Mechanical Behavior of Integrated Multifunctional Prefabricated Insulated Formwork in Severe Cold Regions

To ensure the stress characteristics and durability of high arch dams during the construction and operation process in severe cold regions, this study proposes an integrated multifunctional prefabricated insulated formwork (MPIF). The MPIF not only works with cast-in-place arch dams to share stress but also provides life-cycle thermal insulation. Three full-scale specimens were tested under monotonic and cyclic loading to investigate the out-of-plane mechanical behavior of MPIF. Results indicate that under vertical loading, cracks primarily occur at the mid-span of the bottom beam, the beam-column interfaces and the center of the grid slab. At a load of 1000 kN, the out-of-plane deformation remains within the elastic range. Structural deformation varies slightly under different loading conditions. Under cyclic loading, out-of-plane deformation is considerably larger than under monotonic loading, and the bearing capacity decreases markedly. Numerical analyses were performed to evaluate the influence of boundary conditions, slab thickness, loading sequence and bonding strength between new and old concrete on the stress characteristics of the integrated formwork. These findings provide a foundation for the practical application of MPIF in high arch dams in severe cold regions.