Response Modification Factors for Multi-Span Reinforced Concrete Bridges in Pakistan

Abstract

In Pakistan, updated codes covering seismic provisions for reinforced concrete bridges do not exist. The majority of the bridge design uses different versions of AASTHO-LRFD provisions. Response modification factors recommended for usage in these codes are primarily for bridges derived from conditions and bridges in the United States of America. This research focuses on the seismic assessment of three real multi-spans simply supported reinforced concrete bridges in Pakistan having multiple bents. This typology of bridges is very common in Pakistan. Non-linear static pushover analysis is performed to derive seismic capacity curves for these bridges, which were used to compute response modification factors. The study results show that response modification factors vary between 4.50 and 5.0 for the bridges in the longitudinal and transverse directions. The results of this work may serve as input in developing the seismic design code of bridges in Pakistan.

Keywords

• reinforced concrete bridge
• response modification factor
• multi-spans
• multiple bents
• seismic design