A prefabricated beam construction method and system applied to a viaduct

Abstract

The application relates to a prefabricated beam construction method and construction system applied to a viaduct, the prefabricated beam construction method at least comprising a prefabricated beam preparation step and a prefabricated beam installation step, when the prefabricated beam preparation step and / or the prefabricated beam installation step are executed, the preparation process and / or the installation process of the prefabricated beam can be monitored by introducing a safety guarantee step, in the safety guarantee step, bridge original data information collected in the preparation process and / or the installation process is analyzed and calculated to obtain bridge processing data information which can be compared with a preset threshold value, so that the comparison result can be fed back to the participants of the designated bridge construction project, so that the participants can make a decision to maintain the bridge construction scheme or adjust the bridge construction scheme based on the feedback information. The construction system comprises a service platform and a plurality of operation ends and a plurality of collection ends which are signal connected with the service platform.

Description

Technical Field

[0001] This invention relates to the field of engineering construction technology, and in particular to a method and system for constructing precast beams for viaducts. Background Technology

[0002] The development of large-segment bridge manufacturing and transportation technology in China has greatly promoted the development of bridge engineering technology. However, during the construction of large-segment bridges, the safety of the precast beam structure must be ensured during the overall manufacturing, transportation, unloading, and hoisting processes. For example, during transportation, components need to be placed in a balanced manner and a specially designed fixing frame is used to prevent tipping. Measures also need to be taken to prevent excessive negative bending moments in the components to avoid breakage. Before hoisting the components, the vertical centerline needs to be marked at both ends of each beam, and the longitudinal centerline of the beam, the longitudinal and transverse centerlines of the supports, the transverse lines at the beam end positions, and the specific position of each beam need to be marked on the pier abutment. The transportation distance from the beam production plant to the destination is long, so real-time monitoring is required during the manufacturing, transportation, unloading, and hoisting processes of the precast beams to keep track of the construction progress.

[0003] CN205158600U discloses a structural safety monitoring system for bridge construction, comprising: multiple wireless sensors respectively installed on and around a bridge box girder to collect monitoring data; a data processing gateway wirelessly connected to the multiple wireless sensors; and a monitoring host wirelessly connected to the data processing gateway to receive the monitoring data from the multiple wireless sensors through the data processing gateway. This invention enables remote real-time monitoring of the bridge box girder's condition, reduces the difficulty of installing monitoring equipment, and, with the adoption of a GPS module, allows for real-time knowledge of the bridge box girder's location during transport, thus ensuring the smooth execution of the construction plan.

[0004] Existing technologies only monitor individual stages of bridge construction projects independently, failing to achieve comprehensive monitoring and management of the entire construction process. This is especially problematic for projects with large construction areas and long durations (e.g., spanning multiple rainy and winter seasons). Such projects require not only coordinated planning of all stages but also precise and timely monitoring of safety at each stage to ensure safe and successful completion. For precast beam construction, both preparation and installation are crucial. Traditional sensor monitoring methods struggle to accurately determine the timing and cause of anomalies, necessitating manual verification and troubleshooting. This not only increases workload but also hinders timely detection of hazards. Failure to investigate the underlying causes of anomalies may lead to inappropriate or incorrect decisions; conversely, expending manpower for individual checks may result in excessively long response times, delaying optimal intervention and potentially causing harm.

[0005] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention provides a method and system for constructing precast beams for viaducts, so as to solve at least some or all of the above-mentioned technical problems.

[0007] This invention discloses a method for constructing precast beams, the method comprising at least the following steps: The precast beam preparation steps include at least the processing and installation of precast beam accessories, precast beam reinforcement engineering, concrete conveying and pouring, precast beam formwork engineering, and precast beam curing measures. The installation steps for precast beams are as follows: the beams are transported to the beam erection platform by ground transport vehicles, and then erected by bridge erection machines.

[0008] Preferably, during the precast beam preparation and / or installation steps, a safety assurance step can be introduced to monitor the precast beam preparation and / or installation processes. In this safety assurance step, the collected raw bridge data related to the preparation and / or installation processes is analyzed and processed to obtain bridge processing data that can be compared with preset thresholds. This comparison result is then fed back to designated personnel involved in the bridge construction project, enabling them to make decisions based on the feedback to maintain or adjust the bridge construction plan. The feedback information at least includes the location of the bridge processing data within a warning range specified by the thresholds. Adjustments to the bridge construction plan include adjusting design parameters, changing bridge construction methods, or implementing auxiliary bridge construction measures.

[0009] According to a preferred embodiment, a composite admixture containing a water-reducing agent can be incorporated into concrete, wherein the selected composite admixture at least meets the following requirements: water reduction rate ≥ 20%, fineness ≤ 10%, cement paste fluidity ≥ 240 mm, sodium sulfate content ≤ 5.0%, and Cl... - Content ≤0.10%, total alkali content ≤10.0%.

[0010] Preferably, the special composite admixture has properties such as high water reduction rate, low slump loss, appropriate air entrainment, ability to refine the pore structure of concrete, ability to significantly improve or enhance the durability of concrete, and good compatibility with cement.

[0011] According to a preferred embodiment, the precast beam can undergo four stages of steam curing before demolding: static curing, heating, constant temperature, and cooling. During static curing, the temperature inside the shed is kept not lower than 5°C. After pouring, the heating rate is not greater than 10°C / h. During constant temperature, the steam temperature does not exceed 45°C, the core concrete temperature of the beam does not exceed 60°C, and the cooling rate is not greater than 10°C / h.

[0012] Preferably, in the precast beam curing measures, to accelerate beam fabrication and shorten the construction period, steam curing with a curing hood is used before formwork removal, followed by natural curing by water spraying after formwork removal. The curing hood should be installed promptly during concrete pouring and finishing, ensuring that finishing and covering are essentially synchronized. Water spraying facilities are installed inside the curing hood to spray water on the concrete during the cooling process. Steam pipes are arranged on both sides and inside the outer formwork, and steam must not be blown directly onto the concrete and formwork.

[0013] According to a preferred embodiment, the collected raw bridge data information includes at least image information. Based on the model features of conventional units at the bridge construction site, conventional units are selected and marked in the image information so that the processed image information with marked unit models can be fed back to the designated participants in the bridge construction project. In the process of analyzing and processing the image information, the processed image information can include the markings of conventional unit models and / or the markings of unconventional unit models by additionally introducing the model features of unconventional units.

[0014] This invention discloses a construction system applicable to bridge construction projects. The system includes a service platform and several operating terminals and several data acquisition terminals connected to the service platform via signals. The operating terminals are used by personnel involved in the bridge construction project, and the data acquisition terminals are deployed at several monitoring points at the bridge construction site, which includes a preparation site and / or an installation site. While thresholds are set individually for each situation, in actual use, various unforeseen circumstances cause threshold breaches. A single threshold breach usually does not necessarily indicate danger, but it frequently leads to construction interruptions. Troubleshooting is difficult due to the complexity of the environment and construction conditions, and it cannot resolve issues with inaccurate threshold settings, potentially leading to further threshold breaches. Dynamically adjusting thresholds is complex and cumbersome, especially adjusting individual thresholds.

[0015] This solution, based on the collection and calculation of related information, can determine threshold exceedances based on the correlation of sudden problems, the location of the data collector, and the construction section. It dynamically processes and adjusts the values ​​of related thresholds, enabling relatively simple, convenient, and quick adjustment of various related and unrelated thresholds along the entire construction route. This achieves dynamic adjustment of the entire construction monitoring segment and project, improving construction efficiency while ensuring safety. The architecture is rationally categorized with clear permission divisions, granting supervisors with different permissions the authority to adjust and supervise corresponding construction projects.

[0016] Preferably, the operating terminal and / or the data acquisition terminal can upload original bridge data related to the bridge construction project to the service platform on a regular or irregular basis. This allows the service platform to process the original bridge data and then feed back the processed bridge data to the operating terminal with the appropriate operating permissions. The original bridge data uploaded by the operating terminal includes at least the bridge construction progress. The service platform can input the work breakdown structure of the bridge construction project and update it synchronously based on the uploaded data of the bridge construction progress. The operating terminal can obtain the corresponding operating permissions from the service platform based on the level code of its login account. The level code is associated with the department and / or position of the personnel using the operating terminal in the bridge construction project.

[0017] According to a preferred embodiment, the operator can adjust the connection between the operator and the service platform by switching between enabled and disabled states. The service platform can send verification information that needs to be completed within a preset time interval to one or more operator terminals that are in the enabled state. The deviation set by the service platform for recognizing the feedback answer is adjusted based on the type of verification information sent.

[0018] According to a preferred embodiment, the first receiving module of the service platform can receive the original bridge data information acquired by the acquisition terminal at each monitoring point and send it to the first processing module for analysis and processing. The bridge processing data information obtained after analysis and processing can be compared with a preset threshold in the comprehensive analysis module to obtain the location of the bridge processing data information exceeding the preset threshold within the warning range. The comparison result can be fed back to the designated operation terminal and / or stored in the storage module.

[0019] According to a preferred embodiment, when the comprehensive analysis module determines that the bridge processing data information is within the warning range, it can obtain preset event intelligence to determine the correlation between the data information within the warning range and the preset event. The preset event intelligence can be obtained by the second receiving module from the cloud and then simulated and predicted by the second processing module.

[0020] According to a preferred embodiment, at least based on the work breakdown structure of a bridge construction project, the storage module can pre-store some preset event information using the second receiving module and the second processing module, and when data information within the warning range appears in the comprehensive analysis module, it can first scan the storage module for matching preset event information.

[0021] According to a preferred embodiment, the original bridge data information acquired by the first receiving module includes at least image information. The first processing module that receives the image information selects and marks conventional units in the image information based on the model features of conventional units at the bridge construction site that have been pre-recorded. This enables the comprehensive analysis module to directly feed back the image information marked with conventional unit models to the designated operation terminal and / or introduce model features of unconventional units to generate image information marked with conventional unit models and / or unconventional unit models and feed it back to the designated operation terminal. Attached Figure Description

[0022] Figure 1 This is a flowchart of the precast beam preparation steps in a preferred embodiment of the precast beam construction method provided by the present invention. Figure 2 This is a flowchart of the on-site assembly process of a bridge erecting machine according to a preferred embodiment of the present invention; Figure 3 This is a flowchart of a preferred embodiment of the bridge erecting machine through a hole provided by the present invention; Figure 4 This is a flowchart of a bridge erection machine for a preferred embodiment of the present invention. Figure 5 This is a simplified schematic diagram of the module connection relationship of a construction system according to a preferred embodiment of the present invention.

[0023] List of reference numerals 1: Service platform; 2: Operation terminal; 3: Data acquisition terminal; 4: Cloud; 5: First receiving module; 6: First processing module; 7: Second receiving module; 8: Second processing module; 9: Comprehensive analysis module; 10: Storage module. Detailed Implementation

[0024] The following is a detailed explanation with reference to the accompanying drawings.

[0025] This invention discloses a precast beam construction method, which can be applied to the precast beam construction process of viaducts. It mainly includes the precast beam preparation step and the precast beam installation step.

[0026] Preferably, the precast beam fabrication step in a preferred embodiment can be as follows: Figure 1 As shown.

[0027] Preferably, the preparatory work before the preparation step requires at least the preparation of raw materials that meet the requirements of bridge construction, such as cement, special composite admixtures, and water for mixing and curing concrete. Preferably, the cement can be low-alkali Portland cement or low-alkali ordinary Portland cement with stable quality and a strength grade not lower than 42.5 (with fly ash or slag as admixtures). The specific surface area of ​​the cement should not exceed 350 m². 2 The alkali content should not exceed 0.60%, and the free calcium oxide content should not exceed 1.0%. The C3A content in cement clinker should not exceed 8%, and should not exceed 5% under highly corrosive environments. Preferably, the special composite admixture has properties such as high water reduction rate, low slump loss, appropriate air entrainment, refinement of concrete pore structure, significant improvement or enhancement of concrete durability, and good compatibility with cement. The admixture added to concrete must be tested and qualified before use. Preferably, the water used for mixing and curing concrete should not contain harmful impurities or oils, sugars, etc., that can affect the normal setting and hardening of cement. Wastewater, seawater, acidic water with a pH value less than 5, and water containing sulfate ions should not be used.

[0028] Furthermore, the composite admixtures added to concrete must at least meet the following quality indicators:

[0029] Furthermore, the performance requirements for concrete after adding admixtures are as follows:

[0030] Preferably, the preparation of precast beams may include at least the following: processing and installation of precast beam accessories, precast beam reinforcement engineering, concrete conveying and pouring, beam formwork engineering, and precast beam curing measures.

[0031] Preferably, in the processing and installation of precast beam components, it is necessary to complete the processing and installation of beam steel components, drainage holes, hoisting holes, inspection holes and grounding steel bars.

[0032] Preferably, the steel fittings include: support plates, embedded plates and embedded screws for anti-fall beam supports, embedded parts for expansion joints, embedded plates for general contact wire supports, embedded plates for lower anchor supports, embedded plates for lower anchor wires, fixing nuts for drain pipes, integrated grounding nuts, grounding nuts for beams, crash barriers, vertical walls for cable troughs, and sidewalk barriers, etc. The embedded steel bars and embedded parts are tied and installed together with the beam steel bars at the corresponding positions to ensure the connection between the embedded steel bars and the beam.

[0033] Preferably, the bridge deck drainage holes are PVC drainage pipes installed longitudinally at certain intervals along the bridge deck inside the crash barrier. The drainage holes are reinforced with grid-like or spiral reinforcement. For example, the spacing can be set to 4m, and the outer diameter of the PVC drainage pipes is set to 160nm. During beam pouring, the holes are formed using molds, and then the PVC vertical drainage pipes are installed. The molds must be fixed and cannot be shifted. The molds should be loosened and removed in time before the concrete initially sets.

[0034] Preferably, the lifting points for the precast beams are located on the top plate inside the web at each end of the beam. Each lifting point consists of four lifting holes. The hole diameter, position, and verticality of the lifting points meet the design requirements. Since the contact surface between the lifting device and the lower edge of the beam top is serrated, the serrated mold at the corresponding position of the lifting hole is fixed in the inner mold, ensuring the minimum protective layer thickness. After the beam is erected, the lifting holes are sealed with non-shrink concrete, and local waterproofing and protective layer construction are carried out.

[0035] Preferably, according to the operating space requirements during maintenance and construction, a groove is set in the bottom plate of the beam end as designed. To reduce stress concentration caused by the groove, an arc chamfer is set at the right angle of the groove. The inspection hole mold is integrated with the end template.

[0036] Preferably, two steel bars are pre-embedded on both sides of the bottom web of the beam, grounding steel bars are pre-embedded at the beam end, and wiring sleeves are pre-embedded on the bridge deck and the bottom of the beam as a comprehensive grounding measure for the precast beam. The two pre-embedded steel bars can be configured as φ20.

[0037] Preferably, in the precast beam reinforcement engineering, a gantry crane is used to lift the tied integral reinforcement cage to the beam fabrication platform. During lifting and transportation, rapid lifting and lowering, as well as rapid travel and braking, are strictly prohibited to avoid twisting and deformation of the reinforcement cage. At the same time, care must be taken to protect the prestressed ducts from damage during the lifting process. After the integral reinforcement cage is lifted into the outer formwork, it is adjusted to ensure that the reinforcement does not deviate from the design position. Then, the top slab reinforcement and the bottom web reinforcement are welded or tied to form an integral cage.

[0038] Preferably, in the conveying and pouring of concrete, multiple forced concrete mixers can be used for concrete mixing, which have a microcomputer-controlled automatic metering system and are equipped with ice-making and heating equipment for mixing water.

[0039] For example, when mixing concrete, first add river sand, cement, and concrete mineral active admixture in sequence and dry mix for 20 seconds. Then add crushed stone and 70%–80% water and mix for 30 seconds. Finally, add water-reducing agent solution and the remaining water. The total mixing time should not be less than 3 minutes. The measurement error of cement and water should be ≤1%, and the measurement error of river sand and crushed stone should be ≤2%.

[0040] Preferably, the air content of the precast beam concrete mixture should be controlled between 2% and 4% before being poured into the formwork. The slump of the concrete mixture should be 16-18 cm with a loss of no more than 10% within 45 minutes. When pouring the precast beam concrete, the formwork temperature should be controlled between 5 and 35°C, and the temperature of the precast beam concrete mixture upon placement into the formwork should be controlled between 5 and 30°C. The precast beam concrete should have good compactness.

[0041] Preferably, the concrete pouring is carried out from one end and proceeds step by step. The thickness of each layer of concrete should not exceed 30cm. Two placing booms pour from one end to the other. The bottom slab is poured from the middle to both ends.

[0042] Preferably, during grouting, a combination of side vibration and immersion high-frequency vibrator is used for compaction. The immersion high-frequency vibrator should be vibrated vertically and not pulled horizontally, and over-vibration and under-vibration should be prevented.

[0043] Preferably, considering the floating of the inner formwork of the precast beam and the compactness of the bottom slab concrete, it is not advisable to seal the bottom of the inner formwork. However, in order to prevent a large amount of concrete mixture from being squeezed out when pouring the web, and to provide resistance to the sinking of the web concrete to ensure the compactness of the web, a grouting plate is added at the corner of the inner formwork side.

[0044] Preferably, in beam formwork engineering, the formwork for precast beams mainly includes bottom mold, inner mold, outer mold, end mold, and various connectors and fasteners. The formwork should have sufficient strength, rigidity, and stability; it should be able to ensure the accurate shape, size, and position of embedded parts of the beam.

[0045] Preferably, pre-embedded devices should be installed simultaneously during the installation of the steel reinforcement cage, mainly including: support plates, pre-embedded steel plates for anti-fall beam brackets, pre-embedded nuts for fixing drainage pipes, pre-embedded iron seats for contact wire supports (lower anchor supports, lower anchor wires), pre-embedded expansion joints at beam ends, and various hole-forming devices (ventilation holes in the web, drainage holes in the bottom plate and top plate, hoisting holes in the top plate, and reserved holes for cable troughs at beam ends, etc.).

[0046] Preferably, the formwork can be removed when the concrete strength of the beam reaches the design requirements, specifically when the drawings require the concrete strength to reach more than 60% of the design strength, the temperature difference between the core and surface of the concrete, the inside and outside of the box girder, and the surface and the environment is no greater than 15℃, and the beam's edges and corners remain intact. Furthermore, the dismantling of the model is carried out in the reverse order of model installation: first, the end formwork is removed; second, the inner formwork; and finally, the side formwork is loosened.

[0047] Preferably, in the precast beam curing measures, to accelerate beam fabrication and shorten the construction period, steam curing with a curing hood is used before formwork removal, followed by natural curing by water spraying after formwork removal. The curing hood should be installed promptly during concrete pouring and finishing, ensuring that finishing and covering are essentially synchronized. Water spraying facilities are installed inside the curing hood to spray water on the concrete during the cooling process. Steam pipes are arranged on both sides of the outer formwork and inside the cavity; steam must not be blown directly onto the concrete and formwork.

[0048] Preferably, the steam curing of the beam concrete is divided into four stages: static curing, heating, constant temperature, and cooling. During the static curing period, the temperature inside the shed should be maintained at no less than 5℃. Heating begins 4 hours after pouring, with a heating rate not exceeding 10℃ / h. During constant temperature curing, the steam temperature should not exceed 45℃, and the temperature of the core concrete of the beam should not exceed 60℃. The cooling rate should not exceed 10℃ / h. During steam curing and when removing the insulation facilities, the temperature difference between the core and surface of the beam concrete, and between the surface and the environment, should not exceed 15℃. Records should be made every hour during steam curing. After steam curing, water curing should begin immediately.

[0049] Preferably, precast beams are only allowed to be loaded onto trucks and shipped after all finishing touches are completed and all inspections have been passed. After the precast beam assembly is completed and meets the technical requirements for shipment, the precast beams are transported to the lifting platform by a beam lifting machine. The beam stretching gantry crane lifts the precast beams onto the beam transport vehicle. After reinforcement and stabilization, the beam lifting gantry crane and the precast beams can be separated, and the beam transport vehicle can transport the precast beams to the arch location for erection.

[0050] Preferably, the installation steps may include at least the precast beam hoisting construction and the bridge erection machine beam erection construction.

[0051] Preferably, during the hoisting of precast beams, the site leveling and compaction work can be carried out in advance. In particular, the travel routes of crawler cranes and beam trucks must be leveled before the start of hoisting. After hoisting, in order to save materials, the leveling materials in the span after hoisting can be moved to the next hoisting site. The graded stone leveling thickness should be 50cm, and it should be compacted every 25cm, with a compaction degree of not less than 96%.

[0052] Preferably, before construction, the longitudinal centerline and cap beam end line of each beam are laid out according to the coordinates of the centerline, pier center, and beam support center, as control lines for support installation and beam hoisting. Before construction, the beam centerline should be marked at both ends of each beam as the basis for beam positioning control.

[0053] Preferably, before the beam is placed, a temporary jack is used to adjust it to the bottom elevation of the beam, and then the beam is placed on the temporary jack, ensuring that the difference in reaction force between each support does not exceed 5%.

[0054] Preferably, a trial lift can be performed before the formal lifting.

[0055] Preferably, during the bridge erection machine's beam erection construction, the operations of on-site assembly of the bridge erection machine, bridge erection machine crossing the span, and bridge erection machine beam erection can be performed.

[0056] Preferably, during the on-site assembly of the bridge erecting machine, it can be done according to the following... Figure 2 The following steps are required to complete the task: (1) Place the middle support lower crossbeam, the front support lower crossbeam, install the middle support legs, and then install the reverse support wheel box; (2) Use a crane to lift the front section of the main beam and place it on the anti-roller box and sleeper frame; (3) Install the front frame with a crane, connect it with pins, and finally insert cotter pins; (4) Install the second, third, fourth, and fifth main beam sections in sequence; (5) Install the upper crossbeam, the upper crossbeam, the hydraulic cylinder of the front outrigger, the front support counter bracket, the front support telescopic tube, and the lower crossbeam of the front support; (6) Install the rear outrigger hydraulic cylinder, rear outrigger counter bracket, rear outrigger telescopic tube, and rear outrigger lower crossbeam; (7) After assembling the trolley crossbeam and the traveling wheel box on the ground, use a crane to lift it onto the main beam, and then install the winch; (8) The front and rear outrigger cylinders are lifted simultaneously to remove the sleeper stack and install the motor, reducer and electrical components.

[0057] Preferably, during the bridge erecting machine's passage through the span, it can be performed according to the following... Figure 3 The following steps are required to complete the task: (1) Preparation for the bridge erecting machine to pass through the hole: After the bridge erecting machine is installed, prepare for the bridge erecting machine to pass through the hole; (2) The front and rear outrigger cylinders lift up simultaneously, the front trolley moves to the middle support position and lifts the middle support part, the front trolley lifts the middle support and moves it forward longitudinally to the front support position; (3) The front outrigger cylinder lifts the front crossbeam to detach it from the cover beam and prepare it to pass through the hole; (4) The main beam of the bridge erecting machine is driven by the front anti-support wheel group and the wheel group under the rear hydraulic support leg crossbeam together, and moves forward 20 meters by itself; (5) Use the lifting equipment on the crane trolley to lift the counterweight beam, so that the wire rope has a certain pre-tension, and move the main beam forward to complete the bridge crane passing through the hole.

[0058] Preferably, during the bridge erection process by the bridge erecting machine, the following can be followed: Figure 4 The following steps are required to complete the task: (1) The front trolley lifts the precast beam to separate the beam from the beam transport vehicle; (2) The front trolley lifting beam and the rear beam transport vehicle move forward at the same time. When the rear beam transport vehicle reaches the position of the front beam transport vehicle, the front trolley and the rear beam transport vehicle stop at the same time. (3) The rear trolley starts the winch to lift the rear end of the precast beam. The front and rear trolleys move forward at the same time and stop moving forward at the same time when they reach the installation position of the precast beam. (4) The two trolleys of the hoist are lowered simultaneously; stop lowering when the bottom surface of the prefabricated girder is 100mm away from the support, activate the transverse power unit of the two trolleys, move the prefabricated girder in place transversely, then lower the girder into place.

[0059] According to a preferred embodiment, when implementing the prefabricated girder construction method, a safety guarantee step can be introduced. Said safety guarantee step can be performed synchronously with the preparation step of the prefabricated girder and / or the installation step of the prefabricated girder, so that the construction process of the prefabricated girder during preparation and / or installation can be monitored, thereby allowing timely prediction, detection, judgment and / or resolution of abnormal conditions when such abnormal conditions occur during construction, so as to ensure the safety of the construction process.

[0060] Preferably, the safety guarantee step can be executed in the form of a safety guarantee program by a construction system proposed in the present invention, which can be applied to the prefabricated girder construction process of viaducts, and can also be applied to other engineering construction processes.

[0061] Preferably, as Figure 5 it is a construction system in a preferred embodiment. Preferably, the construction system may comprise a service platform 1 and at least one operation terminal 2, wherein the service platform 1 can be in communication connection with all activated operation terminals 2 to realize data interaction.

[0062] Preferably, the service platform 1 can analyze and process the original bridge data information obtained from the bridge construction site, so as to obtain processed bridge data information that can be compared with corresponding thresholds. The service platform 1 can directly send the processed bridge data information and / or comparison results to one or more operation terminals 2, so that users can obtain the real-time situation of the bridge construction site through the corresponding operation terminals 2.

[0063] Preferably, a user can activate and deactivate the corresponding operation terminal 2 by means of login and logout, wherein the operation terminal 2 can obtain corresponding operation authority from the service platform 1 based on the level code of its login account. For example, for personnel participating in the safety guarantee step, the operation terminal used by monitoring group personnel responsible for daily monitoring can obtain first-level operation authority; the operation terminal used by the monitoring supervisor responsible for formulating monitoring plans and reviewing analysis data can obtain second-level operation authority; the operation terminal used by the technical负责人 responsible for reviewing monitoring plans and formulating bridge construction countermeasures can obtain third-level operation authority; the operation terminal used by the project manager responsible for making decisions on monitoring plans and bridge construction measures can obtain fourth-level operation authority, wherein the greater the user's authority in the bridge construction monitoring process, the higher the operation authority level that the user's operation terminal can obtain from the service platform 1, and the operations executable by an operation terminal with a higher operation authority level at least include all operations executable by an operation terminal with a lower operation authority level.

[0064] Preferably, in addition to executing safety procedures, the bridge construction system can also perform daily project progress management procedures. Specifically, the service platform 1 can grant corresponding operating permissions to personnel involved in the precast beam preparation and installation steps on their respective operating terminals 2. This allows these personnel to upload and / or view progress based on their duties and the projects they are responsible for. The user terminal can upload original bridge data related to the progress of the bridge construction project, enabling the service platform 1 to extract bridge processing data. In other words, during the precast beam preparation and installation steps, the service platform 1 can synchronize progress to achieve information sharing, but this information sharing is limited to user terminals with the corresponding operating permissions.

[0065] Preferably, the service platform 1 can input the work breakdown structure of the bridge construction project and update it synchronously based on the uploaded completion data of the bridge construction progress. The work breakdown structure is a grouping of project elements based on deliverables. It summarizes and defines the entire scope of the project. Each lower level represents a more detailed definition of the project work. The work decomposed in the work breakdown structure is identified by code to obtain the work breakdown structure code.

[0066] Preferably, the service platform 1 can set several levels of operation permission based on the personnel structure of the monitoring system during bridge construction. The service platform 1 can be restricted to normal operation only if all enabled operation terminals 2 contain at least one or more specified levels of operation permission, or even all levels. When no corresponding operation terminal 2 is enabled for any specified level of operation permission, the service platform 1 can use one or more methods such as reminders, warnings, or delegation to prompt the corresponding operation terminal 2 to be enabled, thereby ensuring the normal operation of the intelligent recognition system. Furthermore, the service platform 1 can periodically or irregularly send verification information to one or more enabled operation terminals 2, requiring users operating the corresponding operation terminal 2 to provide feedback on the verification information within a preset time interval, ensuring the authenticity and real-time nature of the enabled operation terminals 2. The verification information can include text, images, sound, video, biometric information, and / or randomly generated dynamic verification codes. Preferably, the service platform 1 can store feedback answers corresponding to different login accounts for the same verification information. The service platform 1 can only complete the verification if the feedback answer matches the login account. The matching of the feedback answer and the login account can be set with a corresponding deviation amount based on the type of verification information to adapt to different verification methods. For example, the preset verification question and its answer need to match perfectly to complete the verification. The preset fingerprint recognition, facial recognition or voiceprint recognition can complete the verification after reaching a preset similarity.

[0067] According to a preferred embodiment, the intelligent identification system deploys several acquisition terminals 3 at the bridge construction site to collect raw bridge data. Each acquisition terminal 3 is communicatively connected to a service platform 1, enabling the service platform 1 to receive and process the raw bridge data continuously or intermittently. Preferably, the acquisition terminals 3 can be set at corresponding monitoring points within the preparation and / or installation sites. Furthermore, especially at installation sites, where underground pipelines are typically complex and cross highways and railways, the acquisition terminals 3 monitor and measure the deformation of the surface and buildings (structures), as well as the stress and strain of the support structure, that may occur due to construction at major risk sources during bridge construction. This enables information-based bridge construction, timely feedback on design parameters, and timely adjustments to design parameters, thereby ensuring the safety and reliability of bridge construction.

[0068] Preferably, the acquisition terminal 3 can establish horizontal and vertical displacement monitoring and control networks. The horizontal displacement monitoring network uses ground plane control points as main control points, forming a planar monitoring network with other monitoring points, arranged in an axial shape according to the structure. The vertical displacement monitoring network uses the local local elevation control network as primary control points, forming a surface elevation and displacement monitoring network with observation points such as surface settlement. Preferably, the main control points are firmly and stably buried, and the monitoring points can be buried in the undisturbed soil layer with protective devices.

[0069] Preferably, the acquisition terminal 3 can set up corresponding monitoring points for one or more measurement items related to bridge construction. Among them, the measurement items related to bridge construction include, but are not limited to: geological and support condition monitoring, building settlement and tilt monitoring, underground pipeline displacement monitoring, bridge settlement monitoring, and bridge tilt monitoring.

[0070] For example, the acquisition terminal 3 can perform geological and support condition monitoring after each excavation to determine the crack status of the support structure; the acquisition terminal 3 can combine surface settlement points to set up monitoring points for building settlement and tilt monitoring; the acquisition terminal 3 can set up monitoring points for underground pipeline displacement monitoring along the pipeline extension direction at 10m intervals, with pipelines of first-level environmental risk and pressurized pipelines, rainwater and sewage within a 15m range on both sides. When the surface monitoring points are close to the important pipeline monitoring points, the two monitoring points can be considered together, with the pipeline monitoring points as the main focus; the acquisition terminal 3 can set up bridge pier and abutment settlement monitoring points on each bridge pier and abutment, with two monitoring points set up on each pier and abutment, and an appropriate increase in monitoring points for pile abutments; the acquisition terminal 3 can set up tilt monitoring points on each pier within the influence range of one depth of construction excavation.

[0071] According to a preferred embodiment, the service platform 1 can be configured with a first receiving module 5 for receiving raw bridge data information from the acquisition terminal 3 and a first processing module 6 connected to the first receiving module 5, so that the raw bridge data information acquired by the first receiving module 5 can be sent to the first processing module 6 for analysis and processing.

[0072] Preferably, the service platform 1 can acquire the original bridge data information of the acquisition terminal 3 of all monitoring points deployed at the bridge construction site by configuring one or more first receiving modules 5 and one or more corresponding first processing modules 6. The number of first receiving modules 5 and first processing modules 6 configured is determined based on the number of monitoring points deployed at the acquisition terminal 3 and the computational analysis load.

[0073] Preferably, the first processing module 6 that receives the original bridge data information can process it in a timely manner, eliminate errors in the operation process such as instrumentation and reading, remove and identify various gross, accidental and systematic errors, avoid missed measurements and incorrect measurements, ensure the reliability and integrity of monitoring data, and complete data sorting and preliminary qualitative analysis.

[0074] Preferably, the first processing module 6 can organize the original bridge data information, such as sorting by size and displaying a set of data distributions in the form of frequency distribution, calculating the numerical characteristic values ​​of the data, and discarding outliers.

[0075] Preferably, the first processing module 6 can obtain data that conforms to the measurement law but has not been measured, based on the measured data and using a function approximation method.

[0076] Preferably, the first processing module 6 can perform regression analysis on the monitoring results using statistical analysis methods. The first processing module 6 can set multiple thresholds to achieve multi-level management. For example, the first processing module 6 can use 70% of the control value as the warning value, 80% as the alarm value, and 90% as the stop value, defining the range between the alarm value and the stop value as the warning range. Preferably, data exceeding the stop value can also be included in the warning range, but adjustments and responses are usually required when the data is between the alarm value and the stop value; that is, values ​​exceeding the stop value are generally unlikely to occur.

[0077] Preferably, the first processing module 6 can send data information within the warning range to the comprehensive analysis module 9, so that the comprehensive analysis module 9 can analyze the correlation between the data information within the warning range and the preset event information. This correlation can be the relationship between the simulated and predicted consequences of the preset event and the data information within the warning range. If the consequence of obtaining data information within the warning range is obtained when the preset event occurs, it means that there is a correlation between the two; conversely, if the consequence of not obtaining data information within the warning range is obtained when the preset event occurs, it means that there is no correlation between the two. Furthermore, if there is no correlation, it indicates that the data information within the warning range may be caused by other factors, and the causes of these other factors and corresponding countermeasures can be determined. These other factors could be, for example, unconventional factors in the bridge construction process.

[0078] According to a preferred embodiment, the simulated predicted consequences of a preset event can be obtained by the second receiving module 7 and the second processing module 8. The second receiving module 7 can obtain basic information on various preset events related to the construction process from the cloud-based database 4, especially basic information on preset events related to the bridge construction process, and send it to the second processing module 8. The second processing module 8 can perform simulation prediction based on the basic information on the preset event, adapting it to the current bridge construction plan, to obtain the predicted consequences. Preferably, when obtaining a preset event, the second receiving module 7 can download the model information and corresponding consequences related to the preset event from the cloud-based database 4. The model information and corresponding consequences related to the preset event can be uploaded to the cloud-based database 4 by other intelligent recognition systems through their service platforms 1. Preferably, the cloud-based database 4 can establish communication relationships with the service platforms 1 of several intelligent recognition systems, so that any service platform 1 can upload to the cloud-based database 4 after completing the prediction simulation and result comparison of the preset event, thereby realizing the information update of the cloud-based database 4. Based on the information update of the cloud-based database 4, the simulation model and prediction results of the second processing module 8 can be calibrated.

[0079] Preferably, the preset event information obtained by the second processing module 8 can be directly sent to the comprehensive analysis module 9 for correlation comparison with the bridge processing data information sent by the first processing module 6 within the comprehensive analysis module 9, and / or can be first sent to the storage module 10 for temporary, short-term or long-term storage, and after the comprehensive analysis module 9 receives the bridge processing data information sent by the first processing module 6, it can extract the corresponding preset event information from the storage module 10 to complete the correlation comparison. The storage period of the storage module 10 can be updated periodically or irregularly based on the administrator's permission settings. The preset event information sent to the storage module 10 can include time information, bridge construction history records and / or work breakdown structure codes, etc.

[0080] Preferably, the second receiving module 7 can spontaneously obtain the updated preset event information of the specified preset event from the cloud database 4 based on the management authority settings. That is, after the service platform 1 of other intelligent recognition systems completes the upload work, if the preset event information uploaded by it at least includes the preset event specified by this service platform 1, the second receiving module 7 can download it and extract the time information, bridge construction history and / or work breakdown structure code and other information through the second processing module 8 as preset event information that can be stored in the storage module 10.

[0081] Preferably, the comparison results between the bridge processing data information and one or more thresholds in the first processing module 6 can also be sent to the storage module 10 for storage. This can address situations where the comprehensive processing module experiences excessive computational load in a short period. By transferring the data to the storage module 10, the first processing module 6 can continue to analyze and process the original bridge data information without being inactively occupied for an extended period. This also allows all the bridge processing data information to be compared in an orderly manner by the comprehensive analysis module 9, reducing the configuration requirements of the comprehensive analysis module 9. Furthermore, the first processing module 6 can obtain the priority ranking of each monitoring point in the acquisition terminal 3 based on administrator permissions. This allows the first processing module 6 to prioritize the processing of bridge data information with a relatively higher priority order when simultaneously receiving multiple original bridge data information from the first receiving module 5. Similarly, when generating multiple bridge processing data information simultaneously, it can prioritize sending the bridge processing data information with a relatively higher priority order directly to the comprehensive analysis module 9, while sending the bridge processing data information with a relatively lower priority order to the storage module 10 for temporary storage. Preferably, the priority ranking of monitoring points can be categorized and assigned based on different monitoring types. Preferably, administrator privileges can be obtained by the operator terminal 2 with the highest level of operating privileges or by the operator terminal 2 designated by it.

[0082] Preferably, the comprehensive analysis module 9 can pre-load several hazard response plans, so that when determining the correlation between data information within the warning range and the corresponding preset event intelligence based on time information, the comprehensive analysis module 9 can provide corresponding response plans for warnings caused by conventional factors and warnings caused by unconventional factors. Warnings caused by data information correlated with preset event intelligence can be set as warnings caused by conventional factors; warnings caused by data information not correlated with preset event intelligence can be set as warnings caused by unconventional factors. Preferably, the analysis results and corresponding hazard response plans of the comprehensive analysis module 9 can be sent to the operation terminal 2 and stored in the storage module 10. The information stored in the storage module 10 can be retrieved by the operation terminal 2 with operating permissions.

[0083] According to a preferred embodiment, in order to confirm warnings caused by unconventional factors, the acquisition terminal 3 can set fixed or movable image monitoring points for key areas to obtain image information of monitoring points where abnormal data occurs. If the number of key areas is small and the location is fixed, fixed image monitoring points can be set; conversely, if the number of key areas is large and they are prone to change, movable image monitoring points can be set, such as mobile devices with shooting and communication functions, such as drones.

[0084] Preferably, the image monitoring point can also belong to the acquisition end 3, that is, the image information acquired by the image monitoring point can be transmitted to the first receiving module 5, so that the acquired image information can be processed by the first processing module 6. The processed image information can be sent to the comprehensive analysis module 9 and / or the storage module 10. Preferably, the image monitoring point can start working only when the comprehensive analysis module 9 determines that a warning caused by an abnormal factor has occurred and / or when it is driven independently, so as to avoid occupying the computing load. Preferably, when the image monitoring point acquires image information, the abnormal monitoring point can simultaneously complete the acquisition of the original bridge data information, and can bind the acquired original bridge data information with the image information for secondary verification. The acquired original bridge data information can be assigned the highest priority sequence so that the first processing module 6 and the comprehensive analysis module 9 can prioritize its analysis and processing.

[0085] Preferably, the first processing module 6 can identify the model features that have been entered in the image information. The model features entered in the first processing module 6 can be features of one or more units selected from the conventional units at the bridge construction site based on the settings of the administrator program. Conventional units may include, for example, bridge construction machinery, bridge construction personnel, bridge construction supplies, bridge construction buildings, etc.

[0086] Preferably, the first processing module 6 can process the received image information using functions. The grayscale or color gradient is defined as:

[0087] in, Let be the gradient vector, which is any point in the image The direction with the maximum rate of change is at that point.

[0088] Preferably, the gradient magnitude is 0 in regions where image pixels remain unchanged, and the gradient value is larger in regions with greater changes. The gradient magnitude can be expressed as:

[0089] in, The following formula can be used to calculate:

[0090] Preferably, the first processing module 6 can calculate the data edge efficiency of the image information using the following formula:

[0091] in, Represents the image grayscale function. Image function ,and and These represent the maximum and minimum grayscale values, respectively.

[0092] Preferably, when the edge effectiveness rate is greater than the threshold, the first processing module 6 can determine that the coordinate point is the edge of the unit model, wherein the threshold is usually between 30% and 70%.

[0093] Preferably, the first processing module 6 can accurately determine the specific type of the recorded unit based on the edge shape of the unit model using artificial intelligence methods such as machine learning. Further, the first processing module 6 can mark the identified unit model and send the marked image information to the comprehensive analysis module 9 and / or the storage module 10. Preferably, the comprehensive analysis module 9 can send the image information of the marked unit model directly or after secondary processing to the operation terminal 2, allowing the user to discover the cause of unconventional factors after excluding conventional units. The comprehensive analysis module 9 can obtain other unit models not recorded in the first processing module 6 from the cloud database 4 from the second receiving module 7 and the second processing module 8 for secondary processing of the image information.

[0094] Preferably, as shown in the figure, this is a bridge hazard intelligent identification method according to a preferred embodiment of the present invention. Preferably, in the judgment feedback stage, hazard factors and bridge construction safety can be judged by manual judgment and / or system judgment. Among them, manual judgment can be based on experience analogy, theoretical analysis, standard requirements, etc., while system judgment can use the comprehensive analysis module 9 of the service platform 1 to make a comprehensive judgment on the correlation with preset event intelligence.

[0095] It should be noted that the specific embodiments described above are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this invention, and these solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and do not constitute a limitation on the claims. The scope of protection of this invention is defined by the claims and their equivalents. This specification contains multiple inventive concepts; terms such as "preferredly," "according to a preferred embodiment," or "optionally" indicate that the corresponding paragraph discloses an independent concept. The applicant reserves the right to file divisional applications based on each inventive concept. Throughout the text, features introduced by "preferredly" are merely optional and should not be construed as mandatory. Therefore, the applicant reserves the right to abandon or delete relevant preferred features at any time.

Claims

1. A method for constructing precast beams, the method comprising at least the following steps: The precast beam preparation steps include at least the processing and installation of precast beam accessories, precast beam reinforcement engineering, concrete conveying and pouring, precast beam formwork engineering, and precast beam curing measures. The installation steps for precast beams are as follows: beams are transported to the girder erection platform by ground transport vehicles, and then erected by a bridge erecting machine. Its features are, When performing the precast beam preparation and installation steps, the preparation and installation processes of the precast beam can be monitored by introducing a safety assurance step. In the safety assurance step, the collected original bridge data related to the preparation and installation processes are analyzed and processed to obtain bridge processing data that can be compared with a preset threshold. The comparison results can be fed back to the designated bridge construction project participants, so that the participants can make a decision to maintain or adjust the bridge construction plan based on the feedback information. The feedback information also includes at least the position of the bridge processing data within the warning range of the specified threshold range. The adjustment of the bridge construction plan includes adjusting design parameters, changing the bridge construction method, or auxiliary bridge construction measures. When it is determined that the bridge processing data information is within the warning range, preset event information is obtained to determine the correlation between the bridge processing data information within the warning range and the preset event; if there is no correlation between the two, it is determined that the warning is caused by an abnormal factor. At this time, the image monitoring point is driven to obtain the image information of the monitoring point where the abnormal data appears, and the original bridge data information collected this time is bound with the image information for secondary verification. The image monitoring points only start working when a warning caused by an abnormal factor is detected. When the image monitoring points collect image information, the monitoring points that have abnormal data simultaneously complete the collection of the original bridge data information, so as to bind the original bridge data information collected in this synchronous collection with the image information, and the original bridge data information collected in this synchronous collection is assigned the highest priority sequence for priority analysis and processing.

2. The construction method according to claim 1, characterized in that, Composite admixtures containing water-reducing agents can be added to concrete. The selected composite admixtures must meet at least the following requirements: water reduction rate ≥ 20%, fineness ≤ 10%, cement paste fluidity ≥ 240 mm, sodium sulfate content ≤ 5.0%, and Cl... - Content ≤0.10%, total alkali content ≤10.0%.

3. The construction method according to claim 1 or 2, characterized in that, Before demolding, the precast beams can undergo four stages of steam curing: static curing, heating, constant temperature, and cooling. During static curing, the temperature inside the shed is kept no lower than 5℃. After pouring, the heating rate is no more than 10℃ / h. During constant temperature, the steam temperature does not exceed 45℃, the core concrete temperature does not exceed 60℃, and the cooling rate is no more than 10℃ / h.

4. The construction method according to claim 1, characterized in that, The collected raw bridge data includes at least image information. Based on the model features of conventional units at the construction site, conventional units are selected and marked in the image information so that the processed image information with marked unit models can be fed back to the designated construction project participants. When analyzing and processing the image information, the model features of unconventional units can be introduced to make the processed image information include the markings of conventional unit models and / or unconventional unit models.

5. A construction system capable of being used in the construction process of a construction project according to any one of claims 1 to 4, comprising: The service platform (1) and several operation terminals (2) and several acquisition terminals (3) connected to the service platform (1) by signal. The operating terminal (2) is used by the personnel involved in the construction project, and the data acquisition terminal (3) is deployed at several monitoring points in the construction site, which includes the preparation site and the installation site. Its features are, The operation terminal (2) and / or the acquisition terminal (3) can upload original bridge data information related to the construction project to the service platform (1) on a regular or irregular basis, so that the comprehensive analysis module (9) of the service platform (1) can process the original bridge data information and feed back the processed bridge data information to the operation terminal (2) with operation authority. The original bridge data information uploaded by the operation terminal (2) includes at least the construction progress. The service platform (1) can enter the work breakdown structure of the construction project and update the data synchronously based on the uploaded construction progress. The operation terminal (2) can obtain corresponding operation permissions from the service platform (1) based on the level code of its login account. The level code is associated with the department and / or position of the participant using the operation terminal (2) in the construction project. When the comprehensive analysis module (9) determines that the bridge processing data information is within the warning range, it can obtain the preset event information to determine the correlation between the bridge processing data information within the warning range and the preset event; if there is no correlation between the two, it is determined to be a warning caused by an unconventional factor. At this time, the driving image monitoring point obtains the image information of the monitoring point where abnormal data occurs, and binds the original bridge data information collected this time with the image information for secondary verification.

6. The construction system according to claim 5, characterized in that, The operation terminal (2) can adjust the connection relationship between the operation terminal (2) and the service platform (1) by switching the enabled or disabled state. The service platform (1) can send verification information that needs to be completed within a preset time interval to one or more operation terminals (2) in the enabled state. The service platform (1) adjusts the deviation of the recognition feedback answer setting based on the delivery type of the verification information.

7. The construction system according to claim 5 or 6, characterized in that, The first receiving module (5) of the service platform (1) can receive the original bridge data information obtained by the acquisition terminal (3) at each monitoring point and send it to the first processing module (6) for analysis and processing. The bridge processing data information obtained after analysis and processing can be compared with a preset threshold in the comprehensive analysis module (9) to obtain the location of the bridge processing data information exceeding the preset threshold within the warning range. The comparison result can be fed back to the designated operation terminal (2) and / or stored in the storage module (10).

8. The construction system according to claim 7, characterized in that, The preset event intelligence can be obtained by the second receiving module (7) from the cloud (4) after obtaining basic information and then by the second processing module (8) through simulation and prediction.

9. The construction system according to claim 8, characterized in that, Based at least on the work breakdown structure of the construction project, the storage module (10) can use the second receiving module (7) and the second processing module (8) to pre-store some preset event information, and when data information within the warning range appears in the comprehensive analysis module (9), it can first scan the storage module (10) for matching preset event information.

10. The construction system according to claim 7, characterized in that, The original bridge data information acquired by the first receiving module (5) includes at least image information. The first processing module (6) that receives the image information selects and marks conventional units in the image information based on the model features of conventional units in the pre-entered construction site, so that the comprehensive analysis module (9) can directly feed back the image information marked with conventional unit models to the designated operation terminal (2) and / or introduce the model features of unconventional units to generate image information marked with conventional unit models and / or unconventional unit models and feed it back to the designated operation terminal (2).

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