Research Interests

Rolling isolation systems (RISs) protect mission-critical equipment and valuable property from earthquake hazards by decoupling the dynamic responses of vibration-sensitive objects from horizontal floor motions. When the RIS’s displacement capacity is insufficient to meet the demands of a disturbance, the performance of the isolator is degraded because of impacts, giving rise to high acceleration responses in isolated objects. Our research group has designed, constructed, and tested high-performance RISs capable of handling strong floor motions: (i) Heavily-damped RISs reduce displacement demands through increased rolling resistance; (ii) Double RISs have larger displacement capacities.

The frequency of earthquakes in Oklahoma has increased remarkably in recent years. Prior to 2009, Oklahoma experienced one to three magnitude 3.0 (M3.0) or larger earthquakes, but this number is steadily increasing. In 2014 Oklahoma experienced more M3.0 or larger earthquakes than any other state—including California and Alaska—with fourteen earthquakes in excess of M4.0. Larger earthquakes (M5.0+) may pose a threat to bridges, buildings, and their contents.

Vision-based motion measurement methods have steadily gained popularity in civil engineering applications because the motion of multiple points can be tracked with a single sensor. Related to our efforts in experimentally testing RISs, we have developed routines to extract the displacements and rotations from video captured using an over-head camera. We are studying innovative applications where vision-based measurements may be more cost-effective than traditional means, such as conditional assessment of structures using existing cameras.