Next Generation of Earthquake-Resistant RC Structural Walls

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In buildings located in regions where significant lateral forces exist, caused by either wind or earthquake actions, reinforced-concrete structural walls are an efficient system to safely transmit the forces from the building to the ground. In Canada, structural walls are found in a large number of buildings (apartment complexes, hospitals, industrial and nuclear facilities) located on seismically vulnerable zones. Observations made during recent earthquakes in Chile, New Zealand and Japan has shown that buildings with adequately designed walls perform well, protecting the structures against collapse. However, wall systems after the earthquake often exhibit severe damage and permanent deformations. For many affected buildings, this means that costly repair or demolition activities are needed after a seismic event. The implications of these findings for the Canadian public are far-reaching. In addition to the significant economic burden involved in repairing a damaged building, the shut-down of critical structures (such as hospitals, bridges, nuclear and telecommunication facilities) may be catastrophic during the post-earthquake relief efforts. Recent investigations have shown the benefits of using innovative, high-performance materials and details to reduce damage and permanent deformations in buildings and bridges. These materials are superior to conventional reinforced-concrete in many aspects; structures built with these advanced materials can withstand severe earthquakes without the need of repairs or down-time for assessment or evaluation. This is very important in the case of hospitals or critical bridge structures during the critical hours or days that immediately follow after a seismic event. It also represents significant savings since the costs of repair can be very high, both in terms of down-time or the technical expertise required. In this proposed research, the use of several advanced materials and details in structural reinforced-concrete walls will be investigated. A Nickel-Titanium alloy with the ability to "remember" its shape after it has been unloaded, a new type of concrete with plastic fibres embedded in the mix, and an unbonded post-tensioning system are the innovative materials to be studied in this research. The experimental part of the study will consist of the seismic testing and response evaluation of several structural walls, detailed with innovative materials in areas vulnerable to damage. After the seismic tests, the ability of the innovative materials to prevent damage and to improve post-earthquake serviceability will be evaluated. Analytical models will be developed to accurately capture and predict the response of the walls, taking into account the contribution of the innovative materials. The aim of the study is to show that it is possible to create truly earthquake-resistant buildings that are cost-effective and feasible to build; structures that require minor or no repairs during the course of their lifetime. It is expected that, ultimately, the products and deliverables of this study (design guidelines and reliable analytical models for high-performance structural walls) lead to a safer and economical designs in buildings and other structures located in zones with high seismicity in Canada, by using innovative materials.