Expansion joint: prevent distortion of the structure

Temperature changes, humidity, climate in general,Seismic and dynamic loads are factors that often lead to structural deformation. So that changes in the volume of building materials (expansion or contraction due to temperature differences) or subsidence of elements (due to errors in the calculation of the foundation or insufficient reliability of the soil) do not result in the destruction of the entire structure, it is desirable to use a expansion joint.

Types of expansion joints

Depending on the prevention of what type of deformation is necessary, the seams distinguish between temperature, shrinkage, antiseismic and sedimentary.

Temperature expansion joint is used forprevent horizontal changes. When calculating an industrial building with a frame construction scheme, the seams are positioned at least every 60 m for heated and 40 m for unheated buildings. As a rule, temperature joints affect only above-ground structures, while the foundation is less susceptible to the effects of temperature differences.

Sedimentary expansion joint is necessary in orderto prevent cracks in structural elements due to the fact that the load is unevenly distributed or the soils are weak and some elements subside. In contrast to the temperature of the seam sediment separates the foundation.

Antiseismic expansion joints in buildings,located in an area with high seismic activity, practically necessary. At their expense, the building is divided into blocks that are essentially independent of each other, and therefore in the event of an earthquake, the destruction or deformation of one block will not affect the others.

If your construction consists of monolithicreinforced concrete walls, shrinkable expansion joint required. The fact is that concrete tends to shrink and shrink in size - that is, the wall, poured directly on the construction site, and not assembled from reinforced concrete panels, will certainly decrease in volume, forming a gap. For the convenience of further work, the shrink seam is made before the next wall is poured, and after the concrete dries out, the seams and gaps are sealed.

Sealing and sealing joints

This aspect is very important to give specialAttention: seams should be well protected from external factors. For this purpose, various types of insulation and aggregate are used. Polyurethane or epoxy sealants are a good option: they have high hardness and are not very elastic; another variant -

use of polyethylene cord withsubsequent seal sealant. Another option is to fill the expansion joint with mineral wool. And the expansion joint in the wall, filled with mineral wool, must be sealed with an elastic mass that is resistant to weather conditions and protects the aggregate from moisture and damp. In addition to fillers, the seam can be protected with a profile or strap of a suitable size.

Sizes of seams

The width of the expansion joints varies from 0.3 cmup to 100, depending on the type of seam, as well as the operating conditions of the building. Temperature seams reach 4 cm (narrow), and shrinkage are medium (4-10 cm) and wide (10-100 cm).