This construction method is used for in-situ concreting of bridges or viaducts with considerable spans. Equipment is positioned at the top of the pier, or segment 0, and is advanced in opposite directions bi-laterally, constructing consecutive segments which form a T shaped, symmetrical construction. Span increments using these systems range between 3.5 and 5 metres. This allows reinforcement to be installed easily and safely.

Equipment comprises the main structure, transfer rails, bed or base panel, external and internal formwork and working platforms. To cast the segment, concrete is poured into the section made up of the external and internal formwork and the bed. These panels are attached to the front section of the main structure and at the rear to the previous segment. The form traveller is advanced to the next section by hydraulically sliding the entire assembly in transfer configuration on the rails.

Equipment for cantilever bridges is able to counteract bridge gradients and section cambers