Comparison of the structural behavior of reinforced concrete tunnel segments with steel fiber and synthetic fiber addition

Fiber reinforced concrete, with different types of fibers, has been increasingly used in underground structures, especially for tunnel lining segments. Macro synthetic fiber reinforced concrete has a considerable structural bearing capacity. Compared to steel fiber reinforced concrete, it has the advantage of corrosion resistance and durability. However, the main application of macro synthetic fiber reinforced concrete is limited to control cracking without considering its mechanical contribution. Besides, few studies have compared the differences in mechanical properties of synthetic fibers and steel fibers. Therefore, an experimental and theoretical study of reinforced concrete segments with steel fiber and synthetic fiber addition was performed. The experiments included both traditionally reinforced concrete segments and fiber reinforced concrete segments with different ratios of steel bars and fiber dosages. By means of comparison between different segments, the advantages of fiber reinforced concrete relative to traditional reinforced concrete segments are shown as well as the differences of the mechanical behavior of reinforced concrete segments with synthetic fibers and steel fibers. In addition, the concrete section design method is extended to reinforced concrete segments with macro synthetic fibers. Using this model, the bearing capacity of experimental segments is analyzed. The results agree well with the experimental results, which indicates the design model for the reinforced concrete segments with macro synthetic fibers is reasonable and applicable.

Publication year:2020

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