Complex sentence: In 1875, the wooden bridge was replaced by a steel pipe truss bridge, which was itself replaced by a steel girder bridge in 1984, still using the old pillars.
Split into simpler sentences: In 1875, the wooden bridge was replaced by a steel pipe truss bridge. More than 100 years later, that bridge was itself replaced by a steel girder bridge in 1984, still using the old pillars.