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23 pages, 6079 KB

Open AccessArticle

Structural Effects of Concrete Creep in a Prestressed Balanced Cantilever Bridge Based on Classical and Fractional Rheological Models

by Krzysztof Nowak, Radosław Oleszek and Artur Zbiciak

Materials 2025, 18(23), 5457; https://doi.org/10.3390/ma18235457 - 3 Dec 2025

Viewed by 222

Abstract

This paper discusses the phenomenon of concrete creep and its impact on bridge structures, with particular emphasis on the mechanical models used to describe it. Classical rheological models, such as the Maxwell and Kelvin–Voigt, along with their generalized and fractional extensions incorporating fractional-order [...] Read more.

This paper discusses the phenomenon of concrete creep and its impact on bridge structures, with particular emphasis on the mechanical models used to describe it. Classical rheological models, such as the Maxwell and Kelvin–Voigt, along with their generalized and fractional extensions incorporating fractional-order derivatives, are presented. These models differ in their complexity and in the accuracy of fit to laboratory test results. The use of non-classical, fractional-order rheological models (the fractional Kelvin–Voigt model and the fractional Zener model) enables better model fitting. The paper further describes methods for estimating creep effects in bridge design. The most popular is the effective modulus method, which is easy to implement but does not account for the load application history. More accurate approaches (e.g., Trost, Bažant, incremental method according to linear elasticity theory) are based on iterative procedures and require advanced computer implementation. The consequences of creep in bridge structures are highlighted: geometric (changes in elevation) and static (redistribution of internal forces and support reactions, changes in sectional stresses). These effects are particularly important in structures erected in stages, such as bridges built using the balanced cantilever method. The analytical section presents the influence of various creep models on changes in static quantities for a three-span prestressed bridge constructed by the cantilever method. The importance of proper selection of the creep model for the accuracy of engineering calculations and for the correct assessment of the long-term behavior of the structure is emphasized. Full article

(This article belongs to the Special Issue Concrete in Structural Engineering: Fabrication and Mechanical Behavior (Third Edition))

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30 pages, 11719 KB

Open AccessArticle

Numerical Simulation of the Post-Tensioned Beams Behaviour Under Impulse Forces Loading

by Anna Jancy and Adam Stolarski

Materials 2025, 18(23), 5432; https://doi.org/10.3390/ma18235432 - 2 Dec 2025

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Abstract

The paper presents the results of numerical simulation of the dynamic behaviour of the post-tensioned beams subjected to a constant force impulse load over time and a short-term force impulse load varying over time. Abaqus programme was used for numerical analysis, introducing necessary [...] Read more.

The paper presents the results of numerical simulation of the dynamic behaviour of the post-tensioned beams subjected to a constant force impulse load over time and a short-term force impulse load varying over time. Abaqus programme was used for numerical analysis, introducing necessary and detailed modifications to the modelling and calibration parameters. The numerical dynamics models were calibrated using results previously obtained from our own experimental and numerical static analysis. To estimate the dynamic strength of structural materials, the dynamic strength coefficient was applied in the concrete damage plasticity model, and the Johnson–Cook model was used to describe the evolution of the dynamic yield strength of steel elements. An explicit procedure was used to solve the dynamic equilibrium equations. The selection of the Rayleigh damping parameter and the methodology for determining the external load in a dynamic problem are discussed. The study presents new results on the influence of the type of force impulse loading and variable prestressing eccentricity in numerical simulations of post-tensioned beams. The results of the simulation show that the post-tensioned beams achieved a lower dynamic load capacity under a constant force impulse load of approximately 5% compared to the static load capacity achieved in the experimental static tests, regardless of the assumed prestressing eccentricity. A dynamic load capacity significantly exceeded the static load capacity under short-term time-varying force impulse loading. The beam with the larger prestressing eccentricity achieved a dynamic load capacity of 211% of the static load capacity, while the beam with the smaller prestressing eccentricity achieved a dynamic load capacity of 198% of the static load capacity. Full article

(This article belongs to the Special Issue Concrete in Structural Engineering: Fabrication and Mechanical Behavior (Third Edition))

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21 pages, 2909 KB

Open AccessArticle

Novel Fractional Approach to Concrete Creep Modeling for Bridge Engineering Applications

by Krzysztof Nowak, Artur Zbiciak, Piotr Woyciechowski, Damian Cichocki and Radosław Oleszek

Materials 2025, 18(15), 3720; https://doi.org/10.3390/ma18153720 - 7 Aug 2025

Cited by 2 | Viewed by 878

Abstract

The article presents research on concrete creep in bridge structures, focusing on the influence of concrete mix composition and the use of advanced rheological models with fractional-order derivatives. Laboratory tests were performed on nine mixes varying in blast furnace slag content (0%, 25%, [...] Read more.

The article presents research on concrete creep in bridge structures, focusing on the influence of concrete mix composition and the use of advanced rheological models with fractional-order derivatives. Laboratory tests were performed on nine mixes varying in blast furnace slag content (0%, 25%, and 75% of cement mass) and air-entrainment. The results were used to calibrate fractal rheological models—Kelvin–Voigt and Huet–Sayegh—where the viscous element was replaced with a fractal element. These models showed high agreement with experimental data and improved the accuracy of creep prediction. Comparison with Eurocode 2 revealed discrepancies up to 64%, especially for slag-free concretes used in prestressed bridge structures. The findings highlight the important role of mineral additives in reducing creep strains and the need to consider individual mix characteristics in design calculations. In the context of modern bridge construction technologies, such as balanced cantilever or incremental launching, reliable modeling of early-age creep is particularly important. The proposed modeling approach may enhance the precision of long-term structural behavior analyses and contribute to improved safety and durability of concrete infrastructure. Full article

(This article belongs to the Special Issue Concrete in Structural Engineering: Fabrication and Mechanical Behavior (Third Edition))

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24 pages, 6864 KB

Open AccessArticle

Mechanical Analysis of HPFRCC Precast Composite Column

by Tingting Lu, Bin Wang, Haowei Jin and Yuxiang Wen

Materials 2025, 18(7), 1567; https://doi.org/10.3390/ma18071567 - 30 Mar 2025

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Abstract

In order to improve the physical and mechanical properties and the ability to perform in practical applications of prefabricated monolithic composite columns, high-performance fiber-reinforced cementitious composites (HPFRCC) material was prefabricated into mold shells to form HPFRCC precast monolithic composite columns. Through the axial [...] Read more.

In order to improve the physical and mechanical properties and the ability to perform in practical applications of prefabricated monolithic composite columns, high-performance fiber-reinforced cementitious composites (HPFRCC) material was prefabricated into mold shells to form HPFRCC precast monolithic composite columns. Through the axial compression test, the axial compression failure form, failure mechanism, bearing capacity, deformation ability, and influencing factors were studied. The results showed that compared with RC precast monolithic composite column, the HPFRCC specimens showed better deformation performance. HPFRCC prefabricated shells provided additional restraint beyond stirrups. The HPFRCC composite columns’ yield compressive strain increased by 11.59% on average compared with the RC composite column, and the peak compressive strain increased by 10.92%. The larger the ρ_v of stirrups was, the larger the compressive strain of the key point of the columns was. Compared with the FC-P-01 (ρ_v was 1.05%), the yield compressive strain of FC-P-02 (ρ_v was 1.48%) increased by 21.63%, and the yield compressive strain of FC-P-03 (ρ_v was 0.74%) decreased by 11.20%. The calculation model of the axial bearing capacity of the HPFRCC composite column was established through theoretical mechanical analysis, and the calculated values of the model fit with the experimental values. Full article

(This article belongs to the Special Issue Concrete in Structural Engineering: Fabrication and Mechanical Behavior (Third Edition))

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19 pages, 4223 KB

Open AccessArticle

Experimental Study on Mechanical Properties of Desert Sand Concrete Under Freeze–Thaw Cycles

by Wenjie Xi, Zhiqiang Li, Yang Zhou, Gang Li and Feng Ji

Materials 2025, 18(7), 1546; https://doi.org/10.3390/ma18071546 - 29 Mar 2025

Cited by 2 | Viewed by 1070

Abstract

This study aims to explore the mechanical behavior of Desert Sand Concrete (DSC) under freeze–thaw (F-T) cycles. By adjusting the number of F-T cycles, the research analyzed the impact of various desert sand replacement ratios on the frost resistance of concrete. The study [...] Read more.

This study aims to explore the mechanical behavior of Desert Sand Concrete (DSC) under freeze–thaw (F-T) cycles. By adjusting the number of F-T cycles, the research analyzed the impact of various desert sand replacement ratios on the frost resistance of concrete. The study focused on the dynamic changes in mass loss of concrete specimens, relative dynamic elastic modulus, cubic compressive strength, splitting tensile strength, and axial compressive strength. Scanning electron microscopy was employed to analyze the micro-morphology of specimens after F-T cycles. This analysis aimed to predict the service life of DSC and provide practical recommendations for the maximum compressive strength loss rate within the designed service life. The results indicated that although the frost resistance of DSC was similar to that of ordinary concrete before 50 F-T cycles, it subsequently exhibited a nonlinear degradation trend correlated with increasing desert and replacement ratios, with both frost resistance and compactness reaching optimal levels at a 40% replacement rate. Additionally, the F-T damage model proposed in this study demonstrated high applicability and fitting accuracy. This model provided effective theoretical support for understanding and predicting the mechanical behavior of DSC. Full article

(This article belongs to the Special Issue Concrete in Structural Engineering: Fabrication and Mechanical Behavior (Third Edition))

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20 pages, 4070 KB

Open AccessArticle

An Investigation of the Influence of Paste’s Rheological Characteristics on the Tensile Creep of HVFAC at Early Ages

by Tongyuan Ni, Kang Chen, Fangshi Gao, Xingrui Li, Yang Yang, Deyu Kong and Shuifeng Yao

Materials 2025, 18(2), 305; https://doi.org/10.3390/ma18020305 - 11 Jan 2025

Viewed by 1064

Abstract

The rheological properties of concrete paste significantly influence its tensile creep behavior. In this study, the tensile creep behavior of high-volume fly ash concrete (HVFAC) employing the same cementitious pastes was experimentally investigated, and the rheological properties of the paste containing a high [...] Read more.

The rheological properties of concrete paste significantly influence its tensile creep behavior. In this study, the tensile creep behavior of high-volume fly ash concrete (HVFAC) employing the same cementitious pastes was experimentally investigated, and the rheological properties of the paste containing a high volume of fly ash using the nanoindentation (NI) technique was investigated in order to explore the influence of the paste’s rheological properties (such as micro-mechanical properties and microscopic creep) on the early-age tensile creep of HVFAC. The results demonstrated that the micro-strain of paste containing a high volume of fly ash (HVFA) showed a larger value than that without fly ash. As the test age extends, a decreasing trend in microscopic creep was observed which could be attributed to the growth of the content of HD C–S–H (high density C–S–H) gel. Moreover, within the same age period, the experimental data revealed that the incorporation of fly ash resulted in the reduction of the values of the creep modulus C and characteristic time τ. The effects of fly ash dosages and loading age on the creep properties of concrete was consistent with the micro-creep properties of the cementitious paste. The tensile specific creep values derived from the ZC (“ZC” are initials for the word ‘‘self-developed” in Chinese) model based on nanoindentation data closely match those obtained from experiments. Full article

(This article belongs to the Special Issue Concrete in Structural Engineering: Fabrication and Mechanical Behavior (Third Edition))

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15 pages, 6516 KB

Open AccessArticle

Reversed Cyclic Behavior of Carbon Nanofiber-Reinforced Concrete Shear Walls

by Liang Lu, Musaab Suliman and Wanqiu Xia

Materials 2024, 17(23), 5786; https://doi.org/10.3390/ma17235786 - 26 Nov 2024

Cited by 1 | Viewed by 860

Abstract

This study investigates the effects of integrating carbon nanofibers (CNF) into concrete to enhance the mechanical properties and reversed cyclic behavior of framed shear walls, addressing the need for improved seismic performance and durability. Despite the known benefits of CNF in improving concrete [...] Read more.

This study investigates the effects of integrating carbon nanofibers (CNF) into concrete to enhance the mechanical properties and reversed cyclic behavior of framed shear walls, addressing the need for improved seismic performance and durability. Despite the known benefits of CNF in improving concrete properties and enabling structural health monitoring, its application in framed shear walls has been limited. Through the design and testing of nineteen CNFC formulations, this research established a constitutive relationship allowing the Cyclic Softened Membrane Model (CSMM) to be applied to CNFC. Finite element analysis of shear walls under reversed cyclic loading revealed notable improvements in shear force capacity and ductility when CNF was incorporated. These findings highlight the dual role of CNFC in advancing both material performance and structural resilience, offering a significant contribution to the fields of material science and earthquake engineering. Full article

(This article belongs to the Special Issue Concrete in Structural Engineering: Fabrication and Mechanical Behavior (Third Edition))

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22 pages, 4773 KB

Open AccessArticle

Shear Strengthening of RC Beams Using Prestressed Near-Surface Mounted Bars Reducing the Probability of Construction Failure Risk

by Sabry Fayed, Mohamed Ghalla, Jong Wan Hu, Ehab A. Mlybari, Abdullah Albogami and Saad A. Yehia

Materials 2024, 17(23), 5701; https://doi.org/10.3390/ma17235701 - 21 Nov 2024

Cited by 30 | Viewed by 2022

Abstract

In this study, shear-critical reinforced concrete (RC) beams were strengthened by combining the prestressing and near-surface mounted (NSM) rods approaches. The potential danger of failure in such RC beams is a substantial concern as it is considered a potential threat. This study addresses [...] Read more.

In this study, shear-critical reinforced concrete (RC) beams were strengthened by combining the prestressing and near-surface mounted (NSM) rods approaches. The potential danger of failure in such RC beams is a substantial concern as it is considered a potential threat. This study addresses its careful mitigation through experimental identification and numerical analysis to enhance the safety and sustainability of buildings by reducing the probability of failure risk for these RC beams. Nine of the ten RC beams that were tested had strengthened, and one had not. Internal prestressing (IP) within the beam body, external prestressing NSM (PNSM), internal embedment (IE) inside the beam with or without prestressing, and NSM are the strengthening technologies that were employed. The range of the extra shear reinforcement ratios (μs) was 0.87% to 1.60%. We investigated how strengthened beams behaved structurally in terms of the cracking load, ultimate load, load–deflection response, ultimate deflection, and stiffness. The insertion of five pairs of PNSM rods (μs = 1.45%) and five pairs of IP rods (μs = 1.6%), respectively, increased the beams’ shear capacity by 57.8% and 70.4%. Shear capacity increased by 23.2% when three pairs of IE rods (μs = 1.02%) were installed. The prestressing location had an impact on shear capacity, with the interior case surpassing the external one. Compared to the control, the stiffness of the strengthened beams rose by 20%, 82%, and 84.4% when three, four, or five pairs of internal prestressing rods were added. A formula is proposed to calculate the shear capacity of all beams strengthened using various methods. Full article

(This article belongs to the Special Issue Concrete in Structural Engineering: Fabrication and Mechanical Behavior (Third Edition))

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