Resumo (PT):
Abstract (EN):
Railway bridges, due to the high intensity moving loads to which they are subjected, are structures
where the dynamic effects may reach significant values, which must be considered in the design.
These effects are being given greater importance at present, in consequence of the increment on the
circulation speed both in existing and new railways, as is the case for those intended for the highspeed trains. In high-speed railways, the dynamic effects tend to increase even more considerably,
essentially as a result of the so-called resonance effects, which occur due to the passage of trains
composed by several groups of regularly spaced axles.
The knowledge of these dynamic effects is of major importance for the case of railway bridges for
the following reasons: i) the vibrations induced by the passage of the trains over the bridge originate,
in general, displacements or internal efforts in the structures, greater than those produced when the
loading is statically applied; ii) the excessive vibrations of the structure may lead to a magnification
of the fatigue phenomena; iii) the deformations and accelerations of the bridge should be controlled
and kept within certain limit values, in order to ensure the stability of the track and of the contact
wheel-rail at all times; iv) the accelerations in the vehicles should be limited so that the passengers
comfort can be guaranteed.
For a correct evaluation of the mentioned dynamic effects, it is necessary to have adequate
analysis tools that enable to translate the complexity of the bridge-vehicle system in a realistic
manner. In this work, a short description of the calculation program developed at the Faculty of
Engineering of the University of Porto, where the bridge, the moving train and the respective
interaction can be modelled, will be presented. Applications of this tool are described namely for
the study of the dynamic behaviour of the Riada Bridge and the Antuã Bridge, conducted under the
scope of the upgrading project of the Northern Line (“Linha do Norte”) of the Portuguese Railways
for the circulation of trains at higher speeds, as is the case of the CPA 4000 “Alfa Pendular” train,
which can reach 220 km/h; of the Luiz I Bridge, which was carried out under the development of
a technical study on the feasibility of its use for the passage of the New Light Metro of Porto; and
of a continuous deck voided slab bridge, part of a high-speed railway line.
Language:
Portuguese
Type (Professor's evaluation):
Scientific
No. of pages:
21