A vertical and horizontal prestressed tendon grouting quality detection system and method for bridges
Through the grouting quality detection system of the vertical and horizontal prestressed ribs of the bridge, the grouting quality of the vertical and horizontal prestressed ribs of the bridge is detected by the vibration device and signal attenuation period, which solves the problem of weak detection signals in the prior art, and achieves fast, simple and accurate grouting density detection.
Patent Information
- Application Number
- CN202210323520.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-03-29
- Publication Date
- 2025-08-05
- Estimated Expiration
- 2042-03-29
AI Technical Summary
The prior art is difficult to accurately detect the grouting quality of the vertical and horizontal prestressed ribs of bridges, especially the single-ended prestressed ribs, which cannot be effectively detected by wave speed, attenuation and frequency methods, and the detection signal is weak, so the accurate grouting density cannot be obtained.
The bridge vertical and horizontal prestressed tendon grouting quality detection system is adopted, including an excitation device, a signal pickup device, a signal transmission cable and a detection host. The elastic wave signal is generated through the excitation device, and the grouting density is determined using the signal attenuation period, and the detection is carried out in combination with the energy attenuation method calibration process.
It realizes rapid, simple and accurate detection of the grouting quality of vertical and horizontal prestressed ribs on the bridge, ensures the quality of the construction, and provides a reference value calibration method for the grouting quality of the prestressed rib channel.
Smart Images
Figure CN114689461B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of bridge detection, and in particular relates to a system and method for detecting the quality of grouting of vertical and transverse prestressed reinforcements of a bridge. Background Art
[0002] Currently, testing the grouting quality of prestressed tendons in bridges generally uses methods based on wave velocity, attenuation, and frequency, according to standards. This precondition requires that both anchorage ends of the tendons in the structure under test be exposed, with suitable locations for installing sensors and excitation. However, since most horizontal and vertical prestressed tendons in bridges do not have both anchorage ends exposed, methods based on wave velocity, attenuation, and frequency cannot be used for testing.
[0003] During construction, the anchorage ends of the horizontal and vertical prestressed tendons in bridges are cast into the concrete. Tensioning and grouting are then performed after the required construction age is met. Therefore, when testing the grouting of this structure, signal excitation and reception can only be performed at the exposed tensioned ends. Furthermore, the design placement of the horizontal and vertical prestressed tendons in bridges is typically located where the concrete is thick (mostly exceeding 80cm), making accurate detection impossible by testing along the path of the holes on the concrete surface.
[0004] The vertical and transverse prestressed tendons are pre-stressed and then grouted to lock the prestress. According to research, the amount of prestress applied is related to the diameter of the tendon. The larger the diameter of the tendon, the greater the prestress it bears, and the greater the prestress that can be applied. Under normal circumstances, the prestress of the vertical and transverse prestressed tendons of prestressed bridges is generally 600kN. When the grouting quality is poor, air, water, etc. will enter the interior of the channel, and the prestressed tendons are prone to rust and cracking. At the same time, under the impact of the reciprocating load of the vehicle, it is easy to cause brittle fracture of the vertical and transverse prestressed tendons.
[0005] Local and industry standards have emerged for testing the grouting density of double-ended prestressed tendons in bridges, but there are few reports on testing the grouting density of vertical and transverse prestressed tendons in single-end anchored and single-end tensioned bridges.
[0006] After research, it was found that the factors affecting the grouting quality of vertical and transverse prestressed tendons of bridges are mainly reflected in the following: the anchorage end of the prestressed tendons is poured concrete, the prestressed tendons are relatively long, the signal attenuates rapidly, and at the same time, the impedance difference between the prestressed tendons and concrete is small, resulting in weak bottom reflection signals, making it impossible to obtain the signal position, and it is also impossible to detect the grouting density through reflection-based methods.
[0007] Due to the many drawbacks of existing methods and the continuous emergence of a large number of prestressed bridges, there is a huge demand for grouting quality inspection of vertical and transverse prestressed tendons. Through in-depth research, a detection system and method for accurately detecting the grouting density of vertical and transverse prestressed tendons of bridges are proposed. By fully combining the structural characteristics of vertical and transverse prestressed tendons, an energy attenuation method benchmark value calibration process is proposed to achieve accurate detection of the grouting density of vertical and transverse prestressed tendons of bridges. Summary of the Invention
[0008] The purpose of the present invention is to solve the problem of how to establish a benchmark value for grouting density detection using the energy attenuation method and how to use the benchmark value to detect the quality of grouting density. A system and method for detecting the grouting quality of vertical and transverse prestressed tendons of bridges are proposed.
[0009] The technical solution of the present invention is: a bridge vertical and transverse prestressed tendon grouting quality detection system includes bridge concrete, an excitation device, vertical and transverse prestressed tendons, a signal pickup device, a signal transmission cable and a detection host;
[0010] The vertical and transverse prestressed tendons are arranged on one side of the bridge concrete; the excitation device and the signal pickup device are both fixedly connected to the vertical and transverse prestressed tendons; the signal pickup device is communicatively connected to the detection host through a signal transmission cable.
[0011] Furthermore, the axial direction of the signal pickup device overlaps or is parallel to the axial direction of the vertical and transverse prestressed tendons.
[0012] Furthermore, the vibration device includes a vibration cone and a hard vibration hammer for colliding with each other.
[0013] The beneficial effects of the present invention are as follows: the present invention provides a set of bridge vertical and transverse prestressed tendon grouting quality detection system, which effectively detects the grouting quality of the bridge vertical and transverse prestressed tendons and ensures the construction quality of the project.
[0014] Based on the above system, the present invention also proposes a method for detecting the grouting quality of vertical and transverse prestressed reinforcement of a bridge, comprising the following steps:
[0015] S1: Install the bridge vertical and transverse prestressed reinforcement grouting quality detection system;
[0016] S2: In the bridge vertical and transverse prestressed tendon grouting quality inspection system, a vibration device is used to vibrate the ends of the bridge vertical and transverse prestressed tendons in different grouting states to determine the attenuation period of the excited elastic wave signal propagating axially along the bridge vertical and transverse prestressed tendons;
[0017] S3: The grouting density index of the vertical and transverse prestressed tendons of the bridge is obtained based on the attenuation period of the excited elastic wave signal propagating axially along the vertical and transverse prestressed tendons of the bridge.
[0018] Furthermore, in step S1, the specific method for installing the bridge vertical and transverse prestressed tendon grouting quality detection system is: polishing the ends and sides of the vertical and transverse prestressed tendons of the bridge to be tested, applying coupling agent to the polished ends and sides of the vertical and transverse prestressed tendons of the bridge to be tested, and installing signal pickup devices on the ends and sides of the vertical and transverse prestressed tendons of the bridge to be tested, and using signal transmission cables to connect the detection host and the signal pickup device.
[0019] Furthermore, in step S2, in the relationship expression between the grouting density of the vertical and transverse prestressed tendons of the bridge and the attenuation period, the grouting density in the dense state and the grouting density in the un-grouting state are set to 1 and 0, respectively, to obtain the attenuation period in the dense state and the un-grouting state;
[0020] The relationship between the grouting density of vertical and transverse prestressed reinforcement of bridges and the attenuation period is expressed as follows:
[0021] T i (D i )=aD i +b
[0022] Among them, D i Indicates the grouting density of the known i-th state, T i represents the decay period of the i-th state, a represents the first correlation coefficient, and b represents the second correlation coefficient.
[0023] Furthermore, in step S3, the bridge vertical and transverse prestressed reinforcement grouting density index D i The calculation formula is:
[0024]
[0025] Where T represents the attenuation period obtained by testing and analyzing the vertical and transverse prestressed tendons, T i (1) represents the decay period of the dense state, T i (0) represents the decay period of the ungrouted state.
[0026] The beneficial effects of the present invention are as follows: the present invention provides a set of calibration methods for prestressed tendon duct grouting quality detection benchmark values, which facilitates the rapid, simple and accurate detection of the grouting density of prestressed tendons in bridges. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 This is the structural diagram of the bridge vertical and transverse prestressed reinforcement grouting quality detection system;
[0028] Figure 2 This is a structural diagram of the excitation device;
[0029] Figure 3 This is a flow chart of the quality inspection method for grouting of vertical and transverse prestressed reinforcement in bridges;
[0030] Figure 4 Schematic diagram of the attenuation cycle in dense state and ungrouted state;
[0031] Figure 5 This is a test waveform diagram for testing prestressed tendons;
[0032] Figure 6 This is the analysis result diagram of the prestressed tendon test;
[0033] In the figure, 1. Bridge concrete; 2. Vibration device; 2-1. Vibration cone; 2-2. Hard vibration hammer; 3. Vertical and transverse prestressed tendons; 4. Signal pickup device; 5. Signal transmission cable; 6. Detection host. DETAILED DESCRIPTION
[0034] The embodiments of the present invention will be further described below with reference to the accompanying drawings.
[0035] like Figure 1 As shown, the present invention provides a bridge vertical and transverse prestressed tendon grouting quality detection system, including bridge concrete 1, an excitation device 2, vertical and transverse prestressed tendons 3, a signal pickup device 4, a signal transmission cable 5 and a detection host 6;
[0036] The vertical and transverse prestressed tendons 3 are arranged on one side of the bridge concrete 1; the excitation device 2 and the signal pickup device 4 are fixedly connected to the vertical and transverse prestressed tendons 3; the signal pickup device 4 is communicatively connected to the detection host 6 through a signal transmission cable 5.
[0037] The detection system's measuring points are located on the sides or tops of prestressed tendons. The detection host collects, displays, stores, and analyzes signals.
[0038] In the embodiment of the present invention, the axial direction of the signal pickup device 4 overlaps or is parallel to the axial direction of the vertical and transverse prestressed tendons 3. The signal pickup device is provided with magnetic coupling, and the coupling material of the signal pickup device includes but is not limited to butter, toothpaste, and vaseline.
[0039] In the embodiment of the present invention, Figure 2 As shown, the excitation device 2 includes an excitation cone 2-1 and a hard excitation hammer 2-2 for colliding with each other. When generating elastic wave signals, two collisions are required, which is a combined device for generating signals.
[0040] The left end of the excitation cone 2-1 is made of nylon, and the right end is made of hard material.
[0041] Based on the above system, the present invention also proposes a method for detecting the quality of grouting of vertical and transverse prestressed tendons of bridges, such as Figure 3 As shown, the following steps are included:
[0042] S1: Install the bridge vertical and transverse prestressed reinforcement grouting quality detection system;
[0043] S2: In the bridge vertical and transverse prestressed tendon grouting quality inspection system, a vibration device is used to vibrate the ends of the bridge vertical and transverse prestressed tendons in different grouting states to determine the attenuation period of the excited elastic wave signal propagating axially along the bridge vertical and transverse prestressed tendons;
[0044] S3: The grouting density index of the vertical and transverse prestressed tendons of the bridge is obtained based on the attenuation period of the excited elastic wave signal propagating axially along the vertical and transverse prestressed tendons of the bridge.
[0045] In an embodiment of the present invention, in step S1, the specific method for installing the bridge vertical and transverse prestressed tendon grouting quality detection system is: polishing the ends and sides of the vertical and transverse prestressed tendons of the bridge to be tested, applying coupling agent to the polished ends and sides of the vertical and transverse prestressed tendons of the bridge to be tested, and installing signal pickup devices on the ends and sides of the vertical and transverse prestressed tendons of the bridge to be tested, and using signal transmission cables to connect the detection host and the signal pickup device.
[0046] In the embodiment of the present invention, Figure 4 As shown, in step S2, in the relationship expression between the grouting density of the vertical and transverse prestressed tendons of the bridge and the attenuation period, the grouting density in the dense state and the grouting density in the un-grouting state are set to 1 and 0, respectively, to obtain the attenuation period in the dense state and the un-grouting state;
[0047] The relationship between the grouting density of vertical and transverse prestressed reinforcement of bridges and the attenuation period is expressed as follows:
[0048] T i (D i )=aD i +b
[0049] Among them, D i Indicates the grouting density of the known i-th state, T i represents the decay period of the i-th state, a represents the first correlation coefficient, and b represents the second correlation coefficient.
[0050] In the embodiment of the present invention, in step S3, the bridge vertical and transverse prestressed reinforcement grouting density index D i The calculation formula is:
[0051]
[0052] Where T represents the attenuation period obtained by testing and analyzing the vertical and transverse prestressed tendons, T i (1) represents the decay period of the dense state, T i (0) represents the decay period of the ungrouted state.
[0053] In an embodiment of the present invention, before testing, it is necessary to determine that the end of the prestressed tendon to be tested is about 5 cm away, the end and side of the prestressed tendon must be polished, a coupling agent must be applied to the end face or side of the prestressed tendon, and then a signal pickup device must be installed on the side or top. The pickup device must be parallel to or in the same line as the prestressed tendon in the longitudinal direction. A signal transmission cable must be used to connect the detection host and the signal pickup device. A special excitation device must be used to excite the end of the prestressed tendon. The excited elastic wave signal must propagate along the axial direction of the prestressed tendon and be reflected at the bottom. The attenuation period of the signal must be analyzed to infer the grouting density index of the prestressed tendon.
[0054] This detection technology and equipment are based on the attenuation characteristics of elastic waves, and the detection method is the local attenuation method. This invention uses a special columnar excitation device to excite the prestressed tendons. The device can generate a wavelength long enough so that the vibration energy can be transmitted to the bottom of the rod and return. When the grouting quality is poor, the prestressed tendons will produce continuous vibrations after being vibrated, and the signal pickup device will collect the vibration signal. When the prestressed tendons have grouting material, the vibration signal energy is absorbed by the grouting material and attenuated. The denser the grouting material, the faster the signal attenuation. That is, the shorter the vibration attenuation period, the longer the vibration attenuation period when the grouting quality is poor. Combined with the calibration results of the dense state and the un-grouting state, analysis is performed to obtain the grouting density index.
[0055] The density decay period T is determined by conducting calibration tests on vertical and transverse prestressed bars with different grouting conditions. i (1) and the decay period T of the ungrouted state i (0), the density index D of the object to be tested i , calculate according to the following formula.
[0056] Dense decay period T i (1) and the decay period T of the ungrouted state i (0) Determine by following the steps below:
[0057] 1) Based on the object to be measured, cast a concrete model (the concrete strength grade is the same as that of the object to be measured). The shortest side of the concrete model cross section should be larger than the shortest side of the measured boundary size or not less than 20cm. The internal pre-buried pipe should be in the middle of the shortest side of the model cross section.
[0058] 2) The number of prestressed holes in the model shall be no less than 3;
[0059] 3) Insert the prestressed steel bar, anchor it and tension it. The tensioning force should be consistent with the design tensioning force of the object being tested.
[0060] 4) Grouting is performed on the tested duct, and the grouting density (P i (D i , Ti ) index is not less than 3, and grouting is performed on different prestressed tendons. i represents the density of the grouting in the known i-th state, T i represents the decay period of the i-th state;
[0061] 5) After reaching the age, the prestressed tendons in different states are tested and the attenuation period of the test signal in each state is analyzed;
[0062] 6) Grouting density is negatively correlated with the decay period, that is, T i (D i )=aD i + b. Analyze using at least three known density states and the analyzed decay period to obtain the coefficients a and b.
[0063] 7) Let the density state D i When it is 1 or 0 (i.e. D i =1 means full grouting, D i =0 means no grouting), according to the negative correlation, the lower limit of the analysis and judgment threshold T i (1) and T i (0).
[0064] The present invention will be described below with reference to specific embodiments.
[0065] This method was used to test the grouting quality of the transverse prestressed reinforcement on a high-speed bridge in Guizhou. According to relevant documentation, the prestressed reinforcement was made of JL32 finely rolled rebar, 590 cm long, with a controlled tension force of 639 kN under the anchor, using single-end tensioning. The prestressed conduits were 45 mm diameter metal bellows, each equipped with a grouting pipe. Prior to testing, a concrete model similar to the test object was constructed for calibration of benchmark parameters.
[0066] Through the calibration test of the model, the decay period of the model in the dense grouting and un-grouting state is analyzed to be 1.4ms and 23.7ms respectively. The prestressed tendons are tested using this benchmark value. Please refer to the test waveform. Figure 5 , please refer to the analysis results Figure 6 .
[0067] Field testing revealed defects in the grouting of the prestressed tendons. During subsequent grouting, the volume of grout injected was close to the volume of the prestressed channel. This method can accurately detect grouting conditions and identify quality issues, providing a reliable basis for improving project quality.
[0068] The working principle and process of the present invention are as follows: a special magnetic signal pickup device is installed on the top or side wall of a completed or existing structure. The axial direction of the device is parallel to or in line with the prestressed tendons. The coupling between the device and the prestressed tendons includes but is not limited to butter, toothpaste, and vaseline. A special automatic excitation device is used to excite the top plate of the prestressed tendons. The elastic wave signal generated by the excitation is transmitted along the axial direction of the pile to the bottom of the pile and reflected. The reflected signal is amplified by a charge amplifier and then transmitted to the display terminal and calculated through the device host and analog-to-digital conversion card. Before the invention of this detection equipment, this detection technology method was first invented. The excitation is carried out by a special excitation tool and the excited signal is received and processed. The efficiency and accuracy of the detection results have achieved significant breakthroughs.
[0069] The beneficial effects of the present invention are:
[0070] (1) The present invention provides a set of bridge vertical and transverse prestressed tendon grouting quality detection system, which can effectively detect the grouting quality of the bridge vertical and transverse prestressed tendons to ensure the construction quality of the project;
[0071] (2) The present invention provides a calibration method for benchmark values of prestressed tendon duct grouting quality inspection, which facilitates the rapid, simple and accurate inspection of the grouting density of prestressed tendons in bridges.
[0072] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific descriptions and embodiments. Those skilled in the art can make various other specific variations and combinations based on the technical teachings disclosed in the present invention without departing from the essence of the present invention, and such variations and combinations are still within the scope of protection of the present invention.
Claims
1. A method for detecting the grouting quality of vertical and transverse prestressed tendons of a bridge, characterized in that: The following steps are involved: S1: Installing a bridge vertical and transverse prestressed tendon grouting quality detection system; the specific method for installing the bridge vertical and transverse prestressed tendon grouting quality detection system is as follows: polishing the ends and sides of the vertical and transverse prestressed tendons of the bridge to be tested, applying coupling agent to the polished ends and sides of the vertical and transverse prestressed tendons of the bridge to be tested, installing signal pickup devices on the ends and sides of the vertical and transverse prestressed tendons of the bridge to be tested, and connecting the detection host and the signal pickup device with a signal transmission cable; S2: In the bridge vertical and transverse prestressed tendon grouting quality inspection system, an excitation device is used to excite the ends of the bridge vertical and transverse prestressed tendons in different grouting states to determine the attenuation period of the excited elastic wave signal propagating axially along the bridge vertical and transverse prestressed tendons. In the relationship expression between the grouting density of the bridge vertical and transverse prestressed tendons and the attenuation period, the grouting density of the dense state and the grouting density of the un-grouting state are set to 1 and 0, respectively, to obtain the attenuation period of the dense state and the un-grouting state. The relationship between the grouting density of vertical and transverse prestressed reinforcement of bridges and the attenuation period is expressed as follows: in, Indicates that the known i The density of grouting in different states, Indicates the i The decay period of the state, a represents the first correlation coefficient, b represents the second correlation coefficient; S3: Based on the attenuation period of the excited elastic wave signal propagating axially along the vertical and transverse prestressed tendons of the bridge, the grouting density index of the vertical and transverse prestressed tendons of the bridge is obtained; the grouting density index of the vertical and transverse prestressed tendons of the bridge is obtained. The calculation formula is: in, T It represents the attenuation period obtained through the test analysis of vertical and transverse prestressed tendons. represents the decay period of the dense state, Indicates the decay period of the un-grouted state.