Building Structures Research Articles

Characteristics of Mould Growth in Pine and Spruce Sapwood and Heartwood under Fluctuating Humidity

The importance of maintaining a healthy indoor climate has recently increased, as has the durability of building structures, and for this issue, we need to predict mould growth. To prepare this model under real conditions is challenging, and this work aimed to contribute data to this model. This article presents the findings of a laboratory study investigating the effects of fluctuations in the relative humidity and temperature conditions on mould growth on pine and spruce. The study compared the results to a previous steady-state experiment, demonstrating that fluctuations in relative humidity and temperature prolonged the onset of mould growth. The mould growth observed depended on the type of wood with pine or spruce wood exhibiting different growth patterns compared to heartwood or sapwood. In sapwood, mould growth was found to be almost independent of the direction of the fiber. The first microscopic indications of mould growth on pine sapwood were observed around day 76, with the first macroscopic indications observed around day 90. On the contrary, spruce sapwood demonstrated a limit for mould growth. The mould growth was only visible under the microscope with the first indications observed between the 72nd and 80th day. Furthermore, heartwood was found to be unsuitable for mould growth under fluctuating conditions.

Experimental investigation on the compression-bending performance of rubberized concrete columns confined by galvanized corrugated steel tubes

In the construction of building structures, numerous components simultaneously experience axial pressure and lateral bending moments. This concurrent influence plays a pivotal role in structural design considerations. This paper presents an experimental investigation of the compression-bending performance of rubberized concrete-filled corrugated steel tubes (RuCFCST). Twenty-two specimens were tested to evaluate the effect of eccentricity, length-diameter ratio, and confinement factor on the failure mode, load-displacement response, stiffness, compression-bending capacity, and ductility of the columns. The study also conducted a stress analysis on the corrugated steel tube to understand its confinement effect on the core rubberized concrete. The results demonstrate that the confinement factor emerges as a pivotal and sensitive parameter that impacts the compression-bending bearing capacity of RuCFCST columns. The study further elucidated the non-uniform confinement and failure mechanisms of the RuCFCST column, and subsequently assessed the applicability of the specimen's compression-bending bearing capacity as calculated by current specifications. The proposed RuCFCST columns offer new insights and serve as a reference for developing composite member systems with large hoop stiffness, small wall thickness, and environmental sustainability.

FEATURES OF WASHING WATER-SOLUBLE PHOSPHORUS-AMMONIUM SALTS OF FIREPROOF WOOD COATING

The article analyzes fire-resistant materials for wooden building structures and establishes the need to develop reliable methods of researching the process of washing out flame retardants from the surface of the building structure, which are necessary for the creation of new types of fire-resistant materials. Therefore, there is a need to determine the conditions for the formation of a barrier for leaching and to establish a mechanism for inhibiting the transfer of moisture to the material. In this regard, a mathematical model of flame retardant leaching has been developed, when a polymer shell made of organic material is used as a coating, which allows evaluating the effectiveness of the polymer shell based on the amount of flame retardant washed out. According to experimental data and theoretical dependences, the dynamics of release of flame retardants from the fire-resistant layer of the coating, which does not exceed 1.0%, is calculated, and accordingly provides fire protection of wood. The results of determining the loss of mass of the sample during exposure to water indicate an ambiguous effect of the nature of the protection on leaching. In particular, this assumes the availability of data sufficient for qualitatively carrying out the process of inhibiting moisture diffusion and identifying, on its basis, the moment in time when the decline in coating efficiency begins. Experimental studies have confirmed that a sample of fire-resistant wood after exposure to water for 30 days withstood the influence of heat flow. In particular, the loss of wood mass after temperature exposure was less than 6%, and the temperature of flue gases did not exceed 185 ºС. Thus, there are reasons to assert the possibility of targeted regulation of wood fire protection processes through the use of polymer coatings capable of forming a protective layer on the surface of the fire retardant material, which inhibits the rate of flame retardant leaching.

APPLICATION OF BASIC PRINCIPLES OF BUILDINGS AND STRUCTURES PROTECTION IN THE CONDITIONS OF POSSIBLE SHELLINGS BY THE EXAMPLE OF REINFORCED CONCRETE LONG-SPAN TRUSS

For developing recommendations for the protection of buildings and structures under the threat of potential shelling, a summary and analysis of the scientific and technical work conducted by the SRIBP has been carried out, taking into account the principles and guidelines outlined in current regulations. The proposed recommendations can be used to develop national building codes and standards for the protection of building objects from potential shelling. Three groups of objects have been identified based on the risk of shelling, depending on the level of risk: highest risk (Group 1), increased risk (Group 2), and moderate risk (Group 3). The proposed approaches (with their advantages and disadvantages) for protecting construction objects from shelling include: direct calculation for shelling impacts, considering the most likely and unfavorable scenarios; application of direct structural requirements that will most likely ensure the overall survivability of the object or structure after being hit during shelling; general reserve of load-bearing capacity, usually by increasing reliability coefficients. Their application has been considered depending on the risk group and the responsibility classes of the construction object. For Group 1, a comprehensive set of all the mentioned measures is applied; for Group 2, mandatory minimum structural requirements; for Group 3, there are no specific requirements. As an example, a large-span roof structure of an industrial building from Group 1, which is subject to a damage scenario from a projectile impact, has been considered. During the summary of inspection and research results conducted by SRIBP, statistical data on types of large-span reinforced concrete roof structures of industrial buildings have been collected. It has been established that 24-meter-long reinforced concrete trusses are significantly widespread, and they have been selected for consideration as an example of applying the proposed protection approaches. Based on the summary of inspection results, a damage scenario for the truss has been defined, which involves the complete or partial loss of one of the elements (diagonal and vertical web members) due to a projectile impact on the roof structure. Approaches to developing protection for load-bearing structures, adapted for the 24-meter reinforced concrete truss in question, which has sustained element loss after impact, are presented.

An overview of the constructions of conveyors for moving bulk materials, comparison and study of their parameters

The production of concrete mixes, along with their use in the production of building materials and structures, is one of the key processes in the construction industry during the construction, restoration and repair of buildings and structures. Because of this, the need to create modern concrete mixing plants that will meet the requirements of minimum energy consumption and maximum productivity of concrete mixture production is an urgent task. Not only the main operations, which include the dosing of the components of the mixture and their mixing, but also the maintenance operations, namely operations that ensure the timely movement of the components of the concrete mixture from warehouses to the main technological equipment, affect the set rhythm of the concrete mixture production. Conveyors of various types and designs are used to move bulk materials, such as crushed stone and sand. For the rational selection of such equipment in accordance with the characteristics of the cargo to be transported, knowledge of the types of conveyors, their structures and parameters, understanding of operation issues and methods of parameter calculation are required. In addition, it is worth paying attention to the following parameters: maximum cargo transportation productivity, low energy consumption per unit of moved products, low metal content of the structure. The work reviewed the most common designs of conveyors used to move bulk materials in concrete mixing plants, analyzed the disadvantages and advantages of conveyors, as well as technical parameters. As a result, the predominant directions for the use of belt and plate conveyors at construction enterprises were determined. The advantages of belt conveyors, which contribute to their widespread distribution, are high productivity, simplicity of design, reliability, quiet operation, low specific power consumption. When choosing a conveyor, it is recommended to choose the equipment with the highest productivity and the lowest power of the drive motors, however, the performance should be clearly related to other technological equipment.

BUILDING AND CONSTRUCTION RECONSTRUCTION DESIGN

In order to create the necessary conditions for life and development of society, the production of various products are organized. The nomenclature and consumer qualities of the produced products are determined by the level of scientific and technical development, economic and social living conditions. For the production of products, houses and buildings are erected, which are equipped with certain means of production. The term of functioning of means of production is due to physical and moral wear and tear of machines and mechanisms. Buildings and structures in, which means production are located and function also age physically and morally, although this aging occurs slower than the means of production.Scientific and technical progress is currently characterized by a faster onset of wear and tear of the nomenclature of manufactured products. In addition, in connection with the changes taking place in society, the nomenclature of manufactured products replaced. The problem of retooling the functioning industry (replacing morally or physically outdated means of production, the emergence of need to produce new types of products) arose before humanity a long time ago.Under reconstruction - the production of works, which carried out according to single project:- with a change in volume-planning decisions;- replacement or strengthening of existing structures;- demolition of existing and construction of new structures related to the operation of technological equipment;- with the replacement of obsolete or physically worn equipment;- with mechanization, production automation, etc. When carrying out the reconstruction of the main production facility, as a rule, significant volumes of work are always performed on auxiliary and service facilities.Reconstruction also includes the construction of new workshops and facilities instead of those, which being liquidated, the further operation of which is deemed impractical due to technical and economic conditions. They can be erected both on free territories and on areas vacated as a result of the liquidation (demolition) of the object.Technical re-equipment is clear as the implementation of a set of measures in accordance with the technical development plan of the enterprise according to projects and estimates for individual objects and types of work (without expanding existing production areas) to raise the technical level of individual areas of production, aggregates, and installations to modern requirements by introducing new equipment and technology, mechanization and automation of production processes, modernization and replacement of obsolete or physically worn equipment with new, more productive ones.Sometimes technical rearmament considered as a type of reconstruction with a relatively small amount of construction and installation work. As it is not difficult to see from the given definitions, new construction and expansion are in fact new construction, while the difference between them is only in the conditions of execution of works. Expansion of construction is carried out in difficult (compressed) conditions. Technical rearmament, as it was emphasized, mainly involves the organization of the dismantling of the old and the installation of new equipment on the existing foundations.In the future, the main attention will be paid to the issues of actual reconstruction, namely:- organization of works related to the strengthening of existing building structures, their replacement with temporary transfer of loads;- replacement of beams and trusses in areas of the covering located in areas difficult to reach for installation cranes;- by increasing the pitch of the columns without disassembly.

CRACKING PATTERN ANALYSIS OF THE TURNING BAND METHOD (TBM) APPLICATION ON A SINGLE-REINFORCEMENT BAR CONCRETE BEAM MODELLING USING THE MAZARS DAMAGE

The development of crack patterns in reinforced concrete structures is a randomly stochastic process influenced by the heterogeneous nature of concrete materials, which impacts the sensitivity to damage and variability in mechanical properties. The numerical simulation of damage pattern appearance on the reinforced concrete for special building structures needs a realistic result, especially in terms of crack distribution. The Turning Band Method (TBM) serves as a tool for assessing the variability of concrete heterogeneity, functioning as an operator to generate a random variable for each specific field. In this study, the investigation of crack patterns in reinforced concrete structures involves using a simple concrete beam sample, measuring 10x10x50 cm3, with a single longitudinal reinforcement cast in the centre. This beam is subjected to an axial tensile loading, while the Mazar Damage Model is employed as the concrete behaviour law. Through the implementation of The Turning Band Method (TBM) and the variation of the random field parameters, distinct crack patterns are observed, not only the number but also the locations of cracks. The use of a smaller correlation length showed 2 cracks while the larger size had around 1 to 3 cracks, with the first crack localizations of each sample generally occurring in the middle surface, in which a noticeable contrast to non-TBM modelling just displays 1 crack. Furthermore, the resulting probability of cracks for ten random draws demonstrates similarity to experimental tests and numerical simulation of the previous study, both at global and local levels.

CIRCULARITY OF CONSTRUCTION MATERIALS IN ARCHITECTURAL HERITAGE PRESERVATION

Historic buildings represent an ensemble of related to architecture, materials and technology of the era in which they were built and contribute to the knowledge of contemporary ones. Materials resulting from the demolition of old buildings, such as: bricks, wood and vegetal materials, concrete, gravel, stone and sand, masonry and rubble, metals, plastic, glass, drywall, cardboard and paper, sanitary fixtures, fibers (asbestos, glass, steel, natural), can get a new life, becoming part of a new building, streets, facades or even a city, in the context of circular architecture and the Smart City concept. The case of the specimens based on polyurethane waste will be discussed in this paper, as partial substitutes in the composition of new building structures. Also, methods for characterization and testing of these new compositions will be discussed and evaluated.

Prediction and optimization framework of shear strength of reinforced concrete flanged shear wall based on machine learning and non-dominated sorting genetic algorithm-II

Reinforced concrete (RC) flanged shear wall has good lateral strength and stiffness, which has been widely used in building structures. Due to the coupling effect of many factors such as wall section shape, shear span ratio, so the shear performance evaluation of flanged wall is still very limited. This paper proposed a prediction framework for the shear capacity of RC flanged shear walls. A database containing 14 input variables, 1 output variable and 153 samples was constructed to evaluate the prediction accuracy of 11 existing design methods. The Pearson coefficient was used to preliminarily analyze the correlation between variables. The grid search was used to optimize the hyperparameters of 4 machine learning models, and six statistical indicators ( R2, R, RMSE, SD, MAE, and MAPE) were used to comprehensively compare the prediction results of the ML models to determine the best model. On this basis, SHapley Additive exPlanations (SHAP) was used to enhance the interpretability of the prediction models, and the mechanism of the input variables on the shear capacity was quantified. A graphical user interface (GUI) was proposed to guide the engineering design. A multi-objective model (MOO) was established to analyze the trade-off between shear performance and cost, thereby determining the best optimal scheme. The results show that the prediction accuracy of the ML models is better than the existing design methods. The XGB model has the best prediction performance, with R2, R, RMSE are 0.99, 0.99, 118.96, respectively. The SHAP method can effectively enhance the interpretability of the ML models, and tw, lw and f ′c are the key parameters affecting the shear capacity of the flanged shear wall.

Leveraging drone technology for enhanced thermal performance analysis in sustainable architecture: a case study of GBI-certified buildings in Malaysia

ABSTRACT In recent years, the realm of architecture has witnessed a significant transformation marked by a notable surge in focus on sustainable practices and energy efficiency. Architects and engineers increasingly recognize the innovative role of thermal efficiency in enhancing building performance. Such recognition emphasizes the critical importance of thermal analysis in understanding the thermal attributes of building materials and structures. Against this backdrop, this paper aims to bridge a current gap in architectural practices and sustainable design within the Malaysian context. It proposes a case study leveraging drone thermal mapping techniques on Green Building Index (GBI)-certified buildings. The study seeks to examine how architectural designs interact with environmental conditions and identify areas for improvement in sustainable building practices, particularly within Malaysia’s tropical climate context. The primary objective is to assess the effectiveness of drone technology in analysing building thermal performance and to explore how the findings can inform design interventions to enhance sustainability. To achieve this, a structured methodology comprising five procedural phases is employed in a case study focused on three iconic GBI-certified buildings in Putrajaya, namely Putrajaya Holdings Tower, Energy Commission Building, and Heriot-Watt University Malaysia. By integrating thermal imaging with visuospatial data and 3D modeling techniques, the study demonstrates the effectiveness of drones in analysing heat patterns, highlighting their potential as a tool for strategic design interventions. As an exploratory study, this paper serves as a catalyst for further investigations into the integration of drone technologies with architectural design, particularly within the context of tropical climates.

RESEARCH OF THE DESTRUCTION CONDITIONS OF GLAZING OF ENCLOSING STRUCTURES UNDER THE CONDITIONS OF THERMAL INFLUENCE OF FIRE

The article presents the main results of mathematical modelling of the destruction of glazing of enclosing building structures with translucent elements under fire conditions. The authors analyse literature data on calculating the fire resistance of enclosing building structures with glazing. The results show that improving methods for predicting the fire resistance of glazing is relevant. Mathematical models for the numerical study of the behaviour of glazing under the thermal influence of the standard fire temperature regime are substantiated. Mathematical models of the heat transfer process involve using a non-stationary differential equation of heat conduction with boundary conditions of the third kind, accounting for the convective and radiant heat exchange between the air in the room with the fire and the glazing. As a criterion for the destruction of glazing under the influence of fire, the authors establish the temperature resistance parameter, which is determined based on the mechanical characteristics of the glass. The article highlights the relevant data on the study of temperature indicators and the mechanism of glazing failure, using mathematical modelling with well-founded mathematical models. It obtains the results of the thermal calculation by applying the finite difference method for solving the non-stationary differential equation of thermal conductivity. The methodology for determining the time of glazing failure under the influence of the standard temperature regime of a fire using the calculation parameters obtained based on well-founded mathematical models is substantiated. An analysis of the adequacy of the obtained calculation data was carried out by comparing them with the results of experimental studies using statistical criteria. As a result of the analysis, the authors confirmed the validity of the calculation data. A complete factorial experiment was conducted based on well-founded mathematical models, which revealed the regularities of the dependence of the parameters of thermomechanical processes in single-layer glass on its structural characteristics. The revealed regularities have the form of linear regression dependences of the destruction time on the thickness of the glazing and the maximum length of the glass panel without bars. Using the regularities of the dependence of the parameters of thermomechanical processes in single-layer glazing on its structural characteristics, the authors constructed reference tables for evaluating the fire resistance of enclosing structures with glazing. The research obtained new scientific data on the study of the behaviour of glazing of enclosing building structures under the thermal influence of fire through mathematical modelling, which is the basis for improving the methods of calculating the fire resistance of enclosing structures with translucent elements. Keywords: enclosing building structures, glazing, fire resistance limit, calculation method, glass heat resistance.

ОБЕСПЕЧЕНИЕ ПОЖАРНОЙ БЕЗОПАСНОСТИ МНОГОЭТАЖНЫХ ЗДАНИЙ ИЗ ДЕРЕВЯННЫХ КОНСТРУКЦИЙ

Проведен обзор современного деревянного домостроения в России и за рубежом. Проанализированы результаты испытаний строительных материалов из древесины на пожарную опасность, а также деревянных строительных конструкций различных типов на огнестойкость и пожарную опасность как без огнезащиты, так и с огнезащитой различных видов. Разработаны предложения в нормативные документы. Намечены направления дополнительных исследований пожарной опасности зданий из деревянных конструкций. The paper considers the issues of ensuring fire safety of multi-storey buildings made of timber frame construction. At present, wooden houses in Russia are built mainly in the individual housing sector and account for 22% of the total construction volume, while industrial wooden houses account for no more than 3% of the wooden houses built annually. Abroad, wood is also widely used in the construction of buildings of various functional purposes: hotels, sports facilities, public and administrative buildings, low-rise and multi-storey buildings. The achievements of science, technology and engineering in the field of timber construction make it possible to design and build buildings of any type and purpose. Modern technology makes it possible to build high-rise timber houses. For example, high-strength composite materials based on wood are used for the construction of multi-storey buildings, in particular LVL beams and CLT panels. Numerous tests carried out at VNIIPO on load-bearing elements made of solid wood (frames, beams) and load-bearing structures made of CLT panels (walls, ceilings) have shown that they provide a significant limit of fire resistance in terms of load-bearing capacity. It is well known that wood is a highly flammable material (G4). This circumstance significantly complicates the use of various building structures in construction from the point of view of ensuring fire safety requirements, including in multi-storey buildings. A set of necessary engineering, technical and organisational measures to ensure fire safety has been developed for buildings with wooden structures up to 4 storeys. Based on the results of these tests, there have been developed proposals to include fire technical parameters in the regulatory requirements for buildings of classes I–III of fire resistance and structural fire hazard class C3. Further research is necessary to develop proposals for inclusion in the regulatory documents for fire safety of multi-storey residential and public buildings made of timber structures up to 28 metres in height.

Development of data-driven models to predict seismic drift response of RC wall structures: An application of deep neural networks

This research aimed to develop data-driven models using deep neural networks (DNNs) that can rapidly predict the seismic drift responses of reinforced concrete (RC) wall structures in building frame systems, aiming to overcome the challenges of costly seismic performance evaluation of building structures. A total of 46 RC wall structures ranging from four to 40 stories were analyzed and subjected to 1,000 ground motions including far-field, near-field-pulse, and near-field-no-pulse types. Two input sets were investigated initially. The first input set comprises peak ground acceleration (PGA), spectral accelerations at 1 s–6 s with 1-s intervals, and the first five natural periods of the wall structure. The second input set contains PGA and spectral accelerations at the first five natural periods of the wall structure. The DNN model developed based on the first input set demonstrated superior accuracy achieving an R2 value of 0.880, and slightly outperformed other reputable machine learning models. To enhance the applicability of the developed model, the ground motion type was incorporated as an additional variable to the first input set, which led to an R2 value of 0.869. Ultimately, two DNN models, one based on the first input set and the other considering the ground motion type, were proposed in this study. Finally, the two models were applied to quickly predict seismic drift responses of a new 24-story RC wall structure, and the predicted results were then utilized to efficiently construct the fragility function. The findings highlight the potential of DNNs as an efficient solution to address complex and costly challenges in the earthquake engineering domain.

Building detection in VHR remote sensing images using a novel dual attention residual-based U-Net (DAttResU-Net): An application to generating building change maps

In today's era, increasing access to very high-resolution remote sensing images (VHR-RSIs) has enhanced building detection and change assessment capabilities. These applications provide accurate urban mapping, facilitate effective land management, and support disaster assessment by delivering detailed insights into building structures and their temporal changes. This study uses a two-stage process to present a pioneering approach for generating precise building maps (BMs) and subsequent building change maps (BCMs) from VHR-RSIs. The primary question addressed by the research is how to enhance the U-Net architecture to improve its sensitivity to both high-level semantic features (HLSF) and low-level spatial features (LLSF) in the building detection task. For this purpose, in the initial stage of the method, a novel deep learning model called dual attention residual-based U-Net (DAttResU-Net) is introduced. This model incorporates two significant modifications to the conventional U-Net, enhancing its capacity to yield bi-temporal BMs. Firstly, each standard convolutional block (CB) is replaced with an optimized CB incorporating a channel-spatial attention module attuned to the building objects' crucial HLSF. Secondly, an additional attention module is integrated into the encoder-decoder path of the model, heightening the sensitivity of U-Net to vital LLSF of buildings while disregarding extraneous background spatial information during the fusion of HLSF and LLSF. In the subsequent stage, the bi-temporal BMs generated by the DAttResU-Net are subjected to a box-based class-object change detection methodology to produce accurate BCMs. The effectiveness of the proposed architecture is rigorously evaluated against state-of-the-art models in both BM and BCM generation contexts, utilizing the well-established WHU dataset for experimentation. The experimental results indicated that the DAttResU-Net model, boasting an average of PFN/ PFP value of 2.33/1.34 (%) surpasses the performance of the state-of-the-art models in generating bi-temporal BMs. Furthermore, the building change detection outcomes demonstrated the proficient role of the bi-temporal BMs predicted by the proposed model in leading to the most optimal BCMs, exhibiting average PFN/ PFP value of 2.63/8.93 (%), outperforming comparative networks. Finally, we concluded that the proposed DAttResU-Net architecture is a highly promising and applicable model for producing reliable BMs and BCMs.

Seismic performance investigation of new buckling-restrained steel plate for resilient rocking column foot joint

Seismic damage-controllable components and design approaches are crucial for achieving the seismic resilience and post-earthquake recovery of building structures. To improve the seismic resilience of reinforced concrete (RC) frame structures, this study proposed a novel assembled replaceable rocking column foot joint. The column foot joint is composed of a concrete foundation, short steel-tube concrete column in the center, and four new buckling-restrained steel plates (BRSPs) on the periphery. A detailed design method for the BRSPs was developed, and six BRSP specimens were designed with different core weakening forms and thicknesses. The specimens were cyclically tested and the failure mode and hysteresis behavior were examined. The test results confirmed that the proposed BRSPs exhibit satisfactory energy-dissipation capacity and achieve damage control. The refined numerical models were developed using ABAQUS and verified using the test results. Parametric analyses were conducted for the BRSPs to examine the influence of core plate thickness, gap size, and restraint plate thickness. A numerical analysis model of the column foot joint was established, and the influence of the axial compression ratio and BRSP bearing capacity on the seismic performance of the column foot was investigated. This study provides a reference for the construction of resilient RC frame structures.

Experimental research of corroded concrete beams with natural cooling after fire considering the bond deterioration

The residual bearing capacity after fire is of great significance for safety assessment and repair of building structures. To accurately evaluate the residual strength of corroded beam after natural cooling, this study investigated the residual bearing capacity of corroded beam considering the bond deterioration after fire exposure. First, the bond behavior and flexural-deformation capacity was conducted by pullout test and bending test after corrosion erosion and fire temperatures damage. The bond deterioration test shows that when the temperature rises above 200℃ and the corrosion level exceeds 4.3%, the bond strength decreases by 16.5%. At the temperature reaches 600℃ or the corrosion degree reaches 13.8%, the bond behavior damage exceeds 50%. The bending test indicates that corrosion and high temperature damage both decrease the bending bearing capacity of the beam, but the influence of high temperature damage on the residual bearing capacity is greater than that of corrosion. The bond property deterioration decreases the strain value of the tensile rebar during the bending process, and decreases the bending capacity of the beam. Finally, a bond-slip constitutive model suitable for corroded beams after fire is proposed, which is applied to the calculation of the ultimate moment of the beam. The modified value of beam bearing capacity considering bond deterioration has better collimation and higher safety margin. The bond-slip constitutive model and the modified calculation method of bending moment of beam are helpful to provide more accurate performance assessment of beam after the coupling effect of corrosion and fire damage.

Прогнозирование безопасной эксплуатации сооружений при вибрационных динамических воздействиях работающего промышленного оборудования и транспорта

Vibrational process excited in foundation soils by the operation of industrial equipment and transport traffic causes dynamic vibrations of building structures located in proximity to industrial enterprises and transport communications, which leads to additional dynamic force in building structures and violations of sanitary and hygienic norms when operating premises designed, inter alia, for working personnel and passenger services. This causes the reduction of operational characteristics of structures such as cracking and local destructions. A computational model «the source of dynamic load (equipment of industrial buildings, moving automotive and railroad transport) — medium of load transfer (soil) — building structure (receiver of impacts)» to assess such impacts has been proposed. When formating computational schemes, a simplifying assumption on the discretization of the computational scheme based on the Dalembert principle has been taken into account. Solution of the motion equations must be sought in the decomposition by appropriate vibration forms. Some simplifications of the computational model to obtain numeric engineering observable results have been substantiated. The simplified methodology to solve the problem of vibrations of bearing and enclosing structures of buildings and facilities impacted by vibrations spread in foundation soils under operating industrial equipment wheeled and railroad transport has been theoretically substantiated. The suggested methodology is based on the division of the structural scheme into separate core structures, dynamic support deviation calculation of which is to be performed sequentially. The calculation of building structures for vibrations caused by dynamic impacts of transport traffic and equipment operation can be used as a theoretical basis for the design and construction of buildings and facilities in order to ensure their safe operation.

Guest Editorial: What Engineers Should Know About the Expanding Generative AI Toolkit

Generative artificial intelligence (AI) is the art of creating new things inspired by the old. To understand what generative AI does, ask yourself what you would do if you wanted to create a new hit song. You wouldn't want to start from scratch. Instead, you'd listen to 100 popular songs, analyze the rhythms, melodies, and chord progressions. You would learn how these elements are structured and combined. Then, with this knowledge you would use your creativity to mix and match them in new and exciting ways—resulting in a fresh, original song that may be the next big hit. That's essentially what generative AI does. It devours massive amounts of training data, whether it's music, images, text, or scientific data. It learns the underlying patterns and relationships within that data. Then, it uses this knowledge to generate entirely new content that shares characteristics with the training data, but with a unique twist. Generative AI operates like a master mimic, following a three-step process to create entirely new content. 1. Find the building blocks. As mentioned, generative AI begins by analyzing vast amounts of training data. The goal is to identify the underlying building blocks and structures that define the data. For example, different rooms in a house contain different objects—kitchens have different items than bedrooms. Think of it like understanding the grammar of a language or the architectural styles that make up different cityscapes. For example, generative AI trained on cat images would learn to recognize distinct features like ears, whiskers, and fur patterns. 2. Decipher the unwritten rules. Next, it calculates the conditional probability distribution of these structures. In other words, it finds the order and relationship between various structures and the building blocks. Imagine that kitchen again. We know that knives are more likely to be found near cutting boards than, say, pillows, and that a sofa is typically found in front of a TV in the living room. Generative AI quantifies such relationships which allows it to then understand the underlying rules of how likely certain elements are to co-occur and in what order. 3. Perform a bold and creative remix. Finally, armed with this knowledge of building blocks and the rules of their order and structure, generative AI can create entirely new samples. It combines the learned structures and their conditional probabilities in novel ways, producing something entirely new yet rooted in the representations extracted from the training data. This could be a photorealistic image of a cat with unique markings, a catchy song inspired by popular hits, or even a compelling scientific hypothesis based on existing research.

Анализ изменения стойкости бетонных конструкций в промышленности при химическом воздействии с учетом потенциальных рисков для работников и окружающей среды

The requirements for industrial facilities’ resistance to external impacts and reliability are higher when compared with other facilities. The most common construction material, inter alia, in various industrial sectors is concrete due to its easy production and use, relatively low cost, and wide application. The environmental cleanliness is traditionally considered one of the advantages of concrete. All lifecycle stages of concrete, however, from the production process until the end of the service life of ready-to-use objects, imply serious environmental risks. Therefore, already at the design stage of (ferro)concrete structures, it is necessary to consider, in addition to the functions of the future object, the external impacts it will be exposed to. Concrete properties are not constant and change from the moment of mixing, during the transportation, and until its complete hardening. Apart from the composition and compliance with standards, many factors affect the properties. One of the main factors is an aggressive environment, whose impact can not only damage but completely disable building structures. The design service life of structures must exceed the operation lifecycle or comply with it. Concrete is considered durable if, during the design service life, it withstands loads and negative impacts of external factors and remains undamaged, taking into account industrial operation and timely maintenance. Already at the beginning of design jobs, the duration of the design service life must be estimated correctly. Both under- and overestimation of the design service life of ferroconcrete structures reduce safety and reliability and cause an unjustified rise in production and operating costs. The authors of the study analyze problems that may arise at the plants of the chemical industry in case of destruction of concrete under the impact of the aggressive liquid medium by conducting a practical study in conditions as realistic as possible. Within the framework of accelerated study, the authors examined the changes in concrete strength by control samples under pressure impacted by hydrochloric acid and sodium hydroxide. Test trials have clearly demonstrated the importance of the correct definition of concrete class in accordance with the medium of application. This must be considered during the practical work of employees of disaster protection agencies at industrial facilities with tanks to collect and store aggressive liquids, including firewater.

Intelligent building construction cost optimization and prediction by integrating BIM and elman neural network

This study aims to address the challenges of capturing design changes, supply chain fluctuations, and labor cost variations to improve the accuracy and real-time nature of intelligent building construction cost predictions. It seeks to accurately forecast and optimize project costs. The study innovatively constructs an intelligent building construction cost prediction model based on Building Information Modeling (BIM) and Elman neural networks (ENNs), denoted as the BIM-ENN model. The BIM-ENN model first introduces BIM technology to digitize and visualize information related to building structures, electromechanical systems, and pipelines. The digitized data obtained through BIM technology is then used as input data for the ENN, which optimizes the neural network parameters to predict and optimize intelligent building construction costs. Finally, the BIM-ENN model is experimentally evaluated. The results demonstrate that the prediction value of the construction cost of the intelligent building by this model closely matches the original information price, with a prediction accuracy of 95.83 %. Compared with the single ENN, the root mean squared error of the BIM-ENN model is less than 75, and the determination coefficient is above 0.95. This indicates that this model can explain more than 95 % of the construction cost prediction results, making it a feasible solution for actual prediction problems and achieving satisfactory results. The intelligent building construction cost prediction model reported here exhibits high accuracy and reliability. It can successfully forecast construction costs, providing robust decision support for the digitalization and intelligent development of construction enterprises. The practical significance of this study lies in providing the construction industry with an accurate cost management tool that helps enterprises optimize budget control and resource allocation, enhancing risk assessment and management capabilities. Moreover, the potential impact of the BIM-ENN model is its ability to elevate prediction standards within the construction industry, promote technological integration and innovation, enhance enterprise competitiveness, and drive the industry's transition towards digitalization and intelligent sustainable development.