Abstract This study experimentally investigates and analyzes the key factors influencing the tension stiffening effect of ultra-high-performance concrete (UHPC) with embedded reinforcement under thin cover conditions, focusing on the effective tensile cross section and bond coefficient. Unlike conventional concrete, which loses tensile load-carrying capacity after cracking, UHPC can sustain tensile forces depending on the steel fiber content; therefore, the steel fiber volume fraction was selected as the first experimental variable. To evaluate the effect of reduced cover thickness, the second variable, the effective tensile cross section was examined by varying the reinforcement diameter and section height. Twelve specimens were fabricated, and material tests, including compressive, direct tensile, and rebar tests, were performed to assess mechanical properties. The results indicated that the tension stiffening effect increased with higher steel fiber content, while specimens with larger cross-sectional areas exhibited enhanced stiffness and reduced crack formation regions. Failure patterns revealed that both maximum crack width and average crack spacing decreased as the steel fiber content increased, due to the fiber bridging effect and the corresponding improvement in tensile strength. Comparison with existing design codes showed that the effective tensile cross section and bond coefficient of UHPC were underestimated despite the thin cover; hence, a predictive equation incorporating the steel fiber volume fraction was proposed. The proposed coefficient and effective tensile cross section improved the accuracy of the design formula in predicting the tension stiffening behavior of reinforced UHPC with thin cover.
Systems of building construction. Including fireproof construction, concrete construction
Abstract To promote the effective recycling of waste ceramic tiles and alleviate the shortage of natural river sand, this study systematically investigates the strength and durability of concrete incorporating recycled ceramic fine aggregate (RCFA), herein referred to as RCFA concrete, at water-to-binder (W/B) ratios ranging from 0.25 to 0.45. The RCFA was produced by crushing waste ceramic tiles characterized by low water absorption. As indicated by experimental results, RCFA concrete exhibits improved compressive strength and enhanced resistance to freeze–thaw cycles and chloride ion penetration compared to natural aggregate concrete. However, the beneficial effects of RCFA diminish at lower W/B ratios. Furthermore, the incorporation of RCFA significantly reduces autogenous shrinkage and alleviates the decline in internal relative humidity, with these effects being more pronounced at lower W/B ratios. Conversely, RCFA increases drying shrinkage at the W/B ratio of 0.45, although this negative effect is mitigated as the W/B ratio decreases. Mercury intrusion porosimetry and scanning electron microscopy analyses reveal that RCFA improves concrete performance by reducing microporosity and enhancing the interfacial bonding between fine aggregates and hydration products.
Systems of building construction. Including fireproof construction, concrete construction
Portland cement concrete (PCC) is a versatile and widely used construction material renowned for its strength and durability. The mechanical properties of PCC, including compressive strength, flexural strength, and splitting tensile strength, play a pivotal role in ensuring the safety and sustainability of structures such as buildings, bridges, and dams. Traditionally, the determination of PCC’s compressive strength involves destructive testing of standard-size concrete cylinders until they fail. While nondestructive evaluation (NDE) techniques are available for assessing these properties, they often require direct contact between the sensor and the concrete surface, making them less efficient and practical compared to remote sensing techniques. In this paper, three NDE techniques were applied for estimating the mechanical properties of concrete, including synthetic aperture radar (SAR), ultrasonic testing (UT), and a rebound hammer (RH). A total of 48 laboratory concrete cylinders (diameter = 3", height = 6") were manufactured. These cylinders were created with different water-to-cement ratios (0.4, 0.45, 0.5, and 0.55) with a mix design ratio of 1:2:3 for cement: sand: gravel (by mass). Before these cylinders were tested by destructive compression test, they were measured by three NDE techniques. A 10 GHz SAR system, a 54 kHz UT system, and a RH sensor were used to inspect those cylinders at different concrete ages (7, 14, 28, and 96 days). From our result, the performance ranking among three NDE techniques was individually UT, SAR, and RH. When combining two NDE techniques, SAR with UT delivered the best performance. Multiphysical NDE (SAR with UT) outperformed uniphysical NDE (UT with RH) on the prediction of compressive strength of concrete, with a highest R2 value of 0.9918. This research demonstrates the promising potential of multiphysical NDE for other engineering problems.
The scientific work is devoted to a comprehensive study of the stress-strain state of the quay wall, an industrial facility that has been under construction for a long time. A practical assessment of the physical and mechanical characteristics of the materials used in the construction was carried out. Laboratory verification of the obtained data was carried out using the current methodology and in accordance with the requirements of Ukrainian building codes. When constructing piers, materials with various properties are used: wood, concrete, reinforced concrete, steel. Often, pier structures are made of different materials. For example, the base is made of wooden or metal piles, and the deck is made of reinforced concrete. However, the most common are reinforced concrete or concrete structures. Quay wall – is a monolithic reinforced concrete structure, the basis for the construction of the pier as a whole. During a detailed inspection of the retaining wall structures, a visual inspection of the building structures, as well as its individual elements, was carried out to determine their technical condition, degree of physical wear and tear, and bearing capacity. During the field study, the retaining wall was studied in detail. The geometric characteristics of the structures were established. The results of the study show the following: during the visual inspection of the structure, some defects were found, including; the erected sections of the quay wall (1, 2, 3, 7) have a color that is not typical of high-quality concrete. The presence of some cracks. Nevertheless, the opening width is permissible within 0.3 mm. The experimental algorithm for establishing the physical and mechanical characteristics of the quay wall deformability, which has been under construction for a long time, has been improved. A comprehensive study of building structures has been carried out; the actual characteristics of materials have been determined. An additional expert analysis of the structural system of the quay wall has been carried out. Based on the results of the comprehensive theoretical and experimental studies, proposals have been made for further safe operation. The results obtained can be used by engineers in the future to establish the causes of disruptions in the technological process of production.
This study aims to analyze the behavior of steel-concrete composite structures to dynamic loads in high-rise buildings. Steel-concrete composite structures are one of the innovations in the world of construction that combines the tensile strength of steel and the compressive strength of concrete to produce an efficient structural system that is resistant to various types of loads, including dynamic loads such as earthquakes and winds. This study uses a qualitative approach with the literature study method (library research) to examine various previous research results, technical standards, and relevant theories regarding the response of composite structures to dynamic loads. The main data sources come from international journals, civil engineering books, as well as globally recognized composite structure design guidelines. The results of the analysis showed that composite structures have better performance than conventional structures in responding to lateral forces due to dynamic loads, especially in terms of energy dissipation and plastic deformation. In addition, the integration of steel and concrete elements can improve the rigidity of the structure as well as reduce the risk of local failure. However, the effectiveness of these structures is highly dependent on the details of the joints, the method of execution of the construction, and the suitability of the design to the characteristics of the dynamic load. These findings make an important contribution to the development of safer and more efficient multi-storey building structure designs, as well as the basis for further research related to the strengthening of composite structures in earthquake-prone areas.
Abstract In this study, a simplified cross-sectional approach based on finite-element analysis was developed to evaluate the flexural strengthening performance of fire-damaged RC beams using externally bonded steel plates and CFRP strips. The strength degradation of the simplified concrete cross section and reinforcing bars was determined based on the temperature field calculation results from FE software. The strength degradation models proposed in previous literature were adopted and applied based on the obtained temperature distribution. The finite-element model was validated with the previous experimental test to evaluate the accuracy of the model in predicting the residual flexural capacity of RC beams after fire exposure. It is shown that the finite-element model (FEM) was able to predict the flexural behavior of fire-damaged RC members reasonably well. The ISO-834 standard fire curve was applied to the reference flexure beam for 60 min, 90 min, and 120 min of heating before strengthening by employing the proposed methodology. The parametric study in this investigation includes the thickness and width of the strengthening materials for the comparison of the flexural capacity recovery of both retrofitting methods. The analysis results showed that the ultimate load and stiffness of fire-damaged beams strengthened with both materials improved significantly compared to the heated beams without strengthening. The damaged beams group retrofitted with externally bonded steel plates exhibited a greater increase in both ultimate load and stiffness compared to the damaged beams group retrofitted with externally bonded CFRP strips.
Systems of building construction. Including fireproof construction, concrete construction
Samreen Gul, Sarmad Shakeel, Hammad Anis Khan
et al.
Structural Concrete Insulated Panels (SCIPs) offer a precast, lightweight, and off-site option for several types of construction including residential, commercial, and industrial structures. This study addresses a critical gap in the existing literature by investigating the flexural behavior of Structural Concrete Insulated Panels (SCIPs) under pinned-ended conditions—unlike prior research that focused primarily on fixed-ended configurations. It further introduces original variations in reinforcement placement and spacing, offering a novel perspective on enhancing composite action and deflection performance in floor slab applications. By experimentally evaluating four distinct SCIP configurations using four-point bending tests, the research contributes new empirical data to inform optimized structural design. The findings reveal ultimate moment capacities ranging from 2.84 to 5.70 kN m, and degrees of composite action between 6.5% and 28.2%. Notably, SCIP-2 and SCIP-3 satisfied ACI 318-19 deflection criteria, demonstrating their viability for structural flooring systems. The findings emphasize the capacity of SCIPs to transform the building sector by providing practical and sustainable solutions for floor systems.
Robotic systems are increasingly being deployed for the inspection of buildings and infrastructures due to their ability to enhance safety, efficiency, and precision. These systems, comprising self-contained or semi-autonomous robots equipped with advanced sensors, are designed to evaluate structural integrity, detect flaws, and monitor deterioration in real time. This systematic review investigates the current landscape and advancements in robotic technologies applied to civil engineering inspections. The primary focus is on the development and integration of intelligent robotic systems that ensure effective, accurate, and consistent monitoring of structural conditions. The review methodology complies with the preferred report items for Systematic Evaluations and Meta-Analyses (PRISMA) criteria to ensure transparency and reproducibility. A comprehensive literature search was conducted using multiple academic databases, incorporating stringent inclusion and exclusion criteria to identify high-quality and relevant studies. Data extraction and critical appraisal were performed systematically to ensure the reliability and validity of the findings. The integration of classification robots and machine learning analytics has notably improved defect detection accuracy, enabling more robust and intelligent structural evaluations. The results of the review reveal significant progress in using robotic systems for various civil engineering tasks, including structural inspection, excavation, welding, and concrete placement. These advancements contribute to increased safety and operational efficiency while minimizing human intervention in hazardous environments. Despite these improvements, the review also highlights the need for further research into developing scalable, adaptable, and flexible robotic solutions capable of handling complex and dynamic construction scenarios. In conclusion, robotic systems have revolutionized numerous aspects of civil engineering, and continued innovation is essential for addressing future challenges in the construction industry.
This research aims to: 1. Study the post-tension concrete floor type. 2. Study the case study of the building construction process using post-tension concrete floors by studying the plans and construction steps of post-tension concrete floors from studying the manuals and documents for the construction of prestressed concrete floors, applying the knowledge gained from working and learning on-site to understand the characteristics, types, and plans of prestressed concrete floors and the construction steps of prestressed concrete floors. The results of this research provide information on the plans and steps in the construction of post-tension concrete floors, construction supervision, management to meet the specified time frame, various construction problems and solutions, and the development of knowledge and skills in construction supervision for future use. In conclusion, understanding the work process, construction process control methods, and inspection of various post-tension concrete floor constructions can increase work efficiency and reduce labor costs, time, and damage costs, such as contracting parties for breaches of contract. It was found that the advantages of the post-tension floor system are more floors at the same building height and less wind load at the same number of floors because it can improve long-term performance compared to traditional reinforced concrete and beam-slab systems. In addition, factors that affect the useful labor utilization ratio consist of 4 factors: complexity of building design, work items or work steps that make work difficult; use of appropriate tools and machinery to facilitate work and reduce labor waiting time; use of various innovations or substitute materials to help reduce time in work steps; arranging a team of workers that is appropriate for the size and type of work. These factors directly affect the ratio of useful workers. Results from this research Can be used to improve construction processes and inspection, Including selecting concrete materials to increase efficiency.
Against the backdrop of global challenges such as geopolitical instability, environmental threats, and social crises, Ukraine's energy system has come under unprecedented pressure, requiring tactical responses to the destruction of energy infrastructure as well as long-term strategic solutions to ensure its resilience and energy efficiency. Currently, state efforts focused on operational measures, including the restoration of damaged power plants, support for decentralized energy sources, and mobilizing foreign aid to meet seasonal demands. However, despite existing national programs, such as the National Energy Efficiency Plan, several unresolved aspects require further detailing and adaptation to current conditions. Specifically, there is a lack of concrete steps for integrating decentralized sources into building projects, flexible mechanisms to operate during infrastructure disruptions, and incentives for the widespread use of green technologies in large-scale construction. This research aims to analyze the opportunities and challenges related to enhancing the energy efficiency of Ukraine's construction sector through innovative solutions such as artificial intelligence (AI), machine learning (ML), digital twins, and eco-friendly materials. The study utilizes methods of content analysis, comparative and situational analysis, as well as expert evaluation to develop practical recommendations for both construction companies and government bodies. The results indicate that technologies enhancing building autonomy and resilience, particularly digital twins and IoT, are the most effective during wartime. Larger-scale solutions, such as smart energy-efficient buildings, require foreign investment and they may be implemented in the post-war period. The introduction of AI and ML not only improves energy efficiency but also helps reduce the carbon footprint, which positively affects at the environment and aids in adapting to climate change.
: The application of green building materials in civil engineering is pivotal for sustainable development. This paper explores the use of various materials such as recycled steel and bamboo for structural purposes, and insulation materials like cellulose and wool for non-structural purposes. Innovative materials, including self-healing concrete and low carbon cement, are also discussed. The environmental impact analysis reveals significant reductions in carbon footprint through decreased energy consumption and greenhouse gas emissions. Effective waste management strategies, including the reduction of construction waste and the reuse and recycling of materials, are highlighted. Long-term benefits are assessed through life cycle assessments and end-of-life disposal considerations. Future trends indicate advancements in material technology, integration with smart building systems, supportive policies and incentives, and active community and stakeholder engagement. This paper underscores the crucial role of green building materials in reducing environmental impact and promoting sustainability in civil engineering.
Abstract The ultimate load-carrying capacity of concrete-filled steel tubular (CFST) columns exposed to monotonic loadings can be greatly increased by strengthening those columns, and the occurrence of the steel tube's outward buckling can be postponed. The current research aims to study the possibility of improving the structural characteristics of CFST columns exposed to cyclic loadings in terms of lateral load capacity and absorbed energy by strengthening them with different patterns of fiber-reinforced polymer (FRP) sheets. The ABAQUS software was used to create a three-dimensional (3D) non-linear finite element model (FEM) to simulate the behavior of FRP-strengthened CFST columns exposed to monotonic and cyclic loadings. After ascertaining the accuracy of the proposed model's results in successfully predicting failure patterns and lateral loads compared to the experimental results of tested specimens available in the literature, the model was used to create a parametric study. The parametric study focused on the impacts of the thickness, location, and length of the strengthening sheets on the failure pattern, lateral load-carrying capacity, stiffness, cumulative energy, absorbed energy, and viscous damping factor of the CFST columns exposed to cyclic loadings. The results revealed that the un-strengthened specimen displayed a maximum lateral load of 185 kN and a viscous damping factor of 45.2% at a lateral drift of 5.7%. On the other hand, strengthening the CFST column using five layers of FRP sheets exhibited the highest lateral load of all investigated columns (50% more than the un-strengthened specimen). Additionally, at a lateral drift of 5.7%, the decrease in viscous damping factor of CFST specimens due to strengthening using 1, 2, 3, 4, and 5 layers of FRP sheets with respect to the control specimen was 7.9%, 14.9%, 20.8%, 27.7%, and 30.3%, respectively.
Systems of building construction. Including fireproof construction, concrete construction
Vladimir I. Golovanov, Nikolay S. Novikov, Alexey V. Bulgakov
et al.
This article is devoted to research on the fire resistance of metal pipelines (penetration rates) under pressure from circulating water or steam operated in energy installations. The need for research is due to the lack of a method for testing the fire resistance of intersections of building structures with standardized fire resistance limits. The article presents both the methodology elaborated for testing metal penetration rates for fire resistance and full-scale tests of these penetration rates (dimensions 630 × 45 mm and 65 × 8 mm) in a wall of aerated concrete blocks with a thicknesses of 1200 and 800 mm.
Systems of building construction. Including fireproof construction, concrete construction
Sabry Fayed, Emrah Madenci, Yasin Onuralp Özkiliç
et al.
Abstract In this study, the experimental findings of twenty pull-out tests on the bond efficiency of threaded/ribbed steel rods used in near-surface mounting (NSM) are presented. On a groove (20 × 20 mm) that was slotted in one of the sides of a concrete block measuring 250 × 250 × 200 mm, a pull-out experiment was performed. The primary factors are the slot-filling materials (substrate concrete and epoxy paste), bonded length (equal to 5, 7, 10, and 15 times the rod diameter), surface pattern conditions (conventional ribbed reinforcing rebar and threaded bolt), use of nuts or rings welded at the free end of the bonded length, and use of straight or spiral wire welded along the length of the bonded length. The tested specimens' ultimate bond strength, slip, bond stress–slip response, failure patterns, stiffness, and ductility are recorded and assessed. The results showed that the ultimate bond strength and corresponding slip of ribbed rods cemented with epoxy were higher by 11.11% and 199%, respectively, than those of ribbed rods submerged in the substrate. Over the controls, all NSM epoxy-rods exhibited a greater ductility. As the bonded length increased, the ultimate bond strength of NSM rods fell by 12–32%. As the bonded length increased, the stiffness decreased. On the other hand, the ductility of NSM epoxy-rods increased as the bonded length increased. All applied schemes such as nuts, rings, longitudinal bars, and spiral bars significantly improved the ultimate bond strength (maximum = 25.93%) and corresponding slip (maximum = 166.67%) of NSM threaded rods as compared to the control ones.
Systems of building construction. Including fireproof construction, concrete construction
Ismail Amer, Amr Abdelkhalik, Ola A. Mayhoub
et al.
Abstract Geopolymer concrete (GPC) has achieved a wide popularity since innovating it as an alternative to conventional concrete because of its superior mechanical characteristics and durability, in addition to being a green concrete due to its low negative impact on the environment. However, GPC still suffers from the problem of its poor workability which suppresses its spread in construction applications. This study investigated the most effective parameters on the workability of GPC including GGBFS content, water to binder ratio, and dosage of different types of chemical admixtures, Naphthalene-Based Admixture (NPA) and Polycarboxylate-Based Admixture (PCA), using Taguchi approach and Analysis of Variance (ANOVA) analysis considering the compressive strength at the different concrete ages. It was observed that NPA, in the geopolymer concrete, improved the compressive strength compared to PCA. The NPA-based mixes achieved the highest 28-day compressive strength, 69 MPa, with about 27.8% more than the highest 28-day compressive strength achieved by the PCA-based mixes, 54 MPa. The obtained results revealed that the NPA has achieved the best improvement for both the workability, in terms of initial slump value and slump loss rate, and the compressive strength of GPC mixes compared to PCA.
Systems of building construction. Including fireproof construction, concrete construction
Abstract This detailed review looks at how carbon fiber-reinforced polymer (CFRP) may be used to improve the flexural capacity of reinforced concrete (RC) beams. It investigates the history, characteristics, and research trends of FRP composites, assesses various flexural strengthening methods utilizing FRP, and addresses the predictive power of finite-element (FE) modeling. The assessment highlights the importance of enhanced design codes, failure mode mitigation, and improved predictive modeling methodologies. It emphasizes the advantages of improving FRP reinforcement levels to meet code expectations and covers issues, such as FRP laminate delamination and debonding. The findings highlight the need of balancing load capacity and structural ductility, as well as the importance of material behavior and failure processes in accurate prediction. Overall, this review offers valuable insights for future research and engineering practice to optimize flexural strengthening with CFRP in RC beams.
Systems of building construction. Including fireproof construction, concrete construction
This study investigates the energy performance and carbon emissions of LIDL supermarket buildings in Abuja, Nigeria, under current and future climate conditions. Using a multi-methodological approach, the research evaluates three construction models—Model P1 (steel columns with cladding panels), Model P2 (Poroton blocks), and Model P3 (precast concrete columns with glulam beams)—to understand the impacts of construction techniques and materials on building energy efficiency and sustainability. The study employs Thermal Analysis Software (TAS) v9.5.0 to simulate energy consumption and emissions under different scenarios, utilizing dynamic weather data from the Chartered Institution of Building Services Engineers (CIBSE) for both present and future climate projections (2050s and 2080s). The methodology integrates critical building elements, including floor area, thermal properties, and heating, cooling, and lighting systems, and incorporates site-specific data from Jabi, Abuja, to analyze regional climate effects. Key simulation assumptions include construction details, U-values, and infiltration rates, while databases from ASHRAE are used to model thermal properties and heat transfer. Results highlight the energy demand changes and carbon emissions associated with heating and cooling across seasonal extremes. This research provides actionable insights into optimizing supermarket energy performance and sustainability in response to climate change, offering valuable guidance for building designs in urbanizing and climate-vulnerable regions like Nigeria.
The American Concrete Institute has published ACI 440.11-22, Building Code Requirements for Structural Concrete Reinforced with Glass Fiber-Reinforced Polymer (GFRP) Bars—Code and Commentary. This new code was developed by an American National Standards Institute–approved consensus process and addresses structural systems, members, and connections, including cast-in-place, precast, nonprestressed, and composite concrete construction. ACI 440.11-22 is the first comprehensive building code covering the use of nonmetallic, GFRP reinforcing bars in structural concrete applications. This article provides background on this new code and discusses potential uses for precast concrete components and structures.