RU224579U1 - Dowel-nail with washers - Google Patents

Abstract

The utility model relates to the field of studying the strength properties of concrete, in particular to dowel-nails immersed in concrete, and can be used to control the strength of concrete structures by the force of pulling the dowel-nail out of the tested concrete. The technical result is an increase in the dynamic stability of the dowel-nail structure when introduced into concrete of certain strength ranges. A dowel-nail with a point, a cylindrical part and a head; on the cylindrical part there are three washers at an equal distance along the cylindrical part from the tip to the head with the ability to move along the cylindrical part during the process of introducing the dowel-nail into the tested concrete.

Description

Field of technology

The utility model relates to the field of studying the strength properties of concrete, in particular to dowel-nails immersed in concrete, and can be used to control the strength of concrete structures by the force of pulling the dowel-nail out of the tested concrete.

State of the art

Close in technical essence is the dowel-nail version 2 according to TU 14-4-1731-92, introduced in 1992, containing a rod with a straight corrugated surface with a head and a washer.

The disadvantages of the dowel-nail version 2 according to TU 14-4-1731-92 include the reduced reliability of introducing the dowel-nail into concrete of various grades of certain strength ranges to control the strength of concrete structures.

Close in technical essence is a rough nail according to drawing (GOST) 7811-7120 GE, containing a body with a head made of transverse notches (knurling) on the body.

The disadvantages of rough nails include reduced reliability of implementation into concrete of various grades of certain strength ranges to control the strength of concrete structures.

The closest in technical essence is the dowel-nail according to the Russian Federation patent for invention No. 2706390, which was published on November 18, 2019, according to IPC G01N 3/48, on the cylindrical surface of which a scale is applied.

The disadvantages of the above-described device include the reduced reliability of introducing a dowel-nail into concrete of various grades of certain strength ranges to control the strength of concrete structures.

Disclosure of utility model

To ensure reliable determination of the strength of the tested concretes by the pull-out force of the dowel-nail, for certain strength ranges of the tested concretes, dowel-nails with different length-to-diameter ratios are required.

The purpose of the utility model is to increase the reliability of introducing a dowel-nail into concrete of various grades of certain strength ranges to determine the strength of concrete by determining the force of pulling the dowel-nail out of concrete.

The technical result of the utility model is to increase the dynamic stability of the dowel-nail structure when introduced into concrete of certain strength ranges.

During the experimental development of a method for determining the strength of concrete when driving a dowel-nail using a construction gun, dowel-nails with a larger value of the ratio of length to diameter, at a certain strength of concrete, lost stability during the immersion process (the part of the dowel-nail not immersed in the tested concrete was bent). Using a heuristic method, a proposed design was found that eliminates the loss of stability of the part of the dowel-nail that is not immersed in the concrete under test under similar conditions of implementation (concrete strength, ratio of dowel-nail length to diameter, hardness of the dowel-nail material, initial speed of penetration of the dowel-nail into concrete, etc. .d.). The dowel-nail with washers is designed to be captured by a pulling device.

Technical results are achieved by the fact that in the dowel-nail, to determine the strength by the force of pulling out the dowel-nail from the tested concrete with a tip, a cylindrical part and a head on the cylindrical part, three washers are located at an equal distance along the cylindrical part from the tip to the head with the ability to move along cylindrical part in the process of introducing a dowel-nail into the tested concrete.

In a dowel-nail, the washers can be placed on the cylindrical part of the dowel-nail with an interference fit.

One of the washers, located closer to the head of the dowel-nail, can be made in the longitudinal section of an H-shaped solid or composite.

Brief description of the drawing

The figure shows a schematic version of a dowel-nail.

Implementation of a utility model

The submersible dowel-nail 1 is made, for example, from steel with a hardness of at least 51.5 HRC; during the manufacturing process, washers 3 are placed with tension on the cylindrical part 2. In the process of introducing the dowel-nail 1 into the tested concrete, washers 3 interact with the surface of the concrete and with each other, are mixed along the cylindrical part 2. In the process of determining the strength of concrete in the area where the dowel-nail is captured by the pulling device, the part of the dowel-nail that interacts with the pulling device does not interact with the concrete from which the dowel-nail is pulled out.

The dowel-nail is immersed in concrete, for example, using a construction gun without drilling a hole using assembly and construction cartridges with an energy output of 300 to 700 J.

After immersion in the tested concrete or concrete structure and before pulling out the dowel-nail from the tested concrete or concrete structure, measure the size of the gap for gripping in the area of the dowel-nail head with a pulling device or remove part of the tested concrete in the amount necessary for gripping in the area of the dowel-nail head pulling device, and measure the length along the dowel-nail of the removed part of the concrete being tested.

When determining the strength of concrete or a concrete structure, the size of the gap for gripping in the area of the dowel-nail head by a pulling device or the length along the dowel-nail of the remote part of the tested concrete is taken into account.

The strength is determined by the force of pulling out the immersed dowel-nail from the concrete being tested, in particular the concrete structure, i.e. by the force of tearing off a part of concrete from a concrete structure when pulling out a dowel-nail or by the force of pulling out a dowel-nail without tearing off the concrete from the concrete structure.

When pulled out, the part of the concrete in contact with the tip of the dowel-nail is released from the stress caused by the immersion of the dowel-nail in the concrete. In this case, the compression forces of concrete in the area of contact with the cylindrical part of the dowel-nail and the friction forces, as a rule, will exceed the forces of separation of the part of concrete being torn out from the massif.

The surface of the internal hole of the washer is made corresponding to the outer surface of the cylindrical part of the dowel-nail, allowing the washer to move along the dowel-nail in the direction from the tip to the head.

The H-shaped washer in the longitudinal section can be solid or composite.

The dowel-nail can be made of known materials using known technologies.

The washers can be made of known materials using known technologies.

Claims (2)

1. A dowel-nail with a point, a cylindrical part and a head, characterized in that on the cylindrical part three washers are located at an equal distance along the cylindrical part from the tip to the head with the ability to move along the cylindrical part during the process of introducing the dowel-nail into the tested concrete. 2. Dowel-nail according to claim 1, characterized in that the washers are placed on the cylindrical part of the dowel-nail with tension.