Below, see snapshots of some of our recent publications, find a full list here.

Effect of design methodology on collapse of isolated buildings

Bao Y, Becker TC. Journal of Structural Engineering, 2018.

Previous studies have typically focused on comparing the performance of isolated and fixed-base buildings under design level or maximum considered level earthquakes without modeling the failure of the isolation bearings components or considering the effect of superstructure system design choices. A numerical model which explicitly includes both impact and uplift behavior of the sliding bearings as well as degrading behavior of the superstructure is used to investigate the collapse risk of friction pendulum isolated moment-resisting and concentrically braced frame designs. It is found that the stiffness of the superstructure has a large influence on the overall collapse risk. 

Experimental study on sliding bearing failure

Bao Y, Becker TC, Sone T, Hamaguchi H. Earthquake Engineering and Structural Dynamics, 2018

While friction pendulum isolation bearings provide excellent behavior under design ground motions, their behavior under extreme events is less well known. Furthermore, the restraining rims which significantly affects the behavior at large displacements varies throughout the world. To understand the safety margin within the design of these bearings as well as the necessary design forces for the surrounding structure, we conducted a series of shake table tests at McMaster University to investigate the influence of restraining rims on the extreme behavior of the bearings. Four different restraining rims were considered and high speed cameras helped capture the diverse responses.

Failure of double friction pendulum bearings under pulse-type motions

Bao Y, Becker TC, Hamaguchi H. Earthquake Enigneering and Structural Dynamics, 2017.

We investigated the failure trends of double friction pendulum (DFP) bearings, looking at the effects of mass, and bearing properties on failure under pulses. This was then compared to the behavior under pulse type ground motion histories.

Experimental Investigation of Elastomeric Isolation Bearings with Flexible Supporting Columns

Crowder AP, Becker TC, Journal of Structural Engineering, 2017.

In an effort to mitigate major costs associated with isolation systems, especially in retrofit applications, isolation bearings may be placed on the tops of columns. However, columns under the isolation layer may not provide rigid boundary conditions, resulting in bearing end plates not remaining parallel. We conducted quasi-static cyclic testing of bearing-column subassemblies to investigate the effect of the flexible boundary condition on the bearing performance. We found that flexible end conditions can significantly reduce the lateral stiffness of elastomeric bearings.

Enhanced performance through a dual isolation seismic protection system

Becker TC, Ezazi A. The Structural Design of Tall and Special Buildings, 2016.

Seismic isolation is a well known, accepted method for improving building performance. However, it is difficult to achieve floor accelerations less than 0.3 g without allowing extremely large drifts. This study investigated the use of two isolation layers to address this issue. The system showed improved performance (smaller story drifts and floor accelerations) while maintaining the same peak roof drifts as in a comparable base isolated building.

This research was also presented at the 11th Canadian Conference of Earthquake Engineering.

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