Civil Engineering Reference
In-Depth Information
Chapter 5
Predicting Footbridge Response Using Stochastic Load Models
Lars Pedersen and Christian Frier
Abstract
Walking parameters such as step frequency, pedestrian mass, dynamic load factor, etc. are basically stochastic,
although it is quite common to adapt deterministic models for these parameters. The present paper considers a stochastic
approach to modeling the action of pedestrians, but when doing so decisions need to be made in terms of statistical
distributions of walking parameters and in terms of the parameters describing the statistical distributions. The paper explores
how sensitive computations of bridge response are to some of the decisions to be made in this respect. This is useful as it
pinpoints which decisions to be concerned about when the goal is to predict footbridge response. The studies involve
estimating footbridge responses using Monte-Carlo simulations and focus is on estimating vertical structural response to
single person loading.
Keywords
Probabilistic modeling Footbridge vibrations Walking loads Sensitivity study Vibration comfort
Nomenclature
f
0
Bridge frequency
l
s
Stride length
q
Modal load
k
Response ratio
ζ
Bridge damping ratio
f
s
Step frequency
m
Weight of pedestrian
L
Bridge length
A
Acceleration property
μ
Mean value
F
Walking load
P
Prob. density function
M
Bridge modal mass
α
Dynamic load factor
σ
Standard deviation
