General Information

Product description

Support for drive-on components of engineering structures: bridges, viaducts, pedestrian flyovers - is constructed in most cases through the use of flexible components. Elastomer bearings are such components. The load resistance is ensured by internal reinforcement with steel panels. These bearings are made of polychloroprene rubber or natural rubber.
Thanks to different types of bearings, it is possible to satisfy all that is required of them in engineering structures.
According to Polish Standard PN-EN 1337-3, structural elastomer bearings possess the CE mark, confirming the adherence to particular requirements of the indicated norm by the manufacturer, in this case the company Gumba GmbH. The CE mark issued to the elastomer structural bearings made by Gumba GmbH by MPA Stuttgart, a notified body within the European Union, unequivocally conforms the adherence to requirements of standard PN-EN 1337-3. This document permits the introduction of the bridge bearings onto the European market, including the Polish market.

Elastomer properties allow, to a certain degree, movement of the material itself and twisting by deformation. As compared to other bearing types, they have a certain particular advantage - in many cases one can forgo expensive structures with slip components. If the shift caused by the properties of the elastomer bearing is not sufficient for a particular case, the scope of functionality may be expanded.

Note:
As a result of errors during design and bearing selection, locking of the structure may occur, as well as pressure of the main structure on the abutments, and following that - cracking of front walls, head walls and lower plinths. Altering bearing dimensions also causes flaws, and as a result, it needlessly increases costs of construction and maintenance of the structure.

Every elastomer bearing has a vulcanised label describing the bearing, which contains the following information (image below):

  • CE certificate number
  • norm according to which the bearing was manufactured
  • manufacturer logo
  • bearing number

     

     

     

 

 

 Bearing types

Considering the anchoring method, one can differentiate between four basic elastomer bearing types: type B(1), type C(2), type B/C(1/2) and type C-PSP(5).

 


Type B(1) - reinforced, non-anchored bearing, consisting of at least two steel reinforcement plates. Fulfilment of the condition of minimum load and friction prevents this bearing from slipping. Lack of anchoring eases replacement and servicing of these bearings.

 

 

 

 

Type B/C(1/2) - reinforced bearing with single-side anchoring. The vulcanised external rubber prevents this bearing from slipping, and forms the lower support surface of the part. The method of anchoring of the bearing may be freely configured: welded anchors, protective circular plates or threaded holes. For railway bridges, irrespective of the loads, type B/C(1/2) should always be used.

 

 

 

 

 

Type C(2) - reinforced bearing, anchored on both sides. The vulcanised external sheet steel (support surfaces) prevent this bearing from slipping. Similarly to the type described earlier, the method of anchoring of the bearing is freely selectable: welded anchors, protective circular plates or threaded holes. Replacement of this bearing type is quite complicated, and requires additional operations.

 

 

 

 

 

 

Type C-PSP(5) - reinforced bearing, anchored on both sides. Vulcanised external ribbed metal sheets (support surfaces) prevent this bearing from slipping. The replacement of this bearing type is quite complicated, and requires not only the grout under the bearing, but also the reinforced concrete part above the bearing, to be removed.

 

 

 

Standard Gumba bearing dimension tables


Minimum pressure
≥ 3N/mm²
Minimum pressure
< 3 N/mm²

Typ B(1) Typ C (2) i C (5)
Typ B/C (1/2)
Load
Nz,k
Bearing
dimensions

a x b
Elastomer
layer count

n
Shift
+/-
ex
Bearing
height

d
Elastomer
thickness

t
Shift
+/-
ex
Bearing
thickness

Typ 2
d
Bearing
thickness

Typ 5
d
Elastomer
thickness

t
Shift
+/-
ex
Bearing
thickness

d
Elastomer
thickness

t
Turn
angle

Ø
kN
mm
pcs.
mm
mm
mm
rad/1000
100
150
100x100
100x150
1
7
14
10
-
-
-
-
-
-
-
4

2
11 21 15 7 42 32 10 9 31,5 12,5 8

3
14
28
20
11
49
39
15
12
38,5
17,5
12

4
16
35
25
14
56
46
20
15
45,5
22,5
16

5
18
42
30
16
63
53
25
17
52,5
27,5
20

6
-
-
-
18
70
60
30
-
-
-
24

300
150x200
1
7
14
10
-
-
-
-
-
-
-
3

2
11
21
15
7
42
32
10
9
31,5
12,5
6

3
14
28
20
11
49
39
15
12
38,5
17,5
9

4
18
35
25
14
56
46
20
16
45,5
22,5
12

5
21
42
30
18
63
53
25
19
52,5
27,5
15

6
23
49
35
21
70
60
30
22
59,5
32,5
18

7
25
56
40
23
77
67
35
24
66,5
37,2
21

8
27
63
45
25
84
74
40
26
73,5
42,5
24

9
28
70
50
27
91
81
45
28
80,5
47,5
27

10
-
-
-
28
98
88
50
-
-
-
30

310
630
750
1000
ø200
200x250
200x300
200x400
1
9
19
13
-
-
-
-
-
-
-
3
4
2
15
30
21
11
49
39
16
13
39,5
18,5
6
8
3
20
41
29
17
60
50
24
19
50,5
26,5
9
12
4
26
52
37
22
71
61
32
24
61,5
34,5
12
16
5
30
63
45
28
82
72
40
29
72,5
42,5
15
20
6
34
74
53
32
93
83
48
33
83,5
50,5
18
24
7
36
85
61
35
104
94
56
36
94,5
58,5
21
28
8
-
-
-
37
115
105
64
-
-
-
24
32

Minimum pressure
≥ 3N/mm²
Minimum pressure
< 3 N/mm²

Typ B(1) Typ C (2) i C (5)
Typ B/C (1/2)
Load
Nz,k
Bearing
dimensions

a x b
Elastomer
layer count

n
Shift
+/-
ex
Bearing
height

d
Elastomer
thickness

t
Shift
+/-
ex
Bearing
thickness

Typ 2
d
Bearing
thickness

Typ 5
d
Elastomer
thickness

t
Shift
+/-
ex
Bearing
thickness

d
Elastomer
thickness

t
Turn
angle

Ø
kN
mm
szt.
mm
mm
mm
rad/1000
600
1300
Ø250
250x400
1
9
19
13
-
-
-
-
-
-
-
3
4
2
15
30
21
11
49
39
16
13
39,5
18,5
5
8
3
20
41
29
17
60
50
24
19
50,5
26,5
8
12
4
26
52
37
22
71
61
32
24
61,5
34,5
10
16
5
32
63
45
28
82
72
40
30
72,5
42,5
13
20
6
37
74
53
34
93
83
48
35
83,5
50,5
15
24
7
40
85
61
38
104
94
56
39
94,5
58,5
18
28
8
43
96
69
41
115
105
64
42
105,5
66,5
20
32
9
46
107
77
44
126
116
72
45
116,5
74,5
23
36
10
-
-
-
46
137
127
80
-
-
-
25
40
900
1800
Ø300
300x400
1
9
19
13
-
-
-
-
-
-
-
2
3
2
15
30
21
11
49
39
16
13
39,5
18,5
4
6
3
20
41
29
17
60
50
24
19
50,5
26,5
6
9
4
26
52
37
22
71
61
32
24
61,5
34,5
8
12
5
32
63
45
28
82
72
40
30
72,5
42,5
10
15
6
37
74
53
34
93
83
48
35
83,5
50,5
12
18
7
43
85
61
39
104
94
56
41
94,5
28,2
14
21
8
46
96
69
44
115
105
64
45
105,5
66,5
16
24
9
50
107
77
48
126
116
72
49
116,5
74,5
18
27
10
52
118
85
51
137
127
80
52
127,5
82,5
20
30
11
55
129
93
53
148
138
88
54
138,5
90,5
22
33
12
-
-
-
56
159
149
96
-
-
-
24
36
1200
Ø350
1
11
24
16
-
-
-
-
-
-
-

4
2
19
39
27
15
56
46
22
17
47,5
24,5

8
3
27
54
38
23
71
61
33
25
62,5
33,5

12
4
34
69
49
31
86
76
44
33
77,5
46,5

16
5
42
84
60
39
101
91
55
40
92,5
57,5

20
6
50
99
71
46
116
106
66
48
107,5
68,5

24
7
55
114
82
52
131
121
77
53
122,5
79,5

28
8
59
129
93
57
146
136
88
58
137,5
90,5

32
9
63
144
104
61
161
151
99
62
152,5
101,5

36
10
66
159
115
64
176
166
110
65
167,5
112,5

40

Minimum pressure
≥ 5 N/mm²
Minimum pressure
< 5 N/mm²

Typ B(1) Typ C (2) i C (5)
Typ B/C (1/2)
Load
Nz,k
Bearing
dimensions

a x b
Elastomer
layer count

n
Shift
+/-
ex
Bearing
height

d
Elastomer
thickness

t
Shift
+/-
ex
Bearing
thickness

Typ 2
d
Bearing
thickness

Typ 5
d
Elastomer
thickness

t
Shift
+/-
ex
Bearing
thickness

d
Elastomer
thickness

t
Turn
angle

Ø
kN
mm
pcs.
mm
mm
mm
rad/1000
2400
350x450
3
27
54
38
23
81
61
33
25
67,5
33,5
8

4
34
69
49
31
96
76
44
33
82,5
46,5
10

5
42
84
60
39
111
91
55
40
97,5
57,5
13

6
50
99
71
46
126
106
66
48
112,5
68,5
15

7
55
114
82
52
141
121
77
53
127,5
79,5
18

8
59
129
93
57
156
136
88
58
142,5
90,5
20

9
63
144
104
61
171
151
99
62
157,5
101,5
23

10
66
159
115
64
186
166
110
65
172,5
112,5
25

1900
3000
Ø400
400x500
3
27
54
38
23
81
61
33
25
67,5
35,5
6
9
4
34
69
49
31
96
76
44
33
82,5
46,5
8
12
5
42
84
60
39
111
91
55
40
97,5
57,5
10
15
6
50
99
71
46
126
106
66
48
112,5
68,5
12
18
7
57
114
82
54
141
121
77
56
127,5
79,5
14
21
8
62
129
93
60
156
136
88
61
142,5
90,5
16
24
9
67
144
104
65
171
151
99
66
157,5
101,5
18
27
10
70
159
115
69
186
166
110
70
175,5
112,5
20
30
11
74
174
126
72
201
181
121
73
187,5
123,5
22
33
12
-
-
-
75
216
196
132
-
-
-
24
36
2400
4050
Ø450
450x600
3
27
54
38
23
81
61
33
25
67,5
33,5
6
9
4
34
69
49
31
96
76
44
33
82,5
46,5
8
12
5
42
84
60
39
111
91
55
40
97,5
57,5
10
15
6
50
99
71
46
126
106
66
48
112,5
68,5
12
18
7
57
114
82
54
141
121
77
56
127,5
79,5
14
21
8
65
129
93
62
156
136
88
63
142,5
90,5
16
24
9
70
144
104
67
171
151
99
68
157,5
101,5
18
27
10
74
159
115
72
186
166
110
73
172,5
112,5
20
30
11
78
174
126
76
201
181
121
77
187,5
123,5
22
33
12
82
189
137
80
216
196
132
81
202,5
134,5
24
36
13
85
204
148
83
231
211
143
84
217,5
145,5
26
39

Minimum pressure
≥ 5 N/mm²
Minimum pressure
< 5 N/mm²

Typ B(1) Typ C (2) i C (5)
Typ B/C (1/2)
Load
Nz,k
Bearing
dimensions

a x b
Elastomer
layer count

n
Shift
+/-
ex
Bearing
height

d
Elastomer
thickness

t
Shift
+/-
ex
Bearing
thickness

Typ 2
d
Bearing
thickness

Typ 5
d
Elastomer
thickness

t
Shift
+/-
ex
Bearing
thickness

d
Elastomer
thickness

t
Turn
angle

Ø
kN
mm
pcs.
mm
mm
mm
rad/1000
2900
3600
4500
Ø 500
Ø 550
500x600
3
27
54
38
23
81
61
33
25
67,5
33,5
6
6
4
34
69
49
31
96
76
44
33
82,5
46,5
8
8
5
42
84
60
39
111
91
55
40
97,5
57,5
10
10
6
50
99
71
46
126
106
66
48
112,5
68,5
12
12
7
57
114
82
54
141
121
77
56
127,5
79,5
14
14
8
65
129
93
62
156
136
88
63
142,5
90,5
16
16
9
72
144
104
69
171
151
99
71
157,5
101,5
18
18
10
77
159
115
75
186
166
110
76
172,5
112,5
20
20
11
82
174
126
80
201
181
121
81
187,5
123,5
22
22
12
86
189
137
84
216
196
132
85
202,5
134,5
24
24
13
89
204
148
88
131
211
143
89
217,5
145,5
26
26
14
93
219
159
91
146
226
154
92
232,5
156,5
28
28
15
-
-
-
94
161
141
165
-
-
-
30
30
4100
5000
6300
Ø 600
Ø 650
600x700
3
35
70
50
32
95
75
45
33
82,5
47,5
6
6
4
46
90
65
42
115
95
60
44
102,5
62,5
8
8
5
56
110
80
53
135
115
75
54
122,5
77,5
10
10
6
67
130
95
63
155
135
90
65
142,5
92,5
12
12
7
77
150
110
74
175
155
105
75
162,5
107,5
14
14
8
86
170
125
84
195
175
120
85
182,5
122,5
16
16
9
93
190
140
91
215
195
135
92
202,5
137,5
18
18
10
99
210
155
98
235
215
150
98
222,5
152,5
20
20
11
105
230
170
103
255
235
165
104
242,5
167,5
22
22
12
109
250
185
108
275
255
180
109
262,5
182,5
24
24
13
113
270
200
112
295
275
195
113
282,5
197,5
26
26

Minimum pressure
≥ 5 N/mm²
Minimum pressure
< 5 N/mm²

Typ B(1) Typ C (2) i C (5)
Typ B/C (1/2)
Load
Nz,k
Bearing
dimensions

a x b
Elastomer
layer count

n
Shift
+/-
ex
Bearing
height

d
Elastomer
thickness

t
Shift
+/-
ex
Bearing
thickness

Typ 2
d
Bearing
thickness

Typ 5
d
Elastomer
thickness

t
Shift
+/-
ex
Bearing
thickness

d
Elastomer
thickness

t
Turn
angle

Ø
kN
mm
pcs.
mm
mm
mm
rad/1000
5800
6600
8400
Ø 700
Ø 750
700x800
3
35
70
50
32
95
75
45
33
82,5
47,5
6
6
4
46
90
65
42
115
95
60
44
102,5
62,5
8
8
5
56
110
80
53
135
115
75
54
122,5
77,5
10
10
6
67
130
95
63
155
135
90
65
142,5
92,5
12
12
7
77
150
110
74
175
155
105
75
162,5
107,5
14
14
8
88
170
125
84
195
175
120
86
182,5
122,5
16
16
9
98
190
140
95
215
195
135
96
202,5
137,5
18
18
10
105
210
155
103
135
215
150
104
222,5
152,5
20
20
11
112
230
170
110
255
235
165
111
242,5
167,5
22
22
12
118
250
185
116
275
255
180
117
262,5
182,5
24
24
13
123
270
200
121
295
275
195
122
282,5
197,5
26
26
14
127
290
215
126
315
295
210
127
302,5
212,5
28
28
15
131
310
230
130
335
315
225
131
322,5
227,5
30
30
7500
8500
9600
Ø 800
Ø 850
800x800
3
41
79
59
38
104
84
54
40
91,5
56,5
6
6
4
54
102
77
50
127
107
72
52
114,5
74,5
8
8
5
67
125
95
63
150
130
90
65
137,5
92,5
10
10
6
79
148
113
76
173
153
108
77
160,5
110,5
12
12
7
92
171
131
88
196
176
126
90
183,5
128,5
14
14
8
104
194
149
101
219
199
144
103
206,5
146,5
16
16
9
115
217
167
113
242
222
162
114
229,5
164,5
18
18
10
124
240
185
122
265
245
180
123
252,5
182,5
20
20
11
131
263
203
129
288
268
198
130
275,5
200,5
22
22
12
138
286
221
136
311
291
216
137
298,5
218,5
24
24
13
144
309
239
142
334
314
234
143
321,5
236,5
26
26
14
149
332
257
147
357
337
252
148
344,5
254,5
28
28

Minimum pressure
≥ 5 N/mm²
Minimum pressure
< 5 N/mm²

Typ B(1) Typ C (2) i C (5)
Typ B/C (1/2)
Load
Nz,k
Bearing
dimensions

a x b
Elastomer
layer count

n
Shift
+/-
ex
Bearing
height

d
Elastomer
thickness

t
Shift
+/-
ex
Bearing
thickness

Typ 2
d
Bearing
thickness

Typ 5
d
Elastomer
thickness

t
Shift
+/-
ex
Bearing
thickness

d
Elastomer
thickness

t
Turn
angle

Ø
kN
mm
pcs.
mm
mm
mm
rad/1000
9500
12000
Ø 800
900x900
3
41
79
59
38
104
84
54
40
91,5
56,5
5
5
4
54
102
77
50
127
107
72
52
114,5
74,5
6
6
5
67
125
95
63
150
130
90
65
137,5
92,5
8
8
6
79
148
113
76
173
153
108
77
160,5
110,5
9
9
7
92
171
131
88
196
176
126
90
183,5
128,5
11
11
8
104
194
149
101
219
199
144
103
206,5
146,5
12
12
9
117
217
167
113
242
222
16
115
229,5
164,5
14
14
10
128
240
185
126
265
245

 

 

 

 

Bentonite-halloysite granulate

An innovative mix of sodium bentonite and halloysite, also making up a mat's fill material, used as additional binder for joints as well as packing and face material at key spots of the structure to be insulated.
The putty is prepared by mixing the granulate with water at a weight ratio of 1:3.

 

 

 

 

 

 

Parameter Unit
Bentonite-halloysite mineral mat Norm / test method
BENTIZOL HB 3
BENTIZOL HB 5
Mat condition
-
Surfaces without damage; mat sides protected against the filler mix escaping out Visual evaluation
Thickness under load of 2 kPa
mm
150
334
314
234
151
321,5
236,5
20
20
14
158
332
257
156
357
337
252
157
344,5
254,5
21
21
15
163
355
275
162
380
360
252
163
367,5
272,5
23
23
16
168
378
293
167
403
383
270
391
390,5
290,5
24
24

The tables for reinforced elastomer bearings apply to standard-construction Gumba bearings. They apply to initial dimensions, which only allow a general and fast estimation of the bearing size. The values provided in them are characteristic values for the Serviceability Limit State (SLS). In order to conduct more precise dimensioning of the structural bearings, please contact our representatives in the retail branches, employees of the technical department or alternatively use the software available at the manufacturer's website at www.gumba.de. The software allows optimum bearing selection. It includes only known bearing dimensions with layered structures according to Gumba standards and regular bearing dimensions according to norm EN 1337-3.

 

Calculation basis according to EN 1337-3.

Designing and manufacture of elastomer bearings is based on Polish Standard PN-EN 1337-3, which is harmonised with the Construction Directive 89/106/EEC. This norm covers i. e. reinforced elastomer bearings with a surface area of up to 1200 x 1200 mm2, used between temperature values between -25 °C and +50 °C.
Below, the recommended course of calculations, the expansion of which is found in the norm indicated earlier on, is presented.
Remarks and further hints concerning the presented calculation phases are found in standard PN-EN 1337.
For the calculation of values related to elastomer bearings, characteristic load values need to be applies. The proof takes place at the Ultimate Limit State (ULS) for joint deformation stemming from load and shift.
The table above contains information necessary to dimension bearings according to standard PN-EN 1337-3. The table also contains necessary shore conditions. It may serve the determination and description of structural bearing parameters designed for a particular structure.

Note:
According to Polish Standard PN-EN 1337-3, the bridge structure designer presents all necessary data allowing the selection of structural bearings for such a structure. It is not possible for the bearing manufacturer to calculate this data.

Elastomer bearing calculations

The bearings must correspond to the following requirements:
1. Maximum calculational deformation
At any given point of the bearing, the sum of deformations (Ɛt,d) caused by effects of calculational load (Ed) is given by the formula:

Ɛc,d - calculational deformation caused by compressive calculational loads
Ɛq,d - calculational shear deformation caused by calculational horizontal shifts
Ɛɑ,d- calculational deformation caused by the calculational twist angle
KL - load type coefficient

  •   Calculational deformation caused by compressive calculational loads


Nz,d - vertical force calculational value
G - nominal value of the ordinary non-dilatational strain modulus for an elastomer bearing
Ar - reduced effective area of the elastomer bearing

A’- effective area of a reinforced bearing (surface area of reinforcement sheet steel)
A’ = a’·b’ (for cuboid bearings without openings)
a’ - effective width of reinforced bearing (reinforcement sheet width)
b’ - effective length of reinforced bearing (reinforcement sheet length)
vx,d - maximum horizontal relative shift of a bearing part towards dimension a of the bearing caused by all effects of calculational load
vy,d - maximum horizontal relative shift of a bearing part towards dimension b of the bearing caused by all effects of calculational load

 S - shape coefficient

A’- effective area of a reinforced bearing (surface area of reinforcement sheet steel)
A’ = a’·b’ (for cuboid bearings without openings)
a’ - effective width of reinforced bearing (reinforcement sheet width)
b’ - effective length of reinforced bearing (reinforcement sheet length)
lp - circumference of bearing without load
lp=2·(a’+b’)   
te - effective thickness of individual elastomer layer at compression

  • Calculational shear deformation caused by calculational horizontal shifts.

vxy,d - maximum resultant horizontal relative shift of bearing part obtained from vector sum of  vx,d and vy,d
Tq - total elastomer thickness at non-dilatational strain with upper and lower cover

  • Calculational deformation caused by calculational twist angle

a’ - effective width of reinforced bearing (reinforcement sheet width)
ɑa,d - turn angle about bearing width a
b’ - effective length of reinforced bearing (reinforcement sheet length)
ɑb,d -  turn angle (if applicable) about bearing width b
ti - individual elastomer layer thickness

 2. Maximum extension pressure in reinforcement sheets

  • Reinforcement plate thickness

 

Kp - correction coefficient
      Kp = 1,3
Nz,d - calculational value of vertical force
t1, t2 - elastomer thickness on both sides of metal sheet
Kh - extension pressure coefficient caused in the reinforcement steel sheet
      Kh =1 (without openings)
      Kh = 2 (with openings)
Ɣm - partial safety coefficient, Ɣm= 1,0
Ar - reduced effective elastomer bearing area
fy - steel yield strength

3. Limit conditions

  • Twist limit condition

For reinforced bearings, the limit turn should not be reached when total vertical compression ∑Vz,d meets the following conditions:
For parallel wall bearings:

 

For circular bearings:

 

∑vz,d - total vertical compression causing ɑa  and ɑb
Nz,d - vertical force calculational value

ti - individual elastomer layer thickness
A' - effective reinforced bearing area (surface area of reinforcement sheet steel)
G - nominal value of the ordinary non-dilatational strain modulus for an elastomer bearing
S1 - thickest layers shape coefficient
Eb - volumetric strain modulus Eb = 2000 MPa
a’ - effective width of reinforced bearing (reinforcement sheet width)
ɑa,d - turn angle about bearing width a
b’ -  effective length of reinforced bearing (reinforcement sheet length)
ɑb,d -  turn angle (if applicable) about bearing width b
Kr,d - twist coefficient
       Kr,d = 3
D’ - effective bearing diameter
ɑd - twist angle about diameter D of circular bearing

  •  Dent stability

In reinforced elastomer bearings, the load should conform to the following formula:

 

Nz,d - vertical force calculational value
Ar - reduced effective area of the elastomer bearing
a’ - effective width of reinforced bearing (reinforcement sheet width)
G - nominal value of the ordinary non-dilatational strain modulus for an elastomer bearing
S1 - thickest layers shape coefficient
Te - sum total of all elastomer layers

  • No-slip condition

Non-anchored bearings must conform to the following formula:

 
and under fixed loads

 

Nxy,d - resultant force of all horizontal forces
Nz,dmin - minimum vertical calculational force related to Nxy,d
Ar - reduced effective area of the elastomer bearing
µe - friction coefficient according to the following formula:


Kf = 0,6 for concrete
Kf = 0,2 for all other surfaces including resin mortars and grout
σm - average load tension resulting from Nz,dmin 

 4. Forces, moments and deformations acting on structures

  • mutual contact surface pressure

All that is required is a test whether the average pressure on the surface does not exceed the base layer material strength.

  • result force of resistance against horizontal shift

A - total flat bearing area
G - nominal value of the ordinary non-dilatational strain modulus for an elastomer bearing
vxy,d - maximum resultant horizontal relative shift of bearing part obtained from vector sum of vx,d and vy,d
Te - sum total of all elastomer layers

  • Rotation resistance

Parallel wall bearings


G - nominal value of the ordinary non-dilatational strain modulus for an elastomer bearing
ɑ - bearing angle of rotation
a' - effective reinforced bearing width (reinforcement sheet width)
b' - effective reinforced bearing length (reinforcement sheet length)
n - elastomer layer count
ti - individual elastomer layer thickness
Ks - resistance moment coefficient

Circular bearings


G - nominal value of the ordinary non-dilatational strain modulus for an elastomer bearing
ɑ - bearing angle of rotation
D' - effective bearing diameter
n - elastomer layer count
ti - individual elastomer layer thickness

The Ks resistance moment coefficient is determined using the following table.

b/a
0,5
0,75
1
1,2
1,25
1,3
1,4
1,5
Ks 137
100
86,2
80,4
79,3
78,4
76,7
75,3
b/a
1,6
1,7
1,8
1,9
2
2,5
10
X
Ks 74,1
73,1
72,2
71,5
70,8
68,3
61,9
60