Abstract
Although post-earthquake observations identified spatial variation of ground motion (i.e., multiple-support excitation) as a frequent cause of the unfavorable response of long-span bridges, this phenomenon is often not taken into account in seismic design to simplify the calculation procedure. This study investigates the influence of multiple-support excitation accounting for coherency loss and wave-passage effects on the seismic response of reinforced concrete deck arch bridges of long spans founded on rock sites. Parametric numerical study was conducted using the time-history method, the response spectrum method, and a simplified procedure according to the European seismic standards. Results showed that multiple-support excitation had a detrimental influence on response of almost all analyzed bridges regardless of considered arch span. Both considered spatial variation effects, acting separately or simultaneously, proved to be very important, with their relative significance depending on the response values and arch locations analyzed and seismic records used. Therefore, it is suggested that all spatially variable ground-motion effects are taken into account in seismic analysis of similar bridges.
Highlights
Improvement of seismic design methods always follows new observations and analyses of damage and collapse due to major earthquakes
This study investigated the influence of multiple-support excitation on seismic behavior of deck-type long-span reinforced concrete arch bridges
Multiple-support excitation had a detrimental effect on some aspect of the arch bridge seismic response, regardless of span length
Summary
Improvement of seismic design methods always follows new observations and analyses of damage and collapse due to major earthquakes. Conducted studies identified spatial variation of ground motion as a frequent cause of unfavorable response of long-span bridges, e.g., [1,2], but this phenomenon is usually not taken into account in seismic design to simplify the calculation procedure. Since length and spans of larger bridges are comparable to the seismic wavelength, it is obvious that all bridge supports cannot be excited simultaneously. Additional differences in the seismic input to different supports arise from changes in the frequency content and amplitude of the seismic waves propagating from the base rock to the ground surface. Simple examples of multiple-support excitations include the unseating of the superstructure due to differential displacements of its supports [2,3,4]. The pioneering studies of the phenomenon of ground motion spatial variation occurred in the
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
