ELASTOMERIC BEARINGS
Total number of bearings in normal spans at each end = 6
( 1 ) Design Load on bearings:
MAXIMUM REACTION ON ONE BEARING(t)
SPAN
TYPE LENGTH Dead load Class 70R(wheeled)
(m)
+SIDL +Class A 1Lane
NORMAL
10.0 28.6 29.1
MINIMUM REACTION ON ONE BEARING(t)
SPAN
TYPE LENGTH Dead load Class 70R(wheeled)
(m)
+SIDL +Class A 1Lane
NORMAL
10.0 19.6 -3.2
Design Vertical Load on bearing:
SPAN DESIGN VERTICAL LOAD (t)
TYPE LENGTH
(m) MAXIMUM LOAD MINIMUM LOAD
NORMAL
10.0 57.70 16.40
( 2 ) Design Longitudinal Translation:
Considering the effect of creep , shrinkage & temperature the value of strain
has been taken @ 5x10-4 as per Clause 916.3.4 of IRC:83 Part II
SPAN
LONGITUDINAL TRANSLATION
TYPE LENGTH
(mm)
(m)
NORMAL
10.0 2.50
( 3 ) Design value of Rotation:
SPAN ROTATION DUE TO
TOTAL VALUE OF ROTATION
TYPE LENGTH LIVE
DEAD LOAD (radians)
(m) LOAD
NORMAL
10.0 0.001200 0.000820 0.002020
( 4 ) Design Horizontal Force Per Bearing:
DESIGN HOR.
SPAN MAXIMUM HORIZONTAL FORCE
TYPE LENGTH CLASS 70R(wheeled) + CLASS A FORCE PER
(m) (1 Lane)
BEARING (t)
NORMAL
10.0 10.1 1.68
DESIGN OF ELASTOMERIC BEARING (units in N,mm) FOR SOLID SLAB DECKING: SPAN
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BEARING DIMENSIONS & PROPERTIES:
G Shear modulus 1 MPa
bo Overall breadth 220 mm
lo Overall length 320 mm
hi Thickness of each layer 8 mm
n Number of layers 4
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RESULTS :
hc = side elastomer cover 6 mm
he = hi/2 4 mm
hs = 3/4/6 FOR hi<=8,10/12/16 3 mm
h = n*hi+2*he 40 bo/10 - bo/5 mm
ho = h+(n+1)*hs 55 mm
R = lo/bo 1 <=2
b = bo-2*hc 208 mm
l = lo-2*hc 308 mm
A = b*l 64064 mm2
S = A/(2*(b+l)*hi) 7.76 6-12
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FORCES & DEFORMATIONS MAX LL MIN LL
ON BEARING :
P Load 577000 164000 N
Hb Horizl. force along b 16833 16833 N
Hl along l 0 0 N
Dbd Translation along b 2.50 2.50 mm
Dld along l 0.00 0.00 mm
abd Rotation along b 0.00202 0.00202 radian
ald along l 0.00000 0.00000 radian
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RESULTS :
sm = P/A 9.01 2.56 2-10 MPa
gdb = Hb/A+Dbd/h 0.3253 0.3253
gdl = Hl/A+Dld/h 0.0000 0.0000
gd = sqrt(g +gdl )
db
2 2
0.3253 0.3253 <=0.7
gd,all = 0.1*sm+0.2, but<=0.7 0.7000 0.4560 >=g d
ad = (abd*b+ald*l)/b 0.00202 0.00202 radian
aall = 0.5*n*sm*hi/(b*S*S) 0.01151 0.00327 >=ad radian
tc = 1.5*sm/S 1.741 0.495 MPa
tg =gd 0.3253 0.3253 MPa
abi = 0.5*sm*hi/(b*S2) 0.00288 0.00082 radian
ali = 0.5*sm*hi/(l*S ) 2
0.00194 0.00055 radian
ta =0.5*(b *abi+l *ali)/hi
2 2 2
2.4120 2.4120 MPa
t = tc+tg+ta 4.4783 3.2321 <=5 MPa
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Shear Rating=(lo*bo*G*Dbd/ho)*10-4 0.32 t
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OLID SLAB DECKING: SPAN 10.0.M
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