Resource efficient reinforcement concept for precast tunnel segments

Abstract

The global increase in world population and the growing demand of mobility leads to new huge infrastructure projects all over the world. Due to the circumstance, that every infrastructure project is unique and dependent on local conditions the optimization of single structural elements is not that common in the field of reinforced concrete structures. When it comes to building tunnel structures using a tunnel boring machine (TBM), a lot of almost identical tunnel segments called tubbings are needed. Already a reduction of a few centimeters of the tunnel segment thickness, leads to a significant saving of concrete when it comes to tunnel structures with a length of a few kilometers. The thickness of the tunnel segments mostly depends on the design of the radial joints of the individual tunnel segments. That is why the Institute of Structural Engineering of the TU Wien developed a new reinforcement concept for tunnel segments which increases the load bearing capacity of the radial joints significantly. With a patent application submitted, tunnel segments with the new reinforcement concept were manufactured, tested and it was shown that the TU Wien proposal significantly improves the load bearing capacity of tunnel segments. Due to a presented design approach for determining the load bearing capacity of the segments and a first simplified quantification of the resource saving potential it can be said that the newly developed joint design is a great possibility for constructing tunnels with thinner tunnel segments.