A construction monitoring method for a cast-in-situ continuous beam over water

Abstract

The application relates to a water-surface cast-in-situ continuous beam construction monitoring method, which belongs to the technical field of water-surface continuous beam construction and comprises the following steps: S1: determining a monitoring section and monitoring points; the monitoring section is not less than three in the bridge longitudinal direction, and at least three monitoring points are determined on the monitoring section; S2: installing sensors at the monitoring points; the sensors transmit instantaneous data to terminal equipment in real time; S3: the instantaneous data transmitted by the sensors are transmitted to the terminal equipment for data analysis, and the settlement of a water-surface platform and the settlement of a support are cumulatively analyzed; a safety level, a pre-warning level and a danger level are set in the terminal equipment; if the data analysis result is the safety level, normal construction, inspection and maintenance are carried out; if the data analysis result is the pre-warning level, the monitoring frequency is encrypted, corresponding measures are taken to remove the pre-warning until the data analysis result is reduced to the safety level; if the data analysis result is the danger level, an emergency plan needs to be started, a road needs to be closed, vehicle flow and crowds need to be evacuated until the data analysis result is reduced to the safety level; and S4: forming an analysis report according to the monitoring result.

Description

Technical Field

[0001] This invention relates to the field of construction technology for continuous beams on water, and specifically to a method for monitoring the construction of cast-in-place continuous beams on water. Background Technology

[0002] With the continuous development of transportation infrastructure construction, the number of bridges spanning rivers, including highways, railways, and municipal works, is constantly increasing. Among these, cast-in-place continuous beams with underwater platform supports account for a large proportion. During construction, high-formwork supports with a height exceeding 5 meters are considered high-risk, and those exceeding 8 meters are considered high-risk beyond a certain scale. Due to the diversity, complexity, and high risk inherent in high-formwork systems, collapse accidents occur frequently, consistently accounting for a high proportion of construction accidents and seriously threatening the construction safety of large buildings, drawing widespread attention from all sectors of society. The application of high-formwork support systems in bridge engineering is becoming increasingly common, but due to various reasons, their safety risks remain high. High-formwork collapse accidents are sudden, with only a few minutes between the appearance of danger signs and the actual accident. Coupled with their inherent characteristics of high space and large spans, high-formwork accidents often result in serious casualties and huge economic losses. Currently, monitoring of continuous beam high-formwork construction relies mainly on manual measurement. Some projects have also applied sensors for real-time monitoring, analysis, and early warning of formwork settlement, overall displacement, support system tilt, and bearing load. However, manual measurement suffers from low efficiency, large errors, and poor timeliness. Existing online monitoring methods for high-formwork do not consider the stability and settlement of the platform on the water, resulting in incomplete, unsystematic data that cannot reflect the absolute settlement data of the formwork support. Consequently, they cannot provide timely early warning of high-formwork instability caused by the settlement of the platform on the water, nor can they set the pre-camber according to the absolute settlement of the formwork. Summary of the Invention

[0003] To address the problems of the prior art, this invention provides a method for monitoring the construction of cast-in-place continuous beams on water. This method monitors and analyzes the settlement of the formwork support on the water platform during the construction process, resulting in more accurate data, more timely warnings, safer operations, and better bridge linearity.

[0004] The objective of this invention can be achieved through the following technical solution: a method for monitoring the construction of cast-in-place continuous beams on water, comprising the following steps:

[0005] S1: Determination of monitoring sections and monitoring points: Based on the structure and stress characteristics of the support and continuous beam, the monitoring sections are determined. There are no less than 3 monitoring sections along the bridge direction, and at least 3 monitoring points are determined on each monitoring section based on the stress characteristics.

[0006] S2: Install sensors at the monitoring points, which are used to monitor parameters such as support settlement, pole tilt, pole axial force, and platform settlement in water. The instantaneous data measured by the sensors are transmitted to the terminal equipment in real time.

[0007] S3: The instantaneous data transmitted by the sensor is sent to the terminal device for data analysis, and the submerged platform settlement and support settlement are accumulated and analyzed. The terminal device is equipped with safety level, early warning level and danger level:

[0008] If the data analysis result indicates a safe level, proceed with normal construction, inspection, and maintenance.

[0009] If the data analysis results are at the warning level, the monitoring frequency should be increased, personnel should be dispatched for inspection, and corresponding measures should be taken to lift the warning until the data analysis results are reduced to the safe level.

[0010] If the data analysis results are at a dangerous level, an emergency plan must be activated, roads closed, and traffic and people evacuated until the data analysis results are downgraded to a safe level.

[0011] S4: After the continuous beam construction is completed, the monitoring results are compiled into an analysis report.

[0012] Preferably, in step S1, the determination of monitoring sections and monitoring points is as follows: the monitoring sections are determined according to the structure and stress characteristics of the support and the continuous beam, and three monitoring sections are set at 1 / 4, 1 / 2, and 3 / 4 of the longitudinal span of each beam along the bridge direction; on each monitoring section, three monitoring points are set at the center of the bottom formwork of the box girder corresponding to the top of the support, the edge of the web plate, and the edge of the flange plate, respectively, for settlement, tilt, and axial force; and a water platform settlement monitoring point is set at the water platform corresponding to the monitoring section.

[0013] Preferably, in step S2, the specific installation positions of the sensors are as follows: the vertical displacement sensor for monitoring the settlement of the support is installed below the adjustable support on the top layer of the support; the tilt sensor for monitoring the tilt of the upright is installed below the adjustable nut of the adjustable support on the top layer of the support; the axial force sensor for monitoring the axial force of the upright is installed on the top layer of the support; and the hydrostatic level for monitoring the settlement of the platform in the water is installed on the steel plate of the platform in the water.

[0014] Preferably, in step S2, the terminal device includes a wireless data acquisition unit and a comprehensive analyzer. The corresponding wireless data acquisition unit is fixed at the corresponding sensor, and the wireless data acquisition unit wirelessly transmits the acquired data to the comprehensive analyzer.

[0015] Preferably, in step S2, after the sensors, wireless data acquisition unit, and integrated analyzer are installed, each device needs to be debugged first. Turn on all sensors, start the wireless data acquisition unit, and turn on the integrated analyzer to check whether each device is operating normally. If it is not operating normally, debug it until it is operating normally. If it is operating normally, initialize the sensors and initialize the total settlement value of the platform settlement and support settlement in the water separately. After initialization, it can enter the monitoring state, and the instantaneous data measured by the sensors is transmitted to the terminal device in real time.

[0016] Preferably, in step S3, the time period for transmitting the instantaneous data from the sensor to the integrated analyzer is divided into: preloading, unloading, and concrete pouring.

[0017] The advantages of this invention include: The monitoring method in this application, based on Internet of Things (IoT) technology, generates signals for vertical displacement of the support structure, tilt of the uprights, axial force of the uprights, and settlement of the platform in the water by monitoring parameters such as support settlement, upright tilt, axial force of the uprights, and platform settlement. These signals are transmitted in real time to an wireless data acquisition instrument, converted into data, and analyzed by a comprehensive analyzer to achieve functions such as report output and over-limit alarms, thus reducing the risk of support collapse. This monitoring method collects data on the settlement of the platform in the water, performs separate analysis and over-limit alarms on the platform settlement, and performs cumulative analysis and alarms on the platform settlement and support settlement, thus avoiding support collapse caused by instability and settlement of the platform in the water and eliminating the loss of support pre-camber caused by platform settlement in the water. The monitoring method in this application is systematic and comprehensive, realizing report analysis and over-limit alarms for both the platform and support system in the water, and providing a basis for the design optimization of the platform and support system in the water. Attached Figure Description

[0018] Figure 1 This is a flowchart of the monitoring system in Embodiment 1 of the present invention.

[0019] In the accompanying drawings, the same parts are labeled with the same reference numerals; the drawings are not drawn to scale. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Example 1

[0022] The objective of this invention can be achieved through the following technical solution: a method for monitoring the construction of cast-in-place continuous beams on water, comprising the following steps:

[0023] S1: Determination of monitoring sections and monitoring points: Based on the structure and stress characteristics of the support and continuous beam, the monitoring sections are determined. Three monitoring sections are set at 1 / 4, 1 / 2, and 3 / 4 of the longitudinal span of each beam along the bridge direction. On each monitoring section, three monitoring points are set at the center of the bottom formwork of the box girder corresponding to the top of the support, the edge of the web plate, and the edge of the flange plate, respectively, for settlement, tilt, and axial force. A settlement monitoring point for the underwater platform is set at the corresponding underwater platform of the monitoring section.

[0024] In addition, for special types of continuous beams, the number of monitoring sections can be adjusted or reduced according to the design characteristics and stress characteristics of the support. For highway and municipal bridges with a wide span, five sets of monitoring points should be set up. The setting of monitoring points must take into account the location of the maximum stress on the support under the web of the continuous beam. The location of the maximum stress on the support needs to be combined with the support design drawings to find the most unfavorable location as a reference.

[0025] S2: Install sensors at the monitoring points. The specific installation locations of the sensors are as follows: the vertical displacement sensor for monitoring the settlement of the support is installed below the adjustable support on the top layer of the support; the tilt sensor for monitoring the tilt of the uprights is installed below the adjusting nut of the adjustable support on the top layer of the support, where the settlement is equivalent to the settlement of the template; the axial force sensor for monitoring the axial force of the uprights is installed on the top layer of the support; and the hydrostatic level for monitoring the settlement of the underwater platform is installed on the steel plate of the underwater platform.

[0026] When installing each sensor, the measurement cable should be laid. All sensor cables should be fixed to the steel pipe of the formwork system with cable ties. Data cables should be loosely bundled and should not be placed directly on the ground. They should be kept away from water accumulation and grout. Data cables should not be bundled with other cables on the construction site. The cable layout should take into account the impact of other personnel and facilities on the data cables.

[0027] The terminal equipment includes a wireless data acquisition unit and a comprehensive analyzer. The wireless data acquisition unit can be fixed to a pole or crossbar near the corresponding sensor using a single ring buckle. When installing the wireless data acquisition unit, try to ensure that it is set horizontally. The comprehensive analyzer can be fixed on the construction site of the support structure or placed in the command room where normal communication is possible, depending on the actual situation. In order to ensure the communication effect, the 4G antenna and RF433 antenna of the comprehensive analyzer should be moved to an outdoor location with good signal to ensure that the wireless data acquisition unit can wirelessly transmit the collected data to the comprehensive analyzer.

[0028] After the sensors, wireless data acquisition unit, and integrated analyzer are installed, each device needs to be debugged to check whether the terminal devices and sensors are connected normally. Turn on all sensors, start the wireless data acquisition unit, and turn on the integrated analyzer. After the LCD display shows everything is normal, check whether each device is operating normally. If it is not operating normally, debug it until it is operating normally. If it is operating normally, initialize the sensors by setting the initial values ​​in all analyzers to 0. In particular, it is necessary to set the total settlement value after the sum of the platform settlement and the support settlement in the water to a separate initial value of 0. After initialization, it can enter the monitoring operation state.

[0029] Sensors at each monitoring point are used to monitor parameters such as support settlement (displacement gauge), pole tilt (inclinometer), pole axial force (axial force gauge), and underwater platform settlement (hydrostatic level). The instantaneous data measured by the sensors are transmitted to the terminal equipment in real time.

[0030] S3: The time periods for transmitting instantaneous data from the sensor to the integrated analyzer are divided into: preloading, unloading, and concrete pouring. The data collected during each time period is analyzed by the integrated analyzer and compared with the control baseline of the monitoring system. The total settlement value, including the settlement of the platform in the water and the settlement of the support, is also analyzed. The integrated analyzer is equipped with safety, early warning, and danger levels.

[0031] If the data analysis result is at the safety level, take the following measure: continue normal construction and maintain routine inspections and maintenance.

[0032] If the data analysis result is at the warning level, take the second measure: increase the monitoring frequency, send personnel to patrol, and take corresponding measures to lift the warning until the data analysis is reduced to the safe level.

[0033] If the data analysis result is at the danger level, the third measure is to activate the emergency plan, close the road, evacuate traffic and surrounding personnel, have the technical department analyze and propose solutions, implement reinforcement and acceptance, until the data analysis is reduced to the safe level.

[0034] S4: After the continuous beam construction is completed, the monitoring results are used to form an analysis report, which analyzes the settlement and elastic deformation of the underwater platform, the settlement and elastic deformation of the support, etc., as the basis for adjusting the pre-camber setting. Combined with the monitoring results of the poured concrete, an analysis report is formed to guide the design optimization of the underwater platform and support system in the next continuous beam. Through the data analysis report, compared with the mechanical calculation report of the support design, the design optimization of the underwater platform and support system of the next continuous beam is carried out on the basis of ensuring the safety of the support and the linearity of the continuous beam.

[0035] The advantages of this invention include: The monitoring method in this application, based on Internet of Things (IoT) technology, generates signals for vertical displacement of the support, tilt of the uprights, axial force of the uprights, and settlement of the platform in the water by monitoring parameters such as support settlement, upright tilt, axial force of the uprights, and platform settlement. These signals are transmitted in real time to an wireless data acquisition instrument, converted into data, and analyzed by a comprehensive analyzer to achieve functions such as report output and over-limit alarms, thus reducing the risk of support collapse. This monitoring method collects data on the settlement of the platform in the water, performs separate analysis and over-limit alarms on the platform settlement, and performs cumulative analysis and alarms on the platform settlement and support settlement, thus avoiding support collapse caused by instability and settlement of the platform in the water and eliminating the loss of support pre-camber caused by platform settlement in the water. The monitoring method in this application is systematic and comprehensive, realizing report analysis and over-limit alarms for the entire system including the platform and support system in the water, and providing a basis for the design optimization of the platform and support system in the water.

[0036] Example 2

[0037] The 15th span of a highway bridge across a river is a cast-in-place continuous beam with 3-35m supports. The bridge deck is 2-28m wide and constructed in sections. The piers are 18m high, and all the disc-lock scaffolds are 14.5m high. This is considered a high-support formwork project with significant risks due to its large scale. Monitoring sections are arranged along the bridge direction, with 3 monitoring sections per span. Three monitoring sections are also arranged at 1 / 4, 1 / 2, and 3 / 4 of the longitudinal span of each span, for a total of 9 sections across the 3 spans of the bridge. Following the characteristics of a highway box girder continuous beam, 5 sets of monitoring points are selected for each section. Safety monitoring was successfully completed during construction using the monitoring method described in Example 1. After the continuous beam construction was completed, the monitoring results were compiled into an analysis report.

[0038] Example 3

[0039] Based on Example 2, the 16th span of the highway bridge across the river is a continuous beam cast in place with a 3-35m support structure, a bridge deck width of 2-28m, constructed in sections, and a pier height of 18m. The difference is that part of the support structure is a steel pipe support and part is a disc-lock support, with a total support height of 16.5m. This is considered a high formwork support with a relatively high risk due to its large scale.

[0040] Before construction, based on the analysis report of Example 2, the support structure was optimized and designed before construction, and safety monitoring was successfully completed during construction.

[0041] The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0042] The present invention has been described above with reference to preferred embodiments, but the scope of protection of the present invention is not limited thereto. All technical solutions falling within the scope of the claims are within the scope of protection of the present invention. Various modifications can be made to the present invention, and components can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way.

Claims

1. A method for monitoring construction of a cast-in-situ continuous beam over water, characterized by, The method comprises the following steps: S1: determination of monitoring sections and monitoring points: according to the structure and stress characteristics of the support and the continuous beam, the monitoring sections are determined, and the monitoring sections are not less than 3 in the bridge longitudinal direction, and at least 3 monitoring points are determined on each monitoring section according to the stress characteristics; according to the structure and stress characteristics of the support and the continuous beam, 3 monitoring sections are arranged at the 1 / 4, 1 / 2 and 3 / 4 span positions of the beam longitudinal direction of each hole in the bridge longitudinal direction; three monitoring points of settlement, inclination and axial force are arranged at the center of the box girder bottom mold, the web edge line and the flange plate edge of the support top of each monitoring section respectively, and a water platform settlement monitoring point is arranged at the corresponding water platform of the monitoring section; S2: sensors are installed at the monitoring points for monitoring the parameters of support settlement, stand rod inclination, stand rod axial force and water platform settlement, and the instantaneous data measured by the sensors are transmitted to the terminal equipment in real time; the vertical displacement sensor for support settlement monitoring is installed below the adjustable support of the top layer of the support, the inclination sensor for stand rod inclination monitoring is installed below the adjusting nut of the adjustable support of the top layer of the support, the axial force sensor for stand rod axial force monitoring is installed at the top layer of the support, and the static water level gauge for water platform settlement monitoring is installed on the steel plate of the water platform; S3: the instantaneous data transmitted by the sensors are transmitted to the terminal equipment for data analysis, the water platform settlement and the support settlement are cumulatively analyzed, the water platform settlement is separately analyzed and over-limit alarm is given, and the water platform settlement and the support settlement are cumulatively analyzed and alarm is given; the terminal equipment is provided with a safety level, a warning level and a danger level: if the data analysis result is the safety level, normal construction and inspection and maintenance are performed; if the data analysis result is the warning level, the monitoring frequency needs to be encrypted, people need to be dispatched for inspection, and corresponding measures need to be taken to remove the warning until the data analysis is reduced to the safety level; if the data analysis result is the danger level, an emergency plan needs to be started, roads need to be closed, and vehicle flow and crowd need to be evacuated until the data analysis is reduced to the safety level; S4: after the continuous beam construction is completed, an analysis report is formed based on the monitoring results.

2. The method according to claim 1, wherein In the step S2, the terminal equipment comprises a wireless acquisition instrument and a comprehensive analysis instrument, the corresponding wireless acquisition instrument is fixed at the corresponding sensor, and the wireless acquisition instrument wirelessly transmits the collected data to the comprehensive analysis instrument.

3. The method according to claim 2, wherein In the step S2, after the sensors, the wireless acquisition instrument and the comprehensive analysis instrument are installed, each device needs to be debugged first, all the sensors are turned on, the wireless acquisition instrument is started, the comprehensive analysis instrument is turned on, and whether each device is normally operated is checked: if not, the debugging is performed until the device is normally operated; if the device is normally operated, the sensors are initialized, the total settlement value of the water platform settlement and the support settlement is separately initialized, and after the initialization, the monitoring state is entered, the instantaneous data measured by the sensors are transmitted to the terminal equipment in real time.

4. The method according to claim 3, wherein In the step S3, the time period of the instantaneous data of the sensors collected by the comprehensive analysis instrument is divided into: preloading, unloading and concrete pouring.

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