Prediction of the Remaining Service Life of Reinforced Concrete Structures

The main indicators of durability, which characterize the time of operation of the structure before the onset of an emergency condition, are the total service life and the remaining service life, the determination of which allows a more reasonable approach to the issue of planning current or major repairs in the building. The most common engineering techniques that allow predicting the remaining service life for reinforced concrete structures are considered: according to standard terms and analogous objects, according to external signs, based on changes in reserve coefficients and strength criteria. Their modifications are given for a number of techniques. Based on the results of the analysis of the methods, their main advantages and disadvantages were established. As a proposal to improve the existing approaches, a methodology is proposed in which the interval between visual examinations is taken for the remaining period of operation

Improving the Regulatory Framework for the Standardization of Precast Concrete Structures

The article considers the structure of regulatory documents for precast reinforced concrete structures. The directions of development of the regulatory framework by updating and developing standards (GOST and GOST R) for certain types of precast reinforced concrete structures are given. It is noted that the purpose of the development and updating of standards is to establish current technical requirements for precast reinforced concrete structures, due to changes in the regulatory framework for the design of reinforced concrete structures, in particular in SP 63.13330.2018 "SNiP 52-01-2003 Concrete and reinforced concrete structures. The main provisions", and the improvement of technological requirements. In recent years, JSC "Tsniipromzdaniy" has developed and updated more than 20 standards (GOST and GOST R) only by the Department of Structural Systems No. 1, in which a number of new provisions have been adjusted and developed based on the analysis of domestic and foreign regulatory framework, modern manufacturing and installation technologies. It is advisable to develop standards for individual structures taking into account the requirements given in the fundamental GOST 13015-2012 "Concrete and reinforced concrete products for construction. General technical requirements. Rules of acceptance, marking, transportation and storage". The structure of the standard standard for precast reinforced concrete structures is considered

Mechanical safety of reinforced concrete structures at all stages of the life cycle

Ensuring the mechanical safety of operated buildings at all stages of the life cycle is an urgent task. This is especially important when planning major repairs and reconstruction in buildings, as well as determining the period of safe operation from the moment of the survey, i.e. clarification of the remaining service life. The total service life at the design stage is set by the customer and the general designer in accordance with the recommendations of GOST 27751-2014 «Reliability for constructions and foundations. General principles». Mechanical safety and durability are ensured when calculating structures using the limit state method, assigning protection measures depending on the operating conditions, as well as complying with the requirements of SP 255.1325800.2016 «Buildings and structures. Operating rules. General Provisions». A method for preliminary assessment of the mechanical safety of buildings and their structures is proposed for consideration, which eliminates some of the shortcomings of existing methods for calculating the residual life by physical wear (damage) of building structures based on the results of a visual inspection, the basis of which is the dependence of the allowable safe operation period on the percentage of reduced bearing capacity. It is proposed to use the results of a visual inspection performed in accordance with GOST 31937-2011 «Buildings and constructions. Rules of inspection and monitoring of the technical condition»

Development of the Method for Calculation of Reinforced Concrete Structures on the Formation and Opening of Normal Cracks

This paper presents the history of the development of the method for calculating the crack resistance of reinforced concrete elements according to Soviet and modern design standards, which was based on the work of the Soviet and foreign scientists, such as: A.F. Loleit, V.I. Murashev, A.A. Gvozdev, S.A. Dmitriev, A. Clark, J. Monier and others. Also, the article discusses the currently updated calculation methods for the formation and opening of normal cracks according to domestic and foreign standards

V.G. Shukhov Radio Tower – history, current state and prospects

The Moscow Radio Tower was erected in 1922 and is an object of cultural heritage of the Russian Federation, a monument of architecture and engineering. The tower consists of six sections, each about 25 m high. The frame of the sections is a hyperboloid structure, the principle of which was developed by V.G. Shukhov at the end of the XIX century and is still used worldwide in the design and construction of tower structures. The technical inspections carried out confirmed the emergency condition of the Moscow Radio Tower. The results of laboratory studies have shown the heterogeneity of the strength and chemical characteristics of steel, its non-weldability and cold breakage. Analysis of the development of defects over time revealed that the condition of the tower is deteriorating. The performed emergency measures exclude a sudden collapse, but do not eliminate the emergency condition of metal structures. Taking into account the need for urgent restoration work with the elimination of the emergency condition of the tower, the development of project documentation began in 2023. The design assignment provides for the maximum possible preservation of the original elements. When carrying out the project, it should be taken into account that it is impossible to remove individual elements without completely unloading the entire structure. All elements of the tower that have mechanical or corrosion damage that reduces the cross-section even in certain sections are not repairable and must be replaced with new ones. When reusing existing elements, it will be technically difficult to carry out the reverse assembly with the necessary accuracy

Development of a Stress Sensor for Solids

The paper presents the results of experimental design of a cortex of the embedded stress sensor, which allows to determine stresses in the cross-section of large-scale laboratory monolithic structures made on the basis of mineral and polymer binders (concrete, gypsum, etc.). The objectives of the design were to develop a constructive solution of the stress sensor housing based on strain gauges, which has small dimensions, low manufacturing cost, as well as high resolution and stability of readings over the entire sensitivity area (stress up to 400 kgf/cm2).The stress sensor allows to determine the stress in laboratory structures with high accuracy, without significantly affecting the stress-strain state of the section at different stages of operation of the structural element

Methodology for the assessment of PV capacity over a city region using low-resolution LiDAR data and application to the City of Leeds (UK)

An assessment of roof-mounted PV capacity over a local region can be accurately calculated by established roof segmentation algorithms using high-resolution light detection and ranging (LiDAR) datasets. However, over larger city regions often only low-resolution LiDAR data is available where such algorithms prove unreliable for small rooftops. A methodology optimised for low-resolution LiDAR datasets is presented, where small and large buildings are considered separately. The roof segmentation algorithm for small buildings, which are typically residential properties, assigns a roof profile to each building from a catalogue of common profiles after identifying LiDAR points within the building footprint. Large buildings, such as warehouses, offer a more diverse range of roof profiles but geometric features are generally large, so a direct approach is taken to segmentation where each LiDAR point within the building footprint contributes a separate roof segment. The methodology is demonstrated by application to the city region of Leeds, UK. Validation by comparison to aerial photography indicates that the assignment of an appropriate roof profile to a small building is correct in 81% of cases

Estimating the impact of azimuth-angle variations on photovoltaic annual energy production

The performance of a photovoltaic (PV) installation is affected by its tilt and azimuth angles, because these parameters change the amount of solar energy absorbed by the surface of the PV modules. Therefore, this paper demonstrates the impact of the azimuth angle on the energy production of PV installations. Two different PV sites were studied, where the first comprises PV systems installed at –13°, –4°, +12° and +21° azimuth angles in different geographical locations, whereas the second PV site included adjacent PV systems installed at –87°, –32°, +2° and +17° azimuth angles. All the investigated PV sites were located in Huddersfield, UK. In summary, the results indicate that PV systems installed between –4° and +2° presented the maximum energy production over the last 4 years, while the worst energy generation were observed for the PV system installed at an azimuth angle of –87°. Finally, the probability projections for all observed azimuth angles datasets have been assessed. Since PV systems are affected by various environmental conditions such as fluctuations in the wind, humidity, solar irradiance and ambient temperature, ultimately, these factors would affect the annual energy generation of the PV installations. For that reason, we have analysed the disparities and the probability of the annual energy production for multiple PV systems installed at different azimuth angles ranging from –90° to +90° degrees, and affected by different environmental conditions. These analyses are based on the cumulative density function modelling technique as well as the normal distribution function

Association between Incidental Pelvic Inflammation and Aggressive Prostate Cancer

The impact of pelvic inflammation on prostate cancer (PCa) biology and aggressive phenotype has never been studied. Our study objective was to evaluate the role of pelvic inflammation on PCa aggressiveness and its association with clinical outcomes in patients following radical prostatectomy (RP). This study has been conducted on a retrospective single-institutional consecutive cohort of 2278 patients who underwent robot-assisted laparoscopic prostatectomy (RALP) between 01/2013 and 10/2019. Data from 2085 patients were analyzed to study the association between pelvic inflammation and adverse pathology (AP), defined as Gleason Grade Group (GGG) > 2 and ≥ pT3 stage, at resection. In a subset of 1997 patients, the association between pelvic inflammation and biochemical recurrence (BCR) was studied. Alteration in tumor transcriptome and inflammatory markers in patients with and without pelvic inflammation were studied using microarray analysis, immunohistochemistry, and culture supernatants derived from inflamed sites used in functional assays. Changes in blood inflammatory markers in the study cohort were analyzed by O-link. In univariate analyses, pelvic inflammation emerged as a significant predictor of AP. Multivariate cox proportional-hazards regression analyses showed that high pelvic inflammation with pT3 stage and positive surgical margins significantly affected the time to BCR (p ≤ 0.05). PCa patients with high inflammation had elevated levels of pro-inflammatory cytokines in their tissues and in blood. Genes involved in epithelial-to-mesenchymal transition (EMT) and DNA damage response were upregulated in patients with pelvic inflammation. Attenuation of STAT and IL-6 signaling decreased tumor driving properties of conditioned medium from inflamed sites. Pelvic inflammation exacerbates the progression of prostate cancer and drives an aggressive phenotype.</p