Abstract: A connection system between a slide and a very long member, allowing some longitudinal movement of said member in relation to the slide, corresponding to differential deformation, said slide being of the type which comprises a support provided with clamping parts which surround at least a part of said member. In accordance with the invention, the slide comprises, at the clamping zones, plates made of a material with a low coefficient of friction firstly on the surface of the support facing said member and secondly on the internal surface of each of said clamping parts. Application to connection systems for very long rails such as rails which carry travelling cranes and lateral guide rails for public transport vehicles.

Abstract: This casing voussoir is of the type comprising a metallic frame 1, 2, 3.sup.a, 3.sup.b, 9 and a mass 12 of concrete or other like material strong in compression and anchored to that frame, the assembly having the shape of a cylindrical ring sector, characterized in that the frame 1, 2, 3.sup.a, 3.sup.b, 9 comprises two plates 1, 2, arranged along radial faces of the voussoir and interconnected by bars 3.sup.a, 3.sup.b, constituted by distinct parts of these plates 1, 2 and fixed to these latter by means of a filler material 8. A particular applications can be found for this voussoir in the lining of tunnels or similar underground works.