Movement restriction device with energy dissipation using bolted friction joints

Abstract

This study developed a simple and practical seismic movement restriction device for steel railway bridges by incorporating high-strength bolted friction joints into conventional steel brackets. Full-scale dynamic loading tests demonstrated that untreated hot-dip galvanized surfaces provided stable sliding behavior with minimal post-slip load reduction and significant energy dissipation capacity. Adjusting the number of bolts enables flexible performance control and supports rational seismic design under moderate to severe earthquakes.

The device was designed to achieve unidirectional energy dissipation through a single, first-occurrence sliding event at the galvanized interface, based on the premise that restoring-force elements are not used. This concept provides a simple and economical retrofit solution that can be installed without interfering with train operations, making the device suitable for existing bridges where bearing replacement is difficult.

Full-scale loading tests confirmed that post-slip load gradually increased with displacement, primarily due to changes in the galvanized surface condition such as galling and wear. The post-slip force was found to be nearly proportional to the number of bolts, indicating that device capacity can be tuned without significant dependence on bolt arrangement. Time-history response analyses further showed that the high-frequency load fluctuations observed during sliding occurred at frequencies much higher than the natural frequency of bridge components, resulting in negligible influence on structural displacement.