The application experience of non-metallic composite materials is quite wide in foreign countries, as well as systematized and assembled into a single database. In Russia, since the necessary computing resources have become more relevant and accessible for design organizations, independent researchers, and graduate students of higher educational institutions, this question resurfaced only in the last decade. As well as benefits, non-metallic composite reinforcement has its disadvantages, which prevent it from wide usage in structures, including a relatively low elastic module, as well as the inability to bend during installation. To improve the reinforced structures with stressed reinforcement calculation and possible prestressing force loss prediction, the finite element model production has been discussed. This model would allow us to evaluate the damaging shear stresses in the reinforcement region. The bracing formation process in the scope of this model was presented in this article, with the purpose of simulation the contact layer stress-strain state between reinforcement and concrete. The calculation is performed in a linear setting. Model development of a T-section decking component reinforced with a composite reinforcement beam produced via LIRA SAPR software. Exert a force on shank ends that is equivalent to the clamping force when the prestressed reinforcement is released. The authors proposed a selection option of the junction stiffness by stem contact with the anchoring field. The stiffness is assumed to be constant along the entire length of the contact layer. Elastic coefficient variation of the contact layer was performed here. The contact layer is highlighted conditionally as a separate material. A model for three types of materials was discussed. The shear stresses patterns in the contact element region were obtained. The patterns of abutting end reinforcement bars motion are obtained. To create a span element with a pre-tensioned reinforcement, a full-scale experiment was performed, as well as reinforcement abatement. Upon abatement, the retraction was recorded. The retraction results of the shank ends were measured, the values of which are comparable to the numerical motion.

Permafrost soils are common for extensive areas of our country and when building engineering structures in such conditions, it is necessary to take into account the factor supporting subbase on the permafrost soil, which may initially have high stress-related characteristics. But the permafrost degradation phenomenon with frost retreat no less common. It can be happening both for natural reasons due to global warming, and for man-made reasons, when interference during construction and further the structure itself initiates subsoil frost retreat. For the most part, permafrost soils lose their strength and elastic properties during the frost retreat, turning into an almost liquid consistency, which entails the failure of the supports in the bearing capability and position stability. With the road network development and the bridge’s construction in the northern regions at the end of the 60s — early 70s of the XX century, the first principle of the design was widely applied. It was for use and maintenance of the subsoil in a frozen state, which means not require a deep foundation required. However, after 20 — 30 years of operation, cases of unexpected and significant bridge piers sagging began to be noted, as it turned out, was the result of permafrost soils frost retreat to the entire depth of the foundation. It was also noted that in some cases the bridge piers sagging is preceded by its frost boil phenomena, which appear shortly before piers sinking and almost complete failure. In this article case of an unexpected bridge piers failure examined on a specific bridge. After 30 years of proper functioning, pierces received such significant sagging, so in just three years that got to the point when it’s not only traffic safety but the cohesiveness of the entire structure. And before that, a frost boil was noted at some of the bridge pierce. The purpose of this study is to analyze the frost boil mechanism and sagging of the bridge pierce’ foundations due to the progressive permafrost degradation and to suggest restoring and maintaining ways for pierces’ operation capacity. Overall, the reasons and principles of permafrost subbase degradation were analyzed in this paper. through calculations using a specific example, significant sagging and bridge pierce bearing capability loss observations were justified and substantiated the effectiveness of the proposed in this article structural reinforcement measures.

The paper presents the research and engineering experience in the calculation and design of concrete structural elements, reinforced by fiberglass rods. The construction of a concrete beam reinforced by fiberglass rods is presented. Research in preserving prestressing forces in a beam subjected to weathering for about 30 years is considered. The creation and analysis of concrete-steel connection model is presented using LIRA-SAPR software. This is a work of scholarly interest.