Analysis of a high-pier railway bridge under spatial stochastic stationary and non-stationary earthquake excitations

Abstract

Original scientific paper The objectives of this paper are to perform a comparative analysis of the large-scale system of a high-pier railway bridge subjected to stationary and nonstationary spatially varying earthquake excitations using the pseudo-excitation method (PEM), and to estimate whether or not the non-stationary stochastic analysis of the high-pier railway bridges under tri-directional spatial ground motions can be simplified into a stationary random analysis to avoid excessive computation. Based on the finite element software ANSYS, the stationary and non-stationary stochastic excitations analyses of a high-pier bridge were transformed into harmonic analyses and deterministic transient analyses in the study, respectively, by using PEM. The wave-passage effect and the incoherence effect were modelled as the key factors, a total of twelve cases were considered to investigate the wave-passage effect and incoherence effect on the seismic response of a high-pier railway bridge under stationary and non-stationary earthquake excitations. Results show that structural responses under stationary excitation are larger than those under non-stationary by considering either the wave-passage effect or the incoherence effect. Through comparing structural responses under stationary excitation with those under non-stationary one, all the growth rates are less than 25 %, which is acceptable in engineering, meaning that a non-stationary stochastic analysis of high-pier railway bridges under tri-directional spatial ground motions can be simplified into a stationary analysis to avoid excessive computation.Keywords: high-pier railway bridge; incoherence effect; non-stationary stochastic excitation; pseudo-excitation method; wave-passage effect Analiza željezničkog mosta na visokim stupovima pod prostornim stohastičkim stacionarnim i ne-stacionarnim uzbudama potresaIzvorni znanstveni članak Ciljevi ovoga rada su provesti komparativnu analizu velikog sustava željezničkog mosta na visokim stupovima izloženog stacionarnim i ne-stacionarnim prostorno promjenjivim uzbudama potresa primjenom metode pseudo-uzbude (pseudo-excitation method -PEM), te procijeniti može li se ili ne može nestacionarna stohastička analiza željezničkih mostova na visokim stupovima izloženih trosmjernim prostornim podzemnim gibanjima zamijeniti jednostavnijom stacionarnom slučajnom analizom kako bi se izbjegla prekomjerna računanja. Zasnovane na ANSYS softveru konačnih elemenata, analize stacionarnih i ne-stacionarnih stohastičkih uzbuda mosta na visokim stupovima pretvorile su se u harmonične analize i determinističke prijelazne analize u našem istraživanju, primjenom PEM-a. Učinak prolaza vala i učinak nekoherentnosti modelirani su kao ključni čimbenici, a ukupno je razmotreno dvanaest slučajeva u svrhu ispitivanja učinka prolaza vala i učinka nekoherentnosti na seizmičku reakciju željezničkog mosta na visokim stupovima izloženog stacionarnim i ne-stacionarnim uzbudana potresa. Rezultati pokazuju da je reakcija konstrukcije pod stacionarnom uzbudom veća ...

An Evaluation on Bridge Bearing Capacity under Scour and Re-occurrence of Strong Earthquake

“…China is an earthquake-prone country where major earthquakes have frequently occurred in recent years, including the earthquake that happened in Dongguan, Haicheng, Tangshan, Songpan, Wenchuan, Yushu and Lushan in 1974, 1975, 1976, 2008, 2010 and 2013 respectively [1]. Numerous bridges were seriously damaged during earthquake, among which Beam-shape bridge was the bridge mostly affected.…”