Anchor force testing device and method for FRP connector of assembled wall

Abstract

The present invention discloses a device and method for testing the anchoring force of FRP connectors of assembled composite walls. The testing device of the present invention comprises a connecting assembly and a loading assembly, wherein the connecting assembly comprises a sleeve and a tension rod, and the loading assembly comprises a reaction frame, an oil pump and a lock; the sleeve is a hollow circular tube, and the interior of the sleeve is filled with connection fillers; the sleeve is placed inside the reaction frame, and the bottom of the reaction frame and the bottom of the sleeve are at the same horizontal plane, and both are placed on a concrete test block with embedded FRP connectors; the bottom of the tension rod passes through the top of the sleeve and is placed in the connection filler and is located on the same axis as the connector; the reaction frame, the oil pump and the lock are passed through the tension rod in sequence and the three are installed together. The present invention has a simple and reasonable structure, low cost, good effect and is easy to use. It can effectively and accurately test the anchoring force of various types of FRP connectors in concrete, and provide a reliable basis for the design, construction, detection and acceptance of assembled concrete structure engineering composite walls.

Description

Technical Field

[0001] The invention belongs to the technical field of assembled concrete structure detection, and in particular relates to a test device and a test method for detecting the anchoring force of an assembled composite wall FRP connector in concrete. Background Art

[0002] Under the promotion of national and local policies, the proportion of prefabricated buildings in various cities in our province has continued to increase, and more and more projects have adopted prefabricated buildings. At the same time, the sustainable development strategy has made the country put forward higher requirements on the energy consumption of the construction industry, and energy conservation and emission reduction have received more attention. Among them, the prefabricated thermal insulation and decorative composite wall has been widely used in prefabricated concrete structure projects in recent years due to its excellent energy-saving performance, easy production and construction. Therefore, the thermal insulation and decorative composite wall has received high attention from various units and government departments in research, design, production, construction, etc., and has achieved a series of research results and engineering application experience, and new products have continued to emerge.

[0003] In order to ensure the development of prefabricated concrete structures and the application of composite walls, corresponding quality inspection is essential. However, the current research on the quality inspection and acceptance of prefabricated concrete structure projects in my country is not perfect, and some of the relevant standards and specifications still follow the inspection ideas of cast-in-place concrete structure quality control. It is necessary to find suitable inspection devices and inspection methods based on the characteristics of prefabricated composite walls and their components to ensure the quality of prefabricated concrete projects.

[0004] Connectors are key components that connect the precast concrete inner and outer leaf panels of the composite wall with the intermediate insulation layer. They have a great impact on the stiffness and bearing capacity of the composite wall, and are directly related to the safety and durability of the structure. Conducting tensile and pullout tests on connectors can effectively test the anchoring force of connectors in concrete, and is an important means of evaluating the overall performance of prefabricated composite walls.

[0005] Fiber reinforced resin material (FRP) is a new type of material for making prefabricated composite wall connectors. It has the characteristics of high tensile strength and low thermal conductivity. The connectors made have good mechanical properties and will not cause cold and hot bridge effects in the composite wall. In recent years, it has been increasingly used in prefabricated concrete structure projects. Therefore, it is necessary to follow up with corresponding detection technologies to test its anchoring performance in concrete to ensure its safe application in prefabricated composite walls. However, in addition to FRP connectors with circular cross-sections, there are also FRP connectors with cross-shaped or flat cross-sections. It is difficult for traditional pull-out test devices to anchor them by mechanical clamping. The existing FRP connector detection devices and methods (such as "Fiber Reinforced Plastic Connectors for Prefabricated Insulation Walls" JG / T561-2019) are relatively complex and difficult to implement. The amount of materials required for the preparation of the test pieces is large, time-consuming and labor-intensive. Therefore, it is necessary to develop a simple, convenient, easy-to-operate, low-cost pull-out test device and detection method for FRP connectors of prefabricated composite walls to detect the anchoring force of FRP connectors in concrete. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a simple, convenient and easy-to-implement test device and method for testing the anchoring force of FRP connectors of prefabricated thermal insulation composite walls in concrete, which is suitable for testing the anchoring force of different types of FRP connectors, thereby evaluating the combined performance of FRP connectors in the wall and ensuring the engineering quality of prefabricated concrete structures.

[0007] In order to solve the above technical problems, the present invention proposes the following technical solutions:

[0008] The present invention provides an anchoring force testing device for an assembled composite wall FRP connector, comprising a connecting component and a loading component;

[0009] The connection assembly includes a sleeve and a tension rod; the sleeve is a hollow circular tube, and the interior of the sleeve is filled with connection fillers; the bottom of the sleeve filled with connection fillers is placed on a concrete test block at one end of a central embedded FRP connector, and the other end of the FRP connector is placed in the connection filler at the center of the sleeve; the bottom of the tension rod passes through the center of the top of the sleeve and is vertically placed in the connection filler; the tension rod and the FRP connector are located on the same axis and at the center of the sleeve, and are bonded and fixed by the connection filler; the anchorage length of the tension rod in the connection filler meets the "Code for Design of Concrete Structures (2015 Edition)" GB 50010-2010.

[0010] The height of the sleeve is greater than the sum of the anchoring length of the tension rod in the connection filler and the length of the FRP connector placed in the connection filler.

[0011] The main function of the connecting filler is to connect the tension rod and the FRP connector; the connecting filler should have sufficient strength, and anchoring glue or high-strength grouting material can be used. The tensile strength of the connecting filler is greater than the anchoring force of the FRP connector;

[0012] The reinforcing ribs can be evenly and vertically arranged in the connecting filler as required, and 2 or 4 reinforcing ribs can be built into the connecting filler according to the designed pull-out strength of the FRP connector;

[0013] The anchoring glue is a rebar-planting glue, which is an anchoring glue for concrete structural engineering; the high-strength grouting material has a 28-day compressive strength of ≥ 85N / mm 2 Sleeve grouting material for steel bar connection.

[0014] The loading assembly includes a reaction frame, an oil pump and a lock; the reaction frame should have sufficient strength and rigidity (no deformation will occur during the test), the reaction frame is a hollow cylinder with a sealed top and a circular hole on the top, the diameter of the circular hole is larger than the diameter of the tension rod and smaller than the diameter of the oil pump; the inner diameter of the reaction frame is larger than the outer diameter of the casing, the outer diameter should be smaller than the side length of the concrete test block, and its height is larger than the height of the casing, and the difference is larger than the anchoring length of the FRP connector in the concrete test block; the casing is placed inside the reaction frame, the bottom of the reaction frame and the bottom of the casing are in the same horizontal plane, and both are placed on the concrete test block; the oil pump is placed on the reaction frame, the lock is placed on the oil pump, and the tension rod passes through the circular hole on the top of the reaction frame, the oil pump and the lock in sequence and the three are installed together, the lock is locked with the tension rod during the test, and the lock is used to lock the tension rod.

[0015] The tension rod is a hot-rolled ribbed steel bar.

[0016] The FRP connector is a cross-section FRP connector, a straight-section FRP connector or a round rod-type FRP connector.

[0017] The present invention provides a method for testing the anchoring force of an assembled composite wall FRP connector, which specifically comprises the following steps:

[0018] (1) Prepare a concrete block specimen, in which one end of the FRP connector is embedded;

[0019] (2) After the concrete test block is demoulded, the connection assembly is installed, a sleeve is placed on the concrete test block, and reinforcing ribs are arranged in the sleeve; the connection filler is injected into the sleeve, and the tension rod is implanted; the tension rod and the FRP connector should be on the same axis; the pull-out test is started after the connection filler is cured;

[0020] (3) Install the loading assembly, install the reaction frame, oil pump and lock through the tension rod in sequence and place them outside the connecting assembly, and lock the tension rod;

[0021] (4) Apply load evenly through an oil pump to perform a pull-out test on the FRP connector, and record the test results such as the peak force value, displacement, and failure mode when the FRP connector is pulled out and damaged;

[0022] (5) After the inspection, unload the load to restore the oil pump to its original state, and then remove the lock, oil pump and reaction frame in turn.

[0023] The invention has the advantages of simple structure, novelty and rationality, low cost, good effect and convenience in use, and can effectively and accurately test the anchoring force of various types of FRP connectors in concrete, thus providing a reliable basis for the design, construction, inspection and acceptance of components such as composite walls of prefabricated concrete structure engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a cross-sectional view of the connection assembly and concrete test block assembly in the testing device of the present invention.

[0025] Figure 2 It is a top view of the connection assembly and concrete test block assembly in the testing device of the present invention.

[0026] Figure 3 This is a cross-sectional view of the test device and concrete test block combination of the present invention.

[0027] Figure 4 The figure is a schematic diagram of the working process of the test device of the present invention performing a pull-out test on an FRP connector.

[0028] Figure 5 This is a top view of the test device and concrete test block combination of the present invention.

[0029] Figure 6 The FRP connector of the present invention includes (a) a cross-section FRP connector, (b) a straight-section FRP connector, and (c) a round rod-type FRP connector.

[0030] The markings in the figure are: 1. tension rod, 2. reinforcement rib, 3. connecting filler, 4. casing, 5. FRP connector, 6. concrete test block, 7. lock, 8. oil pump, 9. reaction frame. DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0032] The present invention provides an anchoring force testing device for an assembled composite wall FRP connector, comprising a connecting component and a loading component;

[0033] The connection assembly includes a sleeve 4 and a tension rod 1; the sleeve 4 is a hollow circular tube, and the interior of the sleeve 4 is filled with a connection filler 3; the bottom of the sleeve filled with the connection filler 3 is placed on a concrete test block 6 at one end of a central embedded FRP connector 5, and the other end of the FRP connector 5 is placed in the connection filler 3 at the center of the sleeve 4; the bottom of the tension rod 1 passes through the center of the top of the sleeve 4 and is vertically placed in the connection filler 3; the tension rod 1 and the FRP connector 5 are located on the same axis and at the center of the sleeve 4, and are bonded and fixed by the connection filler 3; the anchorage length of the tension rod 1 in the connection filler 3 meets the "Code for Design of Concrete Structures (2015 Edition)" GB50010-2010.

[0034] The height of the sleeve 4 is greater than the sum of the anchoring length of the tension rod 1 in the connection filler 3 and the length of the FRP connector 5 placed in the connection filler 3 .

[0035] The main function of the connecting filler 3 is to connect the tension rod 1 and the FRP connector 5; the connecting filler 3 should have sufficient strength, and anchoring glue or high-strength grouting material can be used. The tensile strength of the connecting filler 3 is greater than the anchoring force of the FRP connector 5;

[0036] The reinforcing ribs 2 can be evenly and vertically arranged in the connecting filler 3 as required, and two or four reinforcing ribs 2 can be built into the connecting filler 3 according to the designed pull-out strength of the FRP connector;

[0037] The anchoring glue is a rebar embedding glue, which is an anchoring glue used in concrete structure engineering; the high-strength grouting material is a sleeve grouting material for steel bar connection with a 28-day compressive strength of ≥85N / mm2.

[0038] The loading assembly includes a reaction frame 9, an oil pump 8 and a lock 7; the reaction frame 9 should have sufficient strength and rigidity (no deformation during the test), the reaction frame 9 is a hollow cylinder with a sealed top and a circular hole on the top, the diameter of which is larger than the diameter of the tension rod 1 and smaller than the diameter of the oil pump 8; the inner diameter of the reaction frame 9 is larger than the outer diameter of the casing 4, and its outer diameter should be smaller than the side length of the concrete test block 6, and its height is larger than the height of the casing 4, and the difference is larger than the anchoring length of the FRP connector 5 in the concrete test block 6; the casing 4 is placed inside the reaction frame 9, the bottom of the reaction frame 9 is in the same horizontal plane as the bottom of the casing 4, and both are placed on the concrete test block 6; the oil pump 8 is placed on the reaction frame 9, the lock 7 is placed on the oil pump 8, and the tension rod 1 passes through the circular hole on the top of the reaction frame 9, the oil pump 8 and the lock 7 in sequence and the three are installed together, and the lock 7 is locked with the tension rod 1 during the test, and the lock 7 is used to lock the tension rod 1.

[0039] The FRP connector 5 is a cross-section FRP connector, a straight-section FRP connector or a round rod-shaped FRP connector.

[0040] Example

[0041] To ensure the use effect, the sleeve is a plastic hollow round tube with an outer diameter of 90mm and an inner diameter of 82mm. The connecting filler has a compressive strength of 90N / mm 2 The sleeve grouting material for steel bar connection is made of cement as the basic material, with fine aggregate, concrete admixture and other materials mixed with water and then formed. The sleeve and the formed connection filler are combined into a cylinder with a diameter of 90mm and a height of 180mm.

[0042] The tension rod is a HRB400 hot-rolled ribbed steel bar with a diameter of 16 mm and a length of 500 mm. The tension rod is anchored to the connecting filler by bonding and is located on the same axis as the FRP connector. The anchoring length is 90 mm.

[0043] The reinforcing ribs are HRB400 hot-rolled ribbed steel bars with a diameter of 6 mm. The reinforcing ribs are evenly distributed in the connecting filler to form a rectangular reinforcing rib grid with a height of 150 mm and a width of 40 mm.

[0044] The testing method using the testing device of the present invention comprises:

[0045] (1) Prepare concrete block specimens under the same conditions, with one end of the FRP connector embedded in the concrete block;

[0046] (2) Place the sleeve on the upper end of the concrete block specimen, ensuring that the FRP connector is located at the center of the sleeve;

[0047] (3) After arranging the reinforcement ribs evenly inside the casing, inject the connection filler into the casing and insert the tension rod. The tension rod should be located on the same axis as the FRP connector and in the center of the casing;

[0048] (4) After the connection filler is formed and cured, the reaction frame, oil pump and lock are sequentially installed through the tension rod to form a loading assembly and placed outside the connection assembly;

[0049] (5) Apply load evenly through an oil pump to perform a pull-out test on the FRP connector, and record required data such as the peak force value when the FRP connector is pulled out and damaged;

[0050] (6) After the inspection, unload the load to restore the oil pump to its original state; remove the lock, oil pump and reaction frame in turn.

[0051] The working principle of the device of the present invention is: when performing a pull-out test on an FRP connector, the FRP connector is connected to a tension rod through a connection assembly. The tension applied to the tension rod by a loading assembly is transmitted to the FRP connector through the connection assembly, and the reaction force is formed by the reaction frame of the loading assembly itself and transmitted to the concrete test block, thereby performing a pull-out test on the FRP connector.

[0052] The invention has a simple structure, novel and reasonable structure, low cost, good effect and convenient use, and can effectively and accurately test the anchoring force of FRP connectors in concrete. The loading assembly can be used repeatedly, and the connection assembly uses a plastic sleeve, sleeve grouting material for steel bar connection, reinforcement bars and tension rods with low usage and low price, which saves costs, is easy to make and use repeatedly, saves manpower and material resources, and is simple to operate. It is an innovation in the pull-out test device and method for testing the anchoring force of FRP connectors, and provides a reliable basis for the design, construction, inspection and acceptance of components such as composite walls of prefabricated concrete structure engineering.

Claims

1. An anchor force testing device for FRP connectors of assembled wall, characterized in that: Includes connection components and loading components; The connecting assembly comprises a sleeve (4) and a tension rod (1); the loading assembly comprises a reaction frame (9), an oil pump (8) and a lock (7); The sleeve (4) is a hollow circular tube, and the interior of the sleeve is filled with a connection filler (3); the bottom of the sleeve (4) filled with the connection filler is placed on a concrete test block (6) at one end of a centrally embedded FRP connector (5), and the other end of the FRP connector (5) is placed in the connection filler (3) at the center of the sleeve (4); The bottom of the tension rod (1) passes through the center of the top of the sleeve (4) and is vertically placed in the connection filler (3); the tension rod (1) and the FRP connector (5) are located on the same axis and are located at the center of the sleeve (4) and are bonded and fixed by the connection filler (3); the height of the sleeve (4) is greater than the sum of the anchoring length of the tension rod (1) in the connection filler (3) and the length of the FRP connector (5) placed in the connection filler (3); The connecting filler (3) is selected from anchoring glue or high-strength grouting material, and the tensile strength of the connecting filler (3) is greater than the anchoring force of the FRP connecting piece (5); The reaction frame (9) is a hollow cylinder with a sealed top and a circular hole on the top, the diameter of which is larger than the diameter of the tension rod (1) and smaller than the diameter of the oil pump (8); the inner diameter of the reaction frame (9) is larger than the outer diameter of the sleeve (4), and the outer diameter is smaller than the side length of the concrete test block (6); the height of the reaction frame (9) is larger than the height of the sleeve (4), and the difference is larger than the anchoring length of the FRP connector (5) in the concrete test block (6); The sleeve (4) is placed inside the reaction frame (9), the bottom of the reaction frame (9) and the bottom of the sleeve (4) are at the same horizontal plane, and both are placed on the concrete test block (6); the oil pump (8) is placed on the reaction frame (9), the lock (7) is placed on the oil pump (8), and the tension rod (1) passes through the circular hole at the top of the reaction frame (9), the oil pump (8) and the lock (7) in sequence, and the three are installed together; The tension rod (1) is a hot-rolled ribbed steel bar; The anchoring glue is a rebar-planting glue, which is an anchoring glue for concrete structural engineering; the high-strength grouting material has a 28-day compressive strength of ≥ 85N / mm 2 Sleeve grouting material for steel bar connection.

2. The anchoring force testing device for FRP connectors of assembled wall according to claim 1 is characterized in that: In the connecting filler (3), reinforcing ribs (2) are evenly and vertically arranged according to the designed pull-out strength of the FRP connecting piece, and the number of the reinforcing ribs is 2 or 4.

3. The anchoring force testing device for FRP connectors of assembled composite wall according to claim 1, characterized in that: The FRP connector (5) is a cross-section FRP connector, a straight-section FRP connector, or a round rod-type FRP connector.

4. A method for testing the anchoring force of FRP connectors of assembled composite walls using the testing device according to any one of claims 1 to 3, characterized in that: The specific steps include: (1) Prepare a concrete block specimen, in which one end of the FRP connector is embedded; (2) After the concrete test block is demoulded, the connection assembly is installed, a sleeve is placed on the concrete test block, and reinforcing ribs are arranged in the sleeve; the connection filler is injected into the sleeve, and the tension rod is implanted; the tension rod and the FRP connector are on the same axis; after the connection filler is cured, the pull-out test is started; (3) Install the loading assembly, pass the reaction frame, oil pump and lock through the tension rod in sequence, install them together and place them outside the connecting assembly, and lock the tension rod; (4) Apply load evenly through an oil pump to perform a pull-out test on the FRP connector, and record the test results such as the peak force value, displacement, and failure mode when the FRP connector is pulled out and damaged; (5) After the inspection, unload and load to restore the oil pump to its original state, then remove the lock, oil pump and reaction frame in turn.

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