Segmental beam 2+3 +2 cantilever assembly construction process

Abstract

The invention belongs to the technical field of segmental beam splicing, and particularly provides a segmental beam 2 + 3 + 2 cantilever splicing construction process which comprises the following steps: firstly, symmetrically splicing two pairs of four segmental beams 1 # and 2 #, and carrying out glue joint, temporary prestress tension and internal prestress tension; then three pairs of six-piece segmental beams 3 #, 4 # and 5 # are symmetrically assembled, and glue joint, temporary prestress tensioning and in-vivo prestress tensioning are carried out on the three pairs of six-piece segmental beams 3 #, 4 # and 5 #; finally, two pairs of four segmental beams 6 # and 7 # are symmetrically assembled, and glue joint, temporary prestress tensioning and in-vivo prestress tensioning are carried out; and in the construction process, the assembling line shape of the segmental beam is monitored. According to the construction technology, the construction efficiency is obviously improved. According to the method, the deformation of the bridge girder erection machine is monitored and measured, the total station is erected at the position of the pier bottom bearing platform to monitor the elevation and control the axis, the deviation of the center line of the pier top block and the elevation of the facade are accurately positioned, and accurate control over the erection line shape of the segmental girder is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of segmental beam assembly, and in particular relates to a 2+3+2 cantilever assembly construction process for segmental beams. Background Art

[0002] Conventional segmental beam assembly requires many prestressing tensioning times, and the construction efficiency is low. Taking the segmental beam assembly of a 60-meter span continuous rigid frame bridge as an example, a T-frame has a total of 15 segments, 1 pier top block, and 7 cantilever assemblies on each side. If the conventional assembly construction process is used, seven prestressing tensionings are required. Moreover, there are many prestressing channels, which are prone to slurry channeling.

[0003] Due to the difficulty in controlling the linear shape of segmental beam assembly, poor linear shape control effects have occurred in many projects. The 2+3+2 cantilever assembly construction process is a domestic first, and there is no similar construction experience to draw on, so linear shape control is difficult. In order to ensure the accuracy of segmental beam erection, how to combine the construction process flow to accurately control the linear shape of the segmental beam erection process is a problem that must be considered and solved. Summary of the invention

[0004] The purpose of the present invention is to provide a segment beam 2+3+2 cantilever assembly construction process to overcome the above-mentioned technical problems existing in the prior art.

[0005] To this end, the technical solution provided by the present invention is as follows: A 2+3+2 cantilever assembly construction process for segmental beams, firstly, symmetrically assemble two pairs of four-piece segmental beams 1# and 2#, perform gluing, temporary prestressing and internal prestressing; then, symmetrically assemble three pairs of six-piece segmental beams 3#, 4# and 5#, perform gluing, temporary prestressing and internal prestressing; finally, symmetrically assemble two pairs of four-piece segmental beams 6# and 7#, perform gluing, temporary prestressing and internal prestressing; and monitor the segmental beam assembly line shape during the construction process. A 2+3+2 cantilever assembly construction process of segmental beams, the specific steps are as follows: Step 1) Assemble the bridge erection machine on site at the first joint. The pier top block hoisting and bridge erection machine assembly are all installed by floating crane. After installation and commissioning, the bridge erection machine is used to hoist the 0# segment beam on the pier top into place, and after measurement and adjustment, it is consolidated with the pier body; Measure and locate the top blocks of the piers for the bridge erection machine assembly; monitor the entire process of the bridge erection machine assembly and the bridge erection machine crane load test; Step 2) Transport the segmental beam to the bridge site, and hoist the 1# and 2# segmental beams on both sides of the n+1 middle pier by the bridge erection machine. Monitor the assembly line of the beam segments, apply epoxy resin between the joints, tension the temporary prestressing force so that the compressive stress between the joints is not less than 0.3MPa until the epoxy is cured, tension the prestressed steel strands in the body, and monitor the axis deviation and facade elevation; Step 3) Hoist the segments on both sides of the top of the n+1 middle pier in sequence to the maximum cantilever state, tension the cantilever steel strands in sequence, grout, and carry out construction measurement and monitoring throughout the process; The order of beam segment hoisting is: 3# segment beam, 4# segment beam and 5# segment beam; 6# segment beam and 7# segment beam; Step 4) The bridge erection machine hoists the 8-piece semi-suspended beam section of the side span, which is hoisted on the bridge erection machine as a whole. The beams are assembled piece by piece in the order from the side span to the middle span, the line shape is monitored, epoxy resin is applied, and temporary prestressing is applied; Compare and analyze the monitoring data with the theoretical data, and make fine adjustments to the line shape if there is any deviation; Cast the wet joint of the side span closure section and tension the side span closure bundle; remove the temporary prestressing and temporary positioning device of the side span, collect and analyze the data of the measuring points on the top surface of the beam, and complete the side span closure; Step 5) The bridge erection machine moves longitudinally to the next span; the same symmetrical construction steps as above are used to construct the n+2 middle pier to the maximum cantilever; Step 6) Install the temporary positioning device for the middle span closure and make fine adjustments to the line shape according to the monitoring data; Pour the concrete of the joint section, tension the steel strands for the middle span joint, collect and analyze the data of the beam top surface measurement points, and complete the middle span joint; Step 7) The bridge erection machine moves forward and constructs each middle span beam section in sequence until the last span; the last span construction is completed according to the construction steps of the first span; Step 8) Collect data from the monitoring points on the top surface of the full-joint beam, tension the external prestress of the full-joint beam, and remove the temporary restraints of the side piers; The second time, data was collected from the monitoring points on the top surface of the full-joint beam, and compared with the theoretical data of the monitoring calculation under this working condition to complete the construction of the full-joint main structure; Step 9) Construct the remaining joints.

[0006] In step 1), a load test is carried out on the overhead crane of the bridge erection machine. By simulating the loading process of the bridge erection machine during segmental beam erection, the bearing capacity and deflection deformation value of the main frame of the bridge erection machine and the bracket beside the pier are analyzed and verified.

[0007] The method for monitoring the elevation of the facade in step 2) is as follows: set up a total station at the pier bottom pedestal, set the total station zenith distance to 90 degrees, erect a level rod at the pier bottom leveling base point, and read the scale reading H with the total station for multiple measurements. 尺 , and then take the mean; Then adjust the total station zenith angle to 0 degrees, and measure the distance D from the instrument to the bottom of the beam top elevation to be determined. h , height of the point to be determined H 引 =H 基 +H 尺 +D h , where H基 It is the height of the pier bottom cap.

[0008] Step 1) The measurement and positioning of the middle pier top block includes the deviation of the central axis and the precise positioning of the facade elevation. The six-point method is used for positioning control, with two points on the axis and four points on the facade elevation, symmetrically distributed on both sides of the axis. Among them, a high-precision total station is used for axis control, and a level is used for facade elevation control.

[0009] Step 4) The method for fine-tuning the centerline shape is as follows: the axis deviation is fine-tuned by applying the horizontal force calculated by monitoring, and the vertical deviation is fine-tuned by applying the vertical force calculated by monitoring.

[0010] The load-bearing test condition of the main truss of the bridge-erecting machine is the semi-suspension hoisting of the first span. The deflection deformation monitoring method is the total station trigonometric height measurement method, and the monitoring points are the mid-span and 1 / 4 position of the main truss.

[0011] The method for monitoring bracket deformation is leveling measurement. Monitoring points are arranged on 1 / 4 and 1 / 2 of the bracket to measure the elevation before and after the pier top block is hoisted and monitor its deformation value.

[0012] After the 0# segmental beam is accurately positioned and fixed, the cantilever assembly of the following segmental beams is mainly based on matching surfaces and supplemented by linearity during the construction process. For incorrect segmental beams, fine-tuning is performed by adjusting the tightness of the 4 hanging hanger nuts corresponding to each segment of the beam until the bridge deck elevation meets the design requirements.

[0013] The beneficial effects of the present invention are: The 2+3+2 cantilever assembly construction process for segmental beams provided by the present invention significantly improves the construction efficiency by symmetrically assembling two pairs of four-piece segmental beams 1# and 2# for the first time, symmetrically assembling three pairs of six-piece segmental beams 3#, 4# and 5# for the second time, and symmetrically assembling two pairs of six-piece segmental beams 6# and 7# for the third time.

[0014] The present invention monitors and measures the deformation of the bridge erecting machine, sets up a total station at the pier bottom pedestal position to monitor the elevation and control the axis, accurately locates the center line deviation and facade elevation of the pier top block, and realizes accurate control of the segmental beam erection line shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of an implementation mode of the present invention; Figure 2 This is the layout diagram of the deformation monitoring points of the main truss of the bridge erection machine; Figure 3 This is a schematic diagram of the height transfer using the zenith distance method; Figure 4 It is a linear control point arrangement diagram; Figure 5 This is a schematic diagram of measuring and positioning the pier top block for assembling the pier position of the bridge erection machine; Figure 6 This is a schematic diagram of the bridge erection machine hoisting the 1# and 2# segment beams on both sides of the n+1 middle pier; Figure 7 This is a schematic diagram of the bridge erecting machine lifting other beam sections in sequence; Figure 8 This is a schematic diagram of the bridge erection machine hoisting the side span semi-suspended 8-piece beam section; Fig. 9 This is a schematic diagram of the bridge erecting machine moving longitudinally to the next span; Fig.10 This is a schematic diagram of the temporary positioning device for installing the mid-span closure; Fig.11 This is a schematic diagram of the bridge erection machine moving forward and constructing each middle span beam section in sequence until the last span; Fig.12 This is a schematic diagram of tensioning the external prestress of the entire joint and removing the temporary restraint of the side piers; Fig.13 This is a schematic diagram of the remaining construction connections. DETAILED DESCRIPTION

[0016] The following describes the implementation of the present invention through specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0017] The exemplary embodiments of the present invention are now described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention.

[0018] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0019] Example 1 This embodiment provides a 2+3+2 cantilever assembly construction process for segmental beams. First, 1# and 2# two pairs of four-piece segmental beams are symmetrically assembled, and then they are glued, temporarily prestressed, and prestressed in the body. Then, 3#, 4#, and 5# three pairs of six-piece segmental beams are symmetrically assembled, and then they are glued, temporarily prestressed, and prestressed in the body. Finally, 6# and 7# two pairs of four-piece segmental beams are symmetrically assembled, and then they are glued, temporarily prestressed, and prestressed in the body. During the construction process, the segmental beam assembly line shape is monitored. Figure 1 shown.

[0020] The 2+3+2 cantilever assembly construction process for segmental beams provided by the present invention significantly improves the construction efficiency by symmetrically assembling two pairs of four-piece segmental beams 1# and 2# for the first time, symmetrically assembling three pairs of six-piece segmental beams 3#, 4# and 5# for the second time, and symmetrically assembling two pairs of six-piece segmental beams 6# and 7# for the third time.

[0021] Example 2 Based on Example 1, this example provides a 2+3+2 cantilever assembly construction process for segmental beams, and the specific steps are as follows: Step 1) Assemble the bridge erection machine on site at the first joint. The pier top block hoisting and bridge erection machine assembly are all installed by floating crane. After installation and commissioning, the bridge erection machine is used to hoist the 0# segment beam on the pier top into place, and after measurement and adjustment, it is consolidated with the pier body; Measure and locate the top blocks of the piers for the bridge erection machine assembly; monitor the entire process of the bridge erection machine assembly and the bridge erection machine crane load test; Step 2) Transport the segmental beam to the bridge site, and hoist the 1# and 2# segmental beams on both sides of the n+1 middle pier by the bridge erection machine. Monitor the assembly line of the beam segments, apply epoxy resin between the joints, tension the temporary prestressing force, make the compressive stress between the joints not less than 0.3MPa until the epoxy is cured, tension the prestressed steel strands in the body, and monitor the axis deviation and facade elevation; Step 3) Hoist the segments on both sides of the top of the n+1 middle pier in sequence to the maximum cantilever state, tension the cantilever steel strands in sequence, grout, and carry out construction measurement and monitoring throughout the process; The order of beam segment hoisting is: 3# segment beam, 4# segment beam and 5# segment beam; 6# segment beam and 7# segment beam; Step 4) The bridge erection machine hoists the 8-piece semi-suspended beam section of the side span, which is hoisted on the bridge erection machine as a whole. The beams are assembled piece by piece in the order from the side span to the middle span, the line shape is monitored, epoxy resin is applied, and temporary prestressing is applied; Compare and analyze the monitoring data with the theoretical data, and make fine adjustments to the line shape if there is any deviation; Cast the wet joint of the side span closure section and tension the side span closure bundle; remove the temporary prestressing and temporary positioning device of the side span, collect and analyze the data of the measuring points on the top surface of the beam, and complete the side span closure; Step 5) The bridge erection machine moves longitudinally to the next span; the same symmetrical construction steps as above are used to construct the n+2 middle pier to the maximum cantilever; Step 6) Install the temporary positioning device for the middle span closure and make fine adjustments to the line shape according to the monitoring data; Pour the concrete of the joint section, tension the steel strands for the middle span joint, collect and analyze the data of the beam top surface measurement points, and complete the middle span joint; Step 7) The bridge erection machine moves forward and constructs each middle span beam section in sequence until the last span; the last span construction is completed according to the construction steps of the first span; Step 8) Collect data from the monitoring points on the top surface of the full-joint beam, tension the external prestress of the full-joint beam, and remove the temporary restraints of the side piers; The second time, data was collected from the monitoring points on the top surface of the full-joint beam, and compared with the theoretical data of the monitoring calculation under this working condition to complete the construction of the full-joint main structure; Step 9) Construct the remaining joints.

[0022] Example 3 On the basis of Example 2, this example takes a 5×60m span segment box girder as an example and adopts a “2+3+2” cantilever assembly construction. The construction steps and process are as follows: (1) The bridge-erecting machine is assembled on site at the first joint. The pier top block of the bridge-erecting machine is hoisted and installed by floating crane. The bridge-erecting machine is assembled and installed by floating crane. After installation and commissioning, the bridge-erecting machine is used to hoist the 0# segment on the pier top into place. After measurement and adjustment, it is consolidated with the pier body (temporary consolidation is performed on the transition pier). (2) Transport the segmental beams to the bridge site by sea or land, lift the segment into place with a bridge erection machine, monitor the assembly line of the beam segments, fully coat the joints with epoxy resin, and tension the temporary prestress to ensure that the compressive stress between the joints is not less than 0.3MPa until the epoxy is cured. Tension the corresponding suspended steel strands and perform grouting. (3) Repeat the previous steps symmetrically until the pier top box girder reaches the maximum cantilever state, lift all precast beam sections of the side span and hang them on the bridge erection machine, adjust the segment position, and after the elevation adjustment, apply epoxy resin between the segments and consolidate them with temporary prestressing. Set up the temporary positioning device for the side span joint, cast the joint wet joint, and when the wet joint strength reaches 100%, tension the side span joint bundle, and remove the temporary prestressing and temporary positioning device. (4) The bridge-erecting machine passes through the hole and repeats the above steps to symmetrically erect the next pier top box girder precast segment to the maximum cantilever state, and then hoist the joint segment. (5) Erect the middle span joint rigid frame, adjust the joint section line, cast the joint wet joint, and tension the middle span joint beam when the wet joint strength reaches 90%, and remove the temporary prestressing and rigid frame. (6) Follow the above steps to construct the side span of the last hole of the first joint. Lift all the precast beam sections of the side span and hang them on the bridge erection machine. Adjust the segment position. After the elevation adjustment, apply epoxy resin between the segments and consolidate them with temporary prestressing. Set up the temporary positioning device for the side span closure, cast the wet joint for closure, and tension the side span closure beam when the wet joint strength reaches 90%. Remove the temporary prestressing and temporary positioning device. (7) The bridge-erecting machine moves to the lower section and prepares for the next section of construction.

[0023] (8) Collect and analyze data from the top surface of the whole beam, tension the external prestressed tendons, complete the construction of one box beam, collect data from the top surface of the whole beam again, and compare and analyze with the theoretical values.

[0024] Example 4 On the basis of Example 2, this example provides a 2+3+2 cantilever assembly construction process for segmental beams. In step 1), a load test is carried out on the overhead crane of the bridge erecting machine. By simulating the loading process of the bridge erecting machine during segmental beam erection, the bearing capacity and deflection deformation value of the main frame of the bridge erecting machine and the pier side bracket are analyzed and verified.

[0025] In order to ensure the safety and quality of segmental beam erection, heavy-load tests are carried out on the bridge-erecting machine to examine its bearing capacity and deflection deformation. By simulating the loading process of the bridge-erecting machine during segmental beam erection, the bearing capacity (focusing on the pier-side brackets) and deformation values ​​of the main frame and other components of the bridge-erecting machine are analyzed and verified. While eliminating inelastic deformation, the influence of elastic deformation on the line shape of segmental beam erection and the solution are analyzed.

[0026] Example 5 On the basis of Example 2, the present invention provides a segmental beam 2+3+2 cantilever assembly construction process, wherein the method for monitoring the elevation of the facade in step 2) is as follows: a total station is set up at the pier bottom pedestal position, the zenith distance of the total station is set to 90 degrees, a level ruler is erected at the pier bottom leveling base point, and the total station is used to measure multiple times to read the ruler surface reading H 尺 , and then take the mean; Then adjust the total station zenith angle to 0 degrees, and measure the distance D from the instrument to the bottom of the beam top elevation to be determined. h , the height of the point to be determined is H = H 基 +H 尺 +D h , where H 基 It is the height of the pier bottom cap.

[0027] Select the "zenith distance method" for elevation transfer. This method only uses the precise distance measurement function of the high-precision total station and does not require angle measurement or correction of the refractive index. This method has the characteristics of high precision and is conducive to the linear control of segmental beam erection. Figure 3 shown.

[0028] Example 6 Based on Example 2, this example provides a 2+3+2 cantilever assembly construction process for segmental beams, in which step 1) the measurement and positioning of the pier top block includes the precise positioning of the center axis deviation and the facade elevation, and the six-point method is used for positioning control, with two points on the axis and four points on the facade elevation, symmetrically distributed on both sides of the axis; wherein a high-precision total station is used for axis control, and a level is used for facade elevation control.

[0029] During the construction process, the displacement caused by the elastic compression and shrinkage creep of the segmental beams, as well as the longitudinal slope of the bridge will affect the line shape of the completed bridge and the width of the expansion joint slots. During the construction process, the monitoring data must be corrected and the bearing plates on the bearings must be pre-biased.

[0030] The installation of the pier top block is also called the first segment installation. The positioning accuracy will directly affect the change trend of the geometric line shape of the subsequent segments. Therefore, the center line deviation and elevation of the pier top block must be accurately positioned. The monitoring system adopts the six-point method for control. The measurement points are arranged as follows: Figure 4 shown.

[0031] The axis deviation accuracy is controlled within 3mm, and the control point error is controlled according to the same direction principle. The six control points are mainly composed of two axis control points and supplemented by elevation control points. Since the centering rod cannot be absolutely vertical, in order to eliminate the measurement error caused by its inclination, the centering rod bubble is first centered, and the plane coordinate observation is carried out by two rounds of measurement and the average value is taken. Then the centering rod is rotated 180 degrees, and two rounds of measurement are observed and the average value is taken. Finally, the average value before and after the rotation is taken as the basis for the axis control of the pier top block until it is adjusted to within 3mm.

[0032] A level is used for elevation control, and the elevation accuracy of the facade is controlled within ±3mm. The error is also controlled according to the same direction principle. The six control points are mainly composed of four elevation control points and two axis control points as auxiliary.

[0033] Example 7 On the basis of Example 3, this embodiment provides a segmental beam 2+3+2 cantilever assembly construction process, wherein the specific linear monitoring measurement of the segmental beam includes the following steps: Step 1: According to the monitoring instructions, measure and locate the top block of the bridge erection machine pier assembly position; monitor the whole process of bridge erection machine assembly and bridge erection machine crane load test; Figure 5 As shown; Step 2: The bridge erection machine hoists the 1# and 2# blocks on both sides of the n+1 middle pier; Figure 6 As shown; Test assembly, monitor the geometric posture of beam segments, apply epoxy resin to joints, tension temporary prestress, monitor axis deviation and facade elevation, compare and analyze with the monitoring command data under the working condition, and feed back the data to the monitoring unit; Tension the prestressed steel strands in the body, monitor the axis deviation and facade elevation, compare and analyze with the monitoring command data under the working condition, and feed back the data to the monitoring unit; Step 3: hoist the segments on both sides of the top of the n+1 middle pier in sequence to the maximum cantilever state; Figure 7 As shown; Tension the cantilever steel strands and grouting in sequence, and carry out construction measurement and monitoring throughout the entire process; The order of beam segment hoisting is: 3#, 4# and 5#; 6# and 7#; Step 4: The bridge erection machine hoists the side span semi-suspended 8 beam segments, which are hung on the bridge erection machine as a whole. They are assembled piece by piece in the order from the side span to the middle span, the line shape is monitored, epoxy resin is applied, and temporary prestressing is applied; Figure 8 As shown; According to the comparison and analysis between the monitoring data and the theoretical data, if there is any deviation, the linear shape is fine-tuned, the axis deviation is fine-tuned by applying the horizontal force calculated by monitoring, and the vertical deviation is fine-tuned by applying the vertical force calculated by monitoring, the wet joint of the side span closure section is cast, and the side span closure bundle is tensioned; Remove the temporary prestressing and temporary positioning devices of the side span, collect and analyze data from the measuring points on the top surface of the beam, and complete the closure of the side span.

[0034] Step 5: The bridge erecting machine moves longitudinally to the next span; Fig. 9 As shown; Following the aforementioned symmetrical construction steps, construct the n+2 middle pier to the maximum cantilever.

[0035] Step 6: Install the temporary positioning device for the middle span closure and make fine adjustments to the line shape according to the monitoring data; Fig.10 As shown; Pour concrete in the joint section, tension the steel strands for the middle span joint, collect and analyze data from the beam top surface measurement points, and complete the middle span joint.

[0036] Step 7: The bridge erection machine moves forward and constructs each middle span beam section in sequence until the last span; Fig.11 As shown; Complete the construction of the last span according to the construction steps of the first span.

[0037] Step 8: Collect data from the monitoring points on the top surface of the whole joint beam, tension the external prestress of the whole joint, and remove the temporary restraint of the side pier; Fig.12 As shown; 2. Data is collected from the monitoring points on the top surface of the entire joint beam for the second time, and compared with the theoretical data of the monitoring calculation under this working condition to complete the construction of the entire joint main structure.

[0038] Step 9: construct the remaining joints. Fig.13 shown.

[0039] Example 8 Based on Example 3, this example provides a 2+3+2 cantilever assembly construction process for segmental beams. The load-bearing test condition of the main truss of the bridge erection machine is the semi-suspension hoisting of the first span. The deflection deformation monitoring method is the total station trigonometric height measurement method, and the monitoring points are the mid-span and 1 / 4 positions of the main truss.

[0040] like Figure 2As shown, the bracket deformation monitoring method is leveling measurement. Monitoring points are arranged on the bracket to measure the elevation before and after the pier top block is hoisted to monitor its deformation value.

[0041] Example 9 Based on Example 3, this example provides a 2+3+2 cantilever assembly construction process for segmental beams. The bracket deformation monitoring method is leveling measurement. Monitoring points are arranged on the bracket 1 / 4 and 1 / 2 to measure the elevation of the pier top block before and after hoisting to monitor its deformation value.

[0042] In order to improve the efficiency of measurement work and the efficiency of segmental beam erection, it is necessary to convert the monitoring instruction coordinates in the drawing coordinate system into coordinates in the bridge axis coordinate system. After conversion using the coordinate conversion software, it must be reviewed and signed before it can be used.

[0043] Example 10 Based on Example 1, this example provides a 2+3+2 cantilever assembly construction process for segmental beams. After the 0# segmental beam is accurately positioned and fixed, the cantilever assembly of the subsequent segmental beams is mainly based on matching surfaces and supplemented by linearity during the construction process. For incorrect segmental beams, fine-tuning is performed by adjusting the tightness of the 4 hanging hanger nuts corresponding to each beam segment until the bridge deck elevation meets the design requirements.

[0044] The main factors affecting the accuracy of segmental beam erection into bridge line shape are prefabrication accuracy and pier top block installation accuracy, which is the key prerequisite for achieving gasket-free deviation correction construction. After the first segment is accurately positioned and fixed, the cantilever assembly construction process of the following segments follows the principle: matching surface as the main, linear as the auxiliary. For the incorrect segments, fine-tune by adjusting the tightness of the 4 hanging hanger nuts corresponding to each beam segment until the bridge deck elevation meets the design requirements. In this process, it is necessary to pay attention to monitoring the longitudinal and transverse plane positions of the beam segments. After the cantilever is symmetrically assembled to the maximum cantilever state of the pier top box beam, the wet joints are cast and closed. After the wet joint strength reaches the required strength, the prestressing is tensioned. After the prestressing tendons are tensioned, the data collection and analysis of the monitoring points on the top surface of the second box beam are carried out. After the whole joint construction is completed, the external prestressing construction is carried out. After the external prestressing tensioning is completed, the prestressing test is carried out. After passing the test, the data collection and analysis of the monitoring points on the top surface of the whole beam are carried out (compared with the calculated data of the segment in the theoretical state of the monitoring instruction, and the deviation is calculated).

[0045] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A 2+3+2 cantilever assembly construction process for segmental beams, characterized in that: First, symmetrically assemble two pairs of four-piece segmental beams, 1# and 2#, and carry out gluing, temporary prestressing, and internal prestressing. Then, symmetrically assemble three pairs of six-piece segmental beams, 3#, 4#, and 5#, and carry out gluing, temporary prestressing, and internal prestressing. Finally, symmetrically assemble two pairs of four-piece segmental beams, 6# and 7#, and carry out gluing, temporary prestressing, and internal prestressing. Monitor the segmental beam assembly line during the construction process.

2. The 2+3+2 cantilever assembly construction process of segmental beams according to claim 1 is characterized in that: The specific steps are as follows: Step 1) Assemble the bridge erection machine on site at the first joint. The pier top block hoisting and bridge erection machine assembly are all installed by floating crane. After installation and commissioning, the bridge erection machine is used to hoist the 0# segment beam on the pier top into place, and after measurement and adjustment, it is consolidated with the pier body; Measure and locate the top blocks of the piers for the bridge erection machine assembly; monitor the entire process of the bridge erection machine assembly and the bridge erection machine crane load test; Step 2) Transport the segmental beam to the bridge site, and hoist the 1# and 2# segmental beams on both sides of the n+1 middle pier by the bridge erection machine. Monitor the assembly line of the beam segments, apply epoxy resin between the joints, tension the temporary prestressing force so that the compressive stress between the joints is not less than 0.3MPa until the epoxy is cured, tension the prestressed steel strands in the body, and monitor the axis deviation and facade elevation; Step 3) Hoist the segments on both sides of the top of the n+1 middle pier in sequence to the maximum cantilever state, tension the cantilever steel strands in sequence, grout, and carry out construction measurement and monitoring throughout the process; The order of beam segment hoisting is: 3# segment beam, 4# segment beam and 5# segment beam; 6# segment beam and 7# segment beam; Step 4) The bridge erection machine hoists the 8-piece semi-suspended beam section of the side span, which is hoisted on the bridge erection machine as a whole. The beams are assembled piece by piece in the order from the side span to the middle span, the line shape is monitored, epoxy resin is applied, and temporary prestressing is applied; Compare and analyze the monitoring data with the theoretical data, and make fine adjustments to the line shape if there is any deviation; Cast the wet joint of the side span closure section and tension the side span closure bundle; remove the temporary prestressing and temporary positioning device of the side span, collect and analyze the data of the measuring points on the top surface of the beam, and complete the side span closure; Step 5) The bridge erection machine moves longitudinally to the next span; the same symmetrical construction steps as above are used to construct the n+2 middle pier to the maximum cantilever; Step 6) Install the temporary positioning device for the middle span closure and make fine adjustments to the line shape according to the monitoring data; Pour the concrete of the joint section, tension the steel strands for the middle span joint, collect and analyze the data of the beam top surface measurement points, and complete the middle span joint; Step 7) The bridge erection machine moves forward and constructs each middle span beam section in sequence until the last span; the last span construction is completed according to the construction steps of the first span; Step 8) Collect data from the monitoring points on the top surface of the full-joint beam, tension the external prestress of the full-joint beam, and remove the temporary restraints of the side piers; The second time, data was collected from the monitoring points on the top surface of the full-joint beam, and compared with the theoretical data of the monitoring calculation under this working condition to complete the construction of the full-joint main structure; Step 9) Construct the remaining joints.

3. The 2+3+2 cantilever assembly construction process of segmental beams according to claim 2 is characterized by: In step 1), a load test is carried out on the overhead crane of the bridge erection machine. By simulating the loading process of the bridge erection machine during segmental beam erection, the bearing capacity and deflection deformation value of the main frame of the bridge erection machine and the bracket beside the pier are analyzed and verified.

4. The 2+3+2 cantilever assembly construction process of segmental beams according to claim 2 is characterized in that: The method for monitoring the elevation of the facade in step 2) is as follows: set up a total station at the pier bottom pedestal, set the total station zenith distance to 90 degrees, erect a level ruler at the pier bottom leveling base point, and read the ruler surface reading H with the total station for multiple measurements. 尺 , and then take the mean; Then adjust the total station zenith angle to 0 degrees, and measure the distance D from the instrument to the bottom of the beam top elevation to be determined. h , the height of the point to be determined is H 引 =H 基 +H 尺 +D h , where H 基 It is the height of the pier bottom cap.

5. The 2+3+2 cantilever assembly construction process of segmental beams according to claim 2 is characterized in that: Step 1) The measurement and positioning of the middle pier top block includes the deviation of the central axis and the precise positioning of the facade elevation. The six-point method is used for positioning control, with two points on the axis and four points on the facade elevation, symmetrically distributed on both sides of the axis. Among them, a high-precision total station is used for axis control, and a level is used for facade elevation control.

6. The 2+3+2 cantilever assembly construction process of segmental beams according to claim 2 is characterized by: Step 4) The method for fine-tuning the centerline shape is as follows: the axis deviation is fine-tuned by applying the horizontal force calculated by monitoring, and the vertical deviation is fine-tuned by applying the vertical force calculated by monitoring.

7. The 2+3+2 cantilever assembly construction process of segmental beams according to claim 3 is characterized by: The load-bearing test condition of the main truss of the bridge-erecting machine is the semi-suspension hoisting of the first span. The deflection deformation monitoring method is the total station trigonometric height measurement method, and the monitoring points are the mid-span and 1 / 4 position of the main truss.

8. The 2+3+2 cantilever assembly construction process of segmental beams according to claim 3 is characterized by: The method for monitoring bracket deformation is leveling measurement. Monitoring points are arranged on 1 / 4 and 1 / 2 of the bracket to measure the elevation before and after the pier top block is hoisted and monitor its deformation value.

9. A 2+3+2 cantilever assembly construction process for segmental beams according to any one of claims 3 to 8, characterized in that: After the 0# segmental beam is accurately positioned and fixed, the cantilever assembly of the following segmental beams is mainly based on matching surfaces and supplemented by linearity during the construction process. For incorrect segmental beams, fine-tuning is performed by adjusting the tightness of the 4 hanging hanger nuts corresponding to each segment of the beam until the bridge deck elevation meets the design requirements.

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