Equipment and method for rapid detection of prestress under whole-hole anchors in prestressed concrete bridges

Abstract

The present invention discloses a device and method for rapid detection of prestress under the whole-hole anchor of a prestressed concrete bridge. The device and method have the advantages that a signal transmitting device is added to the working anchor to send out timing signals when each working clip is separated from the working anchor ring, and strain gauges electrically connected to a computer are pasted on the prestressed tendons one by one, so that the computer can collect the effective prestress values ​​under the anchor of all corresponding prestressed tendons according to the timing signals and the resistance values ​​of the corresponding strain gauges during a reverse tensioning operation of a through-hole jack, thereby greatly improving the detection efficiency and making the reading of the detection values ​​more convenient and intuitive. For example, if a bundle of prestressed tendons fails the detection, it can be targeted and re-tensioned.

Description

Technical Field

[0001] The invention belongs to the field of effective prestress detection under anchors, and in particular relates to a device and method for quickly detecting prestress under whole-hole anchors of prestressed concrete bridges. Background Art

[0002] Prestressed concrete bridges boast advantages such as fully utilizing material properties, low weight, large spans, high load-bearing capacity, excellent crack resistance, high rigidity, minimal deflection, and long structural life. Prestressing technology is widely adopted in modern bridge construction. However, with the rapid development of prestressing technology, some problems have also emerged. For example, over-tensioning can easily lead to over-tension cracks in the beam, while under-tensioning can cause excessive deflection, cracking, and collapse. Excessive prestressing unevenness can cause beam distortion and endanger project safety. Prestressing construction is a critical step in the overall construction phase, and its quality is crucial to the safety and durability of the bridge structure. Numerous surveys and inspections of existing bridges indicate that poor quality control during prestressing construction can be a major source of quality risks. Therefore, testing prestressing quality in actual projects is crucial to ensuring that prestressed concrete components achieve their ideal design conditions.

[0003] The current technologies for detecting effective prestress under anchors are divided into two categories: non-destructive testing and destructive testing. Among them, destructive testing will cause irreversible effects on the bridge structure and is generally not used on newly built bridges or newly cast beams. The ultrasonic testing technology and equivalent mass method testing technology in non-destructive testing have low detection accuracy, and the magnetic flux sensor testing technology has high detection costs and cannot be widely used. At present, the reverse pull method is actually the most widely used testing technology in engineering, but the existing reverse pull method testing equipment is mostly for one prestressed tendon. The detection of multiple bundles of prestressed tendons in one anchor hole requires repeated reverse tensioning operations, which is labor-intensive and inefficient.

[0004] Furthermore, with technological advancements and growing environmental awareness, bridge construction speed and environmental impact are receiving increasing attention from the government and the public. Prefabrication, with its advantages of high construction efficiency, energy conservation, and environmental protection, is a development trend in my country's bridge industry. However, within this general trend of prefabrication, prestressed testing has shown significant shortcomings, including heavy workload, tight timelines, and low efficiency, requiring urgent improvement. Summary of the Invention

[0005] A technical problem to be solved by the present invention is to provide a rapid detection device for prestress under the anchors of the entire hole of a prestressed concrete bridge, which can complete the detection of the effective prestress value under all prestressed tendon anchors in the entire hole through a single reverse tensioning operation.

[0006] The technical solution adopted by this rapid detection equipment is: a rapid detection equipment for prestress under the whole hole anchor of prestressed concrete bridge,

[0007] The invention comprises a working anchor, a through-hole jack and a tool anchor, and a plurality of strain gauges which are sequentially installed on the whole-hole multi-bundle prestressed tendons of a prestressed concrete bridge which has been tensioned but not grouted;

[0008] The working anchor comprises a working anchor ring with a plurality of tapered clip holes therein and a plurality of groups of working clips corresponding to the number of prestressed tendons in the entire hole, and a signal transmitter for respectively sending a timing signal when each working clip is separated from the working anchor ring;

[0009] The strain gauges are pasted on the prestressed tendons in a one-to-one correspondence, and the strain gauges are electrically connected to a computer;

[0010] The computer collects the effective prestress value under the anchor of the corresponding prestressed tendon according to the timing signal and the resistance value of the corresponding strain gauge.

[0011] Compared with the existing technology, the advantage of this rapid detection equipment is that a signal transmitting device is added to the working anchor to send out a timing signal when each working clip is separated from the working anchor ring, and the strain gauges electrically connected to the computer are pasted one by one on the prestressed tendons, so that the computer can collect the effective prestress values ​​of all corresponding prestressed tendons under the anchor according to the timing signal and the resistance value of the corresponding strain gauge during a reverse tensioning operation of the through-hole jack.

[0012] One signal transmitter includes a conductive ring fixed to the outside of each working clip, two separate conductive contacts disposed within each tapered clip hole, LEDs disposed on each parallel branch, a collection ring disposed outside the working anchor ring to connect the parallel branches, and a power supply. The LEDs illuminate when the working clips are connected to the working anchor ring, connecting the conductive rings on the same parallel branch to the two conductive contacts. The LEDs extinguish when the working clips are pulled away from the working anchor rings, separating the conductive rings from the two conductive contacts. This simple structure allows for direct determination of prestressing unevenness based on the LED extinguishing status.

[0013] Another signal transmitting device includes a conductive ring fixed to the outside of each working clip, two separate conductive contacts disposed within each tapered clip hole, a parallel branch circuit that conducts when the conductive ring contacts the two conductive contacts, a microcontroller unit disposed on a collection ring outside the working anchor ring to connect the parallel branch circuit, and a signal transmitting unit, the signal transmitting unit being communicatively connected to a computer. The microcontroller unit transmits different timing signals to the computer via the signal transmitting unit based on the on / off status of the parallel branch circuit caused by the connection or disconnection of each working clip to the working anchor ring. The computer can directly obtain the timing signals from the signal transmitting unit, eliminating time differences that may occur in manual recording, and achieving high accuracy in the effective prestress value of the prestressed tendon under the anchor.

[0014] Preferably, the connection terminals of the parallel branches are plugged into the plug interfaces on the cable hub, which facilitates assembly and avoids messy wiring arrangements.

[0015] Preferably, a wire groove is provided on the wall of the working anchor ring, and the wires of the parallel branch are buried in the wire groove to avoid contact with the prestressed tendons and prevent the wires from being torn and broken during tensioning.

[0016] Preferably, a jack is provided on the anchor plate between the through-hole jack and the tool anchor. The strain gauge wire collection connector is elastically snapped into the jack. The data interface outside the collection connector is electrically connected to the computer via a data cable. This facilitates the extraction of the strain gauge wires, avoids cluttering the wires, and prevents data errors.

[0017] Another technical problem to be solved by the present invention is to provide a method for quickly detecting prestress under the anchors of the entire hole of a prestressed concrete bridge, which can complete the detection of the effective prestress value under all prestressed tendon anchors in the entire hole through a single reverse tensioning operation.

[0018] The technical solution adopted by this rapid detection method is: a method for rapid detection of prestress under anchorage in the entire span of a prestressed concrete bridge. The above-mentioned rapid detection equipment is installed on the entire span of a prestressed concrete bridge with multiple prestressed tendons that have been tensioned but not grouted according to the following steps:

[0019] b1. Paste strain gauges on the surface of each prestressed tendon exposed on the beam body;

[0020] b2 Install the working anchor, first anchor plate, through-hole jack, second anchor plate and tool anchor in sequence on the multi-beam prestressed tendons in the whole hole, and apply a certain oil pressure to pre-tighten;

[0021] b3 Connect the strain gauge to the computer;

[0022] Then, the whole hole multi-bundle prestressed tendons are tested through the following steps:

[0023] S1 applies oil pressure at a constant speed, and the through-hole jack is pulled outward;

[0024] When each working clip S2 is pulled off the working anchor ring, the signal transmitter sends a timing signal respectively;

[0025] The S3 computer collects the effective prestress value under the anchor of the corresponding prestressed tendon based on the timing signal and the resistance value of the corresponding strain gauge until all the working clips are pulled off.

[0026] Compared with the existing technology, the advantage of this rapid detection method is that the signal transmitting device of the working anchor sends a timing signal when each working clip is separated from the working anchor ring during the outward tensioning process of the through-hole jack. The computer collects the effective prestress value of the corresponding prestressed tendon under the anchor based on the timing signal and the resistance value formed by the change in resistance of the strain gauge corresponding to the time point due to the reverse tensioning of the prestressed tendon, so that the effective prestress value of the prestressed tendons under the anchor in the entire hole is collected in one reverse tensioning operation of the through-hole jack.

[0027] Preferably, in the installation of the working anchor in step b2, the working anchor ring is first installed on the multi-bundle prestressed tendons of the entire hole, and then the collection ring is fixed to the outside of the working anchor ring by bolts, and then the connection terminal of the parallel branch is plugged into the collection ring, and then the working clip and the working anchor ring are pressed tightly to complete the electrical connection between the signal transmitting unit and the computer.

[0028] As an improvement, after attaching the strain gauge in step b1, apply AB glue on top of the strain gauge and attach a PET sticker to protect the strain gauge and achieve waterproof and airtight sealing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a top perspective view of the rapid detection device of the present invention.

[0030] Figure 2 This is a rear perspective view of the rapid detection device of the present invention (perspective view from inside the jack).

[0031] Figure 3 This is a three-dimensional diagram of a special device for the rapid detection equipment of the present invention.

[0032] Figure 4 This is an exploded view of the working anchor of the rapid detection device of the present invention.

[0033] Figure 5 This is a simplified diagram of the strain gauge and its protective layer of the rapid detection device of the present invention.

[0034] As shown in the figure: 1. Working anchor, 1.1. Working anchor ring, 1.1.1. Conical clip hole, 1.1.2. Wire trough, 1.2. Working clip, 1.3. Conductive ring, 1.4. Conductive contact, 1.5. LED lamp bead, 1.6. Wire collection ring, 1.6.1. Plug interface, 1.7. Power supply, 1.8. Data output interface, 1.9. Wiring terminal, 2. First anchor plate, 3. Through-hole jack, 4. Second anchor plate, 5. Tool anchor, 6. Strain gauge, 7. Computer, 8. Wire collection connector, 11. AB glue, 12. PET sticker, 101. Beam, 102. Prestressed tendons. DETAILED DESCRIPTION

[0035] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0036] This preferred embodiment is as follows Figures 1 to 3 The figure shows a prestressed concrete bridge whole hole anchor fast detection device, comprising a working anchor 1, a first anchor plate 2, a through-hole jack 3, a second anchor plate 4 and a tool anchor 5, and a plurality of strain gauges 6, which are sequentially installed on the whole hole multi-beam prestressed tendons 102 of the prestressed concrete bridge that have been tensioned but not grouted; the working anchor 1 is as shown in FIG. Figure 4 The device shown includes a working anchor ring 1.1 with multiple tapered clip holes 1.1.1, multiple sets of working clips 1.2 corresponding to the number of prestressed tendons 102 in the entire hole, and a signal transmitter that emits a timing signal when each working clip 1.2 separates from the working anchor ring 1.1. Strain gauges 6 are affixed to the prestressed tendons 102 in a corresponding manner and are electrically connected to a computer 7. Computer 7 collects the effective prestress value of the corresponding prestressed tendon 102 under the anchor based on the timing signal and the resistance value of the corresponding strain gauge 6. The tensile stress value of the strain gauge 6 corresponding to the resistance value of the strain gauge 6 is provided by the manufacturer of the strain gauge 6. The beam 101 shown in the figure is for illustration only, illustrating the connection between the rapid testing equipment and the beam 101. The structure of the working anchor ring 1.1 is customized according to the distribution of the multi-beam prestressed tendons 102 in the entire hole. The distribution of the prestressed tendons 102 generally adopts one or several fixed styles in prefabricated and assembled prestressed concrete bridges; the working clip 1.2 is a two-petal type; the computer 7 can be a portable smart device such as a laptop computer or a tablet computer.

[0037] The simple signal transmitting device includes a conductive ring 1.3 fixed to the outside of each working clip 1.2, two separate conductive contacts 1.4 fixed to the inside of each conical clip hole 1.1.1 by metal adhesive glue, LED lamp beads 1.5 arranged on each parallel branch, a hub ring 1.6 arranged outside the working anchor ring 1.1 to connect the parallel branches, and a power supply 1.7. The power supply 1.7 is embedded in the battery slot of the protrusion of the hub ring 1.6. Here, a wire groove 1.1.2 is provided on the wall of the working anchor ring 1.1, and the lead-out wires connected to the conductive contacts 1.4 of the parallel branch are buried in the wire groove 1.1.2. A ring groove is provided on the outer wall of the working clip 1.2, and the conductive ring 1.3 is fixed in the ring groove and slightly protrudes from the ring groove. The width of the conductive ring 1.3 is 3mm, and the conductive ring 1.3 is used as a switch. When the working clip 1.2 is pressed and connected to the working anchor ring 1.1, the conductive ring 1.3 outside the working clip 1.2 is connected to the two conductive contacts 1.4 in the conical clip hole 1.1.1 where the working clip 1.2 is located. When the working clamp 1.2 is pulled away from the working anchor ring 1.1, the conductive ring 1.3 separates from the two conductive contacts 1.4, disconnecting the parallel branch and turning off the LEDs 1.5 on the parallel branch. The LEDs 1.5 turning off serve as a timing signal, and the resistance value of the corresponding strain gauge 6 is manually collected on the computer 7. Based on the resistance value of the corresponding strain gauge 6, the effective prestress value of the corresponding prestressed tendon 102 under the anchor is obtained. Here, when the working anchor 1 is made of conductive metal, the surface of the conical clamp hole 1.1.1 is coated with an insulating layer, and the surface of the working clamp 1.2 is also coated with an insulating layer. The conductors of the parallel branch are enameled wires to prevent short circuits.

[0038] In this embodiment, the signal transmitting device also includes a microcontroller unit (not shown) mounted on the outer hub ring 1.6 of the working anchor ring 1.1, which connects to the parallel branch circuit and a signal transmitting unit. The microcontroller unit is mounted on a protrusion on the hub ring 1.6. Contacts electrically connected to the microcontroller unit are located within the battery compartment. The signal transmitting unit is in communication with a computer 7. The microcontroller unit transmits different timing signals to the computer 7 based on the changes in the on / off status of the parallel branch circuit caused by the separation of each working clip 1.2 from the working anchor ring 1.1. Here, the signal transmitting unit is a data output interface 1.8, which is connected to the computer 7 via a data cable. Alternatively, the signal transmitting unit may utilize a wireless communication component such as Bluetooth or Wi-Fi. Since the timing signals are transmitted directly to the computer 7, the LED lamp 1.5 can be omitted. However, the LED lamp 1.5 allows for more intuitive observation of the uneven prestressing of multiple prestressed tendons throughout the entire hole. Among them, an opening is provided at one end of the wire gathering ring 1.6, and the width of the opening is adjusted by bolts and nuts to facilitate the fixation of the wire gathering ring 1.6 and the working anchor ring 1.1; multiple pairs of plug interfaces 1.6.1 are provided at both axial ends of the wire gathering ring 1.6, and pins connected to the microcontroller unit are provided in the plug interfaces 1.6.1. The two terminal ends 1.9 of the same parallel branch are plugged into the opposite plug interfaces 1.6.1 of the wire gathering ring 1.6 to avoid messy wiring.

[0039] Here, a socket (not shown) is provided on the second anchor plate 4 between the through-hole jack 3 and the tool anchor 5, and the wire collection connector 8 of the strain gauge 6 wire is elastically connected to the socket, and the data interface outside the wire collection connector 8 is electrically connected to the computer 7 through a data cable.

[0040] A method for quickly detecting prestress under anchors in the entire span of a prestressed concrete bridge is provided. The aforementioned rapid detection device is installed on the entire span of a prestressed concrete bridge with multiple prestressed tendons 102 that have been tensioned but not grouted according to the following steps:

[0041] b1. Paste the strain gauge 6 on the surface of each prestressed tendon 102 of the exposed section of the beam 101. The strain gauge 6 is pasted with 502 glue;

[0042] b2. Install the working anchor 1, the first anchor plate 2, the through-hole jack 3, the second anchor plate 4 and the tool anchor 5 in sequence on the multi-beam prestressed tendons 102 in the whole hole, and apply a certain oil pressure for pre-tightening;

[0043] b3 Connect the strain gauge 6 to the computer 7; check whether the resistance values ​​of the strain gauge 6 are consistent. If they are inconsistent, it indicates that the prestressed tendons 102 are not subjected to synchronous force, and the tool anchor 5 is readjusted;

[0044] Then, the whole hole multi-bundle prestressed tendons 102 are inspected by the following steps:

[0045] S1 applies oil pressure at a constant speed, and the through-hole jack 3 is tensioned outwards;

[0046] S2 When each working clip 1.2 is pulled off the working anchor ring 1.1, the signal transmitter sends a timing signal respectively;

[0047] S3 The computer 7 collects the effective prestress value under the anchor of the corresponding prestressed tendon 102 according to the timing signal and the resistance value of the corresponding strain gauge 6 until all the working clips 1.2 are pulled off.

[0048] During the installation of the working anchor 1 in step b2, first install the working anchor ring 1.1 onto the multi-beam prestressed tendons 102 of the entire hole, then fix the collection ring 1.6 to the outside of the working anchor ring 1.1 with bolts, then plug the connection terminal 1.9 of the parallel branch into the plug interface 1.6.1 of the collection ring 1.6, and then press the working clip 1.2 and the working anchor ring 1.1 tightly, check whether the LED lamp beads corresponding to each prestressed tendon 102 are lit, and complete the electrical connection debugging of the signal transmitting unit and the computer 7.

[0049] After pasting the strain gauge 6 in step b1, Figure 5 As shown, AB glue 11 is applied on the strain gauge 6, and a PET (polyethylene terephthalate) sticker 12 is pasted on it for waterproof and sealing protection.

[0050] During the testing process, this rapid testing device extracts tensile stress data from the corresponding strain gauges through a single tensioning operation with the through-hole jack, based on the time and sequence of each working clip's detachment from the working anchor. This tensile stress data serves as the effective prestress value under the anchor for each prestressed tendon in the entire hole. This greatly improves testing efficiency, and the reading of test values ​​is convenient and intuitive. If a prestressed tendon fails the test, targeted re-tensioning can be carried out.

Claims

1. A rapid detection device for prestress under the whole hole anchor of prestressed concrete bridge, The invention comprises a working anchor (1), a through-hole jack (3), a tool anchor (5), and a plurality of strain gauges (6) which are sequentially installed on the whole-hole multi-beam prestressed tendons (102) of a prestressed concrete bridge that has been tensioned but not grouted; the working anchor (1) comprises a working anchor ring (1.1) with a plurality of conical clip holes (1.1.1) therein and a plurality of groups of working clips (1.2) corresponding to the number of the whole-hole prestressed tendons (102), Its characteristics are: The working anchor (1) further comprises a signal emitting device which emits a timing signal when each working clip (1.2) is separated from the working anchor ring (1.1); The strain gauges (6) are pasted on the prestressed tendons (102) in a one-to-one correspondence, and the strain gauges (6) are electrically connected to a computer (7); The computer (7) collects the effective prestress value under the anchor of the corresponding prestressed tendon (102) based on the timing signal and the resistance value of the corresponding strain gauge (6); The signal transmitting device comprises a conductive ring (1.3) fixed outside each working clip (1.2), two separated conductive contacts (1.4) arranged in each conical clip hole (1.1.1), an LED lamp bead (1.5) arranged on each parallel branch, a collection ring (1.6) arranged outside the working anchor ring (1.1) and connecting the parallel branches, and a power supply (1.7); the LED lamp bead (1.5) lights up when the working clip (1.2) and the working anchor ring (1.1) are connected so that the conductive ring (1.3) on the same parallel branch is connected to the two conductive contacts (1.4); the LED lamp bead (1.5) goes out when the working clip (1.2) and the working anchor ring (1.1) pull off the conductive ring (1.3) and separates from the two conductive contacts (1.4).

2. The prestressed concrete bridge whole-hole anchor rapid detection device according to claim 1 is characterized by: The signal transmitting device comprises a conductive ring (1.3) fixed outside each working clip (1.2), two separated conductive contacts (1.4) arranged in each conical clip hole (1.1.1), a parallel branch circuit that is turned on when the conductive ring (1.3) contacts the two conductive contacts (1.4), a micro control unit connected to the parallel branch circuit and arranged on a collection ring (1.6) outside the working anchor ring (1.1), and a signal transmitting unit thereof, wherein the signal transmitting unit is communicatively connected to a computer (7); the micro control unit transmits different timing signals to the computer (7) via the signal transmitting unit according to changes in the on-off status of the parallel branch circuit caused by the separation of each working clip (1.2) from the working anchor ring (1.1).

3. The prestressed concrete bridge whole-hole anchor rapid detection device according to claim 1 or 2, characterized in that: The connection terminal (1.9) of the parallel branch is plugged into the plug interface (1.6.1) on the line collection ring (1.6).

4. The rapid prestress detection device for the entire anchor of a prestressed concrete bridge according to claim 1 or 2, characterized in that: A wire groove (1.1.2) is provided on the wall of the working anchor ring (1.1), and the wires of the parallel branch circuit are buried in the wire groove (1.1.2).

5. The rapid prestress detection device for the whole-hole anchor of a prestressed concrete bridge according to claim 1 is characterized by: A jack is provided on the anchor pad between the through-hole jack (3) and the tool anchor (5); a wire collection connector (8) of the strain gauge (6) wire is elastically snap-connected to the jack; and a data interface outside the wire collection connector (8) is electrically connected to a computer (7) via a data cable.

6. A method for rapid detection of prestress under the whole-hole anchor of a prestressed concrete bridge, characterized by: The rapid detection device according to claim 1 is installed on a whole-hole multi-bundle prestressed tendon (102) of a prestressed concrete bridge that has been tensioned but not grouted according to the following steps: b1: attaching strain gauges (6) to the surfaces of the prestressed tendons (102) at the exposed sections of the beam body (101); b2. Installing the working anchor (1), the first anchor plate (2), the through-hole jack (3), the second anchor plate (4) and the tool anchor (5) in sequence on the multi-beam prestressed tendons (102) of the entire hole, and applying a certain oil pressure for pre-tightening; b3 Connect the strain gauge (6) to the computer (7); Then, the whole hole multi-bundle prestressed tendons (102) are tested by the following steps: S1 applies oil pressure at a constant speed, and the through-hole jack (3) is stretched outward; When each working clip (1.2) of S2 is pulled off the working anchor ring (1.1), the signal transmitting device sends a timing signal respectively; The S3 computer (7) collects the effective prestress value under the anchor of the corresponding prestressed tendon (102) according to the timing signal and the resistance value of the corresponding strain gauge (6) until all the working clips (1.2) are pulled off.

7. A method for rapid detection of prestress under the entire anchor of a prestressed concrete bridge according to claim 6, characterized in that: In step b2, during the installation of the working anchor (1), the working anchor ring (1.1) is first installed on the multi-beam prestressed tendons (102) of the entire hole, and then the collection ring (1.6) is fixed to the outside of the working anchor ring (1.1) by bolts. The connection terminal of the parallel branch is then plugged into the collection ring (1.6), and then the working clip (1.2) is pressed against the working anchor ring (1.1), completing the electrical connection between the signal transmitting unit and the computer (7).

8. The method for rapid detection of prestress under the whole-hole anchor of a prestressed concrete bridge according to claim 7 is characterized by: After the strain gauge (6) is attached in step b1, AB glue (11) is applied on the strain gauge (6) and a PET sticker (12) is attached.

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