Cast-in-place concrete beam construction method based on deformation control

Abstract

The invention discloses a cast-in-place concrete beam construction method based on deformation control, and relates to the field of cast-in-place beam construction. S2, foundation treatment; s3, a support is erected and pre-pressed; s4, a formwork is installed; s5, steel bars and prestressed pipelines are installed; s6, concrete construction; and S7, removing the bracket. BIM modeling and an intelligent monitoring system are combined, the foundation treatment range is expanded, an automatic drainage system is arranged, edge settlement and rainwater soaking are effectively avoided, a support system is selected according to needs, anti-sidesway design is strengthened, stress is accurately simulated through graded automatic loading and pre-pressing, reliable deformation data are ensured through double monitoring, pre-camber calculation is scientific, errors are reduced, and the construction efficiency is improved. Formwork, reinforcing steel bars and prestressed pipelines are installed in a standard mode, the structural quality is guaranteed, concrete construction pays attention to temperature control and maintenance, crack reduction and support dismantling are symmetrically carried out in a grading mode, the springback amount is monitored in real time, and construction safety is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the cast-in-place beam construction technical field, in particular to a cast-in-place concrete beam construction method based on deformation control. BACKGROUND

[0002] Due to the complex geological conditions, and part of the box girder needs to cross the existing road or water body, the support foundation is easy to be affected by settlement, and the cast-in-place beam construction period is long, and the concrete shrinkage, prestressed tension and other links may cause deformation, which needs to be controlled through construction to ensure the safety of the beam body line and stress.

[0003] For example, a cast-in-place construction method of a cast-in-place concrete bridge with publication number CN106592437B, the specific steps are as follows: S1: measurement of construction site environment; S2: determine the construction scheme and draw construction drawings, determine the cast-in-place construction scheme; S3: remove construction site obstacles; S4: construction of formwork; S5: inspection of formwork; S6: cast-in-place concrete; S7: maintenance of concrete, S8: form removal; S9: acceptance.

[0004] In the prior art, in the cast-in-place concrete beam construction, the support preloading is the key link to ensure the stability and construction accuracy of the structure, if the load distribution is uneven during preloading, the safety reserve of the support will be partially overdrafted and the overall insufficient, when the local load is far more than the design value, the local load may cause plastic deformation due to stress concentration, node connection bolt loosening or even fracture, which weakens the local bearing capacity, and in the area with insufficient load, the support is not fully preloaded, and the potential deformation is not released, which reduces the risk threshold of the overall system, and makes the geometric size and stress performance of the beam body deviate significantly from the design requirements. SUMMARY

[0005] The purpose of the present application is to provide a cast-in-place concrete beam construction method based on deformation control, to solve the problem of uneven load distribution during preloading, which may cause the safety reserve of the support to be partially overdrafted and the overall insufficient, and reduce the risk threshold of the overall system.

[0006] To achieve the above purpose, the present application provides the following technical scheme: a cast-in-place concrete beam construction method based on deformation control, comprising the following steps:

[0007] S1, construction preparation: according to the design drawings, review the beam body span, cross-sectional size, pre-camber design value, determine the deformation control index, use BIM software to establish the three-dimensional model of the beam body and support, simulate the deformation trend of the whole construction process, optimize the support arrangement, deploy the measurement control network and intelligent monitoring system, and control the equipment and material compliance;

[0008] S2, foundation treatment: after removing weeds and silt on the ground, replace the area with insufficient bearing capacity in layers, pour concrete cushion, and harden the base;

[0009] S3, support erection and preloading: based on modular support erection, check the overall stiffness, check the locking force of the disc mouth node, simulate the preloading process to reserve the inelastic deformation, use hierarchical automatic loading and data closed loop analysis, and quantify the deformation parameters;

[0010] S4, template installation: according to the preloading data, accurately adjust the bottom mold elevation by adjustable jacking, set the pre-camber for variable cross-section beams in sections, and update the actual elevation data in BIM model synchronously;

[0011] S5, steel bar and prestressed pipe installation: use steel positioning jig to fix the main reinforcement spacing, follow the principle of allowing prestressed reinforcement for ordinary reinforcement, adjust the steel position locally, and use cross-shaped positioning reinforcement to fix the corrugated pipe;

[0012] S6, concrete construction: use concrete pouring, cover geotextile and plastic film within 12 hours after pouring, pre-bury temperature sensors, monitor the internal and external temperature difference, use intelligent tensioning equipment for tensioning after the concrete strength meets the standard, carry out grouting within 48 hours after tensioning, and finally seal the anchor;

[0013] S7, support removal: remove the support after the grouting strength reaches 50MPa, use hierarchical unloading, and real-time monitor the beam rebound through wireless sensors.

[0014] Preferably, in step S1, deploying the measurement control network and the intelligent monitoring system specifically includes establishing a second-precision traverse network using a total station, setting permanent benchmarks, using a level to review the pier top elevation, installing wireless sensor nodes at key support nodes, and real-time collecting settlement and displacement data.

[0015] Preferably, in step S2, the foundation treatment specifically includes the following steps:

[0016] S21, after removing weeds and silt on the ground, use geological radar to detect soft soil layer distribution, use slag to replace the area with insufficient bearing capacity in layers, extend the foundation treatment range to 1.5m outside the beam body, and avoid edge settlement;

[0017] S22, use intelligent compaction instrument to real-time monitor the compaction degree, and use heavy dynamic penetration instrument to detect the foundation bearing capacity;

[0018] S23, pour concrete cushion, use laser leveling machine to control flatness, set bidirectional slope on the surface, set 30cm x 30cm brick drainage ditch around, install liquid level sensor, and use automatic drainage of submersible pump to prevent rainwater from soaking the foundation.

[0019] Preferably, in step S3, the scaffolding includes modular scaffolding, the overall rigidity is calculated by finite element software, the locking force of the disc buckle joint is checked, vertical diagonal rods are arranged, the scaffolding is connected with the pier body by steel pipes, the inelastic deformation during the preloading process is simulated by BIM, the deformation amount is reserved in advance, and the actual stress state of the beam body is simulated.

[0020] Preferably, in step S3, the modular scaffolding is disc buckle scaffolding in non-wading sections, and is a steel pipe pile plus Bailey beam system in county flood drainage channel sections, and the transverse spacing of the Bailey beam is 30 cm.

[0021] Preferably, in step S3, hierarchical automatic loading and data closed-loop analysis are used to quantify deformation parameters, including the following steps:

[0022] S31, preloading load and loading process optimization: determine the total weight of preloading, use intelligent jack cluster combined with pressure sensor for hierarchical automatic loading, and simulate the actual stress distribution of the beam body;

[0023] S32, hierarchical loading process: loading is divided into 0, 60%, 100% and 110% according to the hierarchical loading, and each level of loading interval is 12 hours;

[0024] S33, load distribution control: adjusting the arrangement density and loading pressure of the jacks for different stress regions;

[0025] S34, deformation data acquisition and pre-camber calculation: using the dual means of intelligent detection and manual review, quantifying elastic deformation and inelastic deformation, and determining the pre-camber;

[0026] S35, unloading and data archiving: reverse hierarchical unloading, and entering the preloading data of the whole process into the BIM model to form an associated database.

[0027] Preferably, in step S34, the deformation data acquisition and pre-camber calculation specifically include the following steps:

[0028] A1, arranging vibrating wire displacement sensors on the top of the scaffolding, the bottom of the scaffolding and the pier body, additionally arranging horizontal displacement sensors on the curved bridge, and using a second-order level to manually read the key sections and cross-verify the sensor data;

[0029] A2, calculating elastic deformation data and inelastic deformation data;

[0030] A3, determining the pre-camber by superimposing the theoretical calculation value, the elastic deformation value and the concrete shrinkage and creep value.

[0031] Preferably, in step S7, the scaffolding dismantling includes the following steps:

[0032] S71, demolition confirmation: detect the prestressed hole grouting strength, check the beam body appearance, lay strain sensors and displacement sensors at the beam body midspan, 1 / 4 span and support point, and monitor the beam body rebound amount and stress change in real time during the demolition process;

[0033] S72, hierarchical symmetrical demolition: first, remove the top temporary component, then remove the horizontal rod and inclined rod, remove the vertical rod, and finally clean the foundation and components, and track the beam body rebound amount throughout the process;

[0034] S73, data acceptance: after the demolition is completed, check the beam body linear, rebound amount and site cleaning condition, and organize the monitoring data, demolition record and acceptance data.

[0035] Compared with the prior art, the beneficial effects of the present application are:

[0036] The present application combines BIM modeling with intelligent monitoring system, realizes deformation dynamic control throughout the construction process, improves precision and early warning capability, expands the range of foundation treatment and sets up an automatic drainage system, effectively avoids edge settlement and rainwater immersion, selects and strengthens the lateral displacement design of the support system according to needs, and simulates the stress of hierarchical automatic loading preloading accurately, ensures the reliability of deformation data through double monitoring, calculates the camber scientifically, reduces errors; The installation of formwork, steel bars and prestressed pipes is standardized, which guarantees the structure quality, the concrete construction pays attention to temperature control and maintenance, reduces cracks, the support is removed in a hierarchical and symmetrical manner, the rebound amount is monitored in real time, the construction safety is guaranteed, and the safety, accuracy and controllability of cast-in-place concrete beam construction are improved as a whole. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The flowchart of the present application is a cast-in-place concrete beam construction method based on deformation control. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0039] Embodiment 1: refer to Figure 1The construction method of cast-in-place concrete beam based on deformation control is shown, which takes the whole-process deformation control as the core, and realizes the accurate control of the deformation of the beam body through seven key steps of construction preparation, foundation treatment, support erection and preloading, formwork installation, steel bar and prestress construction, concrete pouring and support removal, combined with BIM simulation, intelligent monitoring, hierarchical loading and other technologies. The core logic is to ensure the stability of the support system and the linear shape of the beam body to meet the design requirements by simulating the stress in advance, quantifying the deformation parameters and dynamically adjusting the construction parameters, so as to finally ensure the construction precision and structural safety.

[0040] I. Technical solutions and principles of key steps

[0041] 1. Construction preparation, digital reference establishment and monitoring system construction: based on BIM, a three-dimensional model of the beam body and support is established to simulate the deformation trend of the whole construction process and optimize the support arrangement; a second-order precision traverse network and permanent benchmarks are established, and wireless sensor nodes are installed at the key nodes of the support to realize dynamic early warning by connecting to the cloud platform.

[0042] Specific principle: BIM model provides theoretical basis for subsequent construction parameters (such as pre-camber) by digital simulation and early prediction of the deformation correlation between support and beam body; high-precision measurement control network and intelligent monitoring system realize real-time collection and feedback of deformation data, ensuring that deviations can be found and corrected in time during construction to avoid cumulative errors.

[0043] 2. Foundation treatment, construction of homogeneous bearing foundation: after removing surface debris, use geological radar to detect soft soil layer, and use layered replacement of slag in areas with insufficient bearing capacity; intelligent compaction instrument monitors compaction degree, and heavy dynamic penetration instrument detects foundation bearing capacity; pour concrete cushion (laser leveling control flatness), set bidirectional slope, brick drainage ditch and liquid level sensor linkage drainage.

[0044] Specific principle: The foundation is the "basic carrier" of the support system. Through replacement, compaction and hardening treatment, the hidden danger of uneven settlement of the foundation is eliminated. Soft soil replacement can improve the uniformity of foundation bearing capacity, and concrete cushion can reduce the strength attenuation of the foundation after being soaked in water. Drainage ditch can avoid the softening of foundation caused by rainwater infiltration, thus ensuring the stability of support stress from the source.

[0045] 3. Scaffold erection and preloading, load simulation and deformation parameter quantification are the core of deformation control. Through "accurate erection + scientific preloading", the bearing capacity of the scaffold is verified and the deformation data is quantified: the scaffold is erected by using disc buckle support in the non-flooded section and "steel pipe pile + Bailey beam" system (Bailey beam transverse spacing 30 cm) in the flood discharge channel section; the overall stiffness is calculated by finite element software, vertical diagonal rods and steel pipe tie with pier body are set to enhance the lateral displacement resistance; the preloading control, the total weight of preloading is 110% of the self weight of the beam, compensates for the construction impact load, uses intelligent jack cluster staged automatic loading, 0→60%→100%→110%, each stage interval is 12 hours, the jacks are arranged according to the stress distribution of the beam, the web plate spacing is 1.5m, and the flange plate spacing is 2.5m; through the vibrating wire displacement sensor + manual review, the elastic and inelastic deformation data are collected, the theoretical deflection and shrinkage and creep values are determined to determine the pre-camber; according to 110%→100%→60%→0 reverse staged unloading, data is entered into BIM to form a related database.

[0046] Specific principle: scaffold erection through "differentiation system + stiffness calculation", adapt to the stress demand of different working conditions (land / water); diagonal rods and ties enhance lateral displacement resistance to avoid lateral deformation during construction; the core of preloading is "simulating actual stress", 110% load covers the self weight of the beam and impact load to ensure the safety reserve of the scaffold; staged loading tests the bearing limit of the scaffold and foundation gradually to avoid local damage caused by sudden loading; deformation data quantification (elastic / inelastic deformation) provides basis for subsequent formwork elevation adjustment, inelastic deformation needs to be released in advance, and elastic deformation is offset by pre-camber to ensure that the beam body is linear after forming.

[0047] 4. Formwork installation, accurate adjustment based on preloading data: according to the deformation parameters obtained by preloading, the bottom mold elevation is accurately adjusted by adjustable jacks; pre-camber is set for variable cross-section beams, and BIM model is updated synchronously with actual elevation data.

[0048] Specific principle: formwork elevation adjustment is based on preloading data, which offsets the deformation caused by subsequent concrete pouring and scaffold settlement through pre-set pre-camber, ensuring that the actual linear and design linear of the beam body are consistent after construction (such as mid-span pre-camber needs to cover the elastic deformation of the scaffold + concrete shrinkage and creep).

[0049] 5. Steel bar and prestressed pipe installation, accurate construction of stress system: steel positioning jig fixes main reinforcement spacing, and plum blossom-shaped cushion blocks ensure the thickness of the protective layer; prestressed corrugated pipe is fixed by cross-shaped positioning reinforcement, joint is sealed by double-layer tape, and pipeline patency is verified by through-hole device and pressure detection method.

[0050] Specific principle: The position of steel bars and the thickness of the protective layer directly affect the stress performance of the beam body. The positioning jig and the cushion ensure that the steel skeleton conforms to the design stress model. The sealing and smoothness of the prestressed pipe are the key to avoiding stress loss during tensioning. The corrugated pipe fixation and sealing can prevent the leakage of concrete pouring from blocking the pipe and ensure the effective transmission of force during the tensioning of the prestressed steel bar.

[0051] 6. Concrete construction, material performance and stress control: C50 concrete is used for pouring, and geotextile and plastic film are covered for moisture retention within 12 hours after pouring to monitor the temperature difference between inside and outside (to avoid temperature cracks). After the concrete strength reaches 90% of the design value, the prestressed steel bar is tensioned by intelligent tensioning equipment (with synchronous monitoring of elongation), grouting is performed within 48 hours, and finally C50 micro-expansion concrete is used for anchoring.

[0052] Specific principle: Concrete temperature control (moisture retention and temperature difference monitoring) can reduce internal and external temperature difference cracks caused by hydration heat and ensure material strength. Intelligent tensioning ensures that the prestressed value meets the design by synchronously monitoring the elongation (to avoid over-tensioning or under-tensioning). Grouting and anchoring prevent the corrosion of the prestressed steel bar and ensure long-term stress stability.

[0053] 7. Support removal, uniform load release and structure protection: After the grouting strength reaches 50MPa, the support is removed in a hierarchical and symmetrical manner, starting with the temporary components at the top, followed by the horizontal, diagonal and vertical rods. During the removal process, the sensor monitors the beam body rebound in real time, and the work is paused if the limit is exceeded.

[0054] Specific principle: Hierarchical and symmetrical removal can avoid the "sudden load transfer" when the support is unloaded, ensuring uniform release of beam stress (symmetrical work from the middle to both ends, consistent with the characteristic of "maximum stress in the middle of the beam"). Monitoring the rebound is to verify whether the beam has undergone excessive deformation due to unloading, to avoid structural damage and ensure the stability of the beam after removal.

[0055] II. Core technology innovation and logical closed loop: The core innovation of this scheme lies in "deformation parameter quantization + full-process dynamic control": through hierarchical loading and intelligent monitoring during the preloading stage, the deformation data (elastic / non-elastic) of the support and foundation are converted into directly applicable construction parameters (pre-camber), and through subsequent template adjustment, prestressed tensioning and other steps, a closed-loop control of "preloading data → construction adjustment → final precision" is achieved. The combination of BIM and intelligent monitoring realizes the digital linkage from simulation to construction, greatly improving the accuracy of deformation control.

[0056] Example 2: Referring to Figure 1 the drawings, a cast-in-place concrete beam construction method based on deformation control is provided, which specifically includes the following steps:

[0057] Step one, construction preparation: according to the design drawings, check the beam span, cross-sectional size, pre-arch design value, and determine the deformation control index. Use BIM software to establish a three-dimensional model of the beam and support, simulate the deformation trend of the whole construction process, optimize the support layout, deploy the measurement control network and intelligent monitoring system, and control the compliance of equipment and materials.

[0058] In step S1, deploying the measurement control network and the intelligent monitoring system specifically includes using a total station to establish a second-precision traverse network, setting permanent benchmarks, using a level to review the pier top elevation, installing wireless sensor nodes at key support nodes, collecting settlement and displacement data in real time, and connecting to a cloud platform to achieve dynamic early warning.

[0059] Step two, foundation treatment: after removing weeds and silt on the ground, replace the areas with insufficient bearing capacity in layers, pour a concrete cushion, and harden the base;

[0060] In step S2, foundation treatment specifically includes the following steps:

[0061] 21. After removing weeds and silt on the ground, use a geological radar to detect soft soil layer distribution, replace the areas with insufficient bearing capacity with layering of slag, and extend the foundation treatment range to 1.5m outside the beam body to avoid edge settlement;

[0062] 22. Use an intelligent compactor to monitor compaction in real time, and use a heavy dynamic penetrometer to detect foundation bearing capacity;

[0063] 23. Pour a 20cm thick C20 concrete cushion, use a laser leveling machine to control flatness, set a two-way slope on the surface, a 30cm x 30cm brick drainage ditch around, install a liquid level sensor, and link a submersible pump for automatic drainage to prevent rainwater from soaking the foundation.

[0064] Step three, support erection and preloading: based on modular support erection, calculate overall stiffness, check the locking force of the disc mouth node, simulate the preloading process to reserve non-elastic deformation, use hierarchical automatic loading and data closed-loop analysis to quantify deformation parameters;

[0065] In step S3, support erection includes modular support erection, using disc buckle supports in non-flooded sections and steel pipe pile plus Bailey beam system in sections crossing county flood drainage channels, with a Bailey beam transverse spacing of 30cm. Calculate overall stiffness using finite element software, check the locking force of the disc buckle node, set vertical diagonal rods, use steel pipe tie rods for support and pier body to enhance lateral displacement resistance, simulate non-elastic deformation during the preloading process through BIM, reserve deformation in advance, simulate the actual stress state of the beam body by precisely controlling the loading process, and ensure that the preloading data truly reflects the deformation characteristics of the support and foundation.

[0066] In step S3, hierarchical automatic loading and data closed-loop analysis are used to quantify deformation parameters, including the following steps:

[0067] 31. Pre-pressing load and loading process optimization: determine the total pre-pressing weight, which is 110% of the self-weight of the beam body, to compensate for possible impact loads during construction and ensure safety reserves for the support. Intelligent jack cluster is used in combination with pressure sensors to achieve automatic loading in stages. The jacks are evenly distributed within the projection range of the beam body, with a spacing of 1.5m in the web area and 2.5m in the flange plate area, simulating the actual stress distribution of the beam body.

[0068] 32. Staged loading process: load in stages according to 0→60%→100%→110%, with a 12-hour interval between each stage. In the specific operation process, the intelligent control system is started at the 0→60% stage, and the jacks are loaded synchronously to 60% of the total load. Real-time monitoring of support settlement is performed, and if abnormal deformation occurs, the process is immediately paused and the cause is investigated. After loading to 100%, monitoring is continued for 12 hours. If the cumulative settlement within 12 hours is ≤2mm, the stage is determined to be stable, and the next stage is entered. After loading to 110%, monitoring is continued for 12 hours. If the settlement stability criteria are met, the load state is maintained for 24 hours to ensure that the support and foundation have fully deformed.

[0069] 33. Load distribution control: for different stress areas, adjust the jack arrangement density and loading pressure to achieve differentiated load distribution. The load intensity in the web area is controlled at 26kN / m³ (self-weight of concrete) x 1.1 (safety factor), and the load intensity in the flange plate area is controlled at 18kN / m³, simulating the actual self-weight distribution of the beam body and avoiding deformation errors caused by uneven distribution of traditional pile loading.

[0070] 34. Deformation data collection and pre-camber calculation: use intelligent detection and manual review to quantify elastic deformation and inelastic deformation and determine the pre-camber.

[0071] In step S34, deformation data collection and pre-camber calculation specifically includes the following steps:

[0072] A1. Place vibrating wire displacement sensors on the top of the support (below the bottom mold), the bottom of the support (the surface of the foundation), and the pier body (reference point). For curved bridges, additional horizontal displacement sensors are added to monitor lateral deformation. Use a second-order level gauge to manually read key sections and cross-verify with sensor data to avoid system errors.

[0073] A2. Calculate elastic deformation data and inelastic deformation data. Elastic deformation is the recoverable settlement after unloading, which is the recoverable deformation of the support and foundation under load and is the core parameter for pre-camber setting. Inelastic deformation is the permanent settlement after unloading, mainly due to support joint gaps and insufficient foundation compaction, which needs to be completely eliminated through pre-pressing.

[0074] A3, the pre-camber is determined by superimposing the theoretical calculation value, the elastic deformation value and the concrete shrinkage and creep value, the theoretical calculation value is the deflection of the beam body self weight according to the design drawing, the elastic deformation value is the pre-compaction measured elastic deformation, and the shrinkage and creep value is 3mm / m according to the concrete grade and curing conditions.

[0075] 35. Unloading and data archiving: reverse hierarchical unloading at 110%→100%→60%→0, each level of unloading interval is 30min, to avoid load mutation leading to support rebound impact, the pre-pressing data is recorded into BIM model to form a "pre-pressing-deformation-pre-camber" correlation database, to provide traceability basis for subsequent beam construction.

[0076] Step four, template installation: according to the pre-pressing data, the bottom mold elevation is accurately adjusted through adjustable jacking, the pre-camber is set for the variable cross-section beam in sections, and the BIM model is updated synchronously with the actual elevation data;

[0077] Step five, reinforcement and prestressed pipe installation: the main reinforcement spacing is fixed by using reinforcement positioning jig, plum-blossom-shaped concrete pads are set to ensure the thickness of the protective layer, the principle of ordinary reinforcement allowing prestressed reinforcement is followed, the position of the reinforcement is locally adjusted, the wave-shaped pipe is fixed by using cross-shaped positioning reinforcement, and double-layer adhesive tape is used for sealing at the joint; The through-hole device and pressure detection method are used to check the smoothness of the pipe to ensure that there is no stress loss during tensioning;

[0078] Step six, concrete construction: C50 concrete is used for pouring, and within 12 hours after pouring, geotextile + plastic film is covered, temperature sensors are embedded, the internal and external temperature difference is monitored to avoid temperature cracks, tensioning is carried out after the concrete strength reaches 90% of the design value, intelligent tensioning equipment is used, the elongation is monitored synchronously, and grouting is carried out within 48 hours after tensioning, and finally C50 micro-expansive concrete is used for anchoring;

[0079] Step seven, support removal: the support is removed after the grouting strength reaches 50MPa, the hierarchical unloading is used, the beam rebound amount is monitored in real time through the wireless sensor, and the work is paused when the limit is exceeded;

[0080] In step S7, the support removal includes the following steps:

[0081] 71. Removal confirmation: detect the prestressed duct grouting strength, check whether there are cracks, honeycombs and other defects on the surface of the beam body concrete, confirm that there is no structural damage caused by tensioning or improper curing, avoid stress concentration and aggravate the disease in the removal process, and arrange strain sensors and displacement sensors at the midspan, 1 / 4 span and support point of the beam body to monitor the beam rebound amount and stress change in the removal process in real time;

[0082] 72. Symmetrical dismantling in stages: first, remove the top temporary components, remove the adjustable supports, distribution beams and formwork back ribs at the top of the support, work symmetrically from the middle to both ends of the beam body, the deviation between the two sides of the same section is ≤1m, ensure uniform load release, then remove the horizontal rods and inclined rods, in the same layer, first remove the horizontal rods in the middle of the span, then symmetrically expand to both ends, the removal of the inclined rods follows the principle of synchronous diagonal, remove the vertical rods, remove the vertical rods in groups according to the principle of one in every one, first remove the vertical rods in the middle of the span, then symmetrically advance to both ends, the removal interval of the vertical rods in the same row is ≥3, to avoid the formation of a local open-web area causing the support to lose stability, finally clean the foundation and components, remove the remaining vertical rods and adjustable bases, clean the scattered components on the ground surface, classify the materials, after the removal is completed, check whether the concrete cushion is damaged, dredge the drainage ditch to avoid rainwater accumulation affecting subsequent construction, track the beam body rebound throughout the removal process, set a rebound warning value, if it exceeds the standard, stop immediately;

[0083] 73. Data acceptance: after the removal is completed, check the beam body line, rebound and site cleaning, organize and archive the monitoring data, removal records and acceptance data, provide a reference for subsequent similar projects.

[0084] The application first prepares for construction, reviews the beam body parameters, determines the deformation control indicators, uses BIM software to establish a three-dimensional model to simulate construction deformation and optimize support arrangement, deploys a secondary precision measurement control network and an intelligent monitoring system, real-time collects settlement and displacement data of key nodes of the support, then processes the foundation, removes surface debris, detects soft soil layer, replaces the slag in layers in areas with insufficient bearing capacity, monitors the compaction degree and foundation bearing capacity, pours the concrete cushion and sets the drainage system.

[0085] Then erect the support and pre-press, use disc buckle support for non-flooded sections and steel pipe pile plus Bailey beam system for flood drainage channel sections, check the stiffness and enhance the lateral displacement resistance, automatically load in stages according to 110% of the beam body weight, monitor the settlement, collect deformation data through double means, calculate elastic and inelastic deformation to determine the pre-camber, then reverse the staged unloading and archive the data; then install the formwork, adjust the bottom mold elevation according to the pre-pressing data; then install the steel bars and prestressed pipes, fix the main reinforcement and pipes to ensure that they meet the requirements; then perform concrete construction, maintain and monitor the temperature after pouring C50 concrete, tension the prestressed steel bars, grout and seal the anchor after the strength meets the standard; finally, remove the support, remove it in stages and symmetrically after the grouting strength reaches 50MPa, real-time monitor the beam body rebound, pause when it exceeds the limit, throughout the process, combine BIM, intelligent monitoring and other technologies to control deformation and safety at each link to ensure construction quality.

[0086] Although the present application has been described in detail with reference to the foregoing embodiments, the technical solutions recorded in the foregoing embodiments can be modified, or some of the technical features can be replaced by equivalent features, by those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A cast-in-situ concrete beam construction method based on deformation control, characterized in that: The following steps are involved: S1. Construction Preparation: Review the beam span, cross-sectional dimensions, and pre-camber design values ​​based on the design drawings, clarify deformation control indicators, use BIM software to build a three-dimensional model of the beam and support, simulate deformation trends throughout the construction process, optimize support layout, deploy a measurement control network and intelligent monitoring system, and manage equipment and material compliance; S2. Foundation treatment: After clearing the weeds and silt on the surface, fill the areas with insufficient bearing capacity in layers, pour the concrete cushion layer, and harden the base layer; S3. Scaffolding and preloading: Based on modular scaffolding, the overall stiffness is verified, the locking force of the plate joints is checked, the preloading process is simulated to reserve inelastic deformation, and graded automatic loading and data closed-loop analysis are used to quantify deformation parameters; S4. Formwork installation: Based on the preloading data, the bottom formwork elevation is accurately adjusted through the adjustable top support, and the pre-camber is set for the variable-section beam in sections. The BIM model is synchronized to update the actual elevation data; S5. Installation of steel bars and prestressed pipes: Use steel bar positioning cradles to fix the spacing between main bars. Follow the principle of giving way to prestressed bars for ordinary steel bars. Adjust the position of steel bars locally. Use well-shaped positioning steel bars to fix the corrugated pipes. S6. Concrete construction: Use concrete pouring, cover with geotextile and plastic film within 12 hours after pouring, embed temperature sensors to monitor the temperature difference between inside and outside, use intelligent tensioning equipment to tension the concrete after the strength reaches the standard, grouting is carried out within 48 hours after tensioning is completed, and finally anchoring is carried out; S7. Support removal: After the grouting strength reaches 50MPa, the support is removed, and graded unloading is adopted. The rebound of the beam is monitored in real time through wireless sensors.

2. The method for constructing cast-in-situ concrete beams based on deformation control according to claim 1, characterized in that: In step S1, the deployment of the measurement control network and intelligent monitoring system specifically includes using a total station to establish a second-class precision traverse network, setting permanent leveling points, using a level to verify the pier top elevation, installing wireless sensor nodes at key nodes of the support, and collecting settlement and displacement data in real time.

3. The method for constructing cast-in-situ concrete beams based on deformation control according to claim 1, characterized in that: In step S2, the foundation treatment specifically includes the following steps: S21. After clearing surface weeds and silt, use geological radar to detect the distribution of soft soil layers. Use rough slag to replace the insufficient bearing capacity areas in layers. The foundation treatment range is extended to 1.5m outside the beam body to avoid edge settlement. S22. Use intelligent compactors to monitor compaction in real time and heavy-duty dynamic penetration instruments to test foundation bearing capacity; S23. Pour the concrete base layer, use a laser leveling machine to control the flatness, set up a two-way slope on the surface, set up a 30cm×30cm brick drainage ditch around it, install a liquid level sensor, and link a submersible pump for automatic drainage to prevent rainwater from soaking the foundation.

4. The method for constructing cast-in-situ concrete beams based on deformation control according to claim 1, characterized in that: In step S3, the support erection includes modular support erection, verifying the overall stiffness through finite element software, checking the locking force of the disc-shaped nodes, setting vertical diagonal rods, connecting the support and the pier body with steel pipes, simulating the inelastic deformation of the prestressing process through BIM, reserving the deformation in advance, and simulating the actual stress state of the beam body.

5. The method for constructing cast-in-situ concrete beams based on deformation control according to claim 1, characterized in that: In step S3, the modularized support is erected by using a disc bracket in the non-water-crossing section and a steel pipe pile plus Bailey beam system in the cross-county drainage channel section, with the Bailey beam having a horizontal spacing of 30 cm.

6. The method for constructing cast-in-situ concrete beams based on deformation control according to claim 1, characterized in that: In step S3, the deformation parameters are quantified by using hierarchical automatic loading and data closed-loop analysis, including the following steps: S31. Preloading load and loading process optimization: Determine the total preloading weight, use a smart jack cluster with pressure sensors to perform automatic loading in stages, and simulate the actual force distribution of the beam; S32, graded loading process: graded loading according to 0, 60%, 100% and 110%, with each level of loading interval being 12 hours; S33, load distribution control: adjust the jack arrangement density and loading pressure according to different stress areas; S34, deformation data collection and pre-camber calculation: using intelligent detection and manual verification to quantify elastic and inelastic deformation and determine pre-camber; S35, Unloading and data archiving: Reverse hierarchical unloading, enter the data of the entire preloading process into the BIM model to form an associated database.

7. The method for constructing cast-in-situ concrete beams based on deformation control according to claim 6, characterized in that: In step S34, deformation data collection and pre-camber calculation specifically include the following steps: A1. Vibrating wire displacement sensors are installed at the top and bottom of the supports and on the piers. Horizontal displacement sensors are also installed on curved bridges. Second-class levels are used to manually read the key sections and cross-check the sensor data. A2. Calculate elastic deformation data and inelastic deformation data; A3. Determine the pre-camber by superimposing the theoretical calculated value, elastic deformation value and concrete shrinkage creep value.

8. The method for constructing cast-in-situ concrete beams based on deformation control according to claim 1, characterized in that: In step S7, the bracket removal includes the following steps: S71. Demolition confirmation: Detect the grouting strength of the prestressed ducts, inspect the appearance of the beam, and deploy strain sensors and displacement sensors at the mid-span, quarter-span, and support points of the beam to monitor the springback and stress changes of the beam in real time during the demolition process. S72. Symmetrical dismantling in stages: First, remove the temporary top structure, then the horizontal and diagonal bars, then the vertical bars, and finally, clean the foundation and components, tracking the beam rebound throughout the process. S73. Data acceptance: After the demolition is completed, check the beam line shape, rebound volume and site cleaning conditions, and organize and archive the monitoring data, demolition records and acceptance materials.

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