LASTO® – Elastomeric bearings Unreinforced deformation bearings

Applications and key data Applications • ≤ 20 N/mm2 (at service level) Shape and dimensions • Any, up to 1.20 x 1.20m Bearing type • Deformation bearing, unreinforced Materials • Natural rubber Both varieties are very similar with respect to their mechanical properties, and can thus be designed on the same basis. Maximum permissible shear strain ..6 CR: 74 ± 5 IRHD • Thermal conductivity 0.26W/m � K LASTO®BLOCK F is available in two varieties (i.e. materials). For standard applications, LASTO®BLOCK F NR, of natural rubber, is used. For use in exposed conditions and for heightened demands in relation...

Bearing design A – Simplified procedure Step 1 - Decide on preferred dimensions and calculate the average pressure Step 2 - Check the permissible pressure from Table 1 Step 3 - Check the edge clearance according to Figure 2 • Only subjected to vertical loading • Rectangular bearing without holes Design approaches B – Procedure for all other cases (Formulae: see pages 4 und 5): 0 0 Comments • Vertical bearing deformation should not exceed the maximum permissible compression strain Ԑz ≤ 30% • Rotation or shear deformation of the bearing may arise • maximum vertical load Fz • Horizontal movement...

Design concepts Basic concepts The impact of bearing geometry is considered by the shape factor, S. This is defined as the ratio between the area of the loaded surface and the sum of the areas of the freely deformable sides. Side surfaces which cannot deform freely due to adjacent structural elements (e.g. the side of a bolt hole with little clearance to the bolt) are not considered. Vertical deformation Shape factor Rotation angle The bearing design ensures that the deformed bearing retains adequate thickness trest to prevent a collision between structural elements. The minimum remaining thickness...

Design concepts Check of sliding resistance The coefficient of friction μ is calculated as follows: μ = 0.1 + with Kf = 0.6 for concrete and Kf = 0.2 for all other surfaces. The horizontal restoring force Fx and the check of sliding resistance results from: where vx,y is the total horizontal deformation (vector addition), A is the footprint area and the shear modulus G = 2.2 N/mm2. The permissible horizontal deformation is thus: Remaining thickness trest [%] The horizontal movement of the supported structural element must be limited in order to prevent sliding and displacement of the bearing....

Design tables Table 1: Maximum permissible pressure σz [N/mm2] Thicknesses 20 Maximum permissible pressure in N/mm for a minimum remaining thickness of 70 % of the nominal thickness, depending on side lengths a, b and thickness t. For example, a bearing of dimensions 80 x 200 x 10 mm3 will be compressed to a thickness of 7 mm under a pressure of 12.9 N/mm2. Values for Example A on Page 5 vx,y Table 2: Maximum permissible shear strain Ԑx,y = t [mm] Thicknesses Side length a [mm] 8 16 20 24 32 40 48 60 72 84 100 120 140 168 200 240 [mm] 2

Product range and installation guidelines Product range Material Delivery form Full slabs or cut to size according to clients’ wishes Thicknesses of up to 20 mm are available from stock, other thicknesses on request Installation guidelines LASTO®BLOCK F bearings are generally laid on a smooth flat surface without ridges, burrs or large recesses. When laid on concrete or a mortar bed, it must be ensured that the surface has adequate strength. It must also be ensured that the bearing surfaces are clean and grease-free.

Tender texts Tender texts for bearings of natural rubber (NR) Tender texts for bearings of chloroprene rubber (CR) Supply and installation of high-capacity, unreinforced deformation bearings of natural rubber (NR) Supply and installation of high-capacity, unreinforced deformation bearings of chloroprene rubber (CR) Product: LASTO®BLOCK F The permissible loading depends on the bearing geometry and is limited to max. 20 N/mm2. Product: LASTO®BLOCK F The permissible loading depends on the bearing geometry and is limited to max. 20 N/mm2. Proven remaining bearing thickness under a permanent load...