The analysis of steel structures that pass wide span in exposition buildings

While fairs; were places that people come together for buying and selling, in times they turn into big exhibition areas, that shown developments and changes at industry and technology, that shown new invention, some importanat art and cultural activities.Especially with industrial revolution, fairs had an evolution, and Universal Fairs ?expo ?, which are new fair types, appeared. Expo?s are the big organizations that many countries join and show their own culture, life style and tecnology.In this paper, the occurrence of expos, the evolution of World Expositions in historical process, which was first took place in England in 1851, how the steel materials are used since Crystal Palace, which is the symbol of the First World Exposition, until today, are investigated.