CN212007614U - Vertical effective prestress detection device based on reverse pulling method - Google Patents
Vertical effective prestress detection device based on reverse pulling method Download PDFInfo
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- CN212007614U CN212007614U CN202021157471.0U CN202021157471U CN212007614U CN 212007614 U CN212007614 U CN 212007614U CN 202021157471 U CN202021157471 U CN 202021157471U CN 212007614 U CN212007614 U CN 212007614U
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Abstract
The utility model discloses a vertical effective prestress detection device based on a reverse pulling method, which comprises a reaction frame and a connecting sleeve; the top wall of the reaction frame is provided with a through hole, and connecting deformed steel bars penetrate through the through hole; the lower end of the connecting deformed steel bar extends downwards and is sleeved with the connecting sleeve; a displacement sensor is arranged at the lower side of the top wall of the reaction frame close to the position of the connecting thread steel; an upper anchorage device, an upper backing plate, a lower anchorage device and a lower backing plate are sequentially arranged right below the connecting sleeve; the connecting sleeve, the upper anchorage device, the upper backing plate, the lower anchorage device and the lower backing plate are all spaced at a certain distance. The utility model discloses utilize displacement sensor to detect the displacement volume of finish rolling screw-thread steel for the reaction frame, calculate out the original vertical effective prestressing force of finish rolling screw-thread steel, compare prior art, improve greatly on the measuring accuracy.
Description
Technical Field
The utility model relates to a vertical effective prestressing force detection device, concretely relates to vertical effective prestressing force detection device based on anti-pulling method.
Background
The prestressed concrete box girder adopts a three-dimensional stressed prestressed structure, the integrity, the bending resistance and the torsion resistance of the structure are better than those of other bridge types, the structure is reasonable in stress, the number of telescopic functional devices is small, the travelling crane is relatively stable, the bridge maintenance is convenient, and the service life are also greatly prolonged. Compared with bridges such as cable-stayed bridges, suspension bridges and the like, the prestressed concrete box girder bridge has balanced construction and good technical and economic performance, and is generally the first choice for highway municipal bridges.
The prestressed concrete box girder bridge has relatively stable prestressed design procedure and perfect construction in the structure developed to date. However, such bridges have crack diseases in the operation process so far, and particularly the problem of cracking of the web plates of the box girder bridges is solved. The occurrence of diseases seriously affects the durability of the bridge, and causes great social and economic benefit loss. One of the main causes of cracking of the bridge web is excessive vertical prestress loss or failure. At present, a prestressed concrete box girder bridge is generally provided with vertical prestressed tendons, and the prestress of the vertical prestressed tendons is used for offsetting the main tensile stress of a bridge web to prevent the bridge web from cracking. Although the vertical prestressed tendons are arranged, no matter finish-rolled deformed steel bars or steel strands are adopted as the vertical prestressed tendons, the situation that tensioning is not in place exists in the construction process, and the prestress under the anchor does not meet the design requirement. Because the finish rolling deformed steel bar is convenient to install, convenient to hang basket anchoring, small in looseness and good in durability, the finish rolling deformed steel bar is still adopted by most bridges at present.
In order to solve the problem that the prestress is not tensioned in place, on one hand, an effective prestress detection method and a research and development instrument under the anchor are provided to form corresponding standards, and the construction behaviors of workers can be well restrained and normalized through the effective prestress detection method and the research and development instrument, so that the vertical prestress construction behaviors have controllability; on the other hand, the effective detection means can promote the construction units to improve the construction process and improve the construction reliability, thereby thoroughly solving the problem of overlarge vertical prestress or failure, and having important technical and economic significance for preventing the prestressed concrete box girder bridge web from cracking and improving the durability and reliability of the bridge.
The currently common detection methods for the vertical prestressed tendons comprise the following steps: the method comprises a vertical prestressed tendon exposed section frequency testing method, an oil pressure gauge changing algorithm, a pressure sensor testing method, a strain gauge testing method, a magnetic flux detecting method, a retraction amount detecting method and an ultrasonic stress detecting method. The existing various detection methods have the following defects:
exposed section frequency test method: when the tolerance fit of the nut and the finish rolling deformed steel bar is inconsistent, the rigidity of the anchoring section of the same tension force exposed section is different, so that the measured effective tension force has larger error, and on the other hand, the nut anchoring section and the anchor backing plate transfer force through contact, so that the cantilever beam model simplified into complete fixed connection has error when the tension force is lower.
Oil pressure gauge conversion algorithm: the method only needs one set of pre-stress tension equipment, is simple and easy to operate, and is the most convenient and direct method for controlling the tension force in construction. However, this method is only suitable for controlling the stress of a construction unit during tensioning, and is not suitable for post-detection and spot check.
Pressure sensor test method: the method has high precision of the measuring instrument, and can be used for testing for multiple times after being buried in the box girder, so that the test result is more reliable, and the method is a detection method with higher measuring precision, but the purchase cost of the instrument is higher, and the method is only suitable for scientific research.
Strain gage test method: during construction, the strain gauge is adhered to the surface of the polished and flat reinforcing steel bar by using strong glue, a waterproof measure is made, a lead is led out of the box body, the reading of the strain gauge is collected before tensioning, and data are collected after tensioning for comparison. However, the method has long test period, and the strain gauge is easy to peel off and fail, so the method is less in use.
Magnetic flux detection method: when the finish-rolled threaded steel bar is in a natural state, the magnetic flux of the finish-rolled threaded steel bar can be maintained in a stable interval, after prestress is applied, the magnetic flux of the finish-rolled threaded steel bar can be changed, the change relation between the prestress and the magnetic flux can be calibrated in advance, the change of the magnetic flux is obtained through the test of a miniature electromagnetic sensor, and the actual tension of the steel bar can be obtained according to the calibration relation. The method is a nondestructive testing method, the idea is very novel and unique, but the technology in the aspect is not mature at present, so whether the reliability of the test result of the method is still awaited.
Retraction amount detection method: under normal conditions, the method has high measurement precision, is enough to meet the actual engineering requirements, and is a practical measurement method. However, when the method is applied specifically, the retraction error may be caused by the deflection of the steel bar, so that the measurement result has deviation, therefore, when the dial indicator is installed, the dial indicator and the steel bar are on the same plane as much as possible, the measurement error is reduced, and the accuracy of the measurement result is ensured.
Ultrasonic stress detection method: the ultrasonic wave has the acoustic elasticity phenomenon, and the wave velocity changes along with the change of the stress state, so the tensile force can be estimated by utilizing the corresponding relation between the wave velocity and the stress state. However, the method has higher requirement on the flatness of the end face of the deformed steel bar, and the long steel bar cannot be tested due to the fact that the energy loss is fast, and the effective tensile force test result of the vertical prestressed tendon is smaller than the actual tensile force of the vertical prestressed tendon, and the error is larger.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that utilize above-mentioned background art test to calculate the inconvenient problem that test accuracy is not high of vertical effective prestressing force operation, aim at provides a vertical effective prestressing force detection device based on anti-pulling method, solves above-mentioned problem.
The utility model discloses a following technical scheme realizes:
a vertical effective prestress detection device based on a reverse pulling method comprises a reaction frame and a connecting sleeve;
the top wall of the reaction frame is provided with a through hole, and connecting deformed steel bars penetrate through the through hole;
the lower end of the connecting deformed steel bar extends downwards and is sleeved with the connecting sleeve;
a displacement sensor is arranged at the lower side of the top wall of the reaction frame close to the position of the connecting thread steel;
an upper anchorage device, an upper backing plate, a lower anchorage device and a lower backing plate are sequentially arranged right below the connecting sleeve; the connecting sleeve, the upper anchorage device, the upper backing plate, the lower anchorage device and the lower backing plate are all spaced at a certain distance.
Further, a jack is arranged on the upper side of the top wall of the reaction frame, and a testing nut and a base plate are arranged on the upper side of the jack; one end of the connecting screw steel, which is positioned at the upper part of the reaction frame, sequentially penetrates through the jack, the test nut and the base plate; the side wall of the jack is connected with one end of an oil delivery pipe, and the other end of the oil delivery pipe is connected with an oil pump; and the displacement sensor and the oil pump are connected with the host.
Further, the vertical effective prestress detection device based on the reverse pulling method further comprises a bridge deck, wherein the bridge deck is used for placing a reaction frame; the middle position of the bridge deck, which is opposite to the counterforce frame, is in a concave shape, and the concave surface is used for placing an upper anchorage device and an upper base plate.
Further, a vertical effective prestress detection device based on the reverse pulling method, an oil pressure gauge is further arranged on the oil pump.
Further, a vertical effective prestressing force detection device based on anti-pulling method, connecting thread steel passes through adapter sleeve threaded connection with finish rolling thread steel.
Further, a vertical effective prestress detection device based on a reverse pulling method, wherein the reaction frame is made of carbon steel.
The utility model discloses combine the oil meter algorithm of changing and the principle of the volume of returning detection method of contracting, utilize the stretch-draw system equipment among the oil meter algorithm of changing, carry out reverse stretch-draw to the finish rolling screw-thread steel, stretch out certain length with the finish rolling screw-thread steel, again according to tensile length, finish rolling screw-thread steel elastic modulus and cross-sectional area etc. calculate the vertical effective prestressing force of finish rolling steel indirectly.
The utility model discloses application method as follows:
a preparation stage: and connecting the finish rolling deformed steel bar to be tested with the connecting deformed steel bar through a connecting sleeve, and sequentially penetrating through the reaction frame, the jack, the test nut and the base plate. The jack is arranged on the reaction frame, the test nut and the base plate are arranged on the jack, and the nut is screwed;
fixing the displacement sensor on the finish-rolled deformed steel bar, and enabling a probe of the displacement sensor to abut against the counterforce frame to enable the displacement sensor to have a certain displacement; the displacement sensor, the oil pump and the host are connected, the jack is connected with the oil pump, and the oil pump is further provided with an oil pressure gauge. The connection of each part was confirmed to be good.
Opening the host, confirming that the communication connection among the host, the displacement sensor and the oil pump is good, and recording the displacement value S at the moment0(ii) a Filling relevant parameters (anchoring tension length L, elastic modulus E, cross-sectional area A and the like) into corresponding positions;
the main machine is utilized to control the working state of the oil pump, the oil pump is started to drive the jack to work, and the finish-rolled deformed steel bar is pulled out to a certain distance S1And automatically stopping tensioning. And calculating the vertical effective prestress of the finish rolling deformed steel bar to be measured through software.
And (3) a testing stage: opening the host machine, and confirming that the communication connection among the host machine, the displacement sensor and the oil pump is good; the working state of the oil pump is controlled by the host, the oil pump is started to drive the jack to work, and when the force value of the jack reaches the early warning set value T0Then, the displacement value S at this time is recorded0(ii) a Drawing out the finish-rolled deformed steel bar to a set displacement S1And automatically stopping tensioning. Reading the oil pressure value M at the moment;
early warning set value T0: the force value of the jack can be set according to experience when the system is just tensioned; as a mode for convenient calculation and use test, the connecting deformed steel bar adopts the same specification as that of the finish rolling deformed steel bar to be tested.
For the whole prestressing system, elongation Δ S of the deformed bars (finish-rolled deformed bars to be tested and connecting deformed bars):
△S＝S1—S0
deformation quantity Delta L of connection screw-thread steel1：
B is the cross sectional area of the connecting deformed steel bar;
e is the elastic modulus of the connecting deformed steel bar;
L1is the length of the connecting screw-thread steel;
T1for the pulling force that the connection screw-thread steel received, the pulling force size that size and jack received equals:
T1＝A0*M
A0the cross section area of the oil cylinder of the jack is shown;
m is an oil pressure indication number;
deformation quantity delta L of exposed section of finish rolling deformed steel bar to be measured2:
L2The length of the exposed section of the finish-rolled deformed steel bar;
e is the elastic modulus of the finish-rolled deformed steel bar;
and A is the cross-sectional area of the finish-rolled deformed steel bar.
From the displacement relationship: deformation quantity delta L before and after tension test of finish-rolled deformed steel bar3：
△L3＝△S-△L1-△L2
The relation between deformation and stress is as follows: deformation quantity delta L before and after tension test of finish-rolled deformed steel bar3：
T2Increasing force values before and after tension test for the anchoring section of the finish-rolled deformed steel bar;
l is the length of an anchoring tension section in the finish rolling deformed steel web;
the stress relationship of the finish-rolled deformed steel can be obtained as follows:
T1＝T2+T
t is the original tension force (vertical effective prestress) of the finish-rolled deformed steel bar;
in conclusion, the original tension (vertical effective prestress) of the finish rolling deformed steel bar to be measured can be obtained:
the deformed bar with the same diameter as the finish-rolled deformed bar to be measured is usually taken as a connecting deformed bar, namely B is A;
usually the jack force value reaches the early warning value T0While, the displacement value may be manually set to zero, i.e., S0＝0，△S＝S1(ii) a The above equation can be simplified as:
the reaction frame can be slightly deformed in the stress process, can be ignored under the condition of low precision requirement, and can calculate the deformation quantity delta L of the reaction frame in the stress process according to the elastic modulus and the cross section area of the reaction frame under the condition of high result precision requirement4As displacement compensation: elongation of deformed steel bar (finish-rolled deformed steel bar and connection deformed steel bar):
△S＝S1+△L4
compared with the prior art, the utility model, following advantage and beneficial effect have:
the utility model relates to a vertical effective prestressing force detection device based on anti-pulling method utilizes displacement sensor to detect the displacement volume of finish rolling screw-thread steel for the reaction frame, calculates out the original vertical effective prestressing force of finish rolling screw-thread steel, compares prior art, improves greatly on the measuring accuracy.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:
fig. 1 is a schematic structural diagram of the present invention.
Reference numbers and corresponding part names in the drawings:
1-main engine, 2-oil pump, 3-connecting screw steel, 4-testing nut and backing plate, 5-jack, 6-reaction frame, 7-displacement sensor, 8-connecting sleeve, 9-upper anchorage device and upper backing plate, 10-finish rolling screw steel, 11-lower anchorage device and lower backing plate, and 12-bridge floor.
Detailed Description
To make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the following examples and drawings, and the exemplary embodiments and descriptions thereof of the present invention are only used for explaining the present invention, and are not intended as limitations of the present invention.
Examples
As shown in fig. 1, the utility model relates to a vertical effective prestress detection device based on an anti-pulling method, which comprises a reaction frame 6 and a connecting sleeve 8;
the top wall of the reaction frame 6 is provided with a through hole, and a connecting screw-thread steel 3 penetrates through the through hole;
the lower end of the connecting deformed steel bar 3 extends downwards and is sleeved with the connecting sleeve 8;
a displacement sensor 7 is arranged at the lower side of the top wall of the reaction frame 6 close to the connecting screw-thread steel 3;
an upper anchorage device, an upper backing plate 9, a lower anchorage device and a lower backing plate 11 are sequentially arranged right below the connecting sleeve 8; and a certain distance is reserved among the connecting sleeve 8, the upper anchorage device, the upper backing plate 9, the lower anchorage device and the lower backing plate 11.
Further, a jack 5 is arranged on the upper side of the top wall of the reaction frame 6, and a test nut and a base plate 4 are arranged on the upper side of the jack 5; one end of the connecting screw-thread steel 3, which is positioned at the upper part of the reaction frame 6, sequentially penetrates through the jack 5, the test nut and the base plate 4; the side wall of the jack 5 is connected with one end of an oil delivery pipe, and the other end of the oil delivery pipe is connected with the oil pump 2; and the displacement sensor 7 and the oil pump 2 are both connected with the host 1.
Further, the vertical effective prestress detection device based on the reverse pulling method further comprises a bridge deck 12, wherein the bridge deck 12 is used for placing the reaction frame 6; the middle position of the bridge deck 12, which is opposite to the reaction frame 6, is in a concave shape, and the concave surface is used for placing an upper anchorage device and an upper backing plate 9.
Further, a vertical effective prestressing force detection device based on anti-pulling method, still be provided with the oil pressure gauge on the oil pump 2.
Further, a vertical effective prestressing force detection device based on anti-pulling method, connecting thread steel 3 passes through adapter sleeve 8 threaded connection with finish rolling thread steel 10.
The utility model discloses application method as follows:
a preparation stage: and connecting the finish rolling deformed steel bar 10 to be tested with the connecting deformed steel bar 3 through a connecting sleeve 8, and sequentially penetrating through the reaction frame 6, the jack 5, the test nut and the base plate 4. The jack 5 is arranged on the reaction frame 6, the test nut and the base plate 4 are arranged on the jack 5, and the nut is screwed;
fixing the displacement sensor 7 on the finish-rolled deformed steel bar 10, and enabling a probe of the displacement sensor 7 to abut against the reaction frame 6, so that the displacement sensor 7 has a certain displacement; will displacement sensor 7, oil pump 2 with host computer 1 is connected, jack 5 with oil pump 2 is connected, oil pump 2 on still be provided with the oil pressure gauge. The connection of each part was confirmed to be good.
Opening the host, confirming that the communication connection among the host, the displacement sensor and the oil pump is good, and recording the displacement value S at the moment0(ii) a Filling relevant parameters (anchoring tension length L, elastic modulus E, cross-sectional area A and the like) into corresponding positions;
the main machine is utilized to control the working state of the oil pump, the oil pump is started to drive the jack to work, and the finish-rolled deformed steel bar is pulled out to a certain distance S1And automatically stopping tensioning. And calculating the vertical effective prestress of the finish rolling deformed steel bar to be measured through software.
And (3) a testing stage: opening the main machine 1, confirming the communication connection of the main machine 1, the displacement sensor 7 and the oil pump 2The connection is good; the working state of the oil pump 2 is controlled by the host 1, the oil pump 2 is started to drive the jack 5 to work, and when the force value of the jack 5 reaches the early warning set value T0Then, the displacement value S at this time is recorded0(ii) a Drawing out the finish-rolled deformed steel bar 10 to a set displacement S1And automatically stopping tensioning. Reading the oil pressure value M at the moment;
early warning set value T0: the force value of the jack 5 can be set according to experience when the system is just tensioned; as a way of facilitating the calculation and the use of the test, the connection deformed steel bar 3 is of the same specification as the finish rolled deformed steel bar 10 to be measured.
The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above description is only the embodiments of the present invention, and is not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (6)
1. A vertical effective prestress detection device based on a reverse pulling method is characterized by comprising a reaction frame (6) and a connecting sleeve (8);
the top wall of the reaction frame (6) is provided with a through hole, and a connecting screw-thread steel (3) penetrates through the through hole;
the lower end of the connecting deformed steel bar (3) extends downwards and is sleeved with the connecting sleeve (8);
a displacement sensor (7) is arranged at the lower side of the top wall of the reaction frame (6) close to the position of the connecting screw-thread steel (3);
an upper anchorage and an upper backing plate (9), a lower anchorage and a lower backing plate (11) are sequentially arranged right below the connecting sleeve (8); the connecting sleeve (8), the upper anchorage device and the upper backing plate (9), and the lower anchorage device and the lower backing plate (11) are all separated by a certain distance.
2. The device for detecting the vertical effective prestress based on the reverse pulling method according to claim 1,
a jack (5) is arranged on the upper side of the top wall of the reaction frame (6), and a test nut and a base plate (4) are arranged on the upper side of the jack (5); one end of the connecting screw steel (3) positioned at the upper part of the reaction frame (6) sequentially penetrates through the jack (5), the test nut and the base plate (4); the side wall of the jack (5) is connected with one end of an oil delivery pipe, and the other end of the oil delivery pipe is connected with the oil pump (2); and the displacement sensor (7) and the oil pump (2) are connected with the host (1).
3. The device for detecting the vertical effective prestress based on the reverse pulling method according to claim 2, further comprising a bridge deck (12), wherein the bridge deck (12) is used for placing the reaction frame (6); the middle position of the bridge deck (12) opposite to the reaction frame (6) is concave, and the concave surface is used for placing an upper anchorage device and an upper backing plate (9).
4. The device for detecting the effective vertical prestress based on the reverse pulling method as claimed in claim 2, wherein an oil pressure gauge is further arranged on the oil pump (2).
5. The device for detecting the vertical effective prestress based on the reverse pulling method according to claim 1, wherein the connection screw-thread steel (3) is in threaded connection with the finish rolling screw-thread steel (10) through a connection sleeve (8).
6. The device for detecting the vertical effective prestress based on the reverse pulling method as claimed in claim 1, wherein the reaction frame (6) is made of carbon steel.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112945432A (en) * | 2021-02-07 | 2021-06-11 | 内蒙古自治区交通建设工程质量监督局 | System and method for measuring effective prestress under finish rolling deformed steel bar anchor |
| CN114062248A (en) * | 2021-11-02 | 2022-02-18 | 西南交通大学 | System and method for testing friction resistance value of free section of rock-soil anchor cable pipeline |
| CN114720039A (en) * | 2022-06-02 | 2022-07-08 | 四川升拓检测技术股份有限公司 | Method for measuring effective prestress under anchor of finish rolling deformed steel bar |
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2020
- 2020-06-19 CN CN202021157471.0U patent/CN212007614U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112945432A (en) * | 2021-02-07 | 2021-06-11 | 内蒙古自治区交通建设工程质量监督局 | System and method for measuring effective prestress under finish rolling deformed steel bar anchor |
| CN114062248A (en) * | 2021-11-02 | 2022-02-18 | 西南交通大学 | System and method for testing friction resistance value of free section of rock-soil anchor cable pipeline |
| CN114720039A (en) * | 2022-06-02 | 2022-07-08 | 四川升拓检测技术股份有限公司 | Method for measuring effective prestress under anchor of finish rolling deformed steel bar |
| CN114720039B (en) * | 2022-06-02 | 2022-08-26 | 四川升拓检测技术股份有限公司 | Method for measuring effective prestress under anchor of finish rolling deformed steel bar |
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Inventor after: Wu Jiaye Inventor after: Xu Ziming Inventor after: Zhang Liang Inventor after: Yu Yonghua Inventor after: Gao Yu Inventor after: Zhang Jiayun Inventor after: Fan Dongxu Inventor after: Zhang Jialan Inventor before: Wu Jiaye Inventor before: Xu Ziming Inventor before: Zhang Liang Inventor before: Gao Yu Inventor before: Fan Dongxu Inventor before: Zhang Jialan |