This article investigates the temperature distribution over the thickness of the elements when welding tee joints with fillet welds. The temperature was measured by thermocouples with corresponding readings recorded on an oscilloscope. At the same time 6 thermocouples were recorded, which made it possible to trace the entire process of temperature change (the process of heating and cooling) and to determine the maximum temperature at the points under study. The experimental results were compared with the calculated temperature values. Comparison of the experimental data with the calculation results showed quite satisfactory agreement what makes it possible to use the theory of heat propagation in welding by N.N. Rykalin to the design of temperature in tee joints when welding fillet welds.

Keywords: residual welding stresses, temperature distribution during welding, thermocouples, T-joint with fillet welds, temperature distribution through the thickness of the element, “small” thicknesses, “large” thicknesses

This article discusses the features of the pitched roof for typical residential buildings. The design of gable space-roof structures is carried out within the framework of the application of the constructive system of coverage of panel residential buildings with longitudinal load-bearing walls. The formation of the structural form of the cover is solved by the sequential development of the modular system of blocks. The modular system is based on the regular block, which consists of a double-slope deck of bent sheet profiles, fused by folded joints, and a supporting spatial-rod load-bearing system. The design and calculation provisions for the modular unit are presented, taking into account the peculiarities of the layout of the structural form of the cover. The main findings on the use of double-slope roofs are given. The conclusion gives the prospects for the development of the double-slope roofs with the deck of the bent sheet thin-walled profiles. The use of lightweight structure of the roof allows to expand the possibilities of designing the reconstruction of residential buildings of typical construction with a shallow sloping roof without a significant increase in the load on the foundation. The structural solution makes it possible to implement at the construction site an enlarged assembly of the gable roofing, minimizing the use of multiple hand labor and increasing the safety of construction work.

Keywords: configuration of the gable roof, modular block, bent-sheet thin-walled profile, folding seam assembly, spatial rod system

Engineering calculation and estimation of the stress-strain state of the bearing elements of the superstructure is carried out. The analysis and collection of information on traffic in 2019. The history of the loading bridge real load on the basis of mathematical model (presented in the form of a geometric progression) – showing an annual increase of intensity of traffic on bridge construction. The total fatigue damage of the bearing elements of the superstructure according to the Palmgren - miner hypothesis and the period of exhaustion of the operational resource of the bridge structure are determined.

Keywords: load capacity, loading, history of loading, residual resource, the miner's summation of fatigue durability