original question: What is the structure of [Thomas Bouch]?
answer: the tay bridge
answer type: Structure.
auxiliary information: Sir Thomas Bouch was a British railway engineer in Victorian Britain. He was born in Thursby, near Carlisle, Cumberland, England and lived in Edinburgh. As manager of the Edinburgh and Northern Railway he introduced the first roll-on/roll-off train ferry service in the world. Subsequently as a consulting engineer, he helped develop the caisson and popularised the use of lattice girders in railway bridges. He was knighted after the successful completion of the first Tay Railway Bridge but his name is chiefly remembered for the subsequent Tay Bridge Disaster, in which 75 people are believed to have died as a result of defects in design, construction and maintenance, for all of which Bouch was held responsible. He died within 18 months of being knighted, with his reputation destroyed.
Name the type of structure [Thomas Bouch] is.