Although prestressed concrete crossties have become a convenient option for upgrading rail infrastructure to accommodate heavier loads and higher speeds anticipated for future years, some of these members have exhibited durability issues that have led to their premature replacement. The issues observed often are related to cracking patterns developed in specific parts of the crossties, such as the central and rail seat regions. To address this problem, a novel prestressing approach is proposed, which combines traditional post-tensioning with the localized forces exerted by shape memory alloys (SMAs) after the activation of their shape memory effect (SME). As an initial step in exploring the concept, SMAs were embedded in the middle of four full-scale crosstie prototypes to counteract the vulnerability to cracking in the central region. The SMA reinforcement comprised plain NiTiNb and FeMnSi elements plus two different FeMnSi-based adaptive prestressing system (APS) assemblies. In the first phase of the experimental program, induction heating was implemented to trigger the SME of the SMA arrangements. The data from digital image correlation and strain gauges confirmed that the local prestress induced in the crossties by the SMAs ranged from approximately 5.2 to 11.1 MPa. The second phase evaluated the flexural capacity of the specimens at their rail seat and center regions, following the recommendations of the American Railway Engineering and Maintenance-of-Way Association. The results indicated that the performance of all specimens in the center regions was satisfactory, exceeding the calculated design limits by at least 31.9%. In addition, concentrating prestressing forces has promise in alleviating the need for post-tensioning in other areas, which, in this case, allows certain design requirements for the rail seats to be met. Overall, the research demonstrates the potential of SMAs in localizing prestress and enables future investigations to adopt similar approaches for optimizing current crosstie designs.


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    Titel :

    Experimental Testing of Concrete Crossties Prestressed with Shape Memory Alloys


    Beteiligte:


    Erscheinungsdatum :

    01.10.2025




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch




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