Currently, Industrial Enterprises are Made Steel Metal Structures, The Basis of Which Are Light Alloys and Aluminum. Materials for Metal Structures are Sheet and Profiled Metals. Light -type Metal Structures Began to Be Actively Ussed in the Construction from Only The Twentieta Century. Before that, Metal Structures Were Based on An Alloy of Cast Iron. For Example, During the Construction of the. ISAAC CATHEDRAL. Petersburg, Elements of Just Such a Performance Were used.