The article presents the technical and economic indicators previously proposed solutions truss reinforced concrete beams with combined prestressing. Reducing consumption of concrete and steel in comparison with typical. This reduces the weight of the beams and money. Significant economic effect is achieved by the use of roof beams t profile with a shelf in the stretched area. This effect is achieved due to a significant reduction of the structural height of the coating (beams and slabs). By reducing the volume of the brick walls of the building, which is based on the overlap, the cost of masonry with single-span building, as noted above, reduced by 33% in comparison with a standard solution.

Keywords: truss reinforced concrete beam, combo-prestressing of prestressed reinforcement

The article proposes an analytical description of the deformation diagrams of concrete and pre-stressed high-strength reinforcing steel used for development of calculation methods of reinforced concrete elements with combined prestressing. In the developed method of calculation is the rectangular stress distribution in the compressed area of the flexible reinforced concrete element is adopted actual curved that in the case where the relative height of the compressed zone of the cross section close to the boundary ξ ξR, significantly clarifies the calculation. With this purpose, the curve σв – EV, obtained at a Central compression of the concrete prisms.

Keywords: stress-strain diagram of concrete, stress-strain diagram of steel