A comprehensive methodology for experimental research of nodal connections under static-dynamic loading has been developed. A cruciform model of a frame joint in a multi-story building was chosen as the design scheme. For testing, it is proposed to use a specially developed non-standard drop-weight type setup, integrated into a hydraulic system. This system allows for the simulation of both service and emergency impacts, including the additional dynamic loading of the joint under special conditions. The experimental studies yielded data on concrete and reinforcement deformations, crack formation parameters, and failure characteristics for the prototype frame joints. This was achieved using modern measurement systems, including strain gauge rosettes and high-speed video recording. The obtained experimental data on the static and dynamic resistance of the frame system joints will allow for the verification of analytical models, enhance the current understanding of the behavior of joints made from a new type of concrete, and validate both improved and newly developed analytical models for reinforced concrete building frames.

The article presents an algorithm for the analysis of buildings and structures modeled as systems with a finite number of degrees of freedom, whose structural model includes a dynamic vibration damper intended to limit vibration levels. The algorithm is constructed using a method based on the numerical solution of systems of nonlinear integral equations, to which the systems of nonlinear differential equations of motion for finite-degree-of-freedom systems are reduced. The numerical procedure is implemented using a time-stepping method with iterative refinement of the nonlinear terms.

As a result, computational relationships were obtained that make it possible to analyze buildings equipped with linear and nonlinear vibration dampers, including dampers with additional links that are activated when specified displacements are reached. Calculations were performed for a building with both linear and nonlinear vibration dampers, demonstrating the effectiveness of various types of dampers within the building vibration protection system, and an analysis of the results was carried out.

The relevance of this work is driven by the increasing intensity of impacts from rail and road transport on reinforced concrete structures of transport facilities, necessitating stricter requirements for the resistance of these structures to fatigue under repeated loads. It is shown that laboratory assessment of concrete fatigue strength is regulated by separate standards and is based on establishing the relationship between the ultimate load level and the number of cycles to failure. However, the results of such tests are not directly integrated into the calculation methods used in the design of reinforced concrete structures. Current standards, including SP 63.13330, lack requirements that explicitly link concrete grade to the permissible load level in fatigue calculations. This work establishes a relationship between the design resistance of concrete and the load level under cyclic loads, enabling a comparison of regulatory calculation assumptions with experimental data on concrete fatigue strength. It has been revealed that experimental and analytical studies of the fatigue life of lightweight high-strength concrete are currently virtually nonexistent, preventing the valid application of current regulatory requirements for their use in structures operating under cyclic loading. The combination of these factors determines the relevance of this study.

The analytical method for calculating three-layer shallow shells with a lightweight core based on the Navier solution is presented. Shells with a rectangular contour are considered. Based on the adopted kinematic hypotheses and the equations of three-dimensional elasticity theory, a system of resolving differential equations for the deflection, stress, and averaged displacement functions is derived. To solve this system, a method for an exact analytical solution is proposed by expanding the unknown functions and the load in double trigonometric series, similar to the classical Navier approach. The method is tested using an elliptical paraboloid-shaped shell under a uniform load. High convergence of the series is demonstrated even for a small number of terms. The results of the analytical calculation demonstrated good agreement with the data obtained numerically using the finite difference method. Using the developed method, a parametric analysis of the filler shear modulus effect on the stress-strain state of the structure was carried out. It has been established that a decrease in the shear modulus (during creep) leads to a redistribution of internal forces: transverse forces and bending moments decrease, but longitudinal and shear forces increase. As a result, equivalent stresses in the upper skin can increase by up to 19%, which must be taken into account to ensure the durability of the structure. The proposed method is an effective tool for analyzing the stress-strain state of sandwich shells.

The article addresses the problem of selecting geometric parameters for a driven pile foundation — length 𝐿 and cross-section size 𝑠 — given a required bearing capacity 𝐹_{𝑑,𝑟𝑒𝑞} . A formulation is proposed that directly aligns with SP 24.13330.2021 requirements, including consideration of raft depth and local technological constraints. An engineering algorithm based on discrete monotonic search over length 𝐿with step 𝛥𝐿, combined with ranking alternative sections 𝑠, has been developed to ensure that the condition 𝐹_𝑑 (𝐿, 𝑠) ⩾ 𝐹_{𝑑,𝑟𝑒𝑞 is} achieved with controlled target margin 𝜂. Rational solutions are selected using multi-objective criteria (cost/technology compliance), while intermediate verifications are traceable, facilitating calculation analysis. It is demonstrated that the algorithm supports the analysis of geotechnical data (soil parameters, variations in 𝜂, sensitivity to 𝛥𝐿), as well as allows further acceleration through ML surrogates or Bayesian robust optimization procedures. The presented methodology is aimed at implementation into design practice and ensures reproducible, economically justified selection of 𝐿 and 𝑠 from “required bearing capacity to solution.” Detailed convergence analysis, sensitivity studies, and comparative tests with alternative procedures will be provided in subsequent publications.

The influence of spatially non-uniform reinforcement corrosion on the performance and survivability of flexural reinforced concrete elements is investigated. The distribution of the actual cross-sectional areas of reinforcing bars after corrosion exposure is studied experimentally. The data are obtained using three-dimensional scanning followed by statistical analysis. To quantify local section weakening, a coefficient of corrosion non-uniformity is introduced, and a probabilistic distribution model is proposed, allowing the design minimum cross-section of corroded reinforcement to be determined. It is shown that using the average corrosion level leads to an overestimation of the load-bearing capacity of flexural reinforced concrete elements. Accounting for the localized nature of corrosion changes the degradation path of structural performance and leads to a reduction in survivability. The obtained relationships make it possible to move from evaluating residual strength at a single point in time to an integral assessment of survivability, reflecting the degree to which the structure retains its performance during damage accumulation.

The paper considers the problem of probabilistic assessment of the reliability of truss metal structures, taking into account corrosion wear. Corrosion wear is represented as the accumulation of damage, and the corrosion state of an element is considered from the undamaged level to the limit state corresponding to failure (loss of stability of a rod element of a truss structure). Degradation is described by a sequence of probabilistic transitions between states within a continuous-time Markov model. The time dependencies of the transition probabilities are reconstructed from experimental observations and approximated by parametric dependencies, which allows us to form a consistent time transition matrix for the entire state scale. After the model is calibrated, Monte Carlo simulations are performed for individual rod elements of the truss structure and for the truss system as a whole, taking into account the varying structural significance of the elements. This allows us to obtain reliability estimates and damage accumulation characteristics, which can be used for engineering diagnostics and repair decision-making.

An ideology is proposed for discussion, on the basis of which the development of architectural ecology can be more successful. The main focus is on achieving emotional and psychological comfort based on knowledge of patterns that cause discomfort. The directions based on the methods of intellectual creativity are being investigated, including new data in the science of "Human Cognition": directing, ophthalmology, biolocation, etc. In these scientific areas, it is noted that there are common goals and similarity of methods for creating a positive emotional and psychological state of people in architectural activities. In this direction, options for spatial planning solutions are being considered to reduce the intensity of human activity on the earth's surface into an "aboveground zone" and integrate multilevel intersections with urban objects, involving related scientific fields such as psychology and human cognition through architecture.

This article examines the effect of urease bioadditives on the crack resistance and shrinkage deformation of concrete. The study involved introducing the urease-producing microorganisms Sporosarcina pasteurii and Sporosarcina ureae into the concrete mix. The properties of the concrete mixes were assessed for workability and flowability. The cut surfaces of modified concrete samples were examined, and the pore space was examined using optical and scanning electron microscopes to identify the formation of a new phase in the pore space. It was found that the use of urease additives reduces concrete shrinkage and improves its crack resistance, increases flexural strength by more than 30%, and increases the elastic modulus of concrete by 1.5 times. This is achieved through the formation of calcium carbonate as a result of bacterial activity, which strengthens the structure of the material. The results obtained open up prospects for the development of environmentally friendly and effective methods for improving the properties of building materials