Proksch-Weilguni, C., Decker, M., & Kollegger, J. (2022). LONGITUDINAL JOINT DESIGN FOR ECO-EFFICIENT TUNNEL STRUCTURES. In Concrete innovation for sustainability : proceedings for the 6th fib International Congress 2022 (pp. 2552–2559). Fédération Internationale du Béton – International Federation for Structural Concrete.
A global survey of the International Tunnelling and Underground Space Association (ITA-AITES) in 2019 concluded that yearly approximately 5200 km of tunnels are constructed [1]. This equates to a turnover of 125 billion euros and an annual growth rate of 9% since the last market survey in 2016, which is two times larger than the global construction growth rate. These facts show the enormously growing importance of tunnel structures compared to other industry sectors in civil engineering. A special characteristic when it comes to building tunnel structures using segmental linings, is the fact that the outer dimensions of the tunnel segments have to be almost identical along the tunnel to meet the requirements of the tunnel boring machine (TBM). Usually, every infrastructure project is unique and dependent on local conditions. The optimization of a single structural element is not common in the field of structural concrete. For tunnel structures with a length of many kilometres, the reduction of the tunnel segment by a few centimeters leads to a significant saving in concrete volume.
In many tunnel projects the decisive factor for dimensioning the thickness of prefabricated tunnel segments is the design of the longitudinal joints. This is the reason for the development of a new reinforcement concept for tunnel segments which increases the load-bearing capacity of the longitudinal joints significantly. Based on a patent application, a proof of concept of the design approach was done in the laboratory of the Institute of Structural Engineering.
The paper discusses the results of the experiments and presents the potential for saving resources using the TU Wien tunnel segment reinforcement concept. Due to the experimental results, which will be shown in detail in this paper, it can be concluded that the TU Wien design approach for longitudinal joints is a great opportunity for building tunnel structures more efficiently.
