Location

San Diego, California

Session Start Date

3-26-2001

Session End Date

3-31-2001

Abstract

At present, public transport for mid distances is more and more covered by modern high speed railway links with many examples all over the world being already under construction or in the design process. In case of soft soil conditions or urban areas, many of these projects are being realized as an elevated railway structure utilizing regular viaducts. In seismic active regions earthquake design mainly governs the overall design concept of the bridges, particularly of the piers and foundations. Thus, on the one hand, the structure has to exhibit enough stiffness under serviceability conditions (limitation of rail stresses; safety requirements for high speed trams) while on the other hand, flexibility, energy dissipation and ductility is advantageous with respect to a severe earthquake event. Since the earthquake excitation normally governs the whole structural design in case of high seismicity it is necessary to consider the dynamic loading as early as possible in order to come up with an optimal solution. Modem and efficient numerical simulations using e.g. the Finite Element Method are enabling the design engineers to study the bridge structures under static and dynamic loading conditions, taking into account geometrical and physical nonlinear effects. The following paper describes the design process of a high speed train structure which has been planned in Taiwan. All results presented herein have been gained during the tender phase of the project which has been finalized in the beginning of the year 2000. The bridge structure has been designed as simply supported viaducts consisting of 35 m and 30 m spans. Each span is supported by four reinforced concrete columns at each end, which are supported by 4 piles (see Fig. 1). The bridge spans have been designed as pre stressed box girders, which will be prefabricated and installed at the construction site. Hereby, two earthquake levels have been included, moderate intensity for the serviceability check (elastic response of the structure) and severe earthquake for the ultimate load limit check (elasto-plastic response). The evaluation of the dynamic response has been performed with plane and spatial beam models applying linear and non-linear time history analysis. More practical methods, based on linear superposition principles, such as equivalent static loads or multiple mode response spectrum method have been used for comparison. Time history analyses have been performed by utilizing synthetic acceleration time histories (one and multidimensional), compatible with the governing response spectra. The non-linear elasto-plastic analyses for the severe earthquake situation has been carried out using a single pier model. The advantages for the design by performing a full physical nonlinear analysis will be demonstrated. In addition, displacements and rail stresses as well as the influence of the wave-passage effect have been studied by means of an overall dynamic multi-span model, taking into account a non-linear rail-track bond behavior.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fourth Conference

Publisher

University of Missouri--Rolla

Publication Date

3-26-2001

Document Version

Final Version

Rights

© 2001 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Mar 26th, 12:00 AM Mar 31st, 12:00 AM

Design Concept for High Speed Railway Bridges in Regions with High Seismic Activity and Soft Soil

San Diego, California

At present, public transport for mid distances is more and more covered by modern high speed railway links with many examples all over the world being already under construction or in the design process. In case of soft soil conditions or urban areas, many of these projects are being realized as an elevated railway structure utilizing regular viaducts. In seismic active regions earthquake design mainly governs the overall design concept of the bridges, particularly of the piers and foundations. Thus, on the one hand, the structure has to exhibit enough stiffness under serviceability conditions (limitation of rail stresses; safety requirements for high speed trams) while on the other hand, flexibility, energy dissipation and ductility is advantageous with respect to a severe earthquake event. Since the earthquake excitation normally governs the whole structural design in case of high seismicity it is necessary to consider the dynamic loading as early as possible in order to come up with an optimal solution. Modem and efficient numerical simulations using e.g. the Finite Element Method are enabling the design engineers to study the bridge structures under static and dynamic loading conditions, taking into account geometrical and physical nonlinear effects. The following paper describes the design process of a high speed train structure which has been planned in Taiwan. All results presented herein have been gained during the tender phase of the project which has been finalized in the beginning of the year 2000. The bridge structure has been designed as simply supported viaducts consisting of 35 m and 30 m spans. Each span is supported by four reinforced concrete columns at each end, which are supported by 4 piles (see Fig. 1). The bridge spans have been designed as pre stressed box girders, which will be prefabricated and installed at the construction site. Hereby, two earthquake levels have been included, moderate intensity for the serviceability check (elastic response of the structure) and severe earthquake for the ultimate load limit check (elasto-plastic response). The evaluation of the dynamic response has been performed with plane and spatial beam models applying linear and non-linear time history analysis. More practical methods, based on linear superposition principles, such as equivalent static loads or multiple mode response spectrum method have been used for comparison. Time history analyses have been performed by utilizing synthetic acceleration time histories (one and multidimensional), compatible with the governing response spectra. The non-linear elasto-plastic analyses for the severe earthquake situation has been carried out using a single pier model. The advantages for the design by performing a full physical nonlinear analysis will be demonstrated. In addition, displacements and rail stresses as well as the influence of the wave-passage effect have been studied by means of an overall dynamic multi-span model, taking into account a non-linear rail-track bond behavior.