Abstract: The present invention relates to improvements in U-shaped tunnel framings for poured concrete constituted of two half shells or half casings in the form of a right-angled dihedron. The framings are characterized by the combination in each half casing of a horizontal beam composed of two telescopic sections, a set of panels of modular width resting on the two sections of the horizontal beam and being juxtaposed exactly with respect to it and a horizontal reinforcing beam for stiffening and supporting the bottom of the half casing and located inwardly of its vertical panel. The invention is applicable to the simultaneous construction of walls and ceilings of poured concrete.