Mixed beam cable-stayed bridge side span concrete main beam cast-in-place support and its dismantling construction method

Abstract

The application relates to the technical field of bridge construction, in particular to a mixed beam cable-stayed bridge side span concrete main beam cast-in-place support and a dismantling construction method thereof. The cast-in-place support comprises a side main beam support frame, a roof support frame and a distribution structure; the distribution structure comprises a plurality of load-bearing main beams and a plurality of distribution beams; a plurality of sand cylinders are arranged to support the load-bearing main beams; a plurality of Bailey beams are arranged at intervals between the load-bearing main beams and the distribution beams; the distribution beams support the side main beam pouring formwork and the roof support frame respectively, and the roof support frame supports the roof pouring formwork. Through the multistage load distribution structure of the load-bearing main beams, the distribution beams and the sand cylinders, the load distribution of the support points is optimized, the overall stability of the support is improved, the Bailey beams effectively disperse the load through the stress mechanism of the beams and trusses, a rigid connection system is formed with the load-bearing main beams, and the overall cross-section flexural rigidity of the load-bearing component is increased; the application can ensure that the support system maintains a stable geometric shape during the construction process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of bridge construction technology, and particularly relates to a mixed beam cable-stayed bridge side span concrete main beam cast-in-place support and a dismantling construction method thereof. BACKGROUND

[0002] In the field of mixed beam cable-stayed bridge construction, the cast-in-place support system of the side span concrete main beam is a key link to ensure the quality of the structure. When dealing with the pouring of the concrete main beam, the traditional support structure often faces the problems of uneven load distribution of the support points and insufficient overall stability, especially in the side span area. Because the main beam includes the top plate and the side main beam extending downward on both sides of the top plate, the complex configuration of the main beam makes the formwork support prone to deformation or settlement deviation, resulting in a decrease in the pouring precision of the concrete and a decrease in the construction efficiency. In addition, the existing support lacks effective adjustable mechanism and load distribution design, and is difficult to adapt to different terrains or construction changes, increasing the construction risk and maintenance cost. SUMMARY

[0003] The present application provides a mixed beam cable-stayed bridge side span concrete main beam cast-in-place support and a dismantling construction method thereof, which can effectively solve the problems pointed out in the background art.

[0004] In order to achieve the above purpose, the technical solution adopted by the present application is:

[0005] The mixed beam cable-stayed bridge side span concrete main beam cast-in-place support, the concrete main beam includes a top plate and side main beams located on both sides of the top plate and extending downward, the cast-in-place support includes a side main beam support frame, a top plate support frame and a distribution structure;

[0006] The distribution structure includes:

[0007] A plurality of load-bearing main beams and a plurality of distribution beams extend along the transverse direction of the bridge and are distributed along the longitudinal direction of the bridge, the distribution beams are located on the top of the load-bearing main beams;

[0008] A plurality of sand cylinders support the load-bearing main beams at different points on the top of the side main beam support frame;

[0009] A plurality of bailey beams are arranged at intervals between the load-bearing main beams and the distribution beams;

[0010] The distribution beams support the side main beam pouring formwork and the top plate support frame, and the top plate support frame supports the top plate pouring formwork.

[0011] Further, the distribution structure further includes a locking structure, and the locking structure includes two pull rods and a pressing rod;

[0012] Two said pull rod one end is fixedly connected with the top of the sand cylinder, two said pull rod the other end is respectively fixedly connected with the both ends of the pressure rod, the pressure rod across the bottom of the beam body, and under the action of the pull rod tension on the bottom of the beam body pressure;

[0013] Each said sand cylinder in the load-bearing girder two sides correspond to set two said locking structure.

[0014] Further, the end of the pull rod is through the sand cylinder top steel plate, and is fixedly connected with the sand cylinder inside.

[0015] Further, the pressure surface of the sand cylinder is embedded with an annularly distributed pressure sensor array, and the number of sensors corresponding to a single sand cylinder is greater than or equal to 4;

[0016] The pressure sensor is connected with an electric control system, and the electric control system judges the support state of the sand cylinder to the load-bearing girder according to the monitoring data of each pressure sensor.

[0017] Further, the electric control system judges the support state of the sand cylinder to the load-bearing girder according to the monitoring data of each pressure sensor array, including:

[0018] Calculate the average value and the first variance of the data collected by each pressure sensor corresponding to a single sand cylinder;

[0019] Calculate the second variance for the average value corresponding to each sand cylinder;

[0020] The first variance and the second variance are weighted and summed, and the support state of the sand cylinder to the load-bearing girder is judged according to the calculated value.

[0021] Further, when the weighted sum result exceeds the first threshold value, it is judged that the support state is abnormal, and the support adjustment of the set sand cylinder is carried out;

[0022] The selection of the set sand cylinder includes the sand cylinder whose average value exceeds the second threshold value, and / or the sand cylinder whose first variance exceeds the third threshold value.

[0023] Further, the weight of the first variance, the weight of the second variance, the first threshold value, the second threshold value and the third threshold value are dynamically generated by an online learning engine, and the online learning engine performs:

[0024] Input vector, including historical load distribution data, concrete age temperature coupling coefficient, sand cylinder settlement rate;

[0025] Output vector, which is a combination vector of the weight of the first variance, the weight of the second variance, the first threshold value, the second threshold value and the third threshold value;

[0026] And, based on the deviation of the release rate of the support state abnormality after adjustment and the target rate, the combination vector is optimized reversely.

[0027] Further, the distribution beam supports the side main beam pouring formwork through a first batten, which is perpendicular to the distribution beam; and the top plate support frame top supports the top plate pouring formwork through a main keel batten and a second batten in sequence, the main keel batten being perpendicular to the second batten.

[0028] The mixed beam cable-stayed bridge side span concrete main beam cast-in-place support dismantling construction method as described above sequentially dismantles the top plate support frame, the distribution structure and the side main beam support frame.

[0029] During the dismantling of the top plate support frame, the sand cylinder maintains the original support state, and the monitoring of the support state is continuously performed.

[0030] During the dismantling of the distribution structure, the sand cylinder performs an unloading process, and the monitoring of the support state is continuously performed during the unloading process.

[0031] The mixed beam cable-stayed bridge side span concrete main beam cast-in-place support dismantling construction method as described above, in the longitudinal bridge direction, the cast-in-place support includes a plurality of sections, each section being arranged corresponding to a pouring section of the concrete main beam, and each section of the cast-in-place support includes a plurality of pier numbers.

[0032] The dismantling method comprises:

[0033] After the secondary tensioning of the partial cable of the Xth concrete pouring section is completed, at least part of the pier numbers of the cast-in-place support corresponding to the set concrete pouring section are dismantled, X being greater than or equal to 3.

[0034] When the set concrete pouring section cast-in-place support retains part of the pier numbers, the pier numbers serve as temporary auxiliary piers and are dismantled before all the cable adjustments.

[0035] The technical solutions of the present application can achieve the following technical effects:

[0036] The multistage load distribution structure of the bearing main beam, the distribution beam and the sand cylinder in the application optimizes the support point load distribution, reduces the local stress concentration and improves the overall stability of the support. The transverse stiffness and deformation resistance of the bearing main beam are enhanced by using the Bailey beam between the bearing main beam and the distribution beam. The Bailey beam is a standard steel truss unit, has the characteristics of high-strength truss structure, and can effectively disperse the load through the stress mechanism of the truss when it is arranged between the bearing main beam and the distribution beam along the transverse direction. The Bailey beam and the bearing main beam form a rigid connection system, which significantly increases the overall bending stiffness of the bearing member, thereby inhibiting the deflection deformation of the bearing main beam under the concrete pouring load, ensuring that the support system maintains a stable geometric shape during construction, and ensuring that the top plate and side main beam formwork of the concrete main beam are accurately positioned during pouring. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0038] Figure 1 It is a working state schematic diagram of the mixed beam cable-stayed bridge side span concrete main beam cast-in-place support;

[0039] Figure 2 It is a working state schematic diagram of the mixed beam cable-stayed bridge side span concrete main beam cast-in-place support; Figure 1 It is a local enlarged view of A in the figure;

[0040] Figure 3 It is a schematic diagram of the distribution beam supporting the side main beam pouring formwork and the top plate support frame respectively;

[0041] Figure 4 It is a working state schematic diagram of the mixed beam cable-stayed bridge side span concrete main beam cast-in-place support; Figure 3 It is a local enlarged view of B in the figure;

[0042] Figure 5 It is a working state schematic diagram of the mixed beam cable-stayed bridge side span concrete main beam cast-in-place support; Figure 3 It is a local enlarged view of C in the figure;

[0043] Figure 6 It is a schematic diagram of the side main beam support frame supporting the distribution structure;

[0044] Figure 7 It is a working state schematic diagram of the mixed beam cable-stayed bridge side span concrete main beam cast-in-place support; Figure 6 It is a local enlarged view of D in the figure;

[0045] Figure 8 It is a schematic diagram of the connection between the Bailey beam and the sand cylinder;

[0046] Figure 9 It is a working state schematic diagram of the mixed beam cable-stayed bridge side span concrete main beam cast-in-place support; Figure 8A local enlarged view at E;

[0047] Figure 10 As Figure 8 A local enlarged view at F;

[0048] Figure 11 A partial view of the removal of the cast-in-place support after the secondary tensioning of the No. 12 cable-stayed cable;

[0049] Figure 12 A partial view of the removal of the cast-in-place support after the secondary tensioning of the No. 18 cable-stayed cable;

[0050] Figure 13 A partial view of the removal of the cast-in-place support after the secondary tensioning of the No. 23 cable-stayed cable;

[0051] Figure 14 A partial view of the removal of the cast-in-place support after the secondary tensioning of the No. 25 cable-stayed cable;

[0052] The figure mark: 100, the concrete main beam; 110, the roof; 120, the side main beam; 200, the side main beam support frame; 300, the roof support frame; 400, the distribution structure; 410, the bearing main beam; 420, the distribution beam; 430, the sand cylinder; 440, the Bailey beam; 441, the bottom rod body; 450, the pull rod; 460, the compression rod; 500, the roof pouring formwork; 600, the side main beam pouring formwork; 710, the No. 12 cable-stayed cable; 720, the first concrete pouring section; 730, the No. 18 cable-stayed cable; 740, the second concrete pouring section; 750, the first temporary auxiliary pier; 760, the No. 23 cable-stayed cable; 770, the second temporary auxiliary pier; 780, the No. 25 cable-stayed cable. DETAILED DESCRIPTION

[0053] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments.

[0054] Embodiment one

[0055] As Figures 1 to 10 shown, a cast-in-place support for a concrete main beam of a hybrid girder cable-stayed bridge side span is provided in the embodiment, the concrete main beam 100 includes a roof 110 and a side main beam 120 located on both sides of the roof 110 and extending to the bottom, and the cast-in-place support includes a side main beam support frame 200, a roof support frame 300 and a distribution structure 400.

[0056] The distribution structure 400 includes:

[0057] A plurality of load-bearing main beams 410 and a plurality of distribution beams 420 extend along the transverse direction of the bridge and are distributed along the longitudinal direction of the bridge, the distribution beams 420 are located on top of the load-bearing main beams 410; a plurality of sand cylinders 430 support the load-bearing main beams 410 at different points on top of the side main beam support frame 200; and a plurality of Bailey beams 440 are arranged at intervals between the load-bearing main beams 410 and the distribution beams 420.

[0058] The distribution beams 420 support the side main beam pouring formwork 600 and the roof support frame 300, and the roof support frame 300 supports the roof pouring formwork 500.

[0059] In the present application, the multi-level load distribution structure 400 of the load-bearing main beams 410, the distribution beams 420 and the sand cylinders 430 optimizes the load distribution of the support points, reduces local stress concentration and improves the overall stability of the support. The Bailey beams 440 are used between the load-bearing main beams 410 and the distribution beams 420 to enhance the lateral stiffness and anti-deformation ability of the load-bearing main beams 410. The Bailey beams 440 are standard steel truss units with high-strength truss structure characteristics. When they are arranged at intervals between the load-bearing main beams 410 and the distribution beams 420 along the transverse direction of the bridge, they can effectively disperse the load through the force mechanism of their truss bars. The Bailey beams 440 form a rigid connection system with the load-bearing main beams 410, significantly increasing the overall cross-sectional bending stiffness of the load-bearing member, thereby inhibiting the deflection deformation of the load-bearing main beams 410 under the concrete pouring load, ensuring that the support system maintains a stable geometric shape during construction, and ensuring that the roof 110 and the side main beam 120 formwork are accurately positioned during the pouring process.

[0060] During implementation, the sand cylinders 430 can adjust the height of each support point according to construction needs, effectively adapt to uneven ground or load changes, avoid formwork settlement deviation, and the distribution beams 420 simultaneously support the side main beam pouring formwork 600 and the roof support frame 300, realizing the collaborative transmission of the pouring load of the roof 110 and the side main beam 120, ensuring the forming precision of the complex cross section, and ultimately reducing the risk of deformation of the support during construction, improving the linear control quality and construction safety of the concrete main beam 100.

[0061] As a preferred embodiment of the above embodiment, as shown in Figure 8 and 9 The distribution structure 400 further includes a locking structure, which includes two tension rods 450 and a compression rod 460. One end of each of the two tension rods 450 is fixedly connected to the top of the sand cylinder 430, and the other end of each of the two tension rods 450 is fixedly connected to the two ends of the compression rod 460. The compression rod 460 spans the bottom bar body 441 of the Bailey beam 440 and exerts pressure on the bottom bar body 441 under the action of the tension of the tension rod 450. Two locking structures are provided on both sides of each sand cylinder 430 corresponding to the load-bearing main beam 410.

[0062] In the preferred embodiment, the locking structure formed by the tension rod 450 and the compression rod 460 actively restricts the vertical displacement and lateral slip of the bailey beam 440 corresponding to the position of the sand cylinder 430 under load. Of course, in the specific implementation process, the sand cylinder 430 is not arranged one by one above and below the bailey beam 440, and the preferred embodiment is only for bailey beams 440 and sand cylinders 430 corresponding in position.

[0063] In the implementation process, the compression rod 460 forms a continuous compression force on the bailey beam 440 under the tension of the tension rod 450, enhances the connection rigidity of the bailey beam 440 and the load-bearing main beam 410, and improves the overall cooperative stress performance of the distribution structure 400. The locking structure symmetrically arranged on both sides of each sand cylinder 430 balances the transmission of the restraining force, prevents local instability of the bailey beam 440, and ensures the deformation resistance and construction safety of the support system during the concrete pouring stage. The locking structure is directly fixed to the top of the sand cylinder 430, avoiding the additional occupation of support space and optimizing the compactness of the structure.

[0064] As a further preferred embodiment of the above embodiment, as shown in Figure 10 The end of the tension rod 450 penetrates the top steel plate of the sand cylinder 430 and is fixedly connected inside the sand cylinder 430, so as to ensure the anchoring rigidity of the locking structure and the sand cylinder 430, eliminate the risk of loosening of the tension rod 450, enhance the pullout strength of the connection point, improve the stability of the locking structure under dynamic load, avoid exposure of external connecting parts, reduce the influence of environmental corrosion on the restraining performance, and ensure long-term construction safety. In the specific implementation, the connection is covered by the concrete filled in the top of the sand cylinder 430, so as to ensure more stable connection.

[0065] As a preferred embodiment of the above embodiment, the pressure bearing surface of the sand cylinder 430 is embedded with an annular array of pressure sensors, and the pressure bearing surface here is the top surface; the number of sensors corresponding to a single sand cylinder 430 is greater than or equal to 4; the pressure sensors are connected to an electric control system, and the electric control system judges the support state of the sand cylinder 430 to the load-bearing main beam according to the monitoring data of the pressure sensors.

[0066] In the preferred embodiment, the annular array of pressure sensors is used to monitor the load distribution of the pressure bearing surface in real time, identify the risk of eccentric load and uneven settlement of the sand cylinder 430, cover the full pressure gradient with multiple pressure sensors of a single sand cylinder 430, and build a high-precision support state evaluation basis, so that the electric control system can dynamically associate multiple data sources to realize real-time diagnosis of support stability.

[0067] As a further working optimization of the electric control system, the electric control system judges the support state of the sand cylinder 430 to the load-bearing main beam according to the monitoring data of the pressure sensor array, including:

[0068] The average value and the first variance of the data collected by each pressure sensor corresponding to a single sand cylinder 430 are calculated, the second variance is calculated for the average value corresponding to each sand cylinder 430, and the first variance and the second variance are weighted and summed to determine the support state of the sand cylinder 430 to the main load-bearing beam according to the calculated value.

[0069] In the preferred embodiment, the first variance quantifies the internal load dispersion of a single sand cylinder 430, the second variance evaluates the collaborative balance of multiple sand cylinders 430, the weighted sum combines the local and overall stability indicators, and a comprehensive risk evaluation standard is established to build a support state comprehensive evaluation model.

[0070] In the implementation process, a more specific optimization method is to determine that the support state is abnormal when the weighted sum result exceeds the first threshold value, and to set the support adjustment of the sand cylinder 430; the selection of the sand cylinder 430 includes the sand cylinder 430 whose average value exceeds the second threshold value, and / or the sand cylinder 430 whose first variance exceeds the third threshold value.

[0071] In the preferred embodiment, the weighted comprehensive judgment avoids single indicator fluctuation false positives and only triggers adjustment when local and system stability jointly deteriorate to a critical value, significantly reducing invalid responses caused by environmental interference; wherein, the average value exceeding the second threshold value identifies the macro load imbalance of the main load-bearing beam 410, and the first variance exceeding the third threshold value locates the internal sand flow liquefaction risk of the sand cylinder 430, accurately matching multiple types of fault scenarios, supporting single fault independent adjustment and composite fault synchronous disposal, avoiding missing critical risk points, and finally determining the high-priority sand cylinder 430 for disposal to restore system stability with the minimum intervention intensity and maximize the inhibition of disturbance to concrete solidification during the adjustment process.

[0072] In the implementation of the preferred embodiment, the support adjustment includes:

[0073] For the sand cylinder 430 whose average value exceeds the second threshold value, the height of the pressure-bearing surface of the sand cylinder 430 can be directly changed by the built-in screw lifting mechanism in the sand cylinder 430 without increasing or decreasing the amount of sand, instantaneously compensating for the elevation deviation, and achieving mechanical pose correction. In this process, the density change rate under the condition of constant sand amount is controllable and below the sand flow liquefaction critical value, which does not affect the support performance; in some embodiments of the present application, the main part of the screw lifting mechanism is connected with the base of the sand cylinder 430, and the linear power part is connected with the top of the sand cylinder 430, so that the height of the pressure-bearing surface can be changed relative to the base of the sand cylinder 430 during power output.

[0074] For the sand cylinder 430 whose first variance exceeds the third threshold value, the piezoelectric ceramic screen built in the sand cylinder 430 can be specifically started to optimize the sand distribution; in some embodiments of the present application, the piezoelectric ceramic sheet is annularly attached to the inner surface of the base of the sand cylinder 430, covering more than 80% of the bottom area, and the vibration frequency controller is externally connected to the ceramic sheet through a pressure-resistant cable; the screen layer is arranged 8 to 12 mm above the piezoelectric ceramic sheet, and a honeycomb-shaped stainless steel screen can be specifically used to apply variable frequency micro-vibration to promote the reorganization and distribution of sand particles, eliminate stress concentration caused by local voids, and ensure uniform transmission of vibration energy by blocking the sand displacement channel; for the fixation of the screen layer, as a specific implementation, the outer edge of the screen can be embedded in the annular groove of the cylinder wall and fixed by a silicone sealing ring.

[0075] Preferably, the above two adjustment methods are decoupled and operated to avoid resonance effects caused by energy coupling by independent operation.

[0076] In the present application, the sand cylinder 430 directly bears the pouring load of the concrete main beam 100, and its support stability determines the linear precision and structural safety of the main beam. The load redistribution caused by the solidification and shrinkage of concrete cannot be self-adaptively compensated by the traditional sand cylinder 430. In the above preferred scheme, the sand cylinder 430 cooperatively controls as a dynamic control part to compensate for the support point deviation caused by the construction load redistribution and the concrete shrinkage and creep through real-time sensing and intelligent leveling, and forms a rigid-flexible cooperative defense system with the static part of the distribution structure 400, which can completely eliminate the risk of support bias.

[0077] As a preferred embodiment of the above embodiment, the weight of the first variance, the weight of the second variance, the first threshold value, the second threshold value and the third threshold value are dynamically generated by an online learning engine, and the online learning engine performs:

[0078] The input vector includes historical load distribution data, concrete age temperature coupling coefficients and sand cylinder settlement rate; the historical load distribution extracts the spatio-temporal evolution law of the load, the concrete age temperature coupling coefficient quantifies the attenuation effect of concrete creep on support force, and the sand cylinder settlement rate reflects the rheological properties and density evolution of sand;

[0079] The output vector is a combination vector of the weight of the first variance, the weight of the second variance, the first threshold value, the second threshold value and the third threshold value;

[0080] And, based on the deviation of the removal rate of the abnormal support state from the target rate, the combination vector is inversely optimized to finally approach the system optimal steady state. In the preferred scheme, through the rate deviation feedback mechanism, the adjustment efficiency is directly related to the system stability recovery time, avoiding the lag response of the static threshold to the construction progress change; the rate deviation simultaneously integrates the time cost of the removal speed and the energy cost of the adjustment amplitude, realizing the Pareto optimal balance of energy consumption and time consumption, and the creep acceleration effect caused by the concrete age growth is automatically included in the dynamic correction of the rate target, without the need for manual parameter resetting.

[0081] In the above preferred scheme, the online learning engine constructs a three-dimensional input vector by real-time collection of historical load distribution, concrete age temperature coupling coefficient, and sand cylinder settlement rate, dynamically outputs the globally optimal combination vector of the first variance weight, the second variance weight, and the three-level threshold value through deep time series modeling and reinforcement learning strategy; at the same time, relying on the deviation feedback of the removal rate of the abnormal support state from the target rate, the weight and threshold parameters are iteratively optimized in reverse, which can realize the Pareto balance of energy consumption and time consumption.

[0082] As a preferred embodiment of the above, the load-bearing main beam 410 and the distribution beam 420 are both formed by parallel welding of I-beams, and the welds are equal in length to the beam bodies. Figure 9 The structure of the load-bearing main beam 410 obtained by parallel welding of three I-beams is shown in FIG. 4, and the composite beam body formed by parallel welding of I-beams significantly enhances the cross-sectional flexural rigidity and load-carrying capacity of the load-bearing main beam 410 and the distribution beam 420, effectively disperses the concrete pouring load, and equal-length continuous welds ensure uniform stress transfer between I-beams, avoiding the risk of weld cracking caused by local stress concentration; the integrated structure obtained by welding improves the overall stability of the beam body, suppresses local deformation, ensures the long-term reliability of the support during construction, and simplifies the manufacturing process through standardized I-beam component welding process, improving construction efficiency and reducing maintenance costs.

[0083] As a preferred embodiment of the above, the distribution beam 420 supports the side main beam pouring formwork 600 through the first batten, and the first batten is perpendicular to the distribution beam 420; the top plate support frame 300 top supports the top plate pouring formwork 500 in turn through the main batten and the second batten, and the main batten is perpendicular to the second batten; the first batten and the second batten absorb the pouring kinetic energy of the side main beam 120 and the top plate 110.

[0084] Embodiment Two

[0085] In this embodiment, a method for dismantling the side-span concrete main beam cast-in-place support of the hybrid girder cable-stayed bridge as described in Embodiment One is provided, which sequentially dismantles the top plate support frame 300, the distribution structure 400, and the side main beam support frame 200;

[0086] Wherein, during the process of removing the roof support frame 300, the sand cylinder 430 maintains the original support state, and the support state is continuously monitored; during the process of removing the distribution structure 400, the sand cylinder 430 performs the unloading process, and the support state is continuously monitored during the unloading process.

[0087] In the above embodiment, the sand cylinder 430 maintains support when the roof support frame 300 is removed, ensuring the load path of the side main beam 120 is complete, and avoiding structural chain instability caused by roof 110 unloading impact; the sand cylinder 430 can be synchronously unloaded in stages during the removal of the distribution structure 400, dynamically matching the step-by-step load-bearing capacity of the concrete beam, and preventing stress cracks; the support state of the sand cylinder 430 is monitored in real time throughout the process, and the removal can be automatically paused when the trigger threshold is exceeded, ensuring construction safety.

[0088] Other technical effects achieved by the embodiment are as described in Embodiment One, which will not be repeated here.

[0089] Embodiment Three

[0090] The embodiment provides a method for removing a cast-in-place support for a concrete main beam of a side span of a hybrid girder cable-stayed bridge, as described in Embodiment One. In the longitudinal direction of the bridge, the cast-in-place support includes a plurality of sections, each section corresponding to a pouring section of the concrete main beam, and each section of the cast-in-place support includes a plurality of piers;

[0091] The removal method includes:

[0092] After the secondary tensioning of the partial cable corresponding to the Xth pouring section of concrete is completed, at least part of the piers of the cast-in-place support corresponding to the set pouring section of concrete are removed, and X is greater than or equal to 3.

[0093] Wherein, when part of the piers of the cast-in-place support corresponding to the set pouring section of concrete are retained, the piers serve as temporary auxiliary piers and are removed before all cable adjustments.

[0094] The conventional removal of the side main beam support is performed after all the side span cables are installed, and then the supports are removed step by step. This method is low in efficiency. In the embodiment, the supports are removed in sections, which effectively improves the construction efficiency. As a specific implementation:

[0095] Referring to Figure 11 , after the secondary tensioning of the 12th cable 710 corresponding to the third pouring section of concrete is completed, the cast-in-place support of the first pouring section of concrete 720 is removed.

[0096] Referring to Figure 12 , after the secondary tensioning of the 18th cable 730 corresponding to the fourth pouring section of concrete is completed, part of the piers of the cast-in-place support of the second pouring section of concrete 740 are removed, and the retained piers serve as the first temporary auxiliary piers 750.

[0097] Referring to Figure 13 After the secondary tensioning of the 23rd cable-stayed cable 760 corresponding to the 5th concrete pouring section in the figure is completed, the part of the pier numbers of the cast-in-place support of the third concrete pouring section and the fourth concrete pouring section are removed, and the remaining pier numbers in the third concrete pouring section are used as the second temporary auxiliary pier 770.

[0098] Referring to Figure 14 After the secondary tensioning of the 25th cable-stayed cable 780 corresponding to the 5th concrete pouring section in the figure is completed, all the remaining pier numbers of the cast-in-place support of the fourth concrete pouring section and the 5th concrete pouring section are removed.

[0099] Finally, in the above embodiment, before the overall cable adjustment of all the cable-stayed cables, the above first temporary auxiliary pier 750 and the second temporary auxiliary pier 770 are removed.

[0100] Those skilled in the art should understand that the present application is not limited to the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A cast-in-place support for a concrete main girder of a side span of a hybrid girder cable-stayed bridge, the concrete main girder comprising a top plate and side main girders located on both sides of the top plate and extending toward the bottom, characterized in that, The cast-in-place support frame comprises a side main beam support frame, a top plate support frame and a distribution structure; The distribution structure comprises: a plurality of load-bearing main beams and a plurality of distribution beams extending along the transverse bridge direction and distributed along the longitudinal bridge direction, the distribution beams being located on the top of the load-bearing main beams; a plurality of sand cylinders supporting the load-bearing main beams at different points on the top of the side main beam support frame; a plurality of Bailey beams being arranged at intervals between the load-bearing main beams and the distribution beams; the distribution beams supporting the side main beam pouring formwork and the top plate support frame respectively, and the top plate support frame supporting the top plate pouring formwork; The pressure-bearing surface of the sand cylinder is embedded with an annularly distributed pressure sensor array, and the number of pressure sensors corresponding to a single sand cylinder is greater than or equal to 4; the pressure sensors are connected to an electric control system, and the electric control system judges the support state of the sand cylinder on the load-bearing main beam according to the monitoring data of each pressure sensor, including: calculating the average value and the first variance of the data collected by each pressure sensor corresponding to a single sand cylinder; calculating the second variance for the average value corresponding to each sand cylinder; and performing weighted summation on the first variance and the second variance to judge the support state of the sand cylinder on the load-bearing main beam according to the calculated value; When the weighted summation result exceeds a first threshold value, it is judged that the support state is abnormal, and the support adjustment of the set sand cylinder is performed; the selection of the set sand cylinder includes the sand cylinder whose average value exceeds a second threshold value and / or the sand cylinder whose first variance exceeds a third threshold value; the weight of the first variance, the weight of the second variance, the first threshold value, the second threshold value and the third threshold value are dynamically generated by an online learning engine, and the online learning engine performs: input vector, including historical load distribution data, concrete age temperature coupling coefficient and sand cylinder settlement rate; output vector, being a combined vector of the weight of the first variance, the weight of the second variance, the first threshold value, the second threshold value and the third threshold value; and based on the deviation between the removal rate of the abnormal support state after adjustment and the target rate, the combined vector is optimized in reverse. The distribution structure further comprises a locking structure, and the locking structure comprises two pull rods and a pressure rod; One end of each of the two pull rods is fixedly connected to the top of the sand cylinder, and the other end of each of the two pull rods is fixedly connected to the two ends of the pressure rod, respectively; the pressure rod spans the bottom rod body of the Bailey beam and exerts pressure on the bottom rod body under the action of the pulling force of the pull rod; 2. The mixed girder cable-stayed bridge concrete main girder cast-in-situ support of claim 1, characterized in that, Each of the sand cylinders is provided with two locking structures corresponding to the two sides of the load-bearing main beam. The end of the pull rod penetrates the top steel plate of the sand cylinder and is fixedly connected to the sand cylinder inside the sand cylinder. The distribution beam supports the side main beam pouring formwork through a first batten, and the first batten is perpendicular to the distribution beam; the top plate pouring formwork is supported by the top of the top plate support frame in turn through a main keel and a second batten, and the main keel is perpendicular to the second batten.

3. The cast-in-place support for the concrete main girder of the hybrid girder cable-stayed bridge side span according to claim 2, characterized in that, The top plate support frame, the distribution structure and the side main beam support frame are removed in turn; 4. The cast-in-place support for the concrete main girder of the hybrid girder cable-stayed bridge side span according to claim 1, characterized in that, During the removal of the top plate support frame, the sand cylinder maintains the original support state, and the monitoring of the support state is continuously performed; 5. The method according to claim 1, wherein the method is characterized by, ​ ​ During the dismantling of the distribution structure, the sand pot performs an unloading process, and the monitoring of the support state is continuously performed during the unloading process.

6. The method according to claim 1, wherein the method is characterized by, In the longitudinal bridge direction, the cast-in-place support includes a plurality of sections, each section corresponding to a pouring section of the concrete main beam, and each section of the cast-in-place support includes a plurality of pier numbers. The demolition construction method comprises: After the secondary tensioning of the partial cable-stayed cable corresponding to the Xth concrete pouring section is completed, at least part of the pier numbers of the cast-in-place support corresponding to the set concrete pouring section are removed, and X is greater than or equal to 3. When the cast-in-place support of the set concrete pouring section retains part of the pier numbers, the pier numbers serve as temporary auxiliary piers and are removed before all the cable-stayed cables are adjusted.

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