Methods of calculation and design of building structures are considered that make it possible to provide trouble-free operation on time during the service life, and hence the level of reliability. According to the reliability indicator, the following scheme for standardizing the reliability of designed building structures is linked to the assessment of quality indicators of constructed structures. Indicators of design quality that are not related to strength, guaranteed with a given probability of failure-free operation, are introduced: geometric dimensions, modular deformation and elasticity, taking into account the properties of variability and technology. The appropriate safety factors are determined, ensuring mandatory protection of failure-free operation. A scheme for calculating design structures with the required level of reliability during the design, construction and operation of structures is being developed.

Keywords: method of calculation of structures, reliability, safety factor, strength class, reliability index, improvement of calculation of structures

One of the methods for strengthening connections in steel trusses made of cold-formed welded profiles is the use of plate overlays. This article presents their influence on increasing the strength of connections according to the criterion of bearing capacity under compression. The investigations were conducted using the component finite element method. The obtained dependencies of the increase in bearing capacity are demonstrated based on the width and angle of the brace connection. An engineering methodology has been developed to assess the strength of the reinforced connection under compression, utilizing a traditional formula from Russian design standards with the substitution of the thickness of the chord by the equivalent thickness.

Keywords: : reinforcement, connections, cold-formed profiles, bearing capacity, compression