A prefabrication method for precast bridge cap beams

Abstract

This invention discloses a prefabrication method for precast bridge cap beams, comprising the following steps: selecting a production area in the cap beam prefabrication yard and constructing a base for the precast cap beam within the production area; positioning several positioning points on a positioning frame and installing sealing elements for grouting sleeves on the positioning columns; assembling a jig on the base; sequentially installing cap beam stirrup skeleton pieces from the first stirrup at the edge of the grouting sleeve towards the cantilever end in the slots of the jig, according to their numbering sequence; calculating the lifting point positions of the cap beam and setting up lifting components at these positions; completing the installation of the side formwork, cantilever end formwork, and stop block formwork of the cap beam; and pouring concrete into the assembled formwork to complete the prefabrication of the bridge cap beam. The precast cap beam processing and fabrication in this scheme is carried out in a standardized factory, forming an assembly line operation where each step is independent of the others. Suitable processing areas can be set up according to the size requirements of the cap beams, and safe operating procedures are met.

Description

Technical Field

[0001] This invention relates to the field of bridge construction technology, and specifically to a method for prefabricating precast bridge cap beams. Background Technology

[0002] The construction of urban elevated bridges encroaches on the existing road space, significantly impacting residents' travel and the surrounding environment. Prefabricated bridges are gaining increasing attention in the engineering field due to their ease of industrialization and standardization, controllable construction quality, simultaneous on-site construction and post-construction prefabrication, short construction period, and minimal environmental impact from factory prefabrication.

[0003] Currently, the main construction methods for cap beams are divided into ground-supported construction and non-supported construction. Supported construction has disadvantages such as long erection period, restriction by ground traffic, high foundation treatment cost, uneconomical construction of high piers, and large errors in the produced cap beams. In the existing cap beam production process, the safety of the hoisting process is often overlooked. Due to their heavy weight and difficulty in hoisting, it is necessary to ensure the safety of hoisting. Therefore, it is particularly important to select hoisting points reasonably. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides a prefabrication method for prefabricated bridge cap beams that improves the quality of cap beam fabrication and construction safety.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0006] A method for prefabricating precast bridge cap beams is provided, which includes the following steps:

[0007] S1: Select a production area in the precast girder yard, build the base of the precast girder in the production area, and set a positioning frame on the base for positioning the grouting sleeve.

[0008] S2: Locate several positioning points on the positioning frame and set positioning columns on the positioning points. Insert the grouting sleeve into the positioning column to realize the installation of the grouting sleeve. The positioning column is equipped with a sealing element to seal the grouting sleeve.

[0009] S3: Assemble the jig on the base, and install the end plate on the end plate clip in the middle of the jig to ensure that the end plate is vertical; on the operating platform for binding the tail of the jig, pass the main reinforcement through the stirrup skeleton and the main reinforcement reserved opening of the end plate to achieve precise assembly and positioning of the main reinforcement; use positioning slots to control the spacing between the upper and lower main reinforcements and the left and right spacing between the upper and lower rows of main reinforcements.

[0010] S4: Install the cap beam stirrup skeleton pieces sequentially from the first stirrup at the edge of the grouting sleeve to the cantilever end in the slot of the binding frame, according to the numbering order.

[0011] S5: On the placement platform at the tail of the binding frame, pass the horizontal reinforcement through the stirrup skeleton and the end plate, and tie the horizontal reinforcement and stirrup skeleton with tie wire in the reserved opening of the horizontal reinforcement in the end plate for accurate installation.

[0012] S6: Install prestressed ducts in the steel reinforcement cage of the cap beam according to the prestressed spatial coordinate position. On-site tensioning adopts pre-embedded P anchors for single-end tensioning. The steel strands should protrude from the extrusion sleeve at the outer end of the extrusion sleeve.

[0013] S7: Install embedded anchors and deep-buried sleeves at the tail end and middle wet joint of the cap beam, use steel bars to support the anchors to make the anchors horizontal, and install several layers of reinforcing steel mesh at the spiral reinforcement.

[0014] S8: Calculate the lifting point position of the cap beam, set up the lifting components at the lifting point position, use a gantry crane to lift the steel reinforcement cage, after the steel reinforcement cage is put into the formwork, check the position of the steel reinforcement cage to ensure that the bolt holes of the wet joint end plate are aligned with the bolt holes of the bottom formwork, and the tail is placed in the middle of the cantilever section chute to ensure that the protective layer thickness of the steel reinforcement cage reaches the set thickness.

[0015] S9: Complete the installation of the side formwork, cantilever section end formwork, and stop block formwork for the cap beam, and install tie rods on the side formwork at both ends. Apply double-sided tape and silicone sealant to the joints to prevent grout leakage.

[0016] S10: Pour concrete into the assembled template. After the concrete has solidified, remove the template to complete the prefabrication of the bridge cap beam.

[0017] Furthermore, the method for calculating the location of the cap beam lifting points in step S8 includes:

[0018] S81: Extract the dimensions of the cap beam design based on the cap beam design model, including the design volume V and the design mass M;

[0019] S82: Calculate the mass per unit volume of the cap beam design: m = M / V;

[0020] S83: Establish a three-dimensional coordinate system in the design model of the cap beam. The length direction of the cap beam is along the Y-axis. Divide the design model of the cap beam into several cross-sectional elements in the three-dimensional coordinate system. The cross-sectional elements are evenly distributed along the length direction of the cap beam, and the width of the cross-sectional elements is equal. The cross-sectional elements are perpendicular to the length direction of the cap beam.

[0021] S84: Divide each cross-sectional unit into several solid volume calculation units. Each volume calculation unit is a triangular pyramid, and obtain the coordinates of each vertex of each volume calculation unit.

[0022] S85: When designing the hoisting of the cap beam, two hoisting points a and b are required to divide the cap beam into three equal parts, and the mass of each part is M / 3.

[0023] S86: Project each volume calculation element of the cross-sectional element onto the XOY plane of the three-dimensional coordinate system, and calculate the perimeter p of the projected triangle xoy:

[0024]

[0025] The coordinates of the vertices of triangle xoy are (x1, y1), (x2, y2), and (x3, y3).

[0026] S87: Calculate the area s of triangle xoy using the perimeter p:

[0027] s = p × (p - p1) × (p - p2) × (p - p3)

[0028] Where p1, p2, and p3 are the side lengths of triangle xoy, respectively;

[0029] S88: Calculate the volume v of the calculation unit based on the area s:

[0030]

[0031] S89: Obtain the volumes v1, v2, ..., v of each volume calculation element in the cross-sectional element. n Calculate the volume V of the cross-sectional element: V = v1 + v2 + ... + v n n is the number of volume calculation elements in the cross-sectional element;

[0032] S810: Calculate the mass m of each section element based on the design density ρ of the cap beam: m = V·ρ;

[0033] S811: Obtain the mass m1, m2, ..., m of each section element of the cap beam from left to right. n ;

[0034] S812: Mass of all cross-sectional elements, starting from the left and right ends of the cap beam respectively;

[0035] Starting from the left end, calculate the total mass of each traversed section element sequentially. When the t-th section element is reached, if m1 + m2 + ... + m... t <M / 3<m1+m2+···+m t+1 If a hoisting component needs to be installed in the (t+1)th section element, then a hoisting point a exists in the (t+1)th section element.

[0036] Starting from the rightmost end, calculate the total mass of each traversed section element sequentially. When the f-th section element is reached, if m n +m n-1 +···+m f <M / 3<mn +m n-1 +···+m f-1 If f > t, then a hoisting component needs to be installed in the (f-1)th section element; there is a hoisting point b in the (f-1)th section element;

[0037] S813: The centers of the (t+1)th and (f-1)th section elements are used as lifting points a and f-1, respectively, to install the lifting components.

[0038] The beneficial effects of this invention are as follows: The prefabricated cap beams of this solution are manufactured in a standardized factory, forming an assembly line operation where each part does not interfere with the others. Suitable processing areas can be set according to the size requirements of the cap beams, while meeting safe operating procedures. The positioning of each key point and component within the cap beam is precise. The two lifting points of the cap beam are calculated using a design model, greatly increasing the accuracy of the lifting point positioning. This eliminates the need for manual measurement, making the positioning of the lifting points more accurate and reasonable, effectively increasing the stability and safety of the cap beam during lifting. Attached Figure Description

[0039] Figure 1 This is a flowchart of the prefabrication method for prefabricated bridge cap beams. Detailed Implementation

[0040] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0041] like Figure 1 As shown, the prefabrication method for assembled bridge cap beams in this scheme includes the following steps:

[0042] S1: Select a production area in the precast girder yard, build the base of the precast girder in the production area, and set a positioning frame on the base for positioning the grouting sleeve.

[0043] S2: Locate several positioning points on the positioning frame and set positioning columns on the positioning points. Insert the grouting sleeve into the positioning column to realize the installation of the grouting sleeve, and set the sealing element of the grouting sleeve on the positioning column.

[0044] S3: Assemble the jig on the base, and install the end plate on the end plate clip in the middle of the jig to ensure that the end plate is vertical; on the operating platform for binding the tail of the jig, pass the main reinforcement through the stirrup skeleton and the main reinforcement reserved opening of the end plate to achieve precise assembly and positioning of the main reinforcement; use positioning slots to control the spacing between the upper and lower main reinforcements and the left and right spacing between the upper and lower rows of main reinforcements.

[0045] S4: Install the cap beam stirrup skeleton pieces sequentially from the first stirrup at the edge of the grouting sleeve to the cantilever end in the slot of the binding frame, according to the numbering order.

[0046] S5: On the placement platform at the tail of the binding frame, pass the horizontal reinforcement through the stirrup skeleton and the end plate, and tie the horizontal reinforcement and stirrup skeleton with tie wire in the reserved opening of the horizontal reinforcement in the end plate for accurate installation.

[0047] S6: Install prestressed ducts in the steel reinforcement cage of the cap beam according to the prestressed spatial coordinate position. On-site tensioning adopts pre-embedded P anchors for single-end tensioning. The steel strands should protrude from the extrusion sleeve at the outer end of the extrusion sleeve.

[0048] S7: Install embedded anchors and deep-buried sleeves at the tail end and middle wet joint of the cap beam, use steel bars to support the anchors to make the anchors horizontal, and install several layers of reinforcing steel mesh at the spiral reinforcement.

[0049] S8: Calculate the lifting point positions of the cap beam, set up lifting components at the lifting point positions, and use a gantry crane to lift the reinforcing steel cage. After the reinforcing steel cage is placed into the formwork, check the position of the reinforcing steel cage to ensure that the bolt holes of the wet joint end plate are aligned with the bolt holes of the bottom formwork, and that the tail is placed in the middle of the cantilever section chute, ensuring that the protective layer thickness of the reinforcing steel cage reaches the set thickness; the method for calculating the lifting point positions of the cap beam in step S8 includes:

[0050] S81: Extract the dimensions of the cap beam design based on the cap beam design model, including the design volume V and the design mass M;

[0051] S82: Calculate the mass per unit volume of the cap beam design: m = M / V;

[0052] S83: Establish a three-dimensional coordinate system in the design model of the cap beam. The length direction of the cap beam is along the Y-axis. Divide the design model of the cap beam into several cross-sectional elements in the three-dimensional coordinate system. The cross-sectional elements are evenly distributed along the length direction of the cap beam, and the width of the cross-sectional elements is equal. The cross-sectional elements are perpendicular to the length direction of the cap beam.

[0053] S84: Divide each cross-sectional unit into several solid volume calculation units. Each volume calculation unit is a triangular pyramid, and obtain the coordinates of each vertex of each volume calculation unit.

[0054] S85: When designing the hoisting of the cap beam, two hoisting points a and b are required to divide the cap beam into three equal parts, and the mass of each part is M / 3.

[0055] S86: Project each volume calculation element of the cross-sectional element onto the XOY plane of the three-dimensional coordinate system, and calculate the perimeter p of the projected triangle xoy:

[0056]

[0057] The coordinates of the vertices of triangle xoy are (x1, y1), (x2, y2), and (x3, y3).

[0058] S87: Calculate the area s of triangle xoy using the perimeter p:

[0059] s = p × (p - p1) × (p - p2) × (p - p3)

[0060] Where p1, p2, and p3 are the side lengths of triangle xoy, respectively;

[0061] S88: Calculate the volume v of the calculation unit based on the area s:

[0062]

[0063] S89: Obtain the volumes v1, v2, ..., v of each volume calculation element in the cross-sectional element. n Calculate the volume V of the cross-sectional element: V = v1 + v2 + ... + v n n is the number of volume calculation elements in the cross-sectional element;

[0064] S810: Calculate the mass m of each section element based on the design density ρ of the cap beam: m = V·ρ;

[0065] S811: Obtain the mass m1, m2, ..., m of each section element of the cap beam from left to right. n ;

[0066] S812: Mass of all cross-sectional elements, starting from the left and right ends of the cap beam respectively;

[0067] Starting from the left end, calculate the total mass of each traversed section element sequentially. When the t-th section element is reached, if m1 + m2 + ... + m... t <M / 3<m1+m2+···+m t+1 If a hoisting component needs to be installed in the (t+1)th section element, then a hoisting point a exists in the (t+1)th section element.

[0068] Starting from the rightmost end, calculate the total mass of each traversed section element sequentially. When the f-th section element is reached, if m n +m n-1 +···+m f <M / 3<m n +m n-1 +···+m f-1 If f > t, then a hoisting component needs to be installed in the (f-1)th section element; there is a hoisting point b in the (f-1)th section element;

[0069] S813: The centers of the (t+1)th and (f-1)th section elements are used as lifting points a and f-1, respectively, to install the lifting components.

[0070] S9: Complete the installation of the side formwork, cantilever section end formwork, and stop block formwork for the cap beam, and install tie rods on the side formwork at both ends. Apply double-sided tape and silicone sealant to the joints to prevent grout leakage.

[0071] S10: Pour concrete into the assembled template. After the concrete has solidified, remove the template to complete the prefabrication of the bridge cap beam.

[0072] The prefabricated cap beams of this invention are manufactured in a standardized factory, forming an assembly line operation where each process is independent and does not interfere with the others. Suitable processing areas can be set up according to the size requirements of the cap beams, while meeting safe operating procedures. The positioning of each key point and component within the cap beam is precise. The two lifting points of the cap beam are calculated using a design model, greatly increasing the accuracy of the lifting point positioning. This eliminates the need for manual measurement, making the positioning of the lifting points more accurate and reasonable, effectively increasing the stability and safety of the cap beam during lifting.

Claims

1. A method for prefabricating assembled bridge cap beams, characterized in that, Includes the following steps: S1: Select a production area in the precast girder yard, build the base of the precast girder in the production area, and set a positioning frame on the base for positioning the grouting sleeve. S2: Locate several positioning points on the positioning frame and set positioning columns on the positioning points. Insert the grouting sleeve into the positioning column to realize the installation of the grouting sleeve, and set the sealing element of the grouting sleeve on the positioning column. S3: Assemble the jig on the base, and install the end plate on the end plate clip in the middle of the jig to ensure that the end plate is vertical; on the operating platform for binding the tail of the jig, pass the main reinforcement through the stirrup skeleton and the main reinforcement reserved opening of the end plate to achieve precise assembly and positioning of the main reinforcement; use positioning slots to control the spacing between the upper and lower main reinforcements and the left and right spacing between the upper and lower rows of main reinforcements. S4: Install the cap beam stirrup skeleton pieces sequentially from the first stirrup at the edge of the grouting sleeve to the cantilever end in the slot of the binding frame, according to the numbering order. S5: On the placement platform at the tail of the binding frame, pass the horizontal reinforcement through the stirrup skeleton and the end plate, and tie the horizontal reinforcement and stirrup skeleton with tie wire in the reserved opening of the horizontal reinforcement in the end plate for accurate installation. S6: Install prestressed ducts in the steel reinforcement cage of the cap beam according to the prestressed spatial coordinate position. On-site tensioning adopts pre-embedded P anchors for single-end tensioning. The steel strands should protrude from the extrusion sleeve at the outer end of the extrusion sleeve. S7: Install embedded anchors and deep-buried sleeves at the tail end and middle wet joint of the cap beam, use steel bars to support the anchors to make the anchors horizontal, and install several layers of reinforcing steel mesh at the spiral reinforcement. S8: Calculate the lifting point position of the cap beam, set up the lifting components at the lifting point position, use a gantry crane to lift the steel reinforcement cage, after the steel reinforcement cage is put into the formwork, check the position of the steel reinforcement cage to ensure that the bolt holes of the wet joint end plate are aligned with the bolt holes of the bottom formwork, and the tail is placed in the middle of the cantilever section chute to ensure that the protective layer thickness of the steel reinforcement cage reaches the set thickness. S9: Complete the installation of the side formwork, cantilever section end formwork, and stop block formwork for the cap beam, and install tie rods on the side formwork at both ends. Apply double-sided tape and silicone sealant to the joints to prevent grout leakage. S10: Pour concrete into the assembled template, and after the concrete has solidified, remove the template to complete the prefabrication of the bridge cap beam. The method for calculating the lifting point position of the cap beam in step S8 includes: S81: Extract the dimensions of the cap beam design based on the cap beam design model, including the design volume V and the design mass M; S82: Calculate the mass per unit volume of the cap beam design: m = M / V; S83: Establish a three-dimensional coordinate system in the design model of the cap beam. The length direction of the cap beam is along the Y-axis. Divide the design model of the cap beam into several cross-sectional elements in the three-dimensional coordinate system. The cross-sectional elements are evenly distributed along the length direction of the cap beam, and the width of the cross-sectional elements is equal. The cross-sectional elements are perpendicular to the length direction of the cap beam. S84: Divide each cross-sectional unit into several solid volume calculation units. Each volume calculation unit is a triangular pyramid, and obtain the coordinates of each vertex of each volume calculation unit. S85: When designing the hoisting of the cap beam, two hoisting points a and b are required to divide the cap beam into three equal parts, and the mass of each part is M / 3. S86: Project each volume calculation element of the cross-sectional element onto the XOY plane of the three-dimensional coordinate system, and calculate the perimeter p of the projected triangle xoy: The coordinates of the vertices of triangle xoy are (x1, y1), (x2, y2), and (x3, y3). S87: Calculate the area s of triangle xoy using the perimeter p: Where p1, p2, and p3 are the side lengths of triangle xoy, respectively; S88: Calculate the volume v of the calculation unit based on the area s; S89: Obtain the volumes v1, v2, ..., v of each volume calculation element in the cross-sectional element. n Calculate the volume V of the cross-sectional element: V = v1 + v2 + ... + v n n is the number of volume calculation elements in the cross-sectional element; S810: Calculate the mass m of each section element based on the design density ρ of the cap beam: m = V·ρ; S811: Obtain the mass m1, m2, ..., m of each section element of the cap beam from left to right. n ; S812: Mass of all cross-sectional elements, starting from the left and right ends of the cap beam respectively; Starting from the left end, calculate the total mass of each traversed section element sequentially. When the t-th section element is reached, if m1 + m2 + ... + m... t <M / 3<m1+m2+···+m t+1 If a hoisting component needs to be installed in the (t+1)th section element, then a hoisting point a exists in the (t+1)th section element. Starting from the rightmost end, calculate the total mass of each traversed section element sequentially. When the f-th section element is reached, if m n +m n-1 +···+m f <M / 3<m n +m n-1 +···+m f-1 If f > t, then a hoisting component needs to be installed in the (f-1)th section element; there is a hoisting point b in the (f-1)th section element; S813: The centers of the (t+1)th and (f-1)th section elements are used as lifting points a and f-1, respectively, to install the lifting components.

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