Dynamic seismic response of skewed and curved integral bridges

Abstract

Road alignment, including bridge geometry in the plan, is influenced by multiple factors such as vehicle speed, existing road alignment, land availability, budget constraints, and more. These practical considerations often lead to the design and construction of skewed and curved bridges. Ensuring the seismic performance of bridges is vital for maintaining uninterrupted traffic flow over their considerable lifespan. Bridge construction involves specialized skills, significant costs, and labour-intensive processes, making it imperative to ensure their longevity for economic reasons. Integral bridges, known as lightweight and stable structures, are recommended by IRC: SP: 114 – 2018 for regions prone to high seismic activity. While numerous analytical and experimental studies exist on straight integral bridges, research on skewed and curved integral bridges is limited. Therefore, this study aims to investigate the impact of various parameters such as central angle, radius of curvature for curved bridges, and skew angle for skewed bridges on crucial design parameters like time period, bending moment, torsional moment, and support reactions. Numerical analysis results generated using Midas Civil software are interpreted from a practical engineering perspective to derive meaningful recommendation which would help in design of curved and skewed integral bridges. An indication is also provided that codal recommendation of restricting skewness to 30° might be over-conservative. Thus, this study aims at proposing design guidelines for abutment and bents in integral bridges considering the cases where there is no backfill and when backfill exists. Additionally, the study outlines future research possibilities in this area.