A complex segmental concrete block retaining wall structure for the reconstruction of a historical bridge

A historical bridge, made up of sandstone masonry, crossing a river in Northern Italy, suffered heavy damage to the wing walls of the abutment on the right side of the river, due to a large upslope landslide. The two wing walls, 7.0 m high, had the shape of a quarter circle and the face was made up of sandstone blocks. The design of the new wing walls was based on the technique of segmental concrete blocks for the face and high tenacity polyester geogrids for soil reinforcement. The concrete blocks were designed approximately with the same dimensions of the original sandstone blocks, with split face and yellow sandstone color to preserve the original external finish. To support the excavation of the unstable sand - lime soil, a micro-pile diaphragm wall, tied by steel tendons driven into the backfill, was designed. Both the design principles and the construction methods used for the reconstruction of the wing walls are described.