Including bolt sockets, dowels, spacers, grout/lifting sockets, plugs, and non-return valves. High-strength fasteners for steel and concrete bridge structures. With decades of expertise in connection solutions for concrete segmentally lined. We at TOBSTEEL are a leading specialist in all the materials required for tunnel and bridge construction. We have the right. Our bridge clamps are manufactured from 304 Stainless Steel and 'bridge' the spiral helix to provide an effective clamp and seal. For those of you who work in construction contracts within concrete complements, we have a wide range. Clamp for parallel installations. Injection mortar ResiFIX EPP SF Plus,.