The flexural behavior of slender (1/40) long-span precast high-strength concrete girders was experimentally investigated as a competing solution to steel alternatives for highway overpasses. Half-scale specimens were produced using an economical and high-strength (120 MPa) concrete mixture, non-fiber reinforced, designed only with conventional raw materials, currently available at Portuguese precast companies. Two girder specimens were subjected to quasi-static short-term loading up to structural failure in bending. Results have shown the typical behavior of conventional reinforced concrete members in bending, despite the brittle behavior of non-fiber-reinforced high strength concretes. Results also showed acceptable ductility (2.6) and the ability of the girder specimens to experience large deformation without significant softening. An analytical approach, based on plane sections and short-term stress–strain constitutive model recommended by the Eurocode 2 for concrete up to the C90/105 strength class, showed to predict accurately the behavior of girders in bending, both to ultimate and serviceability limit states, including cracking, yielding, maximum loads, and ultimate deflections.

中文翻译：

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细长大跨度预制预应力高强混凝土梁的抗弯性能

细长 (1/40) 大跨度预制高强度混凝土梁的弯曲行为被作为公路立交桥钢材替代方案的竞争解决方案进行了实验研究。半比例试样是使用经济和高强度 (120 MPa) 的非纤维增强混凝土混合物生产的，仅使用传统原材料设计，目前在葡萄牙预制公司有售。两个梁试样经受准静态短期载荷直至弯曲结构失效。结果表明，尽管非纤维增强高强度混凝土具有脆性，但传统钢筋混凝土构件在弯曲时的典型行为。结果还显示了可接受的延展性 (2.6) 和大梁试样经受大变形而不显着软化的能力。