An expansion joint in masonry is an artificially created crack between the monolithic layers. People who do not know anything about construction and resistance believe that this should not be, and that houses without cracks are the most durable. But builders know that artificially created shear joints increase seismic resistance and structural strength.
The purpose of the expansion joint
What is an expansion joint in masonry for? Logically, it can be assumed that to increase the strength of the building, protection from deformation and destruction.
How does this happen? The construction of the building is divided into compartments, special attention is paid to the corners, the division occurs by gaps, which are just deformation seams. They are filled with special sealed material, which helps to increase strength, eliminating the possibility of cracks in the walls and window openings, and a strong and uneven subsidence of the new room.
How to understand if they are needed? Often needed. This need is primarily determined by external conditions and geometric parameters. In Russia, the climate has a sharp change in temperature, a large difference in these indicators depending on the time of year. Since the country is large, that is, regions prone to unstable soil, the manifestation of dangerous weather conditions, seismological instability. All this affects the construction, because the building must comply with a number of rules and regulations, so that you do not have to rebuild and equip a new room each time. Properly designed construction will last for many years and protect the life and health of the owners.
There are two types of seams. Mandatory design documentation for construction should contain information about their location and purpose.
Seam classification
There are two types of seams:
- The horizontal horizontal expansion joint in masonry, which is necessary due to regular changes in the ambient temperature and the difference in performance in the room and on the street, because this expands or narrows the layer between the bricks.
- Shrinkage is used to reduce the effects of subsidence of the foundation of a new building, especially needed in places with high soil activity in earthquake-resistant areas.
They have an identical design, but differ in their intended purpose.
Kinds
Sedimentary joints are the most popular, because very often the subsidence of the structure occurs unevenly along the entire length and there is a risk of building destruction for this reason. These seams are made from the foundation to the roof. When erecting, you need to take into account that all joints must be dried, and the shear thickness should not exceed 1/4 of the brick.
The thickness of the expansion joint in brickwork: a node of 10-20 millimeters, it replaces part of the vertical ones.
An urgent need arises when the old wall adjoins the new, when connecting the two parts of the building, construction on the ground with uneven settlement and the erection of structures in hazardous areas, that is, those where earthquakes, hurricanes and the like regularly occur.
Special attention should be paid to temperature-shrink seams. Why? Because they protect buildings from the appearance of cracks, damage associated not only with changes and temperature differences, but also with shrinkage. Summarizing, we can say that they are relatively universal.
Usually they are used when there is a strong temperature difference between the winter and summer periods, for example, as is the case in Russia. Their thickness depends on the season and temperature during installation and is indicated in the code of building codes (SNiP).
SNiP requirements
This set of rules sets the standards for the design of stone and stone-stone structures. But all requirements are subject to change and do not apply in dynamic and earthquake-prone areas where unstable soil.
The basic rules for designing and creating an expansion joint in brickwork (SNiP) are as follows:
- Seams that are in places connecting the masonry with steel or reinforced concrete structures must exactly match. If necessary, make additional expansion joints in the brickwork.
- Shrink joints are recommended to be created when there is a risk of uneven subsidence of the structure, that is, when the soil is unreliable. In order to determine this, you need to do calculations using special formulas.
- The rules for temperature and shrink seams also indicate that it is necessary to provide a tongue that is filled with any elastic material. Explanation: A tongue is a protrusion on one side of a seam and a hollow on the other, in other words, a shift to create empty space. This is done so that the wall is not blown out and is resistant to a hurricane.
- The rules for laying such seams are negotiated very sparingly. The location is taken according to SNiP as the maximum length of the intermediate region between them. When creating an expansion joint in masonry, it is not recommended to take a distance less than that specified in SNiP.
Building Protection Technology
Typically, the protection of structures is organized through several technologies and measures. There is a set of recommended rules on this topic, which was mentioned above.
This article talks about protection technology by creating expansion joints - this is a fairly effective and time-tested method. There are modern technologies being introduced, which are at the stage of experimental testing, so it is better to use either temperature, or shrink, or a combined technique. It’s worth choosing depending on the type of building, soil and climate.
Strength, stability and reliability are the three pillars of building protection and the proper organization of construction. It all starts with the design phase, where you need to study the terrain, climate and weather, depending on the time of year, the purpose of the room, the activity of its use and load. The expansion joint in masonry ensures compliance with all available and recommended levels of structural safety.
All this, one way or another, affects the safety and integrity of the building.
conclusions
Summing up, it is worth noting that building structures are exposed to the destructive effects of the environment, such as temperature extremes, drying out by the sun. Rain, salt, snow and wind, the effects of moisture coming from inside the building, earthquakes, dangerous weather events - all this can lead to cracks and destruction. This is dangerous both financially and socially and in terms of life - people can suffer. Therefore, at the design stage, pay attention to such an important stage as the creation of an expansion joint in brickwork.