Seismic isolation retrofitting solution for an existing steel cable-stayed bridge

Area of Science:

• Civil Engineering
• Structural Engineering
• Earthquake Engineering

Background:

• Existing cable-stayed bridges in high seismic zones face risks of structural failure, as evidenced by the 1988 Saguenay earthquake anchorage plate failure.
• Seismic retrofitting is crucial for ensuring the safety and longevity of bridges in seismically active regions.

Purpose of the Study:

• To investigate the effectiveness of seismic isolation systems for retrofitting an existing cable-stayed bridge.
• To evaluate various seismic isolation configurations for optimal performance in longitudinal and transverse directions.

Main Methods:

• Development of a three-dimensional (3D) model of the cable-stayed bridge.
• Conducting nonlinear dynamic time-history analysis to simulate seismic behavior.
• Comparative performance assessment of five different seismic isolation system configurations.

Main Results:

• Partial seismic isolation provided unidirectional seismic response enhancement.
• Utilizing isolation systems between supports and the deck-tower connection significantly improved the overall seismic response in both longitudinal and transverse directions.

Conclusions:

• Seismic isolation systems are effective for retrofitting cable-stayed bridges in high seismic zones.
• Strategic placement of isolation systems, particularly between supports and deck-tower connections, is key to comprehensive seismic performance improvement.