Embedded parts and metal plates

What are embedded parts

In the 1930s, high-rise buildings began to be constructed and it became necessary to strengthen their foundations. Wood and cast iron were replaced by metal structures made of steel. Around the same time, metal embedded components were developed to simplify construction technology and add strength to the structures under construction. Modern buildings, especially skyscrapers, are built exclusively with the use of embedded structures. With the help of such elements, load-bearing structures are connected to each other, which increases their resistance to loads. The quality of the parts is essential for their manufacture. Initially, carbon steel was used for production, but it was soon found that low-alloy steel embedded elements could withstand higher loads. The process of replacing carbon steel with low-alloy steel did not take long. Externally, metal embedded parts resemble an anchor (one or more) welded to a metal plate whose thickness can vary from 2 to 200 mm. The designs differ in size, as well as in the presence of a thread, which transforms an ordinary element into an adjustable component.

The elements are called embedded because the metal plates are embedded in a concrete or reinforced concrete base. The part of the steel reinforcement that remains on the surface is used to fasten the structures, most often by welding. The process of manufacturing metal embedded elements is not too complicated. Depending on the manufacturing method, they can be welded and stamped. The design of the former is a plate to which four anchor rods are welded. The rods can be connected to the base of the plate:

• in the tavr;
• obliquely;
• crosswise;
• on the plate plane and perpendicular to it.

The plates underlying the metal embedded parts can be square, rectangular, triangular, or diamond-shaped. The elements produced must meet the requirements of GOST 14098-91, according to which the parts may have a structural design:

• one plate (open);
• two plates located at the top and bottom of the metal rods (closed).

In the first case, the parts are more functional, as they can be used in almost all types of construction and installation work. The best option for the use of stamped embedded elements is for parts of the structure under construction, which, for example, transfer loads from wall parts to columns, etc., i.e. at low design loads. Metal bars in the production of embedded parts are Periodic profile reinforcing bars of classes A-II, A-III, Ac -II, produced by hot rolling; Smooth reinforcing bars made by hot rolling technology belonging to class AI. Anchors can have the following cross-sections 8, 10, 12, 14, 16, 18, 20, 22, 25 mm. The concrete grade is also important for calculating the diameter of the bar. All batches of finished metal embedded parts are accompanied by appropriate documentation.

What are embedded parts made of

Depending on the materials used, the security elements can be made of ABS plastic, stainless steel and bronze. Plastic parts are the least expensive. They have low strength and durability. Improper installation and frost can cause them to crack. Metal embedded parts made of stainless steel are characterized by higher cost, strength and durability, as well as minimal sensitivity to temperature changes, which is important in the construction of swimming pools, for example. Bronze embedded parts are characterized by the longest service life, high corrosion resistance and resistance to mechanical damage. Such elements are considered to be of high quality, which determines the scope of their application. One of the disadvantages of bronze bars is their high cost.

Labeling of collateral parts

After manufacturing, a batch of metal embedded parts is labeled with individual labels and a label for the entire batch. The label contains a symbol for the part, which indicates the area of its main use: MD, MN, MS, ZD, A, FN.

MD is a metal embedded part that is used to connect elements of reinforced concrete lighting structures or to secure equipment.

  MN is a non-removable metal element used in the construction of buildings with load-bearing structures, such as multi-story buildings, hangars, bridges, etc.

MS are embedded metal parts with a wide range of applications. They are used in the construction of reinforced concrete structures, for pouring foundations, building construction, mounting fences, tunnel floors, bridge piers, facades and staircases, reinforced concrete columns, elevator shafts, etc.

WP is a metal wall panel used in the construction of main walls, floors and partitions. The panel is mounted directly into the wall and with the help of projecting anchors, additional equipment is installed, including pipelines, canopies, facing masonry, etc.

A – these metal parts have anchors, which are used to connect heavy objects and structures with dense materials.

FM – elements are used for installation of monolithic foundation structures. They are usually installed in the ground and are not often poured with ready-mixed concrete. In addition to data on the scope of application of the elements, the label contains information on the number of parts in the batch, its number, the date of manufacture, as well as a mark affixed by the technical control service of the enterprise that the mortgage or batch of mortgages has been accepted. The package also includes a technical passport and a list of requirements for the installation of embedded structures.

Advantages and scope of use of metal embedded parts

The use of metal embedded parts is characterized by the following advantages:

• Versatility of use.
• High strength.
• Reliability.

Let us consider the last point in more detail. The use of embedded metal elements increases the reliability of the finished structure, increases its service life many times over, and at the same time significantly reduces the time required for the construction of the structure. The elements are inserted directly into the concrete structure, usually at the final stage of production. The panel itself is inside the concrete block and the anchor component remains outside. Anchors are used to securely connect reinforced concrete structures to each other or to metal frame elements. Metal embedded components significantly increase the strength and reliability of buildings and structures under construction. They allow for careful fixing of individual elements. In principle, the construction of monolithic structures is impossible without the use of such parts. The main field of application of metal embedded parts is the construction of prefabricated and monolithic prefabricated buildings. Such construction requires the use of many separate reinforced concrete structures connected to a single base. At the same time, the fasteners not only facilitate the transportation of the blocks, but also allow them to be joined into a high-strength monolith. Thanks to the reliable connection of the blocks to each other, the load is evenly distributed over their entire surface. By using different grades of rebar to create the embedded elements, the load-bearing structures are given the best properties. However, this increases production costs because more material is required to make the blocks and the structural elements must be formed to the desired geometric shape. In the event that spatial reinforcing components are not required at the end of the installation, a simpler rolled metal option, such as large section smooth wire, can be used for one-time use. Due to the properties of the materials used in the manufacture of metal embedded parts, the scope of their application is significantly expanded. They are used in: Construction of buildings and structures made of concrete, reinforced concrete and stone blocks, in which reinforcing elements are placed. In the construction of hangars and bridges. They become particularly relevant when long spans are created without intermediate supports. In restoration and renovation works. In this case, the use of metal embedded parts increases the safety of the construction site and speeds up the process of restoration or reconstruction of objects. When creating architectural facades. It is recommended to fix their individual elements with metal embedded parts. In the construction of elevator shafts and other technologically similar structures.

In particularly strong and heavy fencing systems, which are recommended for use in conjunction with metal embedded parts. The simplest embedded metal parts are in the form of a ring that protrudes above the surface of the panel. The part is fixed to a reinforcing cage placed inside the block. Such elements are joined by welding, as other ways of fastening metal profiles do not provide sufficient strength and reliability. In addition, more complex structural elements are now common. Embedded structures are standardized and purchased during construction because they allow for the design and construction of highly accurate structures and buildings.

Technology of manufacturing metal embedded parts

The process of manufacturing metal embedded parts is quite simple. They are manufactured using classic metalworking technologies – cutting and welding of elements. First of all, it is necessary to calculate the load to which the structure will be subjected during operation. After analyzing the obtained data and the specifics of the subsequent use of the elements, the materials from which the embedded elements will be made are determined to have a sufficient safety margin. Then the production of the required number of embedded structures begins. The sheet metal of the required thickness is cut into blanks, then rolled metal of the required length, cross section and strength is selected. The reinforcement is welded to the plate at specific angles. In the last stage, the finished structures are painted or treated with zinc to increase their corrosion resistance. The excellent properties of the finished metal embedded parts are ensured by strict compliance with GOST requirements. Calculations are made taking into account the dimensions of the finished product, the expected loads and the possibility of using additional elements. In the process of creating embedded structures, we also take into account the expected longitudinal and transverse loads, as well as the unavoidable deviations during the installation of the elements. The result is a variety of embedded metal parts – from the simplest with a single anchor (a plate with a single reinforcing bar) to complex shapes with many bars welded to the plate at different angles. Specific design features directly affect the cost of reinforcing elements. However, the most common calculation system is based on the weight of the finished product. Most often, metal embedded parts are manufactured individually for each project. The label attached to them contains information about:

• brand;
• the number of parts in the batch;
• the date of production;
• deviations that may occur in the batch.

The technical control department also marks the finished products for acceptance and specifies the requirements for installation work. Embedded elements can be manufactured both in batches and individually to order. Anti-corrosion treatment with special agents is essential, as it increases the service life of the parts.The elements can be universal, i.e., compliant with all standards. There are several standard series of metal embedded parts, for example, products of the MN, MS, MD types. The production and subsequent use of the elements affects their types and series.

Manufacturing standards for embedded parts

High quality of metal embedded parts is achieved by strict compliance with GOST requirements. The anchors and the plate must be connected at certain angles prescribed by the standards. The edges of the elements must be cleaned from slag and deposits created during high temperature cutting. Dirt, oil, rust and flaking scale are not allowed on the metal surface. There should be no cracks in the welding area and no undercuts in the transition from the welded part to the base. Existing craters are welded out during the manufacturing process. The weld must also be free of slag, sagging, and hardened areas. Unwelded areas, base burns, and fistulas are not acceptable. However, some variation in the dimensions of the finished products and the design is still possible: The planes of the front surfaces of metal embedded parts relative to the horizontal and vertical surfaces may deviate up to 5 mm. Flat elements may not deviate from the design location by more than 10 mm in any direction. In certain cases, flat elements may deviate from the design location by up to 100 mm if this ensures the possibility of installing parts in accordance with the project requirements. The axes of pipe embedded parts may deviate by 10 mm in any direction. The deviation from the plane of the front surfaces of the components should not exceed 5 mm. The fasteners of the embedded parts shall be designed to withstand the loads during the concreting process and the vibration of the freshly placed concrete mix. Deviations and displacements during concreting of embedded metal parts shall be within the above tolerances. During installation and concreting of embedded members, the deviation between the working reinforcement and its design position should be within the limits specified in the project. The joints of metal embedded elements with vertical and horizontal reinforcement shall be tied with wire, and additional loosening shall be performed by pressing the embedded element against the formwork in accordance with the PPR.

Types of installation of embedded parts

Installation of embedded structures can be done by welding, gluing or bolting. Installation can be done by blind or through installation. With the through installation option, access to the concrete block is possible from any side, it is easily drilled through. This hole will be visible from the front, so to preserve the appearance of the product, it should be drilled from the other side. The hole contains the anchor of the embedded part, which is then welded to the panel. With the blind installation method, the appearance of the unit remains unchanged, i.e. it can be approached from one side. A threaded anchor and a single plate are used for attachment. With this type of installation, the embedded part can be attached using casting and anchoring techniques. The casting, or otherwise mortgage, technology is as follows. A hole made in the concrete is filled with cementitious mortar, then a metal rod is placed inside. Next, the cementing mortar is distributed to the elements, which are then welded to the plates. Concrete, polymer or epoxy mortars are used to join the parts. In the anchored version, fixing is done by means of anchors. An anchor tube is placed in the drilled hole, into which a conical rod with a thread at the narrow end is inserted. The anchor with the tube is turned in the hole to clamp the structure, then a metal washer is placed on the rod and the nut is screwed onto it. The final stage of installation, regardless of the technology used, is to concrete the structure. When the concrete is completely dry, the product is tested for strength. Safety precautions are very important when installing metal embedded parts.

How to choose metal embedded parts

In order to select the correct metal embedded elements, it is necessary to use the design calculations prescribed in the SNiPs. Without the appropriate knowledge and experience, it will not be possible to perform an independent calculation. The choice of metal embedded parts depends on:

• installation sites;
• calculation of concrete working conditions;
• dimensions of the finished reinforced concrete structure;
• the possibility of using additional elements;
• probable transverse and longitudinal loads;
• of permissible deviations;
• the degree of load that will have to be distributed through a particular collateral part.

One of the most important points to consider when calculating the embedded structure is the homogeneity of the steel alloy and the cast reinforced concrete member. This requirement is regulated by SNiPs and applies to all types of metal embedded parts. Even experts sometimes have difficulty determining the type of metal product required. Parameters such as the design of the future embedded element, the number and angle of inclination of the anchor rods, etc. are of great importance. In most cases, embedded elements are manufactured individually for each project according to a pre-selected class, since the project documentation must contain this information. The geometry of the embedded elements is specified prior to the start of construction, and they are delivered to the site ready for use and in the appropriate size for the structure to be reinforced. Any modern construction project involves the use of many types of fasteners that connect metal structures, and the number of varieties is constantly increasing. Studies show that in recent years the most popular fasteners have been steel fasteners, which are also characterized by an affordable price. However, some unscrupulous manufacturers of metal structures save on raw materials, i.e. on the steel used, which is the reason for the reduced functionality of metal embedded parts. Of course, the cost of finished products is also reduced, but no one can guarantee that their use will not result in material or physical damage. Therefore, it is advantageous for construction companies to regularly cooperate with manufacturers of metal embedded parts, to rely on a system of discounts and, at the same time, to protect themselves from purchasing low-quality products.