Precast tunnel segments reinforced by macro-synthetic fibers

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• 作者：Antonio Conforti^a ; ^{antonio.conforti@unibs.it} ; Giuseppe Tiberti^a ; ^{giuseppe.tiberti@unibs.it} ; Giovanni A. Plizzari^a ; ^{giovanni.plizzari@unibs.it} ; Angelo Caratelli^b ; ^{caratelli@ing.uniroma2.it} ; Alberto Meda^b ; ^{alberto.meda@uniroma2.it}
• 关键词：Precast tunnel segments ; Macro-synthetic fibers ; Polypropylene fibers ; Flexural tests ; Point load tests
• 刊名：Tunnelling and Underground Space Technology
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：63
• 期：Complete
• 页码：1-11
• 全文大小：3387 K
• 卷排序：63

文摘

The use of fiber reinforced concrete in tunnel linings, with or without conventional rebars, has increased in the two last decades, especially with regard to precast tunnel segmental linings. In addition, there is a general growing interest in the scientific community on macro-synthetic fibers for use in underground structures.Within this framework, the present study investigates the possibility of using polypropylene (PP) fiber reinforcement in hydraulic precast tunnel segments by means of an experimental program on six full-scale segments of Monte Lirio hydraulic tunnel (Panama). Three different reinforcement solutions were studied both under flexure and point load test: typical conventional reinforcement generally adopted in practice (reference samples, RC); PP fibers only (PFRC specimens); combination of PP fibers and conventional reinforcement (hybrid solution, RC + PFRC segments). Based on the loading configurations considered, experimental results showed that PP fibers (with or without reinforcing bars, depending on loading conditions) represent an efficient reinforcement for hydraulic precast tunnel segments. PP fibers can be used as flexural, splitting and minimum shear reinforcement, while concerning the spalling reinforcement, only PP fiber reinforcement could be used even if the combination with conventional reinforcement (hybrid solution) guarantees a better control of spalling cracks for high load levels.