### Seismic Analysis of Example Bridge 2: Consultant Report

```SEISMIC ANALYSIS OF EXAMPLE
BRIDGE 2: CONSULTANT REPORT
Group 4:
Haque, A. B. M. Tahidul
Khusaibi, Hazim-Al
Krishnappa, Nagarjun
Kumar, Manish (mkumar2)
Kumar, Manish (mkumar3)
OUTLINE

Basic features of bridge

Analysis assumptions

Comparison of results

Summary
2
BASIC FEATURES OF BRIDGE

Geometrical features
Three spans (124ft - 152ft - 124ft)
 25◦ skew at piers and abutments

Site class B
 Location: New Madrid (MO)

3
Spectral Acceleration (g)
SEISMIC HAZARD
0.2
4
EE
MCE
0.15
3
0.1
2
0.05
1
0
0
1
2
Natural Period (s)
0
0
1
2
Natural Period (s)
4
ANALYSIS ASSUMPTIONS

SDOF Analysis

Mass
Superstructure
 Substructure


Stiffness
Weak and strong directions of pier
 Elasto-plastic behavior


Yield strength


Based on pushover analysis
Damping

2% of critical
5
ANALYSIS ASSUMPTIONS…

Assumptions for spine model
2% damping in all modes
 Infinite deformation capacity for bearings
 Other parameters same as in Example 2 bridge
 A

6
NATURAL PERIOD
Consultant model vs. FHWA model
Consultant Model
1
Example 2 (FHWA)
0.9
0.8
Natural Period (s)

0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1
2
Natural Mode
3
7
ANALYSIS RESULTS

Pushover Analysis
8
ANALYSIS RESULTS

Comparison of strength using hand calculations
Axial load ≈ 2% of capacity
 Limiting moment capacity for a beam

xu ,max 
xu ,max 
1  0.416

 0.362
2
d 
d 
f ck  bd
M u ,lim
Mu,lim = 400000 kip-ft (xu,lim/d=0.3)
 Mu,lim = 117000 kip-ft (xu,lim/d=0.5)


Used capacity in analysis ≈ 130000 kip
9
ANALYSIS RESULTS
Moment in weak direction of column
5
6
x 10
SDOF
(elastic)
5
Moment (kip-ft)

4
SDOF
(inelastic)
3
2
1
0
Time Multimode
Uniform
History
1
2
3
4
5
10
ANALYSIS RESULTS

Displacement at midspan
2
2
Longitudinal
SDOF
(elastic)
Displacement (ft)
1.5
1
SDOF
(elastic)
1.5
SDOF
Multimode
Uniform
Time
History
Uniform
1
0.5
0
Transverse
Multimode
Time
History
0.5
1
2
3
4
5
0
1
2
3
4
5
11
ANALYSIS RESULTS…

Capacity Spectrum Analysis
Plastic
P-Δ Capacity
Distribution
Deformation
(inch)
Capacity
Operational
Performance Performance
Capacity
(θPH)
Life Safety
Capacity
Requirement Requirement
(inch)
(inch)
(inch)
Triangular
15.85
169.9
10.7
4.18
Parabolic
12.96
151.2
11.46
4.47
12
CONCLUSIONS
Bridge may remain operational during MCE
 Certainly functional during EE

13
THANK YOU
14
```