"Superstructed" means to construct something on top of an existing structure, but there are various synonyms for this word that can be used to convey the same meaning. Some of the other words that could replace "superstructed" include built-up, erected, raised, added-on, augmented, extended, expanded, and reinforced. These synonyms emphasize the process of adding something onto an existing structure, making it stronger, bigger, or more versatile. For example, we can say that the new floor in a building was "erected" on top of the old one or that an extension was "built-up" to accommodate more resources. Therefore, using synonyms for "superstructed" adds depth, variety, and precision to your writing.