Ruskin Powerhouse Improvements Project - Improving the Seismic Withstand of an 80-Year Old Hydroelectric Powerhouse Structure

摘要

The Ruskin Generating Station, near Mission, British Columbia, Canada is owned and operated by BC Hydro. The original powerhouse, commissioned in 1930, consists of Unit Bays G1 and G2, a service bay and the North Wing structure. The original main powerhouse superstructure consisted of steel truss frames and columns encased entirely in reinforced concrete and a reinforced concrete roof slab. Unit Bay G3 was constructed in 1950 with similar steel truss frames, but the walls were finished with wood frame construction and clad with an exterior asbestos sheathing. The powerhouse superstructure has been determined to be susceptible to damage during a site specific seismic event because the current code-required seismic forces are greater than the withstand capacity of the structure, exacerbated by poor distribution of lateral forces due to the weak Unit Bay G3. A three-dimensional computer model of the powerhouse superstructure was developed to analyze the existing powerhouse and to design Seismic Force Lateral Resisting System upgrades. Modeling has led to improvements being designed for the powerhouse structure to improve the performance, strength, and distribution of the lateral loads uniformly to the entire powerhouse superstructure, thereby protecting operations personnel and the generating resource during and after a seismic event. The final seismic strengthening design consists of a combination of new concrete walls, concrete wall thickening, infilling of openings, and fibre-reinforced polymers. This solution enabled the Project to maintain the aesthetic appeal of the historic architectural finishing, adding several large windows, which provide natural light into the generating station.