Experiments on Large Structures - Dynamic Behavior of Concrete and Seismic Engineering - page 201

Chapter 6
Experiments on Large Structures
Introduction
Realistic modeling of the behavior of civil engineering structures is the first and
most difficult step in dynamic or seismic analysis. The parameters such analysis can
define include mass distribution, damping characteristics, the stiffness of the
strength system as regards inertia, the influence of secondary elements and various
interaction phenomena. Forced or ambient vibration testing of large civil
engineering structures are generally used to validate these parameters at the design
stage.
The ability of particular numerical methods or mathematical models to represent
the different interaction phenomena that determine the dynamic behavior of civil
engineering structures can only be judged by comparing the forecasts they give with
well-documented experimental results. Thus, dynamic tests allow the creation of
experimental databases that can be used to develop and validate specific digital
models, taking particular conditions or special interactions into account.
From a practical perspective, the dynamic testing of real structures is very
important when assessing the safety of large works such as dams and bridges,
because they characterize the fundamental properties of a structure, like the mass
and stiffness at certain vibration frequencies, and also provide information regarding
damping. Variations in these properties give a good indication of the changes the