Bent BFRP rib strength testing device for PCCP

Abstract

The utility model relates to a BFRP rib strength testing device, in particular to a bent BFRP rib strength testing device for a PCCP (prestressed concrete cylinder pipe), and aims to solve the problems that the performance degradation of a prestressed BFRP rib after being bent and the strength prediction method after the degradation are still not comprehensive enough, and the prestressed BFRP rib cannot be used in the PCCP. The two ends of the prestressed BFRP rib are each provided with a threaded anchoring steel pipe, one threaded anchoring steel pipe sequentially penetrates through the steel base plate, the force sensor and the steel base plate to be in threaded connection with the nut, and the other threaded anchoring steel pipe sequentially penetrates through the steel base plate, the oil jack and the steel base plate to be in threaded connection with the nut. The steel base plate close to the end part of the prestressed BFRP rib at each end is clamped on the tensioning pedestal; and the tensioning annular base plate is arranged between the adjusting module and the prestressed BFRP rib. The device is applied to the field of BFRP rib strength testing.

Description

TECHNICAL FIELD

[0001] The utility model relates to BFRP tendon strength testing device, concretely relates to a kind of bending BFRP tendon strength testing device for PCCP, and the utility model is used in BFRP tendon strength testing field. BACKGROUND

[0002] Prestressed concrete cylinder pipe (PCCP for short) is a composite rigid pipe composed of concrete core, steel pipe, high-strength prestressed steel wire and mortar, which is divided into two forms: inner lining type (PCCPL) and embedded type (PCCPE). Because it combines the characteristics of concrete and steel, it has the advantages of economic efficiency, long service life, good seismic performance, simple installation and low operating cost. Therefore, PCCP is widely used in large-scale water transfer projects across regions and long-distance, high-pressure, high-coverage, large-diameter water pipeline projects in water conservancy, municipal, industrial and agricultural fields. However, the high-strength prestressed steel wire inside PCCP often breaks due to hydrogen embrittlement, corrosion and material defects. The occurrence of broken wires often leads to concrete cracking, steel cylinder damage, and even PCCP pipe explosion disasters.

[0003] Currently, the risk of pipe explosion caused by broken prestressed steel wires is reduced by laying monitoring systems and developing corresponding reinforcement methods. Common monitoring methods include distributed acoustic sensing technology and acoustic emission technology. In terms of reinforcement, common reinforcement methods include external CFRP cloth, external prestressed CFRP cloth, external prestressed steel strand, internal CFRP cloth and internal prestressed CFRP cloth, etc. After reinforcement, the bearing capacity of PCCP is significantly improved, and the crack width is reduced or even closed. Although the above methods can effectively reduce the risk of pipe explosion, they are all post-operation and maintenance technologies and cannot avoid the corrosion or hydrogen embrittlement of internal high-strength prestressed steel wires. Moreover, PCCP is mostly underground, resulting in high maintenance costs. In corrosive environments such as coastal areas and humid areas, the risk of corrosion and fracture of prestressed steel wires will further increase.

[0004] Because of its good mechanical properties, strong chemical stability and affordable price, basalt fiber composite reinforcement (BFRP tendon) is considered one of the ideal materials for replacing ordinary steel bars to improve the durability of concrete structures in corrosive environments, and basalt fiber composite reinforcement has no hydrogen embrittlement problem. Using basalt fiber composite reinforcement instead of traditional prestressed steel wire for PCCP production can solve the corrosion and hydrogen embrittlement problems of traditional prestressed steel wire. However, the performance degradation of prestressed BFRP tendon after bending and the strength prediction method after degradation are still not comprehensive enough to guide the use of prestressed BFRP tendon in PCCP.

[0005] In view of the limitations of the above existing technology, an equipment for testing the strength of bent BFRP tendon for PCCP is needed to meet the strength testing of bent BFRP tendon for PCCP. Utility model content

[0006] The utility model aims at the prestressed BFRP muscle performance degradation after bending and strength prediction method still not enough comprehensive, cannot guide prestressed BFRP muscle for PCCP, therefore needs to propose the equipment of bending BFRP muscle strength test of PCCP, satisfies the bending BFRP muscle strength test of PCCP, and then provides a kind of bending BFRP muscle strength test device for PCCP.

[0007] The utility model discloses a technical scheme who adopts to solve the above problem is:

[0008] A kind of bending BFRP muscle strength test device for PCCP, it includes tensioning pedestal, adjusting module, tensioning ring direction backing plate, prestressed BFRP muscle, force sensor, oil jack, two threaded anchoring steel pipes, two nuts and four steel backing plates;

[0009] Adjusting module is embedded in tensioning pedestal, and the both ends of prestressed BFRP muscle are respectively equipped with one threaded anchoring steel pipe, one threaded anchoring steel pipe is sequentially passed through steel backing plate, force sensor and steel backing plate and is connected with nut screw thread, another threaded anchoring steel pipe is sequentially passed through steel backing plate, oil jack and steel backing plate and is connected with nut screw thread, steel backing plate is clamped on tensioning pedestal near the end of each end prestressed BFRP muscle, and tensioning ring direction backing plate is arranged between adjusting module and prestressed BFRP muscle.

[0010] Further, it further includes a plurality of U-shaped bolts and a plurality of short steel bars;Multiple short steel bars are evenly distributed between tensioning ring direction backing plate and adjusting module.

[0011] Further, it further includes a plurality of U-shaped bolts;One end of the U-shaped bolt is mounted on a short steel bar, and the other end of the U-shaped bolt is mounted on the adjusting module.

[0012] Further, the adjusting module is an arc block, and the tensioning ring direction backing plate is an arc plate.

[0013] Further, the short steel bar is centrally processed with a through hole, and the adjusting module is processed with a plurality of through holes at equal intervals, one end of the U-shaped bolt is inserted into the through hole of the short steel bar, and the other end of the U-shaped bolt is inserted into the through hole of the adjusting module.

[0014] Further, the tensioning pedestal is an 'L' shaped frame body, and at least one set of mounting slots is processed on each frame of the 'L' shaped frame body, and each set of mounting slots includes a dovetail groove and a rectangular through slot.

[0015] Further, dovetail-shaped protrusions are respectively processed on the two side surfaces of the adjusting module.

[0016] Further, the dovetail-shaped protrusions on each side of the adjusting module are embedded in dovetail grooves of one frame of the 'L'-shaped frame body, and the steel base plate near the end of the prestressed BFRP tendon is clamped at the rectangular through slot of one frame of the 'L'-shaped frame body.

[0017] Further, the number of installation slots on each frame of the 'L'-shaped frame body is two to five groups.

[0018] Further, the distance between two adjacent groups of installation slots on each frame of the 'L'-shaped frame body is 200mm.

[0019] The beneficial effects of the present application are as follows:

[0020] First, the present application adopts a kind of for PCCP bending BFRP tendon testing device, it can be used to guide BFRP tendon for PCCP manufacturing, to further solve the problem of BFRP tendon strength test in PCCP.

[0021] Second, the bending BFRP tendon testing device of the present application, no prestressed friction loss occurs in tensioning process, the ultimate strength of BFRP tendon under bending state can be accurately measured.

[0022] Third, the bending BFRP tendon testing device of the present application can test the ultimate strength of BFRP tendon with different bending diameters.

[0023] Fourth, the bending BFRP tendon ultimate strength test method of the present application is simple in operation, low in cost and high in efficiency.

[0024] Fifth, by using the present application to test the strength of BFRP tendon, the performance of BFRP tendon material is considered at the same time, and the ultimate strength attenuation of BFRP tendon after bending can be accurately predicted. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the overall structure front view of the present application.

[0026] Figure 2 It is the side view of tensioning pedestal 1.

[0027] Figure 3 It is a schematic diagram of the connection of prestressed BFRP tendon 6 with threaded anchoring steel pipe 7, steel base plate 8, force sensor 9 and nut 10.

[0028] Figure 4 It is a schematic diagram of each short steel rod 4 installed on adjusting module 2 through a U-shaped bolt 3. DETAILED DESCRIPTION

[0029] Specific implementation one: combined with Figures 1-4The embodiment is described, the bending BFRP tendon strength test device for PCCP of the embodiment, it includes tensioning pedestal 1, adjusting module 2, tensioning annular pad 5, prestressed BFRP tendon 6, force sensor 9, oil pressure jack 11, two threaded anchoring steel pipes 7, two nuts 10 and four steel pads 8;

[0030] Adjusting module 2 is embedded in tensioning pedestal 1, both ends of prestressed BFRP tendon 6 are respectively provided with one threaded anchoring steel pipe 7, one threaded anchoring steel pipe 7 is sequentially threaded through steel pad 8, force sensor 9 and steel pad 8 and is threaded with nut 10, the other threaded anchoring steel pipe 7 is sequentially threaded through steel pad 8, oil pressure jack 11 and steel pad 8 and is threaded with nut 10, the steel pad 8 close to the end of prestressed BFRP tendon 6 is clamped on tensioning pedestal 1, and tensioning annular pad 5 is arranged between adjusting module 2 and prestressed BFRP tendon 6.

[0031] In the embodiment, threaded anchoring steel pipe 7 is used to anchor BFRP tendon while fastening the outer steel pad 8 of oil pressure jack 11 at the anchoring end and tensioning end. The ultimate tensile strength of prestressed BFRP tendon 6 after bending is determined by the ultimate tensile strength of prestressed BFRP tendon 6 in straight pulling state and the stress caused by bending of prestressed BFRP tendon 6. Because the outer side of prestressed BFRP tendon 6 is stretched to a greater length, the strength at which the outer side of prestressed BFRP tendon 6 breaks is considered as the ultimate strength after bending. The ultimate tensile strength of prestressed BFRP tendon 6 after bending is defined by subtracting the stress generated on the outer side of prestressed BFRP tendon 6 due to bending from the ultimate tensile strength of BFRP tendon in straight pulling state. The anchoring device at both ends of prestressed BFRP tendon 6 is threaded, which is used to fasten the anchoring end and tensioning end by nut 10.

[0032] Specific embodiment two: in combination Figure 1 、 Figure 2 The embodiment is described, the bending BFRP tendon strength test device for PCCP of the embodiment, it still includes multiple short steel bars 4;Multiple short steel bars 4 are evenly arranged between tensioning annular pad 5 and adjusting module 2. Other methods are the same as specific embodiment one.

[0033] Specific embodiment three: in combination Figure 1 、 Figure 2 The embodiment is described, the bending BFRP tendon strength test device for PCCP of the embodiment, it still includes multiple U-shaped bolts 3;One end of U-shaped bolt 3 is installed on a short steel bar 4, and the other end of U-shaped bolt 3 is installed on adjusting module 2. Other methods are the same as specific embodiment two.

[0034] In the embodiment, tensioning annular pad 5 is placed outside U-shaped bolt 3, which is used to avoid the phenomenon of stress concentration caused by the direct contact between BFRP tendon and U-shaped bolt 3.

[0035] Specific implementation four: combined Figure 1 , Figure 2 This embodiment is described, the embodiment of the present application discloses a kind of bending BFRP bar strength test device for PCCP, adjusting module 2 is arc block, tension ring is arc plate to pad plate 5.It is same with other methods with specific implementation three.

[0036] Specific implementation five: combined Figure 1 , Figure 2 This embodiment is described, the embodiment of the present application discloses a kind of bending BFRP bar strength test device for PCCP, short steel bar 4 center is processed with through hole, adjusting module 2 is processed with multiple through holes at equal intervals, one end of U-shaped bolt 3 is inserted in the through hole of one short steel bar 4, the other end of U-shaped bolt 3 is inserted in one through hole on adjusting module 2.It is same with other methods with specific implementation four.

[0037] In the embodiment, U-shaped bolt 3 connects the through hole of short steel bar 4 and the through hole on adjusting module 2, and ensures that short steel bar 4 can rotate fully when BFRP bar is stretched.

[0038] Specific implementation six: combined Figure 1 , Figure 2 This embodiment is described, the embodiment of the present application discloses a kind of bending BFRP bar strength test device for PCCP, tensioning pedestal 1 is 'L' shape frame body, at least one set of installation slot is processed on each frame of 'L' shape frame body, each set of installation slot includes dovetail slot 1a and rectangular through slot 1b, and the length and structure of each frame of 'L' shape frame body are same.It is same with other methods with specific implementation one.

[0039] In the embodiment, each frame of tensioning pedestal 1 is spaced apart with dovetail slot 1a and rectangular through slot 1b, for fixing adjusting module 2 and placing tension ring pad plate 5.

[0040] Specific implementation seven: combined Figure 1 , Figure 2 This embodiment is described, the embodiment of the present application discloses a kind of bending BFRP bar strength test device for PCCP, dovetail-shaped protrusion 2a is processed on the two sides of adjusting module 2 respectively.It is same with other methods with specific implementation one.

[0041] Specific implementation eight: combined Figures 1-3To illustrate the present embodiment, the present embodiment describes a bending BFRP tendon strength testing device for PCCP, the dovetail-shaped protrusions 2a on each side of the adjusting module 2 are embedded in the dovetail grooves 1a of one frame of the ‘L’-shaped frame body, and the steel base plates 8 near the ends of the prestressed BFRP tendon 6 are clamped at the rectangular through grooves 1b of one frame of the ‘L’-shaped frame body. The other methods are the same as in the sixth or seventh embodiment.

[0042] Embodiment nine: combination Figures 1-3 To illustrate the present embodiment, the present embodiment describes a bending BFRP tendon strength testing device for PCCP, the number of slots installed on each frame of the ‘L’-shaped frame body is two to five groups. The other methods are the same as in the sixth embodiment.

[0043] Embodiment ten: combination Figures 1-3 To illustrate the present embodiment, the present embodiment describes a bending BFRP tendon strength testing device for PCCP, the distance between the two adjacent groups of slots installed on each frame of the ‘L’-shaped frame body is 200 mm. The other methods are the same as in the ninth embodiment.

[0044] Working principle

[0045] Step 1, anchor threaded anchor steel pipes 7 at both ends of the prestressed BFRP tendon 6 in advance, and the test can be performed after the grouting material in the threaded anchor steel pipe 7 is cured to the standard strength;

[0046] Step 2, clamp the adjusting module 2 in the corresponding dovetail groove 1a of the tensioning pedestal 1;

[0047] Step 3, connect the short steel rods 4 one by one through the U-shaped bolts 3 and the adjusting module 2;

[0048] Step 4, place the tensioning ring towards the base plate 5 in the rectangular through groove 1b, and tightly against the short steel rod 4, then place the prestressed BFRP tendon 6 at both ends in the rectangular through groove 1b to complete the bending;

[0049] Step 5, first install the inner base plate 8 at the anchoring end, then install the force sensor 9 and the base plate 8 on the outside, then lock it through the nut 10, and similarly, first install the inner base plate 8 at the tensioning end, then install the oil hydraulic jack 11 and the outer base plate 8, and also lock it through the nut 10;

[0050] Step 6, after the anchoring end and the tensioning end are fastened, the tensioning can be performed, and the corresponding load when the prestressed BFRP tendon 6 is split on the outside is the ultimate load during the tensioning process.

[0051] The above specific implementation can be adjusted in different ways by those skilled in the art without departing from the principles and purposes of the present application, the protection scope of the present application is subject to the claims and is not limited by the above specific implementation, and each implementation scheme within the scope is subject to the present application.

Claims

1. A device for testing the strength of bent BFRP bars for PCCP, characterized in that: It includes a tensioning platform (1), an adjustment module (2), a tensioning circumferential pad (5), a prestressed BFRP bar (6), a force sensor (9), a hydraulic jack (11), two threaded anchoring steel pipes (7), two nuts (10), and four steel pads (8); The adjustment module (2) is embedded in the tensioning platform (1). A threaded anchor steel pipe (7) is installed at each end of the prestressed BFRP tendon (6). One threaded anchor steel pipe (7) passes through the steel pad (8), force sensor (9) and steel pad (8) in sequence and is threaded to the nut (10). The other threaded anchor steel pipe (7) passes through the steel pad (8), hydraulic jack (11) and steel pad (8) in sequence and is threaded to the nut (10). The steel pad (8) near the end of each prestressed BFRP tendon (6) is clamped on the tensioning platform (1). The tensioning circumferential pad (5) is set between the adjustment module (2) and the prestressed BFRP tendon (6).

2. The bending BFRP reinforcement strength testing device for PCCP according to claim 1, characterized in that: It also includes multiple short steel bars (4); the multiple short steel bars (4) are evenly distributed between the tensioning circumferential pad (5) and the adjustment module (2).

3. The bending BFRP reinforcement strength testing device for PCCP according to claim 2, characterized in that: It also includes multiple U-shaped pins (3); one end of the U-shaped pin (3) is mounted on a short steel rod (4), and the other end of the U-shaped pin (3) is mounted on the adjustment module (2).

4. The bending BFRP reinforcement strength testing device for PCCP according to claim 3, characterized in that: The adjustment module (2) is an arc-shaped block, and the tensioning circumferential pad (5) is an arc-shaped plate.

5. The bending BFRP reinforcement strength testing device for PCCP according to claim 4, characterized in that: The short steel bar (4) has a through hole machined in the center, and the adjustment module (2) has multiple through holes machined at equal intervals. One end of the U-shaped pin (3) is inserted into the through hole of the short steel bar (4), and the other end of the U-shaped pin (3) is inserted into a through hole on the adjustment module (2).

6. The bending BFRP reinforcement strength testing device for PCCP according to claim 1, characterized in that: The tensioning platform (1) is an 'L'-shaped frame. Each side of the 'L'-shaped frame is machined with at least one set of mounting slots. Each set of mounting slots includes a dovetail slot (1a) and a rectangular through slot (1b).

7. The bending BFRP reinforcement strength testing device for PCCP according to claim 1, characterized in that: The two sides of the adjustment module (2) are respectively machined with dovetail-shaped protrusions (2a).

8. The bending BFRP reinforcement strength testing device for PCCP according to claim 6 or 7, characterized in that: The dovetail protrusions (2a) on each side of the adjustment module (2) are correspondingly embedded in the dovetail groove (1a) of one side of the 'L'-shaped frame, and the steel pads (8) near the ends of the prestressed BFRP reinforcement (6) are snapped into the rectangular through groove (1b) of one side of the 'L'-shaped frame.

9. The bending BFRP reinforcement strength testing device for PCCP according to claim 6, characterized in that: The number of mounting slots on each side of the 'L'-shaped frame is two to five.

10. The bending BFRP reinforcement strength testing device for PCCP according to claim 9, characterized in that: The distance between two adjacent sets of mounting slots on each side of the 'L'-shaped frame is 200mm.

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