2015 CSCE Annual Conference Regina - Building on our Growth Opportunities

2015 CSCE Annual Conference Regina - Building on our Growth Opportunities Conference

Seismic Strengthening of Reinforced Concrete Squat Walls Using Externally Bonded CFRP Sheets

Mr. Joshua Woods, Carleton University (Presenter)
Mr. Carlos Cruz-Noguez, University of Alberta
Mr. David Lau, Carleton University

Despite significant advances in earthquake resistant design of reinforced concrete (RC) structures over the past two decades, there is still a large stock of existing shear wall structures designed and constructed using older less stringent design standards. Evidence from past earthquakes has shown these structures pose a significant risk to the life-safety of its occupants due to inadequacies in their design. Common structural deficiencies in their design include poor confinement of boundary elements and insufficient shear reinforcement. These deficiencies contribute to poor seismic performance characterized by a lack of strength, ductility and energy dissipation capacity. With the goal of improving the seismic behaviour of deficient RC shear walls, this paper presents experimental results on a minimally disruptive retrofitting scheme consisting of externally bonded fibre-reinforced polymer (FRP) sheets. The test specimens are 2/3 scale RC squat walls with a height-to-length aspect ratio of 0.85 tested to failure under reversed cyclic lateral load. The wall specimens are detailed with the structural deficiencies commonly found in walls designed according to older design standards. The wall specimens are retrofitted using a combination of vertical and horizontal FRP sheets applied to a single side of the wall, designed to eliminate premature shear failure and enhance the flexural load carrying capacity. Results on two different anchor systems are presented including FRP anchors, and a new tube anchor system developed at Carleton University. Results demonstrate the ability of using FRP as a viable retrofitting alternative to improve the seismic performance of deficient RC squat walls.