ABSTRACT
This paper outlines the design challenges and recommendations for use of fibreglass reinforcement in tunnel headwall softeyes as learned through transit construction projects in the Greater Toronto Area (GTA). Tunnel boring machines were used to construct underground transit tunnels requiring the design of shafts with softeyes to facilitate tunneling operations. Variable ground conditions and shaft geometries lead to innovative headwall and tunnel softeye design applications using fibre reinforced polymer (FRP) elements (beams, reinforcing bars, and anchors). This paper outlines the challenges and benefits associated with designing and constructing shafts using various FRP systems including lessons learned throughout design and construction of over 20 structures through the past decade.
