First Use of UHPFRC in Thin Precast Concrete Roof Shell for Canadian LRT Station

摘要

A very thin architectural shell was selected for the roof structure of the new Shawnessy Light Rail Transit (LRT) Station in Calgary, Alberta, Canada. Twenty-four unique, thin-shelled precast concrete canopies measuring 5 x 6 m (16 x 20 ft) and just 20 mm (3/4 in.) thick, supported on single columns, provide an attractive light-filled shelter for commuters. This unprecedented structure was made possible with the design flexibility of a new generation of ultra-high performance fiber reinforced concrete (UHPFRC) materials that offer a combination of superior technical characteristics including ductility, strength, and durability without using mild reinforcing steel, while providing highly moldable products with an excellent surface quality. The UHPFRC compressive strength was 150 MPa (22,000 psi) and flexural strength was 18 MPa (2600 psi). This article reveals the many advantages of this innovative technology, and presents the material's mechanical properties as well as the challenges faced in structural design, manufacturing, and erection.