Abstract:
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The construction of underground lines has a big importance in overpopulated cities such as São Paulo. In that sense, the tunnel boring machine (TBM) method for tunnel construction is a method that allows a high speed of construction. The TBM uses different segments, typically produced with conventional reinforced concrete, which composes the tunnel linings. Regarding new technological advances, steel fibers are added to the concrete mixes in order to create a ductile material. This entails a reduction of the segment damages and also the time consumed in the segment production and thus the construction cost. The aim of this work is proposing a methodology based on the fib Model Code 2010, which allows the design of hybrid segments (structural fibres and traditional reinforcement). This methodology may be used for these cases that the transitory and service solicitations do not entail cracking in the structure. In this document, a direct application equation is presented in order to estimate the FRC residual tensile strength (fR) and an application considering a real segment is performed. |