Calculation of Seismic Force as per Eurocode - Working Example

Calculation of Seismic force as per EURO CODE Working Example

- PRABU R

Seismic force as per EN 1998 - Part 2 - 2005 (For Metro rail loading) 1.0 Individual Pier model (As per Cl. 4.2.2.6 BS EN 1998-2:2005)

2.0 Stiffness of pier: Stiffness =

103799 KN/m

3.0 Calculation of Loads: 2 C/S area of superstructure = 2m Span of superstructure = 30 m No of superstructure per span = 2 Nos. 3 Unit weight = 25 kN/m DL of superstructure = 2×30×2×25 = 3000 kN

LL axle load = 135 kN Impact factor = 1.2 LL with impact factor = 135×1.2 = 162 kN No. of axle per 30m span = 8 Total LL with impact = 162×8 = 1296 kN Factor for railway bridge (as per Cl. 4.1.2 BS EN 1998-2-2005) = 0.3 Net live load considered = 0.3×1296 = 388.8 kN DL of piercap = 1450 kN DL of pier = 103 kN Total load = 6337 kN

SIDL = 23.25 kN/m Span = 30 m No of deck = 2 Nos. Total SIDL = 23.25×30×2 = 1395 kN

4.0 Calculation of fundamental period of pier:

Ti =

2×3.14×(6337/103799)^0.5

5.0 Calculation of design elastic response spectrum: As per EN1998-1, for Ms Ground Type A B C D E

<

5.5 ;

S

TB (S)

TC (S)

TD (S)

1.00 1.35 1.50 1.80 1.60

0.05 0.05 0.10 0.10 0.05

0.25 0.25 0.25 0.30 0.25

1.20 1.20 1.20 1.20 1.20

0.50 Sec

Ground type = S= TB = TC = TD = q= ag = =

e 1.600 0.050 0.250 1.200 1.5

Sec Sec Sec (As per Table 4.1 of BS EN1998-2)

0.028

Actual value Sd(T)

Sd (T)

0.474

0.075

0.038

0.091

0.038