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The basics of bearing selection and use

Rigid zone

Depending on a building’s geometry, location and vertical loading, horizontal loading of approximately 10% of vertical loading can typically be assumed as a first estimate.

These horizontal loads must be resisted by a rigid zone or core of the building, such as a lift shaft. Only deformation bearings, and not sliding bearings, should be used in the rigid zone.

Shrinkage and creep

For slabs with a thickness of up to 25cm in apartment or commercial structures, shrinkage of up to 0.6 ‰ can occur.
The amount of shrinkage depends on slab thickness and the prevailing humidity; the drier and thinner a slab is, the more shrinkage can be expected.

Shrinkage:

∆l= 0.6‰ x l

∆l:

Change in length [m]

l :

Distance from the movement “zero point” [m]

Temperature

Temperature:

∆l= αt x ∆t x l

αt:

Coefficient of expansion due to temperature 10-5/oC

∆t :

Change in temperature [oC]

Expansion due to temperature is generally only significant for external parts of a structure or unheated rooms.

Important:

For thermally uninsulated buildings such as multi-storey car parks or storage halls, only high-durability LASTO®STRIP TS sliding bearings should be used.

Rotation of slabs

Assuming a deflection of l/200, the rotation angle will in normal circumstances (residential or office building with normal use) typically not exceed 20‰.

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