During individual construction in seismic areas, the designer often has to solve problems that violate certain requirements of regulatory documentation on the configuration and number of storeys of the building, architectural and planning solutions of its internal and underground space. In this case, it is necessary to develop special technical conditions (STC) with compensating measures for these deviations, ensuring high seismic resistance of construction objects. The article considers the possibility of using the technology of plastic deformation of the bearing structural elements of the building to ensure the seismic resistance of the object, and also offers a method for assessing the degree of plastic work of the structure.
As a result of the release of GOST 34028-2016 «Reinforcing bars for reinforced concrete structures» the manufacturability of new kinds of reinforcing bars, taking into account the needs of different areas of construction were increased. The materials of the present study prove the ability of reinforcement with a multi-row (six-row and screw four-row) arrangement of transverse ribs on its surface to maintain adhesion with concrete even at the stage of exceeding the limit values of deformation. This factor, as well as high endurance at cyclic dynamic effects, possibility of connection using couplings of four-row screw reinforcing bars and anchoring it with nuts, expands the possibilities of using the new valves not only in earthquake engineering, but also in nuclear power, transport and other types of construction. The new reinforcing bars of domestic production are able to gain a leading position not only in the domestic but also in foreign construction markets.
To meet the safety requirements in the design of reinforced concrete structures in seismically hazardous areas, it is important to ensure the dissipation of seismic input energy in structures when their progressive collapse is included. For this purpose, plastic deformation of the calculated sections of reinforced concrete structures with the opening of cracks in reinforced concrete is allowed much higher than the maximum permissible. These conditions can be met, when a number of design requirements are met. These requirements are reflected in regulatory documents for the design and manufacture of building structures and materials, including reinforcing bar. The article present a comparative analysis of the requirements that have recently been published at normative technical documents, namely the SP 14.13330 and the standard of the organization «Earthquake engineering», and also requirements of the state standard «Reinforcing bar for reinforced concrete design» in relation to design for seismically dangerous areas are stated and explained. So, as one of the possible options, the authors consider the advantages of using screw fittings, for connecting rods with screw fittings it is recommended to replace welded joints with screw couplings.