Test device for measuring bonding shear resistance of template and concrete interface on construction site

Abstract

The utility model belongs to the technical field of bridge engineering, and discloses a shear test device for measuring bonding between a template and a concrete interface on a construction site, which comprises a concrete test block and a template, and pressure devices and pushing devices are arranged around the concrete test block and the template; the pressure device comprises an upper half part and a lower half part, and the upper half part comprises a horizontal steel plate; according to the utility model, the prestress generated by the steel strand is converted into the pressure of the steel plate, so that the same normal stress borne by the experimental template and the field template can be realized, and the measured bonding shear strength is more accurate. The pre-stress can be read by the jack during vertical tensioning, so that redundant sensors do not need to be mounted, the use cost is saved, the test efficiency is improved, excessive test times are not needed, required test equipment and materials are convenient to take on site, the test steps are simple, and the test efficiency is further improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to bridge engineering technical field, concretely relates to a construction site measuring formwork and concrete interface bonding shear test device. BACKGROUND

[0002] In the bridge construction process, the post-tensioning prestress tension often leads to the deformation of cast-in-place beam, and the deformation is restrained by the shear bonding force generated between the formwork and the cast-in-place beam contact surface. The restraint will hinder the cast-in-place beam to reach the designed stress level, and may cause structural defects such as cracks in concrete. In order to accurately evaluate the prestress loss, a series of experiments are usually carried out at the construction site, including prestress duct friction and anchor mouth friction experiments, and measurement of displacement of concrete due to creep.

[0003] However, it is worth noting that the formwork will be surface treated and coated with release agent before the concrete is poured, which makes the traditional measurement method of basic data such as bonding shear strength and friction coefficient of concrete and formwork material difficult to be directly applied at the construction site. Therefore, it is necessary to carry out a special measurement of the formwork and concrete interface bonding shear test at the construction site to obtain accurate shear strength data. Through this test, we can deeply understand the specific influence of bonding shear on post-tensioning prestress, so as to more effectively reduce the loss of prestress. In addition, the test method has certain universality and can be used to measure the bonding shear strength on the interface of composite beam, providing strong support for quality control and structural safety in bridge construction. Therefore, a construction site measurement formwork and concrete interface bonding shear test device is proposed. UTILITY MODEL CONTENT

[0004] The utility model aims at providing a construction site measurement formwork and concrete interface bonding shear test device to solve the problems in the above background technology.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical scheme: a construction site measurement formwork and concrete interface bonding shear test device, comprising a concrete test block and a formwork, the four sides of the concrete test block and the formwork are provided with a pressure device and a pushing device;

[0006] The pressure device comprises an upper half and a lower half, and the upper half comprises a horizontal steel plate, a plurality of vertical channel steels are uniformly arranged above the horizontal steel plate;

[0007] The pushing device is provided with two rows of steel sheet piles on the horizontal two sides, a round steel is installed between the two rows of steel sheet piles, a tool anchor, a jack, a limiting plate and a vertical steel plate are sequentially arranged between the steel sheet pile and the concrete test block from left to right, an anchor clamp and a steel backing plate matched with the jack are installed above the channel steel.

[0008] The upper half and the lower half are completely symmetrical with a horizontal line in the middle axis of the concrete block, and a plurality of steel strands are arranged between the upper half and the lower half, the steel strands passing through the two channel steels, the anchor clamping pieces and the steel backing plates.

[0009] Preferably, the material and surface treatment of the formwork are the same as those of the formwork on the construction site, the concrete strength of the concrete block is the same as that of the beam body on the construction site, the thickness of the concrete block is greater than the outer diameter of the limiting plate, the size of the horizontal steel plate is completely the same as that of the formwork, and the length of the formwork and the horizontal steel plate in the direction perpendicular to the steel sheet pile is greater than that of the concrete block, and the length of the other side of the formwork and the horizontal steel plate is the same as that of the concrete block.

[0010] Preferably, the formwork is a bottom formwork for pouring the concrete block.

[0011] Preferably, the horizontal steel plate is pre-coated with a lubricant on the interface with the concrete block, and the horizontal steel plate is filled with glue on the interface with the formwork.

[0012] Preferably, the total value of the pre-stress generated by one end of the steel strand and the stress generated by the weight of the concrete block, the horizontal steel plate, the vertical steel plate, the channel steel, the anchor clamping piece and the steel backing plate is equal to the normal stress of the beam body on the formwork on the construction site.

[0013] Preferably, the horizontal steel plate is pre-coated with a lubricant on the side close to the channel steel, and the horizontal steel plate is filled with glue between the horizontal steel plate and the formwork.

[0014] Preferably, the normal stress of the beam body on the formwork is equal to the sum of the pre-stress generated by the steel strand and the sum of the pre-stress generated by the weight of the concrete block, the horizontal steel plate, the vertical steel plate and the channel steel.

[0015] Preferably, the pre-stress tension of the steel strand is all vertical single-end tension, and the maximum tension of each steel strand does not exceed 200kN.

[0016] Preferably, the flange of the channel steel close to the horizontal steel plate is welded with the horizontal steel plate.

[0017] Preferably, the vertical steel plate is welded with the concrete block, and the size of the vertical steel plate is equal to the size of the vertical surface of the concrete block.

[0018] Preferably, the vertical height of the round steel support position is the same as that of the jack action position and the horizontal steel plate action position.

[0019] Preferably, the distance between the two rows of steel sheet piles on both sides of the concrete block is slightly greater than the sum of the thickness of the tool anchor, the length of the jack, the thickness of the limiting plate and the length of the horizontal steel plate.

[0020] Compared with the prior art, the utility model has the advantages of

[0021] (1) the utility model discloses a prestress generated by steel strand is converted into the pressure of steel plate, and the same normal stress of the measured formwork can be generated to the concrete test block, so that the jack can read the prestress when tensioning vertically, and therefore, it is unnecessary to install the redundant sensor, the use cost is saved, and the test efficiency is improved.

[0022] (2) the utility model does not need too many test times, and the test equipment and materials required can be found and tested on the construction site, and the test steps are simple, and the test efficiency is further improved.

[0023] (3) the device can calculate the bonding strength between the formwork and the concrete interface, and the prestress loss can be reduced by increasing the control stress and other methods, and the probability of the structure defect of the concrete crack is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0024] Fig. 1 It is the structure schematic view of the utility model;

[0025] Fig. 2 It is the right view of structure A-A of the utility model;

[0026] In the drawing: 1, concrete test block;2, formwork;3, horizontal steel plate;4, channel steel;5, anchor clamping piece;6, steel backing plate;7, steel strand;8, steel sheet pile;9, round steel;10, tool anchor;11, jack;12, limiting plate;13, vertical steel plate. DETAILED DESCRIPTION

[0027] The technical scheme in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

[0028] Please refer to Figs. 1-2 The utility model provides the following technical scheme:

[0029] A construction site measurement formwork and concrete interface bonding shear test device is characterized by comprising a concrete test block 1 and a formwork 2, and the concrete test block 1 and the formwork 2 are provided with pressure devices and pushing devices around.

[0030] The pressure device comprises an upper half and a lower half, and the upper half comprises a horizontal steel plate 3, and a plurality of vertical channel steels 4 are uniformly arranged above the horizontal steel plate 3.

[0031] The pushing device is provided with two rows of steel sheet piles 8 on both horizontal sides, round steel 9 is installed between the two rows of steel sheet piles 8, tool anchor 10, jack 11, limiting plate 12 and vertical steel plate 13 are sequentially arranged between the steel sheet pile 8 and the concrete test block 1 from left to right, anchor clamp 5 and steel backing plate 6 matched with the jack 11 are installed above the channel steel 4;

[0032] In the embodiment, when the personnel need to carry out the adhesive shear test, a concrete test block 1 is prefabricated on the non-hardening open space, and the concrete strength and horizontal size of the concrete test block 1 are the same as those of the beam body to be detected. When the concrete test block 1 is prefabricated, the material and surface treatment method of the formwork 2 at the bottom of the concrete test block 1 are the same as those of the formwork of the measured beam body, and the size of the longer end is about 10 mm more than that of the formwork. The lateral formwork 2 at the end is placed on the bottom formwork 2, then the formwork 2 of the remaining three sides is attached to the lateral formwork 2 of the bottom formwork 2, after the attachment is completed, the poured concrete is cured according to the standard, the bottom formwork 2 is reserved, and the concrete is waited to solidify. When the concrete test block 1 reaches the required strength and elastic modulus, two horizontal steel plates 3 with the same size as the bottom formwork 2 are used to clamp the test block. The channel steel 4 is welded on the horizontal steel plate 3, the notches are outwardly formed in combination, and the spacing is slightly larger than the diameter of the steel strand 7. Then, the steel strand 7 is vertically and single-end tensioned, the total stress is controlled to be equal to the normal stress of the formwork 2 minus the weight of the test block 1, the upper horizontal steel plate 3 and the channel steel 4, then the steel sheet pile 8 is symmetrically inserted into the ground on both sides of the test block 1, is perpendicular to the long side of the test block, and the spacing is considered the size of the tool anchor 10, the jack 11, the limiting plate 12 and the horizontal steel plate 3 and is added by 10 mm. The steel sheet pile 8 is supported by the round steel 9 at the key position, then the jack 11 is horizontally placed and the limiting plate 12 and the tool anchor 10 are installed, the jack 11 is elongated so that the limiting plate 12 and the tool anchor 10 are tightly attached to the vertical steel plate 13 and the steel sheet pile 8 respectively, and the jack 11 is horizontally fixed by the buckle and the iron chain. Start the oil pump, record the force when the jack 11 is elongated, the measured thrust minus the friction with the upper horizontal steel plate 3 is the shear strength of the interface between the formwork 2 and the concrete, the adhesive shear test is completed, the upper half and the lower half are completely symmetrical with the horizontal line in the middle axis of the concrete test block 1, and a plurality of steel strands 7 are arranged between the upper half and the lower half, and the steel strands 7 pass through the two channel steels 4, the anchor clamp 5 and the steel backing plate 6.

[0033] In addition, in the utility model, about the above-mentioned formwork 2:

[0034] The material and surface treatment method of the formwork 2 are the same as those of the formwork at the construction site, the concrete strength of the concrete test block 1 is the same as that of the beam body at the site, the size of the horizontal steel plate 3 is the same as that of the formwork 2, and the length of the formwork 2 and the horizontal steel plate 3 is greater than that of the concrete test block 1, and the width of the formwork 2 and the horizontal steel plate 3 is the same as that of the concrete test block 1.

[0035] And, in the utility model, the template 2 is a bottom template for pouring the concrete test block 1.

[0036] In addition, in order to facilitate the personnel to carry out the experiment, the horizontal steel plate 3 is pre-coated with lubricant on the side close to the channel steel 4, and the horizontal steel plate 3 is filled with glue between the horizontal steel plate 3 and the template 2.

[0037] Regarding the normal stress of the beam body to the template 2, in the utility model, the normal stress of the beam body to the template 2 is equal to the total pre-stress generated by the steel strand 7 and the total pre-stress generated by the weight of the concrete test block 1, the horizontal steel plate 3, the vertical steel plate 13 and the channel steel 4.

[0038] In addition, in the utility model, regarding the steel strand 7, the pre-stress tension of the steel strand 7 is all vertical single-end tension, and the maximum tension of each steel strand 7 does not exceed 200kN.

[0039] In addition, regarding how the channel steel 4 and the horizontal steel plate 3 are connected, the flange of the channel steel 4 close to the horizontal steel plate 3 is welded with the horizontal steel plate 3.

[0040] In addition, in the utility model, regarding how the vertical steel plate 13 and the concrete test block 1 are connected, the vertical steel plate 13 is welded with the concrete test block 1, and the size of the vertical steel plate 13 is equal to the vertical size of the concrete test block 1.

[0041] In addition, in the utility model, the vertical height of the position of the round steel 9 supporting, the position of the jack 11 acting and the position of the horizontal steel plate 3 acting is the same.

[0042] Regarding the distance requirement between the two rows of steel sheet piles 8, in the utility model, the distance between the two rows of steel sheet piles 8 on both sides of the concrete test block 1 is slightly greater than the sum of the thickness of the tool anchor 10, the length of the jack 11, the thickness of the limiting plate 12 and the length of the horizontal steel plate 3, the jack 11 should be kept horizontal, and the method can be that buckles and iron chains act on the steel sheet piles 8, or the steel sheet piles 8 are supported to be horizontal.

[0043] In addition, in the utility model, the following specific construction steps are provided:

[0044] A specific construction step of a composite reinforced subgrade structure suitable for a railway bridge transition section:

[0045] S1: select a piece of non-hardening open space, prefabricate a piece of concrete test block 1, the concrete strength and horizontal size of the concrete test block 1 are the same as the beam body to be detected, the material and surface treatment method of the bottom formwork 2 when the concrete test block 1 is prefabricated are the same as the formwork of the measured beam body, and the longer end is about 10mm more, the lateral formwork 2 of the end is placed on the bottom formwork 2, and the remaining three formworks 2 are in close contact with the lateral formwork 2 of the bottom formwork 2, then the concrete is poured and cured according to the standard, the bottom formwork 2 is not removed, and the concrete is solidified to form the concrete test block 1;

[0046] S2: when the concrete test block 1 reaches the strength and elastic modulus at the time of tension, the concrete test block 1 is clamped by two horizontal steel plates 3, the size of the horizontal steel plate 3 is the same as that of the bottom formwork 2, the channel steel 4 is vertically placed and welded on the horizontal steel plate 3, the two channel steel 4 is a combination with the slot opening outward, and the distance between the two is slightly larger than the diameter of the steel strand 7, after a period of welding, the vertical single-end tension steel strand 7 is used to act on the channel steel combination, and the control stress of the steel strand 7 is equal to the normal stress of the formwork 2 of the measured part minus the weight of the concrete test block 1, the upper horizontal steel plate 3 and the channel steel 4.

[0047] S3: then the steel sheet pile 8 is symmetrically inserted into the ground on both sides of the concrete test block 1, which is perpendicular to the longer side of the concrete test block 1, the distance between the two steel sheet piles 8 is the thickness of the tool anchor 10 plus the length of the jack 11 plus the thickness of the limiting plate 12 plus the length of the longest side of the horizontal steel plate 3 plus 10mm, the steel sheet pile 8 is inserted into two rows on one side, and is supported by round steel 9 at the vertical height of the jack 11 action position and the horizontal steel plate 3 action position respectively, finally the horizontal placement of the jack 11 and the matching limiting plate 12 with the tool anchor 10 is extended by a certain length so that the limiting plate 12 and the tool anchor 10 are in close contact with the vertical steel plate 13 and the steel sheet pile 8 respectively, then the buckle is fixed on the steel sheet pile 8, and the iron chain is connected with the jack 11, so that the jack 11 is fixed and kept horizontal, the oil pump is opened, when the jack 11 appears to be elongated, the size of the force of the jack 11 is recorded, and the measured thrust minus the friction between the concrete test block 1 and the horizontal steel plate 3 is the shear strength between the formwork 2 and the concrete interface, and the bonding shear test is completed.

[0048] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and modifications can be made to these embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A construction site measuring formwork and concrete interface bond shear test device, characterized by: The utility model relates to a concrete test block (1) and a formwork (2), the concrete test block (1) and formwork (2) are provided with pressure device and pushing device around, The pressure device includes upper half and lower half, and the upper half includes horizontal steel plate (3), a plurality of vertical channel steel (4) are evenly arranged on the horizontal steel plate (3), The pushing device is provided with two rows of steel sheet piles (8) on the horizontal two sides, round steel (9) is installed between the two rows of steel sheet piles (8), tool anchor (10), jack (11), limiting plate (12) and vertical steel plate (13) are sequentially arranged between the steel sheet pile (8) and the concrete test block (1) from left to right, anchor clamping piece (5) and steel backing plate (6) matched with jack (11) are installed on the channel steel (4) top, The upper half and lower half are completely symmetrical with the horizontal line in the middle axis of the concrete test block (1) being offset, and a plurality of steel strands (7) are arranged between the upper half and lower half, the steel strands (7) pass through two channel steels (4), anchor clamping pieces (5) and steel backing plates (6).

2. The construction site measuring formwork and concrete interface bonding shear test device according to claim 1, characterized in that: The material and surface treatment method of the formwork (2) are the same as those of the construction site formwork, the concrete strength of the concrete test block (1) is the same as that of the site beam body, the thickness of the concrete test block (1) is greater than the outer diameter of the limiting plate (12), the size of the horizontal steel plate (3) is the same as that of the formwork (2), and the length of the formwork (2) and the horizontal steel plate (3) in the direction perpendicular to the steel sheet pile (8) is greater than that of the concrete test block (1), and the length of the other side of the formwork (2) and the horizontal steel plate (3) is the same as that of the concrete test block (1).

3. The construction site measuring formwork and concrete interface bonding shear test device according to claim 1, characterized in that: The formwork (2) is a bottom formwork for pouring the concrete test block (1).

4. The construction site measuring formwork and concrete interface bond shear test device of claim 1, wherein: The horizontal steel plate (3) is pre-coated with lubricant on the interface with the concrete test block (1), and the interface between the horizontal steel plate (3) and the formwork (2) is filled with glue.

5. The construction site measuring formwork and concrete interface bond shear test apparatus of claim 1, wherein: The total value of the prestress generated at one end of the steel strand (7) plus the stress generated by the weight of the concrete test block (1), the horizontal steel plate (3), the vertical steel plate (13), the channel steel (4), the anchor clamping piece (5) and the steel backing plate (6) is equal to the normal stress of the formwork on the construction site beam body.

6. The construction site measuring formwork and concrete interface bond shear test apparatus of claim 1, wherein: The prestress tension of the steel strand (7) is all vertical single-end tension, and the maximum tension of each steel strand (7) does not exceed 200kN.

7. The construction site measuring formwork and concrete interface bond shear test apparatus of claim 1, wherein: The flange of the channel steel (4) close to the horizontal steel plate (3) is welded with the horizontal steel plate (3).

8. The construction site measuring formwork and concrete interface bond shear test apparatus of claim 1, wherein: The vertical steel plate (13) is welded with the concrete test block (1), and the size of the vertical steel plate (13) is equal to the vertical face size of the concrete test block (1).

9. The construction site measuring formwork and concrete interface bond shear test apparatus of claim 1, wherein: The vertical height of the round steel (9) supporting position is the same as that of the jack (11) acting position and the horizontal steel plate (3) acting position.

10. The construction site measuring formwork and concrete interface bond shear test apparatus of claim 1, wherein: The distance between the two rows of steel sheet piles (8) on the two sides of the concrete test block (1) is greater than the sum of the thickness of the tool anchor (10), the length of the jack (11), the thickness of the limiting plate (12) and the length of the horizontal steel plate (3).

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