The article discusses the method for calculating beams with corrugated walls as three-layer structures of equivalent rigidity. The derivation of resolving equations for a one-dimensional finite element of a three-layer beam is given. A hypothesis is introduced that the shelves fully perceive normal stresses, and the wall only works on shear. When obtaining the basic equations, forced deformations are taken into account, which may include creep deformations, temperature deformations, shrinkage deformations, etc. The solution of the test problem for a beam hinged at the ends under the action of a load uniformly distributed over the length is presented. To control the reliability of the results, a finite element analysis was performed in a three-dimensional formulation in the LIRA software package. Shelves of the beam are modeled by flat triangular shell finite elements, and the wall is modeled by rectangular shell FE.

Keywords: corrugated wall beam, three-layer beam, finite element method, equivalent rigidity, stress-strain state

There is the analysis of energy-efficient technologies in the construction of the specific heat in the building. The definitions of the concepts of energy efficiency, energy saving, "smart home", energy-saving devices are given. Highlighted the causes of irrational consumption of thermal energy and describes a strategy for energy efficiency in construction.

Keywords: energy conservation, energy efficiency, energy saving devices, "smart house", strategy for energy efficiency.

The analysis of the energy-efficient constructive systems in construction, energy-saving engineering systems are held. Examples of the main methods of thermal insulation of external walls are given. A method of superstructure attic floors used in the reconstruction of buildings and structures is described. Identify possible solutions of the problem of energy efficiency.

Keywords: energy efficiency, energy conservation, structural systems, thermal efficiency, reconstruction.