Hasil untuk "Systems of building construction. Including fireproof construction, concrete construction"

M. Smol, J. Kulczycka, A. Henclik et al.

Su Sung Jo, Tan Duy Phan, Do Hyung Lee et al.

Abstract This study provides a comprehensive overview of the material and mechanical properties of lightweight fiber-reinforced cementitious composites (L-FRCCs), focusing on their classification as ultra-high-strength lightweight fiber-reinforced cementitious composites (UL-FRCCs). The L-FRCCs exhibit a density of 1440–2150 kg/m3, thermal coefficient of 0.22–0.33 W/mK, compressive strength of 45–145 MPa, and flexural strength of 4.3–37.5 MPa. The strength of the L-FRCCs increases linearly with matrix strength. Specifically, L-FRCCs with compressive strength > 100 MPa, flexural strength < 15 MPa, density < 1950 kg/m3, and thermal conductivity < 0.5 W/mK can be classified as UL-FRCCs. Pearson correlation analysis reveals that the structural efficiency (SE) of L-FRCCs increases with increasing matrix strength, fiber volume content, and reinforcing index; however, it decreases with an increase in the lightweight aggregate (LWA) ratio. For UL-FRCCs to achieve optimal SE, the LWAs should possess a crushing strength > 70 MPa and specific gravity < 0.5. Additionally, incorporating straight steel fibers at volumes < 2.5% is recommended to achieve strengths > 100 MPa. Compared to nonmetallic fibers such as polymeric fibers, steel fibers offer superior SE for flexural strength, despite their tendency to reduce workability owing to their high stiffness.

Yuan Gao, Xiao Han

Abstract The large-scale application of high-performance fly ash based ceramsite is an effective way to achieve high-value utilization of solid waste such as fly ash. This study investigates high-strength fly ash ceramsite lightweight aggregate concrete (with ceramsite cylinder compressive strength exceeding 20 MPa), focusing on the development of an elastic modulus prediction model and mix design methodology based on compressive strength and apparent density. By integrating a large amount of literature data, we compared and analyzed the elastic modulus prediction models based on compressive strength and apparent density proposed by different scholars. Based on this, we optimized and proposed a modified prediction model with wider applicability and higher accuracy. To simplify the mix design of lightweight aggregate concrete with ceramsite, a calculation model for compressive strength and apparent density of concrete based on physical parameters of mortar and solid waste based ceramsite was further established. The verification of the elastic modulus test of high-strength ceramsite lightweight aggregate concrete shows that the prediction model for the elastic modulus of lightweight aggregate concrete based on the calculation model of concrete compressive strength and apparent density is applicable to ceramsite lightweight aggregate concrete with compressive strength of 20–110 MPa, elastic modulus of 10–45 GPa, and apparent density of 1250–2350 kg/m3. The predicted value is about 7.0% lower than the experimental result, which can provide a safety margin for engineering mix design. The research results not only realize the high-value utilization of industrial solid waste such as fly ash, and also expand the application scope of solid waste based ceramsite in structural engineering, but also provide important theoretical basis and technical support for the development of lightweight, high-strength and green concrete.

E. Barnett, D. Dinehart, Steven M. Anastasio

The building sector accounts for a large percentage of global greenhouse gas emissions, largely from the embodied carbon in common building materials like concrete and steel. Embodied carbon (EC) refers to the greenhouse gases released during the manufacturing, transportation, installation, maintenance, and disposal of building materials. Although growing in popularity, mass timber is still not nearly as common as other building materials. During the early building design stages, engineers often do not have the time or resources to holistically optimize material selection; consequently, concrete and steel remain the materials of choice. This research focused on the development of a fully automated parametric design tool, APDT, to showcase the viability of evaluating and optimizing mass timber in building construction. The APDT was developed using Autodesk’s Revit 2022 and the visual-based programming tool housed within Revit: Dynamo. The automated designer uses parametric inputs of a building, including size, number of stories, and loading, to create a model of a mass timber building with designed glulam columns and beams and cross-laminated timber floor panels. The designer calculates overall material quantities, which are then used to determine the building’s overall embodied carbon impact. Discussed herein is the development of a building design tool that highlights the benefits of optimized mass timber using existing software and databases. The tool allows the designer to expediently provide an estimate of the amount of material and embodied carbon values, thereby making it easier to consider mass timber when determining the structural system at the infancy stage of the project. The methodology outlined herein provides a replicable methodology for creating an APDT that bridges a critical gap in early-stage design, enabling rapid embodied carbon comparisons and fostering consideration of mass timber as a viable low-carbon alternative.

M. Kalai Selvi, R. Manjula Devi, K. S. Elango et al.

Structural deterioration inevitably leads to defects in buildings. It is primarily caused by environmental exposure, material ageing, and long-term service conditions, whereas defects such as poor soil compaction arise from improper construction practices rather than deterioration mechanisms. Major concrete defects include missing portions such as cracking, corrosion, dents, blemishes, and spalling. Failure to identify minor issues can lead to serious problems, which become more expensive and difficult to repair, as well as poorer overall building performance. Traditional structural assessment methods, such as visual inspections and non-destructive testing are typically used for periodic condition evaluation, whereas SHM involves continuous or long-term monitoring using sensor-based systems. However, such approaches can be manual, costly, dangerous, and biased. In order to overcome these limitations, contemporary SHM systems combine traditional approaches with building information modelling (BIM) and artificial intelligence (AI). Different AI algorithms are used, including SVM, random forest, regression, and KNN for machine learning and decision trees; random forest, K-means clustering, CNN, U-Net, ResNet, FCN, VGG16, and DeepLabv3+ for deep learning. This review will survey both the traditional and novel approaches in the field of SHM and the recent advancements.

Sanni Ridwan Olawale

Reinforced concrete (RC) flat slab systems are a preferred choice in modern construction due to their architectural and economic advantages. However, their structural integrity is critically challenged by punching shear, a brittle failure mechanism at slab-column connections that can precipitate catastrophic progressive collapses. This review synthesizes recent research to provide a comprehensive overview of the factors influencing punching shear, the efficacy of predictive models, the evolution of shear reinforcement, and innovative strengthening techniques. The analysis consolidates findings on failure mechanics, highlighting the dominant role of concrete's tensile properties and the complex influence of time-dependent phenomena like creep and shrinkage. It examines a wide array of parameters, including slab depth (size effect), flexural reinforcement ratios, the presence of openings, load eccentricity, complex geometries like edge and re-entrant corners, column rectangularity, non-rectangular column grids, and the use of posttensioning and non-traditional materials like Glass Fiber-Reinforced Polymer (GFRP) bars. A critical assessment of design code provisions (e.g., ACI 318, Eurocode 2) against advanced numerical methods and new proposed standards (FprEN 1992, MC 2010) reveals significant limitations in current codes, particularly for slabs with low reinforcement ratios (flexure-driven punching), significant depth, or non-standard geometries. The review delves into the nuances of shear reinforcement, emphasizing how stirrup detailing—anchorage, inclination, and configuration—profoundly impacts structural performance. A significant focus is placed on the role of Nonlinear Finite Element Analysis (NLFEA), detailing the importance of model calibration and the capabilities of tools like the Concrete Damaged Plasticity (CDP) model, with particular attention to the influence of the dilatancy angle. Lessons from real-world building collapses underscore the imperative of integrating construction-phase analysis and robust design to prevent progressive collapse. Finally, the paper outlines key challenges and charts a course for future research to enhance the safety and resilience of flat slab structures.

Vladimir A. Polyakov, Alexander G. Zemtsov

This article provides a concise analysis of regulatory documents concerning fire protection for the underground infrastructure of railway tunnels. Special attention is paid to the distance between evacuation cross passages, which is a critical factor for the evacuation of passengers with reduced mobility during a fire. The development of a dedicated regulatory document is proposed, one that would account for all the specific aspects of ensuring the safe evacuation of a large number of people (train passengers) from a tunnel.

Yury K. Naganovsky, Andrey B. Sivenkov

The paper presents the results of thermal analysis of samples of woven and textile-felt materials in an inert and air medium. The methods of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used in the study. The features of thermal transformations of various samples of woven, carpet, and textile-felt materials are analyzed. There are obtained thermogravimetric dependences characterizing the behavior of natural, synthetic and artificial fibers in conditions of elevated temperatures.

Zainab Hashim Abbas, Fatima Hashim Abbas

Abstract By 2030, global egg production is expected to reach 90 million tons, generating substantial eggshell waste. This study looks into the use of nano-eggshell powders (NEP) as a portion substitute for cement in HSC (high-strength concrete) mixed with pozzolanic ashes (OA). Seven machine learning (ML) methods were used to forecast the 28-day compressive (CS) and flexural strength (FS) of waste-based HSC. Random Forest Regression (RFR) had the highest reliability (R 2 > 0.97). Model interpretation with SHapley Additive exPlanations (SHAP) revealed that water (negative), cement (positive), and NEP (combined) played the most important roles. For considering CO2 emissions, strength, and cost in addition to mechanical performance, a modern sustainability indicator (SCER) was established. Multi-objective optimization was allowed by applying an integrated approach of RFR and Differential Evolution (DE), causing environmentally friendly high-strength blends. The novelty of this study is the achievement of an equilibrium in economic, environmental, and mechanical performance of concrete by a combination of NEP, pozzolanic ashes, and optimization by ML. This conduct has not been investigated previously in the literature. Graphic Abstract

Daun Jeong, Dong-Hee Son, Chang-Sik Choi et al.

Abstract This study aimed to evaluate the shear friction strength mechanism of monolithically and separately cast concrete members using steel fiber reinforced concrete (SFRC). To achieve this, a total of 30 push-off tests were conducted with variables such as volume fraction of steel fiber, clamping force of shear-friction reinforcement, and concrete compressive strength. The experimental results showed that the inclusion of steel fibers significantly increased the shear friction strength of monolithically cast concrete. Similarly, the strength improvement in the separately cast specimens was notable with the addition of steel fibers. Notably, as the steel fiber content increased, the concrete contribution also improved, which was attributed to the enhancement of dowel action by the shear-friction reinforcement and the increased tensile strength of the concrete. When comparing the experimental results with current design standards, Eurocode2 provided the most accurate predictions, suggesting that the tensile strength of concrete increased by steel fibers can lead to more precise predictions of shear friction strength.

of objects of the Калиолла Ахметжан, А. Ganiyeva, A.Kh. Margulan Институт

The article is devoted to a comprehensive study of the evolution of housing forms in the territory of Kazakhstan from the perspective of archaeological data covering the period from the Eneolithic to the late Middle Ages. The main attention is paid to the peculiarities of house-building traditions in different natural-geographical zones - steppe, foothill, mountainous and high-mountainous - with the analysis of constructive, technological, and functional characteristics of dwellings. The article traces the formation and development of various types of dwelling and household buildings: from ground and semi-ground structures of frame-pillar construction of the Bronze Age to log and stone buildings of the Final Bronze Age and Early Iron Age. Special attention is paid to regional archaeological complexes – settlements of Asy-I, Turgen-II, Tasbas, Kalakay, Talapty, as well as sites of Central Kazakhstan: Begazy, Atasu, Buguly-I, and others, where rich stratigraphic and architectural materials are revealed. On their basis, the construction technologies, internal layout, organisation of economic space, heating and storage systems, as well as traditions of choosing a place for settlement are analysed. It is established that already in the Late Bronze Age, the principles of dwelling zoning, stable roof forms, typology of hearths and sufas were formed, which was reflected in the later ethnographic architecture of Kazakhs. The issue of continuity of architectural forms and principles between ancient buildings and traditional dwellings of Kazakhs of the New Age, including types of winter dwellings (qystau), is also considered. The choice of location for settlements, the orientation of entrances, the methods of insulation and lighting of dwellings, and the types of building materials (wood, clay, stone, straw, reed) are closely linked to the climate, terrain, and economic specialisation of the population (agriculture, livestock householding, crafts). Archaeological and ethnographic parallels reveal the stability of building traditions determined by climate, resource environment and economic specialisation of the population. The materials of the article are relevant for the reconstruction of the everyday life of the ancient population of Kazakhstan, the analysis of economic models, and the social structure of society. The work contributes to the study of cultural continuity and local specifics of the architectural heritage of the Eurasian steppes.

Vitaliy Veselov

To analyze the use of steel­concrete composite structures in single­storey industrial building frames, including those related to transport. To explore potential reductions in material consumption and overall costs associated with the proposed innovative composite building frame design, while enhancing rigidity and reliability. Methods: Analysis of established design solutions for composite structures and calculation of various frame options using calculation software packages in accordance with current methodologies. Results: Conventional industrial building frames that utilize metal structures do not consistently provide adequate rigidity or resistance to progressive collapse. They are susceptible to various forms of damage from force and mechanical stress, as well as specific loads and effects, particularly in transportation context. Typically, frames for industrial buildings with large spans require additional structural measures to mitigate the risk of progressive collapse. The Department of “Building Structures, Buildings, and Constructions” at SPTU (Petersburg State Transport University) is engaged in the development of advanced structural solutions for building frames and their components characterized by enhanced rigidity, load­bearing capacity, and reliability. An innovative design for a highly rigid industrial building has been proposed, which includes columns, roof trusses, gantry beams, as well as a bracing system, roofing, and wall panels. The roofing is constructed from ribbed reinforced concrete slabs with monolithic concrete joints, with the supporting transverse ribs rigidly connected to the upper chord of the roof trusses through welded joints. The wall panels are made of reinforced concrete slabs with monolithic concrete joints, where the supporting transverse ribs are securely welded to the outer surface of the columns. Several options for an industrial building frame have been calculated, establishing the reduction in the weight of the structure, its cost, and the increase in the rigidity of the innovative design. Practical significance: The primary advantages of steel­concrete composite frame structures in single­storey industrial buildings have been evaluated. The innovative frame design demonstrates a weight reduction of 18%, a cost decrease of 25%, and a rigidity increase of 35% compared to traditional metal frame designs. The proposed frame design may prove to be effective in industrial buildings with large spans, as well as on transportation facilities.

Niniek Pratiwi, Abdi Gunawan Djafar, Rahmayanti Rahmayanti et al.

The scientific community has established a clear link between the built environment and various environmental problems. Various strategies have been implemented to mitigate the negative impacts of buildings and to address broader environmental challenges. One such strategy is the adoption of sustainable building practices. Among the factors contributing to the environmental impacts of buildings, efforts to achieve thermal comfort play significant role. Particularly due to the energy consumption involved. At the same time, thermal comfort is also a critical factor influencing human productivity, including academic performance. Comfortable learning environments are known to enhance students’ learning outcomes. This research presents a case analysis conducted at State Elementary School 91 Sipatana, Gorontalo City, Indonesia. Measurements were carried out on December 24, 2022, from 06.00 to 18.00. Room temperature was recorded using an Elitech GSP-6 data logger, and further simulations were carried out using Ladybugs and Honeybees. The purpose of this study is to evaluate building performance in achieving thermal comfort by considering solar radiation exposure, roof surface temperature, room temperature, and Predicted Mean Vote (PMV) values. Comparisons were made across different building materials, including variation in roofing, wall types, and ventilation systems. The wall in the existing structure are composed of concrete with a fiber wall. The findings highlight the impact of roofing materials, wall construction, and ventilation on the PMV, roof surface temperature, and indoor air temperature. Based on-site measurements, the average classroom temperature was 30.5°C. Among the simulation configurations, Model 3 which featured a metal roof with a cool roof technology, concrete walls, and added ventilation demonstrated the best thermal performance. It maintained a roof surface temperature just above 25°C and an indoor air temperature close to 30°C, showing the effectiveness of cool roof technology and adequate ventilation in reducing heat accumulation.

Stefano Baiguera, Nicolas Chagnet, S. Chapman et al.

Quantum complexity of conformal field theory (CFT) states has recently gained significant attention, both as a diagnostic tool in condensed matter systems and in connection with holographic observables probing black hole interiors. Previous studies have primarily focused on cases where all generators of the conformal group contribute equally to the cost of building a circuit. In this work, we present a general framework for studying the complexity of circuits in generic Lie groups, where penalty factors assign relative weights to different generators. Our approach constructs a metric on the coset space of quantum states, induced from a (pseudo-)Riemannian norm on the space of unitary circuits. The geodesics of this metric are interpreted as optimal circuits. The method builds on the formalism of (pseudo-)Riemannian submersions and connects naturally to other prescriptions in the literature, including cost function minimization along stabilizer directions and constructions based on coadjoint orbits. As a concrete application, we compute state complexity for states in one- and two-dimensional CFTs. For specific choices of penalty factors, our prescription yields a positive-definite metric with a viable interpretation as complexity; in other cases, the resulting metric is indefinite. In the viable regime, we derive analytic results when a specific penalty factor is turned off, develop perturbative expansions for small values of the penalty factors, and provide numerical results in the general case. We comment on the relation of our measure of complexity to holography.

O. Gimanov

This paper explores the development and application of timber and glued laminated timber (GLT) in modern construction, particularly for floor systems. Timber has historically been one of the most widely used construction materials, and its utilization remains highly relevant due to its ecological advantages, architectural flexibility, and structural properties. The analysis focuses on the technological advancements that have led to the widespread implementation of GLT, enabling the construction of multi-story wooden buildings worldwide. The study examines scientific publications on the evolution of wooden structures, highlighting key aspects such as sustainability, carbon footprint reduction, sound insulation, vibration resistance, and fire safety. A particular emphasis is placed on the advantages of timber in mitigating environmental concerns associated with conventional construction materials like concrete and steel. Additionally, this paper presents computational models and experimental research addressing the mechanical behavior of cross-laminated timber floor systems. The structural integrity and design optimization of these systems are investigated, along with proposed improvements for connection nodes and innovative approaches for enhancing strength and durability. The findings demonstrate the growing importance of timber in contemporary engineering and urban development. Key directions for future research are outlined, including experimental validation of laminated timber connections, development of advanced fire-retardant treatments, and optimization of the material for large-scale construction applications. The study contributes to the understanding of timber’s role in sustainable architecture, offering recommendations for efficient integration in modern building practices.

George Uwadiegwu Alaneme, K. Olonade, Ebenezer Esenogho

The need to employ technology that replaces traditional engineering methods which generate gases that worsen our environment has emerged in an era of dwindling ecosystem owing to global warming has a negative influence on the earth system’s ozone layer. In this study, the exact method of using artificial intelligence (AI) approaches in sustainable structural materials optimization was investigated to ensure that concrete construction projects for buildings have no negative environmental effects. Since they are used in the forecasting/predicting of an agro-waste-based green geopolymer concrete system, the intelligent learning algorithms of Fuzzy Logic, ANFIS, ANN, GEP and other nature-inspired algorithms were reviewed. A systematic literature search was conducted to identify relevant studies published in various databases. The included studies were critically reviewed to analyze the types of AI techniques used, the research methodologies employed, and the main findings reported. To meticulously sort the crucial components of aluminosilicate precursors and alkaline activators blend and to optimize its engineering behavior, laboratory methods must be carried out through the mixture experiment design and raw materials selection. Such experimental activities often fall short of the standards set by civil engineering design guidelines for sustainable construction purposes. At some instances, specific shortcomings in the design of experiments or human error may degrade measurement correctness and cause unforeseen discharge of pollutants. Most errors in repetitive experimental tests have been eliminated by using adaptive AI learning techniques. Though, as an extensive guideline for upcoming investigators in this cutting-edge and developing field of AI, the pertinent smart intelligent modelling tools used at various times, under varying experimental testing methodologies, and leveraging different source materials were addressed in this study review. The findings of this review study demonstrate the benefits, challenges and growing interest in utilizing AI techniques for optimizing geopolymer-concrete production. The review identified a range of AI techniques, including machine learning algorithms, optimization models, and performance evaluation measures. These techniques were used to optimize various aspects of geopolymer-concrete production, such as mix design, curing conditions, and material selection.

Hongning Ye, Yong Lu

Hamin Eu, Gyuyong Kim, Minjae Son et al.

Abstract This paper presents the influence of supplementary cementitious materials (SCMs), such as fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), and waste glass fine aggregate (GA), on the alkali-silica reaction (ASR) in high-strength and normal-strength mortar using an accelerated mortar bar test (AMBT). Residual mechanical properties and scanning electron micrographs were used to assess the changes in the matrix. GA reduced the mechanical properties of both normal-strength (NGA_OPC) and high-strength mortars (HGA_OPC), contributing to a decline in overall performance. This phenomenon was a result of the slipping of the GA from the matrix owing to its smooth surface. However, the inclusion of reactive SF and GGBS in the HGA improved the slip phenomenon of the GA, leading to a significant enhancement in its mechanical properties. Following the ASR expansion measurement, HGA_OPC demonstrated an ASR expansion rate approximately three times higher than that of NGA_OPC. This was attributed to the dense structure of HGA_OPC, which resulted in greater expansion than that of NGA_OPC. However, with the incorporation of SCMs into both HGA and NGA, a significant reduction in ASR expansion was observed. This was attributed to the delayed ASR of GA due to alkali activation or the pozzolanic reaction of the SCMs. Continuous exposure to the AMBT environment can lead to the destruction of GA. This was caused by the inner ASR that originated from the surface crack of the GA, which resulted in a reduction in the flexural strength of the mortar. The HGA with SF exhibited the highest resistance to ASR expansion and residual mechanical properties’ degradation. Therefore, various durability and long-term performance-monitoring studies on ultra-high-performance concrete or high-strength cementitious composites with very high SF contents and GA can be conducted.

Alexey V. Golkin, Valery G. Shamonin, Stanislav A. Zuev et al.

There is considered the possibility of solving the problem of choosing the optimal width of evacuation curved corridors, both sides of which are parts of an ellipse to further minimize the mixing of human flows (and, accordingly, prevent congestion when people move) during evacuation in case of fire or other emergency situations. Questions on the criterion for dividing corridors into wide and narrow, on the accuracy of Ramanujan formula and on the calculation of the ellipse arc length are analysed.

Zahid Hussain, Antonio Nanni

Abstract The current code provisions in ACI 440.11 are based on the flexural theory that applies to slender members and may not represent the actual structural behavior when the shear span-to-reinforcement depth ratio is less than 2.5 (i.e., deep members). The Strut-and-tie method (STM) can be a better approach to design deep members; however, this chapter is not included in the code. Research has shown that STM models used for steel-reinforced concrete (RC) give satisfactory results when applied to glass fiber-reinforced polymer-reinforced (GFRP)-RC members with a/d less than 2.5. Therefore, this study is carried out to provide insights into the use of STM for GFRP-RC deep members based on the available literature and to highlight the necessity for the inclusion of a new chapter addressing the use of STM in the ACI 440.11 Code. It includes a design example to show the implications of ACI 440.11 code provisions when applied to GFRP-RC deep members (i.e., isolated footings) and compares it when designed as per STM provided in ACI 318-19. It was observed that current code provisions in ACI 440.11 required more concrete thickness (i.e., h = 1.12 m) leading to implementation challenges. However, the required dimensions decreased (i.e., h = 0.91 m) when the design was carried out as per STM. Due to the novelty of GFRP reinforcement, current code provisions may limit its extensive use in RC buildings, particularly in footings given the water table issues and excavation costs. Therefore, it is necessary to adopt innovative methods such as STM to design GFRP-RC deep members if allowed by the code.