In modern construction, a huge amount of various hardware products are used. At the same time, it is unthinkable to do without the longest special fastener, which is called the “foundation bolt”. He also has another, less popular name - "hairpin".
General information about fasteners
According to its design, the foundation bolt is a round bar of great length, made of steel. At its ends there is a thread designed for one of the sizes of nuts. For the production of these hardware products, different types of steel are used. They can be easily identified by the markings applied to this fastener. The parameters of foundation bolts are regulated by GOST 24379.1-80. It indicates the type, length, version, diameter and pitch of the thread, steel grade. There are also detailed descriptions and drawings of various elements of these fasteners.
Depending on the nature of the load and magnitude, type of foundation, supporting structure, these bolts differ according to different criteria:
- according to operating conditions: design (power) and constructive (lightly loaded);
- bydesigns;
- by installation method: embedded and deaf;
- according to the method of fixing in the foundation - embedded in the base during its manufacture, on glue, on a cement-sand mixture, wedged.
Scope of application
The foundation bolt can be used in a wide variety of ways. Most often it is used to create reinforced concrete structures of complex configuration. With the help of foundation studs, strong connections with fixed bases are created. So the practice of using this fastener for the installation of large-sized equipment (machine tools, conveyors) is widespread. This is due to the very large length of the studs and the threaded connection. These features of the foundation bolts make it possible to create a fastening that perfectly resists small dynamic loads in the form of vibration from electric motors.
Types of foundation studs
According to GOST, all these fasteners are divided into 6 types. Foundation bolts come in different lengths and have different thread sizes at their ends. Depending on their design, they may have different attachments to the base. Below are the most common types of this kind of mounts:
- The bolt is curved. It can be of two subspecies: the rod is straight to the bend or bent at an acute angle (15-30 degrees). Fasteners of the second type can withstand a large load.
- Composite bolt. It comes in two subspecies: with nuts according to GOST 5915-70 and GOST 10605-72. These bolts canincrease in length. The extension is carried out using a steel sleeve screwed into the part of the fastener fixed at the base.
- Bolt with anchor plate. There are three types. The first two have different top nuts, while the third has a specially shaped anchor plate.
- Removable bolt. This fastener is of three types. All of them differ from each other by anchor fittings and an external nut. Removable fasteners can be of almost any length. This feature explains why anchor foundation bolts are so popular. GOST 24379.1-80 provides for 3 types of execution of such fasteners. They differ depending on the diameter of the thread. Foundation anchor bolts are most often used in securing equipment. They make it easy and simple to mount or dismantle any machine.
- Straight bolt. This type of fastener is considered a classic. Its lower edge can be welded simply to the reinforcement of a reinforced concrete structure before it is poured with concrete.
- A bolt with a tapered end. It differs from other types in the shape of the end of the hardware, which is attached to the base. It has an expanding conical shape. Thanks to it, the foundation bolt is firmly fixed and it is simply impossible to pull it out of the concrete. There are several varieties of this type of fastener.
