Formwork support system and monitoring method for large-span cast-in-place box beams with intelligent monitoring

Abstract

The present invention discloses a large-span cast-in-place box girder formwork support system and a monitoring method for implementing intelligent monitoring. The large-span cast-in-place box girder formwork support system has made improvements on the existing technology. On the basis of the structural design meeting the engineering requirements, it is easier to find the key points of the structure where sensors are laid out and to lay out sensors at the key points of the structure to achieve the goal of intelligent monitoring. The same type of sensors can be laid out on different layers of the structure, which is convenient for analyzing the cumulative value of the deviation value of each layer of the structure, and can scientifically reflect the local and overall compression state of the combined support, providing a more comprehensive and reliable monitoring result for the construction. At the same time, the monitoring method of the present invention is easy to implement, and the monitoring equipment can be used to timely feedback to the engineering personnel the state of each layer and the overall structure of the combined support in the project as a reliable basis for timely warning to ensure the safe progress of the construction. Compared with the traditional conventional total station and level measurement method, the method of the present invention can save a lot of measurement manpower and equipment resources, and realize dynamic monitoring and intelligent analysis.

Description

Technical Field

[0001] The present invention relates to the technical field of construction and civil engineering, and in particular to a large-span cast-in-place box girder formwork support system and a monitoring method implementing intelligent monitoring. Background Art

[0002] Box beam is a type of beam in bridge engineering. Box beams in reinforced concrete structures are divided into prefabricated box beams and cast-in-place box beams. Cast-in-place box beams are mostly used for large continuous bridges, such as Section II of the Luzhou Second Ring Road North Section (Qianfeng Road) Project, which includes multiple 70m, 65m, and 60m long-span cast-in-place box beams, of which the maximum formwork height of the curved box beam is 30m. In order to achieve safe and orderly construction of ultra-high curved cast-in-place box beams, there are many projects that use a combination of steel pipe columns, Bailey beams and full-frame supports in the support system of the large-span cast-in-place box beam formwork.

[0003] For the large-span cast-in-place box girder composite supports in the project, the monitoring of the traditional formwork support system is mainly divided into three parts: vertical settlement, horizontal displacement, and vertical inclination. The monitoring method mainly uses total stations and levels for fixed-point observation and recording. The monitoring process requires that the monitoring equipment be continuously kept at a fixed measuring point, and surveyors are required to read and observe the data. In the long-term construction of cast-in-place box girders, it is difficult to ensure the accuracy and continuity of the monitoring data. Due to the large scale of the project and limited measuring equipment and human resources, the traditional monitoring method is not conducive to ensuring uninterrupted monitoring throughout the box girder construction process. Summary of the invention

[0004] Aiming at the deficiencies in the prior art, the present invention provides a novel large-span cast-in-place box girder formwork support system implementing intelligent monitoring, and a monitoring method suitable for the support system, based on the prior art.

[0005] The technical solution provided by the present invention is:

[0006] A large-span cast-in-place box girder formwork support system implementing intelligent monitoring, comprising a combined support and a sensor device for monitoring the compression state of the combined support, wherein the combined support comprises a steel pipe column support at the bottom layer, a Bailey support at the middle layer, and a disc-type scaffold at the upper layer, wherein the sensor device comprises a plurality of axial pressure sensors for measuring load pressure and a displacement sensor for measuring deflection data, inclination data, and settlement data, and is characterized in that:

[0007] The steel pipe column support includes a steel pipe column array and a layer of horizontally arranged I-beam distribution beams laid on the top surface of the steel pipe column array. The I-beam distribution beams are fixedly installed at the tops of the steel pipe columns in the same horizontal row. Displacement sensors for monitoring the deflection data of the steel pipe column support are installed in the middle of one or more steel pipe columns. Displacement sensors for monitoring the inclination data of the steel pipe column support are installed at the tops of one or more steel pipe columns. Sensors for monitoring the settlement data of the steel pipe column support are installed in the middle of one or more I-beam distribution beams.

[0008] The Bailey support is installed above the I-beam distribution beam and is composed of truss modules arranged in sequence from front to back. The truss module has a frame structure in the shape of a "day" character, including three parallel Bailey beams in the front, middle, and back. The Bailey beams are sequentially spliced by a plurality of Bailey sheets. The two ends of the three parallel Bailey beams in the front, middle, and back are fixedly connected by a Bailey sheet respectively. And two truss modules are arranged above each two adjacent steel pipe columns, so that at least one side of the front and rear Bailey beams of each truss module is placed on the I-beam distribution beam. Displacement sensors for monitoring the deflection data, settlement data, or inclination data of the Bailey support are evenly arranged at the joints of the two truss modules located at the mid-span position of the steel pipe columns in the vertical direction.

[0009] The disc buckle scaffold includes a scaffold body and a base. The base is a layer of horizontally arranged I-beam support beams laid on the top surface of the Bailey support. The scaffold body includes vertical poles and crossbars connected between the vertical poles. The bottom ends of the vertical poles are fixed on the I-beam support beams, and the top ends of the vertical poles support the box girder formwork through a tightly pressed wooden square. Axial compression sensors for monitoring the vertical load of the disc buckle scaffold are installed between the corresponding vertical poles and the box girder formwork instead of the wooden square. Displacement sensors for monitoring the inclination data of the disc buckle scaffold are installed on the upper parts of one or more vertical poles located below the bottom plate of the box girder formwork. Sensors for monitoring the settlement data of the disc buckle scaffold are installed on the topmost one or more crossbars located below the bottom plate of the box girder formwork.

[0010] On the basis of the above scheme, further improved or preferred schemes include:

[0011] Further, the top and bottom ends of the vertical poles are clamped to the I-beam support beam and the wooden square by U-shaped top supports.

[0012] A monitoring method for a long-span cast-in-situ box girder formwork support system implementing intelligent monitoring as described above, characterized by including the following steps:

[0013] S1. Build the combined support;

[0014] S2. Divide the monitoring area of ​​the combined support from bottom to top into the steel pipe column support monitoring unit, the Bailey support monitoring unit and the disc buckle scaffolding monitoring unit, and then arrange the measuring points and install the sensors in each monitoring unit;

[0015] S3. Use wireless communication technology to establish a communication connection between the monitoring host and all sensors at each measuring point, receive data fed back by each sensor through the monitoring host, and calculate the deviation value of each measuring point and the cumulative value of the deviation value corresponding to the same type of sensor data in each monitoring area, and set control values ​​and alarm values ​​for all deviation values ​​and the cumulative value of each type of deviation value;

[0016] S4. During the concrete pouring process of the box girder, the monitoring host monitors the status of the combined support according to the sensor data it receives. When the deviation value of any measuring point or the accumulated value of any type of deviation value reaches the alarm value, an alarm signal is sent to relevant personnel.

[0017] Furthermore, before the concrete pouring in step S4 begins, a pre-compression test is performed on the assembled support, and the pre-compression test includes the following steps:

[0018] The concrete pouring process is simulated by piling loads on the combined bracket, and the deviation values ​​of each measuring point in the monitoring area and the cumulative values ​​of various deviation values ​​are analyzed during the piling process. When the deviation value of any measuring point or the cumulative value of any type of deviation value reaches the alarm value, an alarm signal is sent to relevant personnel.

[0019] Further, the displacement sensor for measuring deflection data is a laser deflectometer, the displacement sensor for measuring inclination data is a laser inclinometer, and the displacement sensor for measuring settlement data is a pull-rope sensor;

[0020] The process of arranging measuring points and installing sensors in step S2 is as follows:

[0021] Arrange an A1 measuring point in the middle of the steel pipe column located at the four corners of the steel pipe column bracket, install a first laser deflectometer at the A1 measuring point, install the laser target of the first laser deflectometer on the bridge pier or hardened ground, and measure the deflection data of the steel pipe column;

[0022] Arrange A2 measuring points at the top of the steel pipe columns located at the four corners of the steel pipe column bracket, install the first laser inclinometer at the A2 measuring point, install its laser target on the hardened ground, and measure the inclination data of the steel pipe column;

[0023] A3 measuring points are arranged in the middle of the I-beam distribution beam located at the front and rear sides of the steel pipe column support, and the first pull-rope displacement sensor is installed at the A3 measuring point, and the bottom end of the pull rope is connected to the hardened ground to measure the settlement data of the I-beam distribution beam;

[0024] A B1 measuring point is arranged at the connection of two truss modules of the Bailey support at the mid-span position of the steel pipe column, and the B1 measuring point is located in the middle of the height direction of the Bailey support. A second laser deflectometer is installed at the B1 measuring point, and the second laser deflectometer is controlled to emit a horizontal laser beam, and a laser target for comparison is fixedly installed on the outermost Bailey beam of the Bailey support in the monitoring area to measure the deflection data of the Bailey support;

[0025] A B2 measuring point is arranged at the connection of the two truss modules of the Bailey support located at the mid-span position of the steel pipe column. The B2 measuring point is at the bottom of the Bailey support. A second pull-rope displacement sensor is installed at the B2 measuring point, and the bottom end of the pull rope is connected to the hardened ground to measure the settlement data of the Bailey support.

[0026] In the disc-type scaffolding, multiple C measuring point areas are arranged at intervals along the transverse direction of the disc-type scaffolding, and the C measuring point areas are all located below the bottom plate of the box beam formwork. A third laser inclinometer, a third pull-rope displacement sensor and a vertical pole axial force sensor are installed in each C measuring point area;

[0027] The third laser inclinometer is installed on the upper part of the vertical pole, emits a horizontal laser beam, and the laser target for comparison is installed on the bridge pier to measure the inclination data of the vertical pole;

[0028] The third pull-rope displacement sensor is installed on the topmost crossbar below the bottom plate of the box beam template, and the bottom of the pull rope is connected to the I-beam support beam below to measure the settlement data of the disc-type scaffolding;

[0029] The vertical pole axial force sensor is installed between the top of the vertical pole and the box beam template instead of the wooden square to measure the vertical load data of the vertical pole.

[0030] Furthermore, when the first laser deflectometer emits a vertical laser beam and a target for comparing the vertical laser beam is installed on the hardened ground, the first laser deflectometer and the first laser inclinometer installed on the same steel pipe column are set on different sides of the steel pipe column.

[0031] Furthermore, each monitoring area or monitoring unit divided in step S2 has a distance in the front-to-back direction not exceeding three spans of steel pipe columns.

[0032] Preferably, when the sensor data is deflection data, the control value function of the corresponding deviation value is Min(H / 500, ΔH); when the sensor data is settlement data, the control value function of the corresponding deviation value is Min(H / 1000, ΔH), wherein H refers to the frame height between the bottom plate of the box girder formwork and the concrete foundation supported at the bottom end of the steel pipe column, ΔH refers to the preset maximum safety deviation value, and Min() is a minimum value function.

[0033] Furthermore, when the sensor data is inclination data, the corresponding verticality deviation control value should be ≤5‰. The verticality deviation refers to the ratio of the horizontal displacement of the measuring point where the sensor is located to Hc, that is, horizontal displacement / Hc≤1 / 200. Hc refers to the height from the measuring point where the sensor is located to the concrete foundation supported at the bottom of the steel pipe column.

[0034] Furthermore, the alarm values ​​in step S3 are all set to 0.8 times of the corresponding control values.

[0035] Beneficial effects:

[0036] 1) The large-span cast-in-place box girder formwork support system implemented by the present invention is an improvement on the prior art. Its structural design meets the needs of general large-span cast-in-place box girder projects, and it is easy to find key points of the structure and deploy sensors at the key points of the structure to achieve the goal of intelligent monitoring, such as the weak areas of the Bailey support and the sensors installed at the monitoring position. At the same time, the design of the combined support of the support system of the present invention can deploy the same type of sensors for different layers of structures, which is convenient for calculating the cumulative value of the deviation values ​​of the measuring points of each layer of the structure, and can scientifically and accurately reflect the local and overall compression state of the combined support, providing more comprehensive and reliable monitoring results for safe construction.

[0037] 2) The monitoring method provided by the present invention, which is applicable to the large-span cast-in-place box girder formwork support system, can timely feedback the status of each layer of the combined support and the overall structure in the project to the engineering personnel through the monitoring equipment, which serves as a reliable basis for timely early warning to ensure the safe progress of the construction. Compared with the traditional conventional total station and level measurement method, the method of the present invention can save a lot of measurement manpower and equipment resources, and realize dynamic monitoring and intelligent analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of a monitoring unit of the combined support of the support system of the present invention;

[0039] Figure 2 It is a schematic diagram of the sensor layout of the steel pipe column support monitoring unit;

[0040] Figure 3 It is magnified Figure 2 Schematic diagram of the installation of some sensors in the local structure;

[0041] Figure 4 It is a schematic diagram of the installation of the first pull-rope displacement sensor in the steel pipe column support monitoring unit.

[0042] Figure 5 It is a schematic diagram of the sensor layout in the Bailey support monitoring unit;

[0043] Figure 6It is a schematic diagram of the installation of the second laser deflectometer in the Bailey support monitoring unit;

[0044] Figure 7 It is a schematic diagram of the installation of the second pull-wire displacement sensor in the Bailey support monitoring unit;

[0045] Figure 8 It is a schematic diagram of the sensor layout of the disc-type scaffold monitoring unit;

[0046] Fig. 9 This is a schematic diagram of the sensor installation in a C measuring point area in a disc-type scaffold monitoring unit;

[0047] Fig.10 It is a simplified structural schematic diagram of the combined support bracket of the support system of the present invention;

[0048] Fig.11 It is a partial structural schematic diagram of the combined support bracket of the support system of the present invention;

[0049] Fig.12 is a schematic diagram of the structure of various types of sensors used in a specific embodiment of the present invention;

[0050] Fig.12 Among them, (a) is an axial pressure sensor, (b) is a laser inclinometer, (c) is a pull-rope sensor, and (d) is a laser deflectometer. DETAILED DESCRIPTION

[0051] In order to illustrate the implementation method of the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] Taking the cast-in-place box girder project with a span of 70m as an example, the main process flow of the monitoring method of the present invention is: prepare and demonstrate the specific plan of the box girder formwork support system → build the support system → install sensors → install on-site wireless data acquisition terminals and monitoring alarm equipment → debug and set monitoring data → collect initial values ​​→ start monitoring after pouring concrete → analyze and process data → end monitoring when concrete reaches strength → remove sensors.

[0053] The specific implementation content of the core stage in the above process includes the following parts.

[0054] 1. Build a support system

[0055] Assuming that the direction of extension of the box girder of the bridge is longitudinal, first build a combined support consisting of a steel pipe column support 1, a Bailey support 2, and a disc-type scaffolding 3. The steel pipe column support 1 is the bottom structure of the support system, the Bailey support 2 is the middle structure of the support system, and the disc-type scaffolding 3 is the upper structure of the support system. Generally, a socket-type disc-type scaffolding is preferably used.

[0056] (1) The steel pipe column support 1 is provided with a steel pipe column array and strengthening structures such as cross bars and X-shaped bars connected between adjacent steel pipe columns. Taking the horizontal row of the steel pipe column array as a unit, an I-beam distribution beam 17 is erected at the top of the steel pipe columns 12 in the same horizontal row. As Figure 1 shown, the structural load, support load, and construction load are distributed to each steel pipe column 12 through the I-beam distribution beam 17. In this embodiment, the steel pipe column 12 is made of spiral steel pipe, the I-beam distribution beam 17 is welded with ribs using steel plates of the same thickness, and limit steel bars for fixing the I-beam distribution beam 17 are welded on the top surface of the steel pipe column 12 to prevent the horizontal displacement of the distribution beam.

[0057] (2) The Bailey support 2 is laid above the steel pipe column support 1. As Figure 5 shown, the steel pipe column support 1 is composed of truss modules arranged in sequence from front to back. The truss module has a frame structure in the shape of a "day" character, including three parallel Bailey beams in the front, middle, and rear. The left and right sides of these three Bailey beams are connected by a Bailey sheet 18, that is, there is a distance of a Bailey sheet window between the front and middle or middle and rear Bailey beams, and each Bailey beam is spliced by multiple Bailey sheets 18. A set of truss modules is arranged above every two adjacent steel pipe columns. The set of truss modules includes two truss modules. At least one side of the front and rear Bailey beams of each truss module can be fixedly installed above a certain I-beam distribution beam 17. As Figure 5 shown. The truss module needs to be pre-assembled before hoisting and hoisted above the I-beam distribution beam 17, and the uneven parts are padded with steel gaskets.

[0058] (3) The disc buckle scaffold 3 includes a scaffold body and a base. The base is a layer of I-beam support beams 19 laid on the top surface of the Bailey support 2. The scaffold body includes vertical poles 302 and cross bars 301 connected between the vertical poles 302. U-shaped top supports 303 are provided at both the top and bottom of the vertical poles 302. The U-shaped top support 303 at the bottom of the vertical pole 302 has an opening facing downwards and is clamped on the I-beam support beam 19 below it during erection. The U-shaped top support 303 at the top of the scaffold has an opening facing upwards and is used to tightly support the wooden square. The I-beam support beam 19 extends in the horizontal direction, and multiple parallel I-beam support beams 19 are laid flat on the top surface of the Bailey support 2 as the support base of the disc buckle scaffold 3. The wooden square is padded between the box girder formwork 601 and the disc buckle scaffold 3 and is clamped and tightly supported by the U-shaped top support 303 at the top of the vertical pole.

[0059] When building the socket-type disc-type scaffold 3, different heights of vertical poles 302 are selected at different positions in combination with the shape of the box beam, so that the top shape of the scaffold as a whole matches the bottom shape of the box beam template. When building the crossbars in the middle of the disc-type scaffold 3, a layer can be set at a height of about 1.5 meters, and the spacing between the crossbars at the top and bottom of the scaffold is reduced, making the structure more compact. Reinforcement facilities are additionally set at the higher scaffolding positions on both sides of the box beam template to ensure the stability of the template support.

[0060] 2. Divide monitoring units and install sensors

[0061] The setting of the distribution points of sensors in the monitoring equipment is the core point of the present invention. First, the monitoring area is divided into three monitoring units from bottom to top, namely, steel pipe column bracket, Bailey bracket and disc-type scaffolding, and a group of sensors is set in each monitoring unit. Preferably, the front and rear distance of the monitoring area or monitoring unit does not exceed 3 spans of steel pipe columns (1 span refers to the distance between the front and rear two steel pipe columns). Each group of monitoring sensors is relatively independent to meet the support system monitoring requirements under the conditions of disc-type scaffolding, steel pipe column bracket + disc-type scaffolding, steel pipe column bracket + Bailey bracket + disc-type scaffolding, etc., either alone or in different combinations.

[0062] like Figures 1 to 9 As shown in the figure, taking a monitoring area with a front-to-back distance of 3 spans of steel pipe columns as an example, the displacement sensor for measuring deflection data in the combined bracket adopts a laser deflectometer, the displacement sensor for measuring inclination data adopts a laser inclinometer, the displacement sensor for measuring settlement data adopts a pull-rope sensor, and the pressure sensor for measuring load adopts an axial pressure sensor, as shown in FIG. Fig.12 shown.

[0063] The specific arrangement and installation scheme of the sensor is as follows:

[0064] 1) Arrangement and installation of steel pipe column bracket sensor

[0065] The monitoring key points of the steel pipe column support 1 are three key data of the vertical settlement, inclination and horizontal displacement of the steel pipe column 12. The first group of sensors arranged in the monitoring unit of the steel pipe column support includes a first laser deflectometer 101-1, a first laser inclinometer 102-1 and a first pull-wire displacement sensor 103-1. The specific arrangement method is as follows:

[0066] A1 measuring point is arranged in the middle of the steel pipe column 12 located at the four corners of the steel pipe column bracket 1, and a first laser deflectometer 101-1 is installed at each of the four A1 measuring points. The first laser deflectometer 101-1 emits a horizontal laser beam and / or a vertical laser beam, and the laser target for the horizontal laser beam is installed on the bridge pier 4, and the laser target for the vertical laser beam is installed on the pedestal 6 below the steel pipe column 12. Figure 3As shown, the deflection data of the steel pipe column 12 is measured;

[0067] A2 measuring points are arranged at the top of the steel pipe columns located at the four corners of the steel pipe column bracket 1, and a first laser inclinometer 102-1 is installed at each of the four A2 measuring points. The laser target for comparing its vertical laser beam is installed on the hardened ground to measure the vertical inclination data of the corresponding steel pipe column 12; for the first laser inclinometer 102-1 and the first laser deflectometer 101-1 installed on the same steel pipe column 12, in order to avoid interference between the vertical laser beams emitted by the two, the first laser deflectometer 101-1 and the first laser inclinometer 102-1 can be installed on different sides of the steel pipe column 12;

[0068] An A3 measuring point is arranged in the middle of the I-beam distribution beam 17 at the front and rear sides of the steel pipe column support 1, and a first pull-rope displacement sensor 103-1 is installed at the A3 measuring point, and the bottom end of its pull rope is connected to the hardened ground. The settlement data of the I-beam distribution beam 17 is measured by reading the telescopic length of the pull rope 105, and this data can reflect the overall settlement of the steel pipe column support layer.

[0069] In this embodiment, a total of 4 first laser deflectometers 101-1 and 4 corresponding targets, 4 first laser inclinometers 102-1 and 8 corresponding targets, and 2 first pull-wire displacement sensors 103-1 are arranged in the steel pipe column support 1. In order to achieve the installation adaptability of the monitoring equipment, each sensor is equipped with a φ50 mounting fastener (circular ring) to be connected with the L-shaped φ50 steel pipe fastener welded on the steel pipe column 12 and the I-beam distribution beam 17, such as Figure 3 , Figure 4 shown.

[0070] The cap 6 refers to the concrete foundation below the steel pipe column 12, which is a hardened ground.

[0071] 2) Arrangement and installation of Bailey bracket sensors

[0072] Bailey bracket 2 is the middle layer support structure of the combined bracket, and mainly monitors the horizontal offset and vertical settlement of the frame. Since Bailey bracket 2 is connected in the form of a lattice window, the middle connection point is the weakest area of ​​the structure. Therefore, in this embodiment, the B1 measuring point and the B2 measuring point are arranged at the connection between the two truss modules of Bailey bracket 2 at the mid-span position of each steel pipe column. Figure 5 As shown:

[0073] A B1 measuring point is provided on each of the left and right sides of the connection of the truss modules at the three mid-span positions. The B1 measuring point is located in the middle of the height direction of the Bailey support 2. A second laser deflectometer 102-1 is installed at each B1 measuring point. The second laser deflectometer 102-1 can emit a horizontal laser beam and / or a vertical laser beam. The laser target for comparing the horizontal laser beam is fixedly installed on the outermost Bailey beam of the Bailey support, either in the front or rear. The laser target for comparing the vertical laser beam is fixedly installed on the hardened ground to monitor the deflection data of the Bailey beam support 2 in the horizontal and / or vertical directions.

[0074] A B2 measuring point is arranged at the connection of the two truss modules located at the mid-span position of the steel pipe column in front and behind the Bailey support 2. The B2 measuring point is at the bottom of the Bailey support 2 and is located between the two B1 measuring points in the same row. A second pull-rope displacement sensor 103-2 is installed at the B2 measuring point, and the bottom end of its pull rope is connected to the hardened ground to measure the settlement data of the weak point of the Bailey support 2 in the monitoring unit.

[0075] According to actual conditions, if the Bailey support 2 needs to be provided with a sensor for detecting tilt deviation, its measuring point is preferably also provided in the weak area.

[0076] 3) Arrangement and installation of disc-type scaffolding sensors

[0077] The disc-type scaffolding 3 is the uppermost structure of the support system, and the overall force is uniform. The sensor layout is preferably located at the center of the frame. Figure 8 As shown, in the monitoring unit, three C measuring point areas are arranged at intervals along the transverse direction of the disc-type scaffolding 3, and the three C measuring point areas are all located below the bottom plate of the box beam formwork, approximately at 1 / 4, 1 / 2, and 3 / 4 of the transverse direction of the scaffolding frame body.

[0078] A third laser inclinometer 102-3, a third pull-wire displacement sensor 103-3 and a pole axial force sensor 104 are installed in each C measuring point area, wherein:

[0079] The third laser inclinometer 102-3 is connected to the steel pipe column through a fastener, fixedly installed at 2 / 3 of the height of the pole 302, emitting a horizontal laser beam, and the laser target for comparison is installed on the bridge pier 4, for measuring the inclination data of the disc-type scaffolding layer in the monitoring unit;

[0080] The third pull-rope displacement sensor 103-3 is installed on the top crossbar 301, and the bottom of the pull rope is connected to the I-beam support beam 19 below to measure the settlement data of the disc-type scaffolding 3 in the monitoring unit compared with the Bailey support 2;

[0081] The vertical pole axial force sensor 104 is installed between the top of a vertical pole 302 and the box beam template 601 instead of a wooden beam to measure the axial compressive load data of the vertical pole 302 .

[0082] 4) Precautions for sensor installation

[0083] a. The sensor is fixed to the supporting structure with fasteners and must not collide after installation;

[0084] b. The two pressure-bearing surfaces of the axial pressure sensor should be flat and close to each other, and on the same straight line as the vertical pole;

[0085] c. The draw-rope sensor needs to be connected to the fixed end along the deformation direction. The on-site installation uses a steel wire rope to connect. Along the direction of the steel wire rope, the brackets along the way need to be marked every two steps to remind the construction workers to avoid it;

[0086] d. Demonstrate the sound and light alarm and explain to the construction workers that when the sound and light alarm sounds, the construction workers need to pay attention and evacuate quickly.

[0087] 3. Install other monitoring equipment, debug and set monitoring data

[0088] In addition to the sensors installed in each monitoring unit, the monitoring equipment also includes a wireless data acquisition terminal, a monitoring host and an alarm device. The monitoring host and the alarm device are installed on the periphery of the combined bracket and are operated and managed by professional security personnel. Each sensor establishes a communication connection with the monitoring host through the wireless data acquisition terminal, summarizes the data collected by it into the monitoring host, and reports the sensor data of the relevant measuring points of each monitoring unit in real time and dynamically. The monitoring host intelligently analyzes the sensor data of each monitoring unit in a preset software system, and calculates the deviation value of each measuring point and the cumulative value of the deviation value corresponding to the same type of sensor data by comparing the pre-pressure value. The monitoring personnel need to set a first control value and an alarm value for the deviation value of each measuring point, and set a second control value and an alarm value for the cumulative deviation value.

[0089] 4. Preload test

[0090] When monitoring major and dangerous projects, after the support system is erected, at least one monitoring unit must be selected for pre-stressing monitoring. This is done by continuously and evenly piling up steel bars of equal load on the formwork to simulate the load change process during concrete pouring.

[0091] During preloading, the monitoring points are arranged in the same way as the concrete construction monitoring, monitoring the displacement changes such as the settlement of the combined bracket. The monitoring frequency is the initial value when the sensor can stably collect data before loading. The sensor data is monitored and recorded once before the start of preloading, and the sensor data is monitored and recorded again before each level of loading, and the change value of the sensor data is analyzed. When any deviation data exceeds the preset alarm value, the early warning program is activated, and the alarm information is sent to the construction management personnel to take corresponding adjustment measures. After the preloading test is passed, preparations for concrete pouring can be started.

[0092] V. Implementation of monitoring

[0093] Before pouring concrete, the initial value of the monitoring data is collected again, and it is used as a comparison basis to calculate the vertical, horizontal and tilt deviation values ​​of each measuring point during the construction process and the cumulative value of the same type of deviation values ​​of each monitoring unit. During the construction process, if any data exceeds the preset alarm value, the early warning program will be activated and an alarm message will be sent to the construction management personnel to urge them to take corresponding adjustment measures in time until the construction of the large-span cast-in-place box girder is completed, realizing the intelligent monitoring of the large-span cast-in-place box girder.

[0094] The monitoring data in the monitoring host can be synchronized to the mobile phone and computer via the wireless network for real-time viewing by the operator. The high-rise formwork monitoring is mainly to obtain real-time automatic data collection, supplemented by on-site visual inspections. When the deformation is large, inspections should be strengthened, and construction should be stopped if necessary. The reasons should be found out and the construction unit should be notified to take measures until the data deformation stabilizes.

[0095] When concrete pouring construction begins after all data are ready, data can be monitored and recorded every 5 seconds in the early stage. After concrete pouring is completed, if there is no abnormal change in the monitored data, the interval time for monitoring and recording sensor data can be extended, but it is generally required that the interval time does not exceed 1 minute. Monitoring continues until the strength in the concrete pouring area reaches the formwork removal requirements, and monitoring is terminated. During the monitoring process, if the monitored data changes too much, exceeds the alarm value, or the data continues to increase, the monitoring frequency is set to real-time monitoring (collected once every 2 seconds) until the danger is eliminated and the reinforced or adjusted support system is confirmed to be safe, then it is switched to the normal monitoring frequency. The monitoring process in a monitoring area continues until the formwork is removed, that is, it is transferred to the next monitoring area.

[0096] During the preload test and formal monitoring process, the control value and alarm value of each key sensor data can be controlled according to Table 1. Among them, H refers to the frame height (combined bracket) between the bottom plate of the box beam template and the concrete foundation supported at the bottom end of the steel pipe column, ΔH refers to the preset maximum safety deviation value, Min() is a minimum value function, and when the deviation value is greater than any value in the brackets, the early warning program is started.

[0097] Table 1

[0098]

[0099]

[0100] The offset values ​​of the two laser targets of the first laser deflectometer 101-1 correspond to the horizontal displacement and vertical displacement of the monitoring point of the steel pipe column 12, respectively. Both can reflect the deflection deformation of the steel pipe column 12. In specific implementation, one can be set or both can be set to improve data collection efficiency and accuracy. During the box girder concrete pouring stage, the sensor data of each monitoring unit is counted, and the calculation of the deviation value and the cumulative value of the deviation value can be performed according to the following scheme.

[0101] Table 2

[0102]

[0103] If any of the above monitoring data exceeds the alarm value, the box girder construction should be stopped and frame reinforcement measures should be taken.

[0104] Although the cast-in-place box girder frame is divided into three layers of steel pipe columns, Bailey brackets, and buckle brackets, they are combined as the formwork to support the overall structure. In addition to ensuring that the sensor data of each monitoring unit is within the safe range, the cumulative difference of the sensor data must also be considered to ensure the overall safety of the frame. Assume that the overall horizontal displacement control value of the combined bracket is Pk, the overall inclination control value is Qk, and the overall vertical displacement value is Sk. The actual overall horizontal displacement control value of the frame is P = |GPn| + |BSn| + |PSn|, the overall inclination control value Q = |GQn| + |BQn| + |PQn|, and the overall settlement displacement control value S = |GLn| + |BLn| + |PHn|, then the monitoring process must meet P≤Pk, Q≤Qk, S≤Sk.

[0105] The large-span cast-in-place box girder formwork support system and monitoring method of the present invention achieve the monitoring goals of dynamic monitoring, intelligent analysis, and timely early warning. Compared with conventional total station and level measurement methods, it can save a large amount of measurement manpower and equipment resources. It has certain versatility in the high-support formwork support system of bridge engineering composed of steel pipe supports, Bailey supports, and disc-type scaffoldings, and can also be applied to high-support formwork monitoring in the field of building construction.

[0106] The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A long-span cast-in-situ box girder formwork support system for implementing intelligent monitoring, comprising a combined support and a sensor device for monitoring the compressive state of the combined support. The combined support includes a steel pipe column support (1) at the bottom layer, a Bailey support (2) at the middle layer, and a disk-type scaffolding (3) at the upper layer. The sensor device includes a plurality of axial compression sensors for measuring load pressure, and displacement sensors for measuring deflection data, inclination data, and settlement data. It is characterized in that: The steel pipe column support (1) includes a steel pipe column array and a layer of horizontally placed I-beam distribution beams (17) laid on the top surface of the steel pipe column array. The I-beam distribution beams (17) are fixedly installed at the tops of the steel pipe columns in the same horizontal row. Displacement sensors for monitoring the deflection data of the steel pipe column support (1) are installed in the middle of one or more steel pipe columns. Displacement sensors for monitoring the inclination data of the steel pipe column support (1) are installed at the tops of one or more steel pipe columns. Sensors for monitoring the settlement data of the steel pipe column support (1) are installed in the middle of one or more I-beam distribution beams (17). The Bailey support (2) is installed above the I-beam distribution beam (17) and is composed of truss modules arranged in sequence from front to back. The truss module has a frame structure in the shape of a "day" character, including three parallel Bailey beams in the front, middle, and back. The Bailey beams are sequentially spliced by a plurality of Bailey sheets (18). The two ends of the three parallel Bailey beams in the front, middle, and back are each fixedly connected by a Bailey sheet (18). And two truss modules are provided above each two adjacent steel pipe columns, so that at least one side of the front and rear Bailey beams of each truss module is placed on the I-beam distribution beam (17). Displacement sensors for monitoring the deflection data, settlement data, or inclination data of the Bailey support (2) are evenly arranged at the connection of the two truss modules at the mid-span position of the steel pipe column in the vertical direction. The disk-type scaffolding (3) includes a scaffolding body and a base. The base is a layer of horizontally placed I-beam support beams (19) laid on the top surface of the Bailey support (2). The scaffolding body includes vertical poles (302) and crossbars (301) connected between the vertical poles (302). The bottom ends of the vertical poles (302) are fixed on the I-beam support beam (19), and the top ends of the vertical poles (302) support the box girder formwork (601) by pressing against a wooden square. Axial compression sensors for monitoring the vertical load of the disk-type scaffolding (3) are installed between the corresponding vertical poles (302) and the box girder formwork (601) instead of the wooden square. Displacement sensors for monitoring the inclination data of the disk-type scaffolding (3) are installed at the upper parts of one or more vertical poles (302) under the bottom plate of the box girder formwork (601). Sensors for monitoring the settlement data of the disk-type scaffolding (3) are installed on one or more of the topmost crossbars (301) under the bottom plate of the box girder formwork (601).

2. According to the large-span cast-in-place box girder formwork support system implementing intelligent monitoring as described in claim 1, the top and bottom ends of the vertical pole (302) clamp the I-beam support beam (19) and the wooden beam through a U-shaped top support (303).

3. A monitoring method for a large-span cast-in-place box girder formwork support system based on the intelligent monitoring as claimed in claim 1 or 2, It is characterized in that The following steps are involved: S1. Building the combined bracket; S2. Divide the monitoring area of ​​the combined support from bottom to top into the steel pipe column support monitoring unit, the Bailey support monitoring unit and the disc buckle scaffolding monitoring unit, and then arrange the measuring points and install the sensors in each monitoring unit; S3. Use wireless communication technology to establish a communication connection between the monitoring host and all sensors at each measuring point, receive the data fed back by each sensor through the monitoring host, and calculate the deviation value of each measuring point and the cumulative value of the deviation value corresponding to the same type of sensor data in each monitoring unit, and set the control value and alarm value for all deviation values ​​and the cumulative value of the deviation value; S4. During the concrete pouring process of the box girder, the monitoring host monitors the status of the combined support according to the sensor data it receives. When the deviation value of any measuring point or the accumulated value of any type of deviation value reaches the alarm value, an alarm signal is sent to relevant personnel.

4. According to the monitoring method of the large-span cast-in-place box girder formwork support system implementing intelligent monitoring according to claim 3, It is characterized in that Before the concrete pouring in step S4 begins, a pre-compression test is performed on the assembled support; The pre-load test comprises the following steps: The concrete pouring process is simulated by piling loads on the combined bracket, and the deviation values ​​of each measuring point in the monitoring area and the cumulative values ​​of various deviation values ​​are analyzed during the piling process. When the deviation value of any measuring point or the cumulative value of any type of deviation value reaches the alarm value, an alarm signal is sent to relevant personnel.

5. The monitoring method for the large-span cast-in-place box girder formwork support system implementing intelligent monitoring according to claim 3 or 4, It is characterized in that The displacement sensor for measuring deflection data is a laser deflectometer, the displacement sensor for measuring inclination data is a laser inclinometer, and the displacement sensor for measuring settlement data is a pull-rope sensor; The process of arranging measuring points and installing sensors in step S2 is as follows: Arranging an A1 measuring point in the middle of a steel tube column (12) located at four corners of a steel tube column support (1), installing a first laser deflectometer (101-1) at the A1 measuring point, installing a laser target of the first laser deflectometer (101-1) on a bridge pier (4) or hardened ground, and measuring deflection data of the steel tube column; Arranging A2 measuring points at the tops of the steel pipe columns located at the four corners of the steel pipe column support (1), installing a first laser inclinometer (102-1) at the A2 measuring points, installing its laser target on the hardened ground, and measuring the inclination data of the steel pipe column; A3 measuring points are arranged at the middle of the I-beam distribution beam (17) located at the front and rear sides of the steel pipe column support (1), and a first pull-rope type displacement sensor (103-1) is installed at the A3 measuring point, and the bottom end of the pull rope is connected to the hardened ground to measure the settlement data of the I-beam distribution beam (17); A B1 measuring point is arranged at the connection of two truss modules of the Bailey support (2) at the mid-span position of the steel pipe column, the B1 measuring point is located in the middle of the Bailey support (2) in the height direction, a second laser deflectometer (102-1) is installed at the B1 measuring point, the second laser deflectometer (102-1) is controlled to emit a horizontal laser beam, and a laser target for comparison is fixedly installed on the outermost Bailey beam of the Bailey support (2), so as to measure the deflection data of the Bailey support (2); A B2 measuring point is arranged at the connection of two truss modules of the Bailey support (2) at the mid-span position of the steel pipe column, the B2 measuring point is at the bottom of the Bailey support (2), a second pull-rope type displacement sensor (103-2) is installed at the B2 measuring point, and the bottom end of the pull rope is connected to the hardened ground to measure the settlement data of the Bailey support (2); In the disc-type scaffolding (3), a plurality of C measuring point areas are arranged at intervals along the transverse direction of the disc-type scaffolding (3), the C measuring point areas are all located below the bottom plate of the box beam formwork, and a third laser inclinometer (102-3), a third pull-wire displacement sensor (103-3) and a vertical pole axial force sensor (104) are installed in each C measuring point area; The third laser inclinometer (102-3) is installed on the upper part of the vertical pole (302), emits a horizontal laser beam, and the laser target for comparison is installed on the bridge pier (4) to measure the inclination data of the vertical pole (302); The third pull-rope displacement sensor (103-3) is installed on the uppermost crossbar (301) below the bottom plate of the box beam template, and the bottom of the pull rope is connected to the I-beam support beam (19) below to measure the settlement data of the disc-type scaffolding (3); The vertical pole axial force sensor (104) is installed between the top of the vertical pole (302) and the box beam template (601) instead of the wooden plank to measure the vertical load data of the vertical pole (302).

6. The monitoring method for the large-span cast-in-place box girder formwork support system implementing intelligent monitoring according to claim 5, Features: The first laser deflectometer (101-1) emits a vertical laser beam. When a target for comparing the vertical laser beam is installed on a hardened ground, the first laser deflectometer (101-1) and the first laser inclinometer (102-1) installed on the same steel pipe column (12) are arranged on different sides of the steel pipe column.

7. The monitoring method for the large-span cast-in-place box girder formwork support system implementing intelligent monitoring according to claim 3, Features: The monitoring area or monitoring unit described in step S2 does not exceed a distance of 3 steel pipe columns in the front-to-back direction.

8. The monitoring method for the large-span cast-in-place box girder formwork support system implementing intelligent monitoring according to claim 3, Features: When the sensor data is deflection data, the control value function of the corresponding deviation value is Min(H / 500,ΔH); When the sensor data is settlement data, the control value function of the corresponding deviation value is Min(H / 1000,ΔH); The H refers to the frame height between the bottom plate of the box beam formwork and the concrete foundation supported at the bottom end of the steel pipe column, ΔH refers to the preset maximum safety deviation value, and Min() is a minimum value function.

9. The monitoring method for the large-span cast-in-place box girder formwork support system implementing intelligent monitoring according to claim 3, Features: When the sensor data is inclination data, the corresponding verticality deviation control value should be ≤5‰. The verticality deviation refers to the ratio of the horizontal displacement of the measuring point where the sensor is located to Hc. Hc refers to the height from the measuring point to the concrete foundation supported at the bottom of the steel pipe column.

10. The monitoring method for the large-span cast-in-place box girder formwork support system implementing intelligent monitoring according to claim 4, Features: The alarm values ​​in step S3 are all set to 0.8 times of the corresponding control values.

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