The article describes application of precast, cast-in-situ and composite structures on construction site. Importance of Analysis of Russian (SP) and European design standards (EuroCodes) is underlined. Historical review of Russian codes for composite reinforced concrete structures is given. Methods of composite structures calculating according to current Russian Codes are given. Ultimate and service limits states are listed for describing structures. Advantages and disadvantages of cast-in-situ, prefabricated and complex technologies are discussed. Comparison of prefabricated, monolithic and complex technologies is given on example of intermediate floor slab. Examples of sections of prefabricated reinforced concrete composite structures are summarized. Composite structures detailing is given on example of real project of Parking building of Okhta-Mall shopping and entertainment center, Saint-Petersburg. Constructive solutions are presented that increase the bearing capacity and resistance to progressive collapse of structures. Manufacturing photos of prefabricated ready-made reinforced concrete slabs as a part of future composite slab are presented. Examples of detail drawings for composite concrete slabs, executed in accordance to Eurocode, are given. Suggestions for improving the existing Code of Practice are given. Reference to similar scientific papers is presented related to composite reinforced concrete elements. Article is developed with financial and technical information support of AFRY Oy Finland.