Construction method of gravity type road-bridge integrated cantilever pedestrian bridge in confined space

Abstract

The application discloses a construction method of a gravity type road-bridge integrated cantilever pedestrian bridge in a limited space, relates to the construction of a pedestrian bridge crossing a river bridge in a transverse direction, and comprises the following steps: (1) counterweight block construction: excavating the slope protection on the two sides of the river embankment in the transverse direction of the river bridge and binding the counterweight block steel bars at the excavation positions; (2) erecting a support frame and a formwork: arranging a cantilever part connecting the counterweight blocks on the positions crossing the river bridge and erecting a cantilever part support frame; (3) binding a steel framework: integrally binding one end of the steel bars with the upper steel bars of the counterweight block steel bars; (4) closing the formwork: erecting a counterweight block formwork and a cantilever end formwork for concrete pouring; and (5) concrete pouring and demolding: integrally pouring concrete to the enclosed pouring space and demolding after molding. The counterweight foundation and the cantilever platform in the application can be integrally poured and molded at one time, the construction operation can be completed in the limited space, and the problem that the safety of the existing buildings is not influenced.

Description

Technical Field

[0001] This invention relates to the field of pedestrian bridge construction technology, and in particular to a construction method for a gravity-type cantilevered pedestrian bridge integrating road and bridge in a confined space. Background Technology

[0002] During the design and construction of pedestrian bridges, some sections may conflict with the locations of existing buildings or underground facilities due to obstructions. This is especially true for pedestrian bridges traversing confined spaces. The traditional construction process involves "pile foundation + abutment + pier + cap beam + precast box girder hoisting". In the pile foundation construction stage, the impact force generated by the pile driving machinery can affect the foundation of the existing building, impacting its safety. Furthermore, in the subsequent hoisting stage, large hoisting equipment is required to hoist the box girder. Due to the influence of existing buildings, the available working space is limited, which is not conducive to the normal progress of construction work. Summary of the Invention

[0003] The main objective of this invention is to provide a construction method for a gravity-type integrated cantilever pedestrian bridge within a confined space, aiming to solve existing technical problems.

[0004] To achieve the above objectives, this invention provides a construction method for a gravity-type integrated cantilevered pedestrian bridge within a confined space, involving the construction of a pedestrian overpass under a river-crossing bridge for transverse traffic, and includes the following steps:

[0005] (2) Counterweight construction: Excavate the slope protection on both sides of the riverbank in the transverse direction of the cross-river bridge, and tie the counterweight steel bars at the excavation site.

[0006] (2) Erecting support frame and formwork: Set up a cantilever section connecting the counterweights on both sides at the underpass of the cross-river bridge, and erect a support frame for the cantilever section;

[0007] (3) Binding the steel reinforcement cage: Bind the steel reinforcement on the cantilever support frame and extend one end of the steel reinforcement to bind it together with the upper steel reinforcement of the counterweight block;

[0008] (4) Formwork assembly: Erecting counterweight block formwork and cantilever end formwork for concrete pouring;

[0009] (5) Concrete pouring and demolding: The pouring space enclosed by the template in step (4) is poured as a whole, and demolded after forming.

[0010] Furthermore, in step (1), when excavating the riverbank revetment, depending on whether there is an existing concrete block foundation of the riverbank at the excavation site, it is divided into the following two steps:

[0011] S1: If there is an original concrete block foundation for the river embankment, before tying the counterweight reinforcement, first install the reinforcement on the original concrete block foundation for the river embankment, and then tie the counterweight reinforcement.

[0012] S2: If the original riverbank concrete block foundation does not exist, first tie the trapezoidal counterweight block reinforcement at the excavation site and complete the pouring, then tie the upper counterweight block reinforcement on the trapezoidal counterweight block reinforcement.

[0013] Furthermore, in S1, the inserted steel bars are arranged in a quincunx pattern with a spacing of 30*40cm, and a 25mm tongue and groove joint is chiseled into the concrete surface.

[0014] Furthermore, in step (1), while binding the counterweight reinforcement, a temperature measuring element is installed. The temperature measuring element includes a steel pipe with an open top. The steel pipe is pre-embedded in the counterweight reinforcement along the height direction, extending upward from the bottom of the counterweight. The top of the steel pipe is located 30-50cm below the top of the counterweight. Water is poured into the steel pipe for temperature measurement by a thermometer.

[0015] Further, in step (5), the lower part of the counterweight concrete is poured first, leaving a height of 30-50cm above the counterweight concrete. At this time, the top of the steel pipe of the temperature measuring element is exposed outside the concrete. After the lower part of the concrete is poured, a thermometer is placed inside the steel pipe of the temperature measuring element to measure the temperature inside the poured concrete. There are more than three steel pipes of the temperature measuring element. Water of different depths is poured into each steel pipe in sequence to measure the inner surface temperature of the concrete counterweight at different heights after pouring, so as to accurately grasp the inner and outer surface temperature information of the concrete. After the counterweight reaches the expected strength, the part above the counterweight and the cantilever part are poured. The steel pipe of the temperature measuring element is poured into the counterweight concrete together.

[0016] Furthermore, in step (1), after the counterweight reinforcement is tied, a support system is erected on its outside. The support system includes columns set around the counterweight reinforcement mesh and horizontal bars set at the bottom of the counterweight reinforcement mesh. The columns are supported by steel pipes and erected on the bottom reinforcement mesh. Right-angle fasteners are used to connect the columns and horizontal bars at their junction.

[0017] The outermost support system is provided with a scissor brace, and the end of the scissor brace is tied and fixed to the corresponding horizontal bar.

[0018] Furthermore, in step (2), the side formwork of the counterweight block template is made of wood. The outer side of the wood template is provided with two secondary keel timbers arranged in a longitudinal and intersecting manner and two main keel steel pipes. The short side of the two main keel steel pipes is drilled with diagonal tie bars at intervals of 750mm.

[0019] The wooden formwork is provided with two steel pipe diagonal braces with a spacing of 600mm on the back side. The two steel pipe diagonal braces are arranged in a front-to-back position and their tops are connected to the main keel steel pipes at different heights.

[0020] Furthermore, the bottom formwork of the cantilever end template is connected to the cantilever end support frame, and a U-shaped bracket is provided at the connection. A tie rod is passed through the middle of the beam formwork of the cantilever end template, and a vertical steel pipe support is provided at the bottom of the beam, with an additional tie rod.

[0021] The beneficial effects of this invention are reflected in:

[0022] The counterweight foundation and cantilever platform in this invention can be cast in one go. Compared with the traditional construction process of "pile foundation + pile cap + pier + cap beam + precast box girder hoisting", the construction period of a single span is effectively shortened by about 45 days. Moreover, the construction work can be completed in a confined space without causing any safety issues to the existing buildings.

[0023] This invention effectively utilizes the original structure and avoids resource waste: the original pedestrian underpass and riverbank retaining wall under the arch bridge contain an original concrete foundation, which can be connected to the counterweight foundation by rebar installation and can serve as the load-bearing point of the counterweight foundation of the cantilever section structure, avoiding the waste of resources by excavating to make rock-socketed foundations or embedded foundations. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention;

[0025] Figure 2 The diagram below shows an existing concrete block foundation for this invention.

[0026] Figure 3 This is a schematic diagram of the present invention without an existing concrete block foundation.

[0027] Figure 4 This is a schematic diagram of the rebar installation process of the present invention;

[0028] Figure 5 This is a schematic diagram of the arrangement of the temperature sensing elements of the present invention;

[0029] Figure 6 This is a schematic diagram of the template and tie bar layout of the present invention;

[0030] Figure 7 This is a schematic diagram of the elevation structure of the counterweight block template of the present invention;

[0031] Figure 8 This is a schematic diagram of the cantilever slab support frame arrangement of the present invention;

[0032] Figure 9 This is a schematic diagram of the formwork layout for the cantilever beam section of the present invention;

[0033] Figure 10 This is a schematic cross-sectional view of the formwork for the cantilever beam section of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Full-span support frame; 2. Main keel steel pipe 1; 3. Secondary keel timber 1; 4. Tie rods; 5. Main keel steel pipe 2; 6. Secondary keel timber 2; 7. Wooden formwork; 8. Tie bars; 9. Steel pipe diagonal bracing; 10. Formwork. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0038] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied. Furthermore, "multiple" refers to two or more. Moreover, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent.

[0039] Please see Figure 1 This invention discloses a construction method for a gravity-type integrated cantilevered pedestrian bridge within a confined space, specifically for constructing a pedestrian overpass under a river-crossing bridge with transverse traffic. The method includes the following steps:

[0040] (3) Counterweight construction: Excavate the slope protection on both sides of the riverbank in the transverse direction of the cross-river bridge, and tie the counterweight steel bars at the excavation site;

[0041] (2) Erecting support frame and formwork: Set up a cantilever section connecting the counterweights on both sides at the underpass of the cross-river bridge, and erect a support frame for the cantilever section;

[0042] (3) Binding the steel reinforcement cage: Bind the steel reinforcement on the cantilever support frame and extend one end of the steel reinforcement to bind it together with the upper steel reinforcement of the counterweight block;

[0043] (4) Formwork assembly: Erecting counterweight block formwork and cantilever end formwork for concrete pouring;

[0044] (5) Concrete pouring and demolding: The pouring space enclosed by the template in step (4) is poured as a whole, and demolded after forming.

[0045] The counterweight foundation and cantilever platform in this invention can be cast in one go. Compared with the traditional construction process of "pile foundation + pile cap + pier + cap beam + precast box girder hoisting", the construction period of a single span is effectively shortened by about 45 days. Moreover, the construction work can be completed in a confined space without causing any safety issues to the existing buildings.

[0046] In one embodiment, step (1), when excavating the riverbank revetment, is divided into the following two steps depending on whether there is an existing concrete block foundation of the riverbank at the excavation site: Please refer to Figure 2 and Figure 3 ,

[0047] S1: If there is an original concrete block foundation for the river embankment, before tying the counterweight reinforcement, first install the reinforcement on the original concrete block foundation for the river embankment, and then tie the counterweight reinforcement.

[0048] Please see Figure 4 The steps of the rebar installation operation include: (1) Positioning: According to the construction drawings, in the part containing the existing concrete block below the counterweight block (the original reinforced concrete revetment foundation of the river embankment), according to the design or structural requirements, mark the position where the connecting bars are set, mark the horizontal and vertical intersecting lines, and the intersection of the marked lines is the location of the rebar drilling hole for the connecting bars.

[0049] (2) Drilling: Drill holes according to the marked locations using an impact drill. The hole diameter is 25mm and the hole depth is 10d = 20cm. When drilling, the impact drill should be used perpendicular to the structural surface and drilled evenly to control the verticality of the hole. The hole depth is controlled by the top rod of the impact drill. If a main reinforcement bar is encountered during drilling, the drilling position can be horizontally shifted by one reinforcement bar diameter and re-drilled. The unfinished holes drilled in the original drilling process should be filled and leveled with 1:1 cement mortar.

[0050] (3) Hole Cleaning: After drilling is completed, hole cleaning can be performed. Blow away dust from the hole using a special brush and a blower (rubber airbag, hand-push air pump, or manual / electric blower). Use the "four-blow, three-brush" method: first blow away the surface dust, then use the special brush to clean the hole walls. While brushing, pull and rotate the brush inside the hole repeatedly to clean away the dust. Never use water to clean the hole.

[0051] (4) Reinforcing bar treatment: Grind the anchoring part of the reinforcing bar. Oil, rust, dirt and uneven substances on the surface of the anchor bar should be cleaned in time to avoid contaminating the hole during construction.

[0052] (5) Preparation of Rebar Adhesive: If the rebar adhesive is a two-component liquid adhesive, it needs to be prepared on-site. Before preparing the adhesive, the rebar preparation work should be checked to ensure that drilling and hole cleaning work has been completed for one construction section and has been inspected and accepted, and that the concealed works acceptance record has been made. At the same time, the connecting steel bars are ready and the rebar preparation work requirements are met. The adhesive should be prepared according to the usage of the divided construction section. The mixing ratio can be prepared according to the instructions of the selected rebar adhesive and used up within the time specified in the instructions. The amount of adhesive prepared at one time should not exceed 10kg. It should be prepared as little as possible and used immediately after preparation, and should not be stockpiled.

[0053] (6) Rebar Installation: Rebar installation should be carried out immediately after adhesive injection. To ensure full adhesive coverage, after adhesive injection, slowly insert the prepared connecting bar into the installation hole. During operation, rotate it several times in a certain direction while inserting it to ensure that the adhesive adheres tightly to the connecting bar and the concrete hole wall surface. Before rebar installation, thoroughly remove any adhering substances, rust, and oil stains from the surface of the connecting bar. The connecting bar should be inserted to the deepest point in the hole.

[0054] (7) Curing protection: Ensure no disturbance for 24 hours at room temperature. Only after the requirements are met can the next process be carried out.

[0055] S2: If the original riverbank concrete block foundation does not exist, first tie the trapezoidal counterweight block reinforcement at the excavation site and complete the pouring, then tie the upper counterweight block reinforcement on the trapezoidal counterweight block reinforcement.

[0056] This approach effectively utilizes the original structure and avoids resource waste: the original pedestrian underpass and riverbank retaining wall beneath the arch bridge contain an original concrete foundation, which can be connected to the counterweight foundation by rebar installation and can serve as the load-bearing point for the counterweight foundation of the cantilever section structure, avoiding the waste of resources by excavating to build rock-socketed or embedded foundations.

[0057] In one embodiment, in S1, the inserted reinforcing bars are arranged in a staggered pattern with a spacing of 30*40cm, and the concrete surface is roughened and inlaid with 25mm tongue and groove joints. This arrangement facilitates a tighter bond between the cast counterweight foundation and the existing concrete block foundation, resulting in higher connection strength and improved overall structural strength.

[0058] In one embodiment, in step (1), please refer to Figure 5 While tying the counterweight reinforcement bars, temperature sensing elements are installed. Each element consists of a steel pipe with an open top, pre-embedded in the counterweight reinforcement bars along its height, extending upwards from the bottom of the counterweight. The top of the pipe is located 30-50cm below the top of the counterweight. Water is filled inside the pipe for thermometer measurement. This temperature measurement method is convenient and low-cost.

[0059] The specific temperature measurement steps are as follows:

[0060] 1) After the concrete is poured, the temperature shall be monitored no less than 8 times per day.

[0061] 2) The temperature difference between the inner and outer surfaces of concrete (excluding the equivalent temperature of concrete shrinkage) shall not exceed 25℃, and the warning temperature is set at 25℃. This 25℃ temperature difference is a specification requirement; in reality, the temperature difference is less than 25℃, ranging from approximately 10-15℃. To prevent problems, if the temperature difference exceeds 25℃, it should be mitigated by covering the concrete with blankets to retain heat. The monitoring cycle is 3-5 days.

[0062] 3) When pouring concrete, protect the temperature measuring embedded steel pipe to avoid blocking it; when vibrating, the vibrator must not touch the temperature measuring steel pipe.

[0063] In one embodiment, in step (5), the lower part of the counterweight concrete is poured first, leaving a height of 30-50cm above the counterweight concrete. At this time, the top of the steel pipe of the temperature measuring element is exposed outside the concrete. After the lower part of the concrete is poured, a thermometer is placed inside the steel pipe of the temperature measuring element to measure the temperature inside the poured concrete. There are more than 3 steel pipes for the temperature measuring element. Water of different depths is poured into each steel pipe in sequence to measure the inner surface temperature of the concrete counterweight at different heights after pouring, so as to accurately grasp the inner surface temperature information of the concrete. After the counterweight reaches the expected strength, the part above the counterweight and the cantilever part are poured. The steel pipe of the temperature measuring element is poured into the counterweight concrete together.

[0064] In one embodiment, in step (1), after the counterweight reinforcement is tied, a support system is erected on its outside. The support system includes columns set on the periphery of the counterweight reinforcement mesh and horizontal bars set on the lower part of the counterweight reinforcement mesh. The lower part of the columns is supported by steel pipes and erected on the bottom reinforcement mesh. Right-angle fasteners are used to connect the columns and horizontal bars at the junction.

[0065] The outermost support system is equipped with a scissor brace, and the ends of the scissor brace are tied and fixed to the corresponding horizontal bars.

[0066] In one embodiment, in step (2), please refer to Figure 6 and Figure 7 The side formwork 10 of the counterweight block template is made of wood template 7. The outer side of the wood template is provided with secondary keel timber 6 and main keel steel pipe 25 arranged in a longitudinal manner. The short side of the main keel steel pipe 25 is drilled with diagonal tie bars 8 at intervals of 750mm.

[0067] The wooden formwork is equipped with two steel pipe diagonal braces 9 with a spacing of 600mm on the back side. The two steel pipe diagonal braces 9 are set in a front-to-back position and their top ends are connected to the main keel steel pipes 25 at different heights.

[0068] In one embodiment, please refer to Figure 8-10 The bottom formwork of the cantilever end template is connected to the cantilever end support frame. The cantilever end support frame adopts a full-span support frame 1. The bottom formwork is supported by crisscrossing main keel steel pipes 2 and secondary keel timber 3, and U-shaped brackets are provided at the connection. Tie rods are passed through the middle of the beam formwork of the cantilever end template. A vertical steel pipe support is set at the bottom of the beam and an additional tie rod 4 is added.

[0069] This construction method also includes preparatory steps before construction, specifically including:

[0070] (1) Construction preparation: 1. Site survey. The site should be further surveyed based on the selected route of the pedestrian overpass to check the traffic, underground pipelines, operating space and other conditions in the construction section to determine whether the conditions for excavation are met; then, the construction sequence should be reasonably planned according to the survey results, and the site traffic and corresponding equipment should be organized to enter the site.

[0071] 2. Geological exploration work. Conduct site surveys along the pedestrian overpass route to determine the geological conditions and strength beneath the counterweight blocks, and optimize the form and size of the counterweight blocks in a timely manner based on the survey report;

[0072] (2) Surveying and setting out, grid layout: 1. Upon arrival at the site, the measurement benchmarks provided by the owner are checked and verified using a total station according to the technical requirements and accuracy indicators of polygonal traverse network or fourth-order traverse surveying to ensure that the benchmarks are accurate.

[0073] 2. Based on the benchmark points provided by the owner, establish measurement control points in locations with open views and without obstructing traffic. Use GPS to densify the horizontal control coordinate network. Given the project's characteristics, the densified horizontal control network is laid out along the road centerline. Record the coordinates and elevation values ​​of each point. After verification by the surveyors and approval by the supervisor and owner, the measurement results will be compiled. Temporary protective measures should be implemented for the on-site control points to facilitate timely verification of elevations and coordinates during construction.

[0074] (3) Laying out the excavation boundary line: According to the design plan, according to the construction plan, use steel rods and string lines to pull out the control line in the construction section that needs to be excavated. Lay out the excavation boundary line along the control line with talcum powder. Lay out the excavation control line at a distance of 300-500mm from the outside of the excavation boundary line to facilitate the control of the excavation top during excavation.

[0075] (4) Pipeline relocation: Contact the owners of gas, water supply and drainage, electricity, defense and communications pipelines in advance to obtain the existing pipeline location map of the construction site, and clarify the nature, direction, burial depth, pipe diameter and pipeline changes within the construction area; for areas where drawings are missing or pipeline locations are unclear, use a pipeline detector to detect and obtain accurate information on underground pipelines. Develop a pipeline protection and relocation plan before construction.

[0076] (5) Mechanical excavation: Select appropriate small excavators and dump trucks according to the width of the lane and the height of passage to carry out the original road surface demolition and excavation. Since the depth of the foundation pit does not exceed 5m, the excavation is carried out in layers and in stages. The first-level slope is excavated to a depth of 2m at a time with a slope ratio of 1:0.5. The second-level slope is excavated to a depth of about 1-1.5m at a time with a slope ratio of 1:0.75. The platform width is 0.5m. A passageway is reserved during excavation, and 350mm is reserved at the bottom for manual cleaning.

[0077] (6) Manual bottom clearing and trench inspection: When excavating to near the bottom of the trench, the elevation should be measured continuously, and 0.35m of soil should be reserved for manual excavation. During manual bottom clearing, surveyors should mark the horizontal line from the reserved soil surface, and use a steel tape measure, leveling rod, and level to check the elevation at any time. The bottom soil should be removed, the bottom leveled, and over-excavation is strictly prohibited. After the earthwork is excavated to the design elevation, the geological survey unit, design unit, client, and supervision and construction units should inspect the trench. After passing the inspection, the next step of construction should be carried out in a timely manner.

[0078] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A construction method for a gravity-type integrated cantilevered pedestrian bridge in a confined space, involving the construction of a pedestrian overpass under a river-crossing bridge for transverse passage, characterized in that: Includes the following steps, (1) Construction of counterweight blocks: Excavate the slope protection on both sides of the riverbank in the transverse direction of the cross-river bridge, and tie the counterweight blocks with steel bars at the excavation site; (2) Erecting support frame and formwork: Set up a cantilever section connecting the counterweights on both sides at the underpass of the river-crossing bridge, and erect a support frame for the cantilever section; (3) Binding the steel reinforcement cage: Bind the steel reinforcement on the cantilever support frame and extend one end of the steel reinforcement to bind it together with the upper steel reinforcement of the counterweight block; (4) Formwork assembly: Erecting counterweight block formwork and cantilever end formwork for concrete pouring; (5) Concrete pouring and demolding: The pouring space enclosed by the template in step (4) is poured as a whole, and demolded after molding; In step (1), when excavating the riverbank slope protection, depending on whether there is an original concrete block foundation of the riverbank at the excavation site, it is divided into the following two steps: S1: If there is an original concrete block foundation for the river embankment, before tying the counterweight reinforcement, first install the reinforcement on the original concrete block foundation for the river embankment, and then tie the counterweight reinforcement. S2: If the original riverbank concrete block foundation does not exist, first tie the trapezoidal counterweight block steel bars at the excavation site and complete the pouring, then tie the upper counterweight block steel bars on the trapezoidal counterweight block steel bars. In step (1), while binding the counterweight reinforcement, a temperature measuring element is installed. The temperature measuring element includes a steel pipe with an open top. The steel pipe is embedded in the counterweight reinforcement along the height direction and extends upward from the bottom of the counterweight. The top of the steel pipe is located 30-50cm below the top of the counterweight. Water is poured into the steel pipe for temperature measurement by a thermometer. In step (5), the lower part of the counterweight concrete is poured first, leaving a height of 30-50cm above the counterweight concrete. At this time, the top of the steel pipe of the temperature measuring element is exposed outside the concrete. After the lower part of the concrete is poured, a thermometer is placed inside the steel pipe of the temperature measuring element to measure the temperature inside the poured concrete. There are more than 3 steel pipes of the temperature measuring element. Water of different depths is poured into each steel pipe in sequence to measure the inner surface temperature of the concrete counterweight at different heights after pouring, so as to accurately grasp the inner and outer surface temperature information of the concrete. After the counterweight reaches the expected strength, the part above the counterweight and the cantilever part are poured. The steel pipe of the temperature measuring element is poured into the counterweight concrete together.

2. The construction method for a gravity-type integrated cantilever pedestrian bridge in a confined space as described in claim 1, characterized in that: In S1, the inserted steel bars are arranged in a quincunx pattern with a spacing of 30*40cm, and a 25mm tongue and groove are chiseled into the concrete surface.

3. The construction method for a gravity-type integrated cantilever pedestrian bridge in a confined space as described in claim 1, characterized in that: In step (1), after the counterweight reinforcement is tied, a support system is erected on its outside. The support system includes columns set on the periphery of the counterweight reinforcement mesh and horizontal bars set on the bottom of the counterweight reinforcement mesh. The bottom of the columns is supported by steel pipes and erected on the bottom reinforcement mesh. Right-angle fasteners are used to connect the columns and horizontal bars at the junction. The outermost support system is provided with a scissor brace, and the end of the scissor brace is tied and fixed to the corresponding horizontal bar.

4. The construction method for a gravity-type integrated cantilever pedestrian bridge in a confined space as described in claim 1, characterized in that: In step (2), the side formwork of the counterweight block template is made of wood. The outer side of the wood template is provided with two secondary keel timbers arranged in a longitudinal direction and two main keel steel pipes. The short side of the two main keel steel pipes is drilled with diagonal tie bars at intervals of 750mm. The wooden formwork is provided with two steel pipe diagonal braces with a spacing of 600mm on the back side. The two steel pipe diagonal braces are arranged in a front-to-back position and their top ends are connected to the main keel steel pipes at different heights.

5. The construction method for a gravity-type integrated cantilever pedestrian bridge in a confined space as described in claim 1, characterized in that: The bottom formwork of the cantilever end template is connected to the cantilever end support frame, and a U-shaped bracket is provided at the connection. A tie rod is passed through the middle of the beam formwork of the cantilever end template, and a vertical steel pipe support is provided at the bottom of the beam and an additional tie rod is added.

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