Publication Abstract

Proceedings of the 43rd Annual Conference on Deep Foundations, 2018, Anaheim, CA, USA, (DFI)

Tunnel Headwall Softeyes: Fiberglass Design Applications and Constructability Challenges
Shawna Munn, P.Eng., Jakub Huder and P.Eng.

This paper outlines the use of tunneling headwall softeyes for transit construction projects in the Greater Toronto Area (GTA) over the past decade. Due to spatial constraints, tunnel boring machines were used to construct the underground tunnels requiring the design of launch and exit shafts with headwall softeyes to facilitate tunneling operations. Variable ground conditions and shaft geometries lead to the development of innovative headwall and tunnel softeye design applications using fiber reinforced polymer (FRP) elements (beams, reinforcing bars, and tiebacks). This paper outlines the challenges and benefits associated with designing and constructing shafts using various systems. Lessons learned throughout design and construction of more than 20 structures over the past 10 years are outlined. The constructability challenges with using FRP and design performance are also discussed.

 article #3112; publication #1045 (AM-2018)