CN212180149U - Device for detecting external prestress value by using midpoint lateral force-displacement - Google Patents

Abstract

The utility model discloses a device for detecting the external prestress value of the midpoint lateral force-displacement, which is used to detect the prestress value of the external prestressed tendons in the reinforcement of building structures; Displacement meter; the top end of the force-applying rod is suspended at the midpoint of the external prestressing tendon, and the bottom end is used to suspend the force-applying weight; the measuring rod is arranged horizontally and is fixedly connected with the rod body of the force-applying rod; the bracket is located below the measuring rod; the displacement The sensing probe of the meter is facing upward on the rod body of the measuring rod; the top end of the force application rod is suspended at the midpoint of the external prestressing tendon; the displacement meter is zeroed; the second force application weight is suspended from the bottom end of the force application rod The vertical force is applied by the code, and the corresponding displacement value displayed by the displacement meter is read, and the prestress value of the external prestressed tendon is calculated according to the relationship between the force and the geometry. The utility model calculates the tensile force value of the external prestressed tendons through simple structure and formula, has convenient detection, high precision, and is convenient for construction site detection.

Description

A device for detecting external prestress value by midpoint lateral force-displacement

technical field

The utility model relates to the technical field of prestress detection, in particular to a device for detecting external prestress values by midpoint lateral force-displacement.

Background technique

External prestressing reinforcement is one of the important ways to reinforce concrete structures in housing construction. Different from the traditional prestressed reinforcement structure, external prestressed structure reinforcement is a reinforcement technique in which prestressed bundles are arranged outside the main section of the structure to apply prestress.

External prestressed reinforcement has obvious advantages in the reinforcement and reconstruction of concrete structures:

(1) The force is clear, the construction is simple, and it does not even affect the normal use;

(2) Under the condition that the self-weight increase is small, the stress condition of the original structure can be greatly improved and adjusted, and the rigidity and bearing capacity of the structure can be improved;

(3) It is easy to maintain and repair, and the prestressed tendons can be replaced at any time, and the prestressed size can be adjusted;

(4) The damage to the structure is very small, and the original structural section is basically not changed.

The detection of prestressing value has always been the main content of prestressing technology research. How to determine the prestressing value after external prestressing is also a key issue that the industry is concerned about. The conventional method is to use the vibrating wire method to detect and measure the vibration frequency by vibrating the external prestressed tendons, and calculate the prestress value. Stress tendons often have external anti-corrosion layers and fireproof layers. It is difficult to accurately know the quality of prestressed tendons, so it is difficult to predict the quasi-prestressed value.

Therefore, how to provide an in vitro prestress detection device that is simple to operate and accurate to measure is an urgent problem to be solved by those skilled in the art.

Utility model content

In view of this, the present invention provides a device for detecting in vitro prestress value by midpoint lateral force-displacement, aiming at solving the above technical problems.

In order to achieve the above purpose, the utility model adopts the following technical solutions:

A midpoint lateral force-displacement detection device for external prestress value, used for prestress value detection of external prestressed tendons in building structure reinforcement; including: a force application rod, a measuring rod, a bracket and a displacement gauge;

The force-applying rod is arranged vertically, and the top end is suspended at the midpoint of the external prestressing tendon, and the bottom end is used for suspending the force-applying weight;

The measuring rod is arranged horizontally, and one end end is fixedly connected with the rod body of the force applying rod;

The bracket is placed on the ground and is located below the measuring rod;

The displacement meter is placed on the support, with its sensing probe facing upwards and pressing against the rod body of the measuring rod.

Through the above technical solutions, the utility model can realize detection only through a simple structure composed of a force application rod, a measuring rod, a displacement meter and a force application weight, and the force application rod is hung at the midpoint between the steering blocks of the external prestressed tendons. , apply lateral force with weights, measure the displacement value corresponding to the lateral force, and calculate the tensile force value of the external prestressed tendons through a simple formula.

Preferably, in the above-mentioned device for detecting in vitro prestress value by midpoint lateral force-displacement, both ends of the force applying rod have hooks. It is convenient for the suspension of the force application rod and the suspension of the force application weight on the force application rod.

Preferably, in the above-mentioned device for detecting an in vitro prestress value by midpoint lateral force-displacement, the force applying rod is a steel pipe, and the diameter is between 20 mm and 40 mm. Can meet construction needs.

Preferably, in the above-mentioned device for detecting an in vitro prestress value by midpoint lateral force-displacement, the measuring rod and the forcing rod are fixed by welding or by bolted connection. Easy to connect and stable in structure.

Preferably, in the above-mentioned device for detecting an in vitro prestress value by midpoint lateral force-displacement, the height of the bracket is suitable for the operating height of a person. User-friendly operation.

Preferably, in the above-mentioned device for detecting external prestress value by midpoint lateral force-displacement, both ends of the external prestressing tendon are fixed on the concrete beam plate, and the bottom end of the concrete beam plate is fixed through the Two steering block supports. The device is suitable for detecting the prestress value of the horizontal section or the inclined section of the external prestressed tendon in the above-mentioned building structure.

The detection method of the device for detecting the external prestress value of the midpoint lateral force-displacement provided by the utility model comprises the following steps:

S1. Suspend the top end of the force-applying rod at the midpoint of the external prestressing tendon;

S2. Suspend the first force-applying weight at the bottom end of the force-applying rod to stabilize the force-applying rod. The sensing probe of the displacement meter is pressed against the rod body of the measuring rod, and the displacement meter is zeroed at this time;

S3. Suspend a second force application weight at the bottom end of the force application rod to apply a vertical force, and read the corresponding displacement value displayed by the displacement meter, and calculate the prestress value of the external prestressed tendon according to the relationship between force and geometry .

In S2: the weight of the first applying weight is 4-6KG. It can realize the stability of the measuring rod and the top of the induction probe of the displacement meter to prevent it from shaking.

In S3: The relationship between force and geometry is:

Among them: M is the mass of the second force-applying weight, _Δ is the displacement value after the second force-applying weight is applied, L is the length of the external prestressing tendon, and F _p is the length of the external prestressing tendon to be measured. prestress value;

The prestress value of the external prestressed tendons is obtained:

The formula is simple, easy to calculate, and has high detection accuracy.

The first force application weight and the second force application weight are sequentially suspended along the axial direction of the force application rod. Guaranteed measurement stability.

It can be seen from the above technical solutions that, compared with the prior art, the present utility model discloses a device for detecting the prestress value in vitro by the midpoint lateral force-displacement. The simple structure composed of force weights can realize the detection. Hang the force application rod at the midpoint between the steering blocks of the external prestressed tendons, apply the lateral force with the weights, and measure the displacement value corresponding to the lateral force. The formula calculates the tensile force value of the external prestressed tendons, the device is simple, the detection is convenient, the precision is high, and the construction site detection is convenient.

Description of drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description It is only an embodiment of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained according to the provided drawings without creative efforts.

Fig. 1 accompanying drawing is the structural representation of the device measurement state provided by the utility model;

Fig. 2 accompanying drawing is the enlarged structural schematic diagram of the device provided by the utility model;

Figure 3 is a schematic diagram of the midpoint displacement of the external prestressed tendons under lateral force provided by the utility model.

in:

1- External prestressing tendons;

2-Forcing rod;

3- measuring rod;

4- bracket;

5 - displacement meter;

6-Forcing weights;

7 - ground;

8- Concrete beams and slabs;

9- Steering block.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the implementations. example. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

Referring to Fig. 1 and Fig. 2, an embodiment of the present utility model discloses a device for detecting external prestress value by midpoint lateral force-displacement, which is used for prestressing value of external prestressing tendons 1 in the reinforcement of building structures Detection; including: force rod 2, measuring rod 3, bracket 4 and displacement meter 5;

The force application rod 2 is arranged vertically, and the top end is suspended at the midpoint of the external prestressing tendon 1, and the bottom end is used to hang the force application weight 6;

The measuring rod 3 is arranged horizontally, and one end is fixedly connected with the rod body of the force applying rod 2;

The bracket 4 is placed on the ground, and is located below the measuring rod 3;

The displacement meter 5 is placed on the support 4 with its sensing probe facing upwards and pressing against the rod body of the measuring rod 3 .

In order to further optimize the above technical solution, both ends of the force applying rod 2 have hooks.

In order to further optimize the above technical solution, the force application rod 2 is a steel pipe, and the diameter is between 20 mm and 40 mm.

In order to further optimize the above technical solution, the measuring rod 3 and the force applying rod 2 are fixed by welding or by bolted connection.

In order to further optimize the above technical solution, the height of the bracket 4 is suitable for the operation height of a person.

In order to further optimize the above technical solution, both ends of the external prestressing tendons 1 are fixed on the concrete beam plate 8 and supported by two steering blocks 9 fixed at the bottom end of the concrete beam plate 8 .

It should be noted that, when the external prestressed tendons 1 are not horizontal, the corresponding calculation formula can be easily obtained according to the inclination angle of the external prestressed tendons 1 . Therefore, the device can also be used for the detection of non-horizontal sections. When detecting the non-horizontal section, in order to stabilize the suspension of the force-applying rod 2, a section of steel wire can be tightened on the external prestressing tendon 1 to form a hook, and then the force-applying rod 2 is suspended and connected.

The detection method of the device for detecting the external prestress value of the midpoint lateral force-displacement disclosed by the utility model comprises the following steps:

S1. Suspend the top end of the force applying rod 2 at the midpoint of the external prestressing tendon 1;

S2. Suspend the first force application weight 6 at the bottom end of the force application rod 2 to stabilize the force application rod 6, and the sensing probe of the displacement meter 5 is pressed against the rod body of the measuring rod 3, and the displacement meter 5 is zeroed at this time;

S3. Suspend the second force application weight 6 at the bottom end of the force application rod 2 to apply a vertical force, and read the corresponding displacement value displayed by the displacement meter 5, and calculate the external prestressed tendon 1 according to the relationship between force and geometry prestress value.

In S2: the weight of the first applying weight 6 is 4-6KG.

In S3: The relationship between force and geometry is:

Among them: M is the mass of the second force application weight 6, _Δ is the displacement value generated after the second force application weight 6 is applied, L is the length of the external prestressing tendon 1, and F _p is the in vitro prestressing force to be measured. The prestress value of the stress tendon 1; as shown in Figure 3.

The prestress value of the external prestressed tendon 1 is obtained:

The first force application weight 6 and the second force application weight 6 are suspended in sequence along the axial direction of the force application rod 2 .

Take the actual situation on site as an example:

An on-site inspection was carried out on a project. The values were L=3750mm, M=24kg. The test was carried out when the prestressed tension reached 50% of the control force. M=24kg, _Δ =3.55mm, and the external prestressed tendon force value was calculated. for:

When the prestress is stretched to 100% of the control force, the test is carried out, and _Δ = 1.74 mm is obtained. The calculated value of the external prestressed tendon is:

Error analysis of prestressed tendons under vertical deformation:

Assuming that the lateral displacement of the prestressed tendons is 5 mm, we get:

Due to the lateral deformation, the prestressed tendon 1875mm is elongated by 0.007mm, and the corresponding stress is 0.7MPa, which is less than 0.1% compared with the prestress value of about 1000Mpa and can be ignored.

Therefore, the measurement accuracy is high, and the accuracy mainly depends on the displacement measurement accuracy.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method.

The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. a device of midpoint lateral force-displacement detection external prestress value, it is characterized in that, for carrying out prestress value detection to the external prestressed tendon (1) in building structure reinforcement; 2), measuring rod (3), bracket (4) and displacement meter (5); The force applying rod (2) is arranged vertically, and the top end is suspended at the midpoint of the external prestressing tendon (1), and the bottom end is used for suspending the force applying weight (6); The measuring rod (3) is arranged horizontally, and one end end is fixedly connected with the rod body of the force applying rod (2); The bracket (4) is placed on the ground, and is located below the measuring rod (3); The displacement meter (5) is placed on the support (4), and the sensing probe thereof faces upwards and is pressed against the rod body of the measuring rod (3). 2 . The device for detecting in vitro prestress value by midpoint lateral force-displacement according to claim 1 , wherein both ends of the force applying rod ( 2 ) have hooks. 3 . 3. A device for detecting external prestress value by midpoint lateral force-displacement according to claim 1 or 2, characterized in that the force applying rod (2) is a steel pipe, and the diameter is between 20 mm and 40 mm. between mm. 4. A device for detecting external prestress value by midpoint lateral force-displacement according to claim 1, characterized in that, the measuring rod (3) and the forcing rod (2) are fixed by welding or adopting Bolted connection. 5 . The device for detecting in vitro prestress value by midpoint lateral force-displacement according to claim 1 , wherein the height of the bracket ( 4 ) is suitable for the operating height of a person. 6 . 6. The device for detecting external prestress value by midpoint lateral force-displacement according to claim 1, wherein the two ends of the external prestressing tendon (1) are fixed on the concrete beam slab (8) and supported by two diverting blocks (9) fixed at the bottom end of the concrete beam plate (8).

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