Assessment of the stress–strain state of a two-span reinforced concrete bridge subjected to real earthquake records

Abstract

This paper investigates the seismic response and stress-strain state of a two-span reinforced concrete highway bridge subjected to real earthquake records using advanced numerical modeling. A three-dimensional model of a 48 m long bridge was developed considering structural characteristics, support conditions, and soil-structure interaction. Fixed and expansion bearings were included, while soil-structure interaction was represented using an equivalent spring approach. Real acceleration records from the 1994 Northridge and 1992 Landers earthquakes in California were applied as seismic excitations. Northridge produced high-intensity, short-duration motions, whereas Landers generated longer-duration, lower-frequency ground motions. Numerical simulations were performed in CSiBridge v26.3.0 using nonlinear time-history analysis. Longitudinal, transverse, and vertical earthquake components were considered separately. Longitudinal (UX), transverse (UY), and vertical (UZ) displacement variations were evaluated at selected control points, together with normal and principal stress distributions in the bridge superstructure. The results showed that the Northridge earthquake produced significantly higher stress and displacement responses than the Landers earthquake. Maximum principal stresses occurred near the intermediate support, while maximum vertical displacements were observed near the bridge deck mid-spans. These findings demonstrate the significant influence of earthquake characteristics on bridge seismic performance.