Solved Example for bridge bearing designFull description
seleccion para motores electricos
Detailed Design Report
Design Data Contrete Grade Unit W eight of Concrete E of Concrete
M25 3
24 KN/m 2 2.20E+07 KN/m
As per IRC 21-1987 Flexural Comp. Stress ,σcbc
8.3 N/mm
Direct Comp. Stress ,σcd
6.2 N/mm 2
Shear Stress ,σcbc
0.335 N/mm
Bond Stress,σ cbc
1.125 N/mm
Poisson's Ration, υ Modular Modular ratio, m k j R
0.15 10 0.293 0.902 2 1.097 N/mm
2
Structural Component Dimensions Effective Span Total Length of Span Carriageway No. of Longitudinal Girder Spacing of L-Girder
32.00 32.95 7.50 4.00 2.10
m m m Nos m
Design of Elastomeric Bearing Design value Calculation A. Dead Load Intensity on each beam Total Load on each beam
22.91 KN K N/m 1466.00 KN
Load Diagram
22.91 22.91 KN/m KN/m
32 Deflected Diagram 16 θΑ
θΑ
6.68E-05
N K
16
7 5 . 3 1 6
B. Live Load Due to IRC Class A Loading Impact Factor
0.12 %
Bending Moment and Shear Force Calculation BM Influence Line P3
P4 P5
X1
P 1 P2 X2 X3
θΑ O1
X4
X5
X6
X7
O4
O5
RA
P8
X8 O7
O3
O2
P7
P6
θΑ
O8
=a.b.(Leff. + b )/(6 Leff.E.I.)
O6
RB X Leff
Bearing 1
Detailed Design Report
Leff. P1 P2 P3 P4 P5 P6 P7 P8
32 27 27 114 114 68 68 68 68
m KN KN KN KN KN KN KN KN
X1 X2 X3 X4 X5 X6 X7 X8
varies 1.1 3.2 1.2 4.3 3 3 3 18.8
m m m m m m m
Maximum Rotation when X1 = L/2
X=L/2
16 m
Critical when load P4 is at L/2
Position Position Load, KN from A, a from B, b Ord_Code 27 10.50 21.50 O1 27 11.60 20.40 O2 114 14.80 17.20 O3 114 16.00 16.00 O4 68 20.30 11.70 O5 68 23.30 8.70 O6 68 26.30 5.70 O7 68 29.30 2.70 O8 Total * Deflection due to Live Load including including I.F. Load Code P1 P2 P3 P4 P5 P6 P7 P8
θΑ due
to Dl + LL
Max. Vertical Reaction due to DL Max. Vertical Reaction due to LL Max. Vertical Reaction on Bearing Min. Vertical Reaction on Bearing
Load of first train loads Load of rest train loads Londitudinal Force Longitudinal Force due to friction
Selected Size of Bearing Pad Loaded Area According to IRC 21, clause 307.1 Allowable contact pressure Effective Bearing Area required Bearing Stress, σm Thickness of individual elastomer layers Thickness of outer elastomer layer Thickness of steel laminates Side Cover
Shear strain due to creep,shrinkage and temp. per bearing
Shear strain due to translation per bearing
OK
3.00E-06
0.323 <7
Safe
Max. permissible angle of rotation of a single internal layer of elastomer corresponding to σm value 10N/mm2 7.48E-04 radians Permissible rotation
6.39E-03 OK
Under critical loading conditions, Shear strain
Shear stress due to compression Shear stress due to horiz. deformation Shear stress due to rotation
>
mm
0.323 OK
2
0.70 N/mm 2 0.323 N/mm 2 0.375 N/mm 1.40 N/mm
Total shear stress Output: Bearing Details : Elastomeric Bearing Size of Pad 400mm x 650mm Laminated Layer Nos.: 5 Steel + 4 Internal Elastomer + 2 Outer Elastomer Thickness of individual elastomer layers 12.00 Thickness of outer elastomer layer 6.00 Thickness of steel laminates 4.00 Side Cover 10.00 Total thickness of elastomeric pad 80.00
