steel should be slightly larger than the diameter of the fine-rolled rebar and smaller than the outer diameter of the matching nut, preferably the diameter of the fine-rolled rebar plus 2-5mm. When installing the two double-jointed channel steels at the top, they should maintain a parallel relationship and be perpendicular to the side plates of the steel beam sections; the top double-jointed channel steel should be installed before the steel beam sections are hoisted, and should be hoisted to the top surface of the steel beam and placed and securely fixed to prevent falling; in step six, the high-precision rolled threaded steel should be installed along with the top double-jointed channel steel before the steel beam sections are hoisted, and should be hoisted to the top surface of the steel beam or directly installed with the top double-jointed channel steel, and the top nut should be installed before installation; both the nuts on the top surface of the top double-jointed channel steel and the nuts on the bottom surface of the bottom double-jointed channel steel use double nuts to achieve self-locking; the high-precision rolled threaded steel connecting the top and bottom double-jointed channel steels should be kept vertical and parallel to each other; the installation position of the high-precision rolled threaded steel should not be too large or small from the side plates of the steel beam sections and the side end faces of the cap beam, and 5 to 10 cm is appropriate.

6. The method for installing a continuous span segmented prefabricated steel beam without a support according to claim 3, characterized in that: In step 7, the width of the gap between the bottom double-jointed channel steel is consistent with the requirement for the top double-jointed channel steel, but the length is based on the width of the cap beam, which is greater than the width of the cap beam, and the length protruding from the cap beam overlaps with the top double-jointed channel steel on the horizontal projection plane; The installation of the bottom double-jointed channel steel should be carried out manually with the help of a climbing vehicle, which can not only meet the needs of the high-altitude working platform, but also facilitate the maintenance of the bottom double-jointed channel steel when installing the bottom nuts; when installing the two double-jointed channel steels at the bottom, they are also required to maintain a parallel relationship and be perpendicular to the side end face of the cap beam; in step eight, the tightening of the bottom nuts should be carried out in multiple times, first perform the initial tightening, and then tighten again as the lifting machinery unloads step by step; the initial tightening is based on eliminating the gap between the contact surfaces of the top double-jointed channel steel and the steel beam segment, and the bottom double-jointed channel steel and the cap beam; the final tightening is based on the complete unloading of the lifting machinery, and continues to tighten until the elevation of the steel beam segment measurement control point shows a reverse change trend, and tools must be used for the final tightening.

7. The method for installing a continuous span segmented prefabricated steel beam without a support according to claim 3, characterized in that: In step nine, the unloading of the lifting machinery must be carried out after the bottom nut of the tensioning and stabilizing device is initially tightened, and it is advisable to unload step by step with a gradient of 20%. After the lifting machinery is completely unloaded and the bottom nut with the tensioning and stabilizing device is finally tightened, the sling can be unhooked.

8. The method for installing a continuous span segmented prefabricated steel beam without a support according to claim 3, characterized in that: In step ten, after the steel beam sections at both ends are hoisted into place, the steel beam sections at the connection points and the end side steel beam sections must first be welded and limited using yard plates to keep the two aligned and the weld width controlled; the side plates, top plates, and bottom plates of the sections should all be welded with yard plates; after the yard plates are welded, local welding should be performed on the welds between the sections to enhance the connection strength of the sections.

Images