Research

20 pages, 7788 KiB

Open AccessArticle

Experimental and Numerical Investigation of Geosynthetic-Reinforced Pile-Supported Embankments for Loose Sandy Soils

by Rashad Alsirawan, Ammar Alnmr and Edina Koch

Buildings 2023, 13(9), 2179; https://doi.org/10.3390/buildings13092179 - 28 Aug 2023

Cited by 3 | Viewed by 1009

This research focuses on advancing the geosynthetic-reinforced pile-supported embankment technology over loose sandy soil. A small-scale laboratory model supported by floating piles and a geotextile layer was constructed, and a numerical model was validated against laboratory measurements. This study aims to achieve a [...] Read more.

This research focuses on advancing the geosynthetic-reinforced pile-supported embankment technology over loose sandy soil. A small-scale laboratory model supported by floating piles and a geotextile layer was constructed, and a numerical model was validated against laboratory measurements. This study aims to achieve a more uniform distribution of the load over all piles of the system via a parametric study that analyzes the influence of embankment fill material, horizontal reinforcement scenarios, pile cap shape, and pile type. The results demonstrate that using embankment fill with high cohesion and internal friction properties leads to a significant reduction of 46% and 37% in maximum settlements, respectively, and similarly, results in a noteworthy reduction of 48% and 50% in differential settlements. The incorporation of two geotextile layers contributes to a reduction of up to 30% in maximum settlement. The utilization of plus-shaped caps in small areas, with an area equal to three times the cross-sectional area of the pile, has been substantiated as the preeminent approach for the reduction of settlements. Piles with caps also present better behavior regarding differential settlements compared to longer piles and piles with bigger diameters under the same volume condition. Full article

(This article belongs to the Special Issue Advanced Technologies in Foundations Engineering and Construction Materials)

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21 pages, 6690 KiB

Open AccessArticle

Static Modulus of Deformation of Uncemented Layers of the Railway Substructure—Comparison of Values and Determination of Correlation Dependence According to the Test Procedure of the Slovak Railways and Deutsche Bahn A.G.

by Libor Ižvolt, Peter Dobeš, Daniel Papán and Martin Mečár

Buildings 2023, 13(8), 2016; https://doi.org/10.3390/buildings13082016 - 08 Aug 2023

Cited by 2 | Viewed by 699

Abstract

The paper focuses on the analysis of the values of the static modulus of deformation obtained by the application of the test procedure specified in the methodology for the diagnostics of the sub-ballast layers used for German railways (DIN 18 134) and the [...] Read more.

The paper focuses on the analysis of the values of the static modulus of deformation obtained by the application of the test procedure specified in the methodology for the diagnostics of the sub-ballast layers used for German railways (DIN 18 134) and the Railways of the Slovak Republic (Regulation TS4). The purpose of the study was to determine the correlation between the measured values of the static modulus of deformation according to the above-mentioned methodologies based on a series of experimental measurements on an experimental field built at a scale of 1:1. It also aimed to develop a numerical model characterising the behaviour of the loaded environment during the experimental measurements using the finite element method, which can subsequently be used for the design of the structural composition of the sub-ballast layers. For the purpose of the experimental measurements, a sub-ballast layer of 0/31.5 mm crushed aggregate of different design thicknesses was applied to the sub-ballast layers. A polynomial dependence with a high value of the reliability coefficient can be found between the results of the static modulus of deformation obtained using the mentioned measurement methodologies during the quality inspection of the implemented construction works. This dependence is valid for the specific boundary conditions of the experimental measurements performed (subsoil of clay with gravel admixture and the sub-ballast crushed aggregate layer of 0/31.5 mm dolomitic gravel). In the future, establishing correlation dependencies for other boundary conditions and structural material compositions can be considered. Full article

(This article belongs to the Special Issue Advanced Technologies in Foundations Engineering and Construction Materials)

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22 pages, 3248 KiB

Open AccessArticle

Bending Analysis of Stepped Rectangular Plates Resting on an Elastic Half-Space Foundation

by Jian Wu, Jinpeng Zhang and Xue Li

Buildings 2023, 13(7), 1671; https://doi.org/10.3390/buildings13071671 - 29 Jun 2023

Cited by 1 | Viewed by 2484

Abstract

In this paper, the bending behavior of rectangular plates with stepped thickness resting on an elastic half-space foundation is investigated through an analytic method. Combined with the bending theory of the rectangular thin and moderately thick plate, the stepped rectangular plate is divided [...] Read more.

In this paper, the bending behavior of rectangular plates with stepped thickness resting on an elastic half-space foundation is investigated through an analytic method. Combined with the bending theory of the rectangular thin and moderately thick plate, the stepped rectangular plate is divided into upper and lower plates, and the Fourier series is used to obtain the analytical solution of the deflection of the plate and the interaction force between the plate and foundation. The influence of the elastic modulus of the plate, plate theory, and the dimension of the plate on the deflection of the stepped rectangular plate is also discussed. The results show that the analytical solution is basically the same as the existing research results, and it is also verified by the analysis results of the models established by ABAQUS software. The deflection at the center of the stepped rectangular plate increases with the increase of the elastic modulus of the upper plate and the decrease of the side length of the upper plate, while the plate theory has little effect on the deflection of the plate. This method not only overcomes some of the disadvantages of numerical methods but also eliminates the assumptions of the Winkler foundation model and the two-parameter foundation model, thus obtaining a more reasonable and accurate bending performance of the stepped rectangular plate resting on the elastic half-space foundation. Full article

(This article belongs to the Special Issue Advanced Technologies in Foundations Engineering and Construction Materials)

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20 pages, 2874 KiB

Open AccessArticle

Interface Shear Strength Behavior of Cement-Treated Soil under Consolidated Drained Conditions

by Thanh Tu Nguyen, Minh Duc Nguyen, Tong Nguyen and Thanh Chien Phan

Buildings 2023, 13(7), 1626; https://doi.org/10.3390/buildings13071626 - 27 Jun 2023

Cited by 1 | Viewed by 1247

Abstract

This paper presents a series of laboratory tests to determine the shear strength and interface shear strength of cement-treated silty soil under consolidated and drained conditions. The test variables include the effective normal stress, cement content, and curing period. Experimental results indicated that [...] Read more.

This paper presents a series of laboratory tests to determine the shear strength and interface shear strength of cement-treated silty soil under consolidated and drained conditions. The test variables include the effective normal stress, cement content, and curing period. Experimental results indicated that the effective shear strength and interface shear strength of cement-treated soil specimens increased significantly as the cement content increased. After 28 days, the average shear strength ratio increased from 1.28 to 2.4, and the average interface efficiency factor improved from 1.15 to 1.55 as the cement content increased from 3% to 10%. It resulted from an increase in grain size and the fraction of sand-sized particles in the treated soils, approximately in two-time increments for the specimens treated with 10% cement content after 28 days of curing. In addition, the peak and residual values of the shear strength and interface shear strength of the cement-treated soil specimens were determined to assess their brittle behavior under high shear deformation. Last, two new empirical models are introduced herein. The first power equation is to predict the shear strength ratio of cement-treated soil at 28 days of curing using the soil-water/cement content ratio. The other proposed model is useful for assessing the rate of shear strength and interface shear development of cement-treated soil specimens within 56 days of curing. Full article

(This article belongs to the Special Issue Advanced Technologies in Foundations Engineering and Construction Materials)

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16 pages, 13624 KiB

Open AccessArticle

The Influence of the Prestressing Level of the Fully Threaded Anchor Bar on the Corrosion Rate

by Michal Zahuranec, Peter Koteš and Jakub Kraľovanec

Buildings 2023, 13(7), 1592; https://doi.org/10.3390/buildings13071592 - 23 Jun 2023

Cited by 3 | Viewed by 688

Abstract

The article presents experimental research on the corrosion of prestressing steel bars with denotation CKT (fully threaded anchor bars), which are composed of high-quality prestressing steel of the grade Y 1050 (1050 MPa). The experiment was performed using an electrochemical accelerated test. The [...] Read more.

The article presents experimental research on the corrosion of prestressing steel bars with denotation CKT (fully threaded anchor bars), which are composed of high-quality prestressing steel of the grade Y 1050 (1050 MPa). The experiment was performed using an electrochemical accelerated test. The aspects of the electric current value influence, time dependence on the degree of corrosion, and especially the influence of the prestressing level in the prestressing steel bars on the degree of corrosion were observed and examined. The results of the experiment showed that if the sample was in a stressed state, its degree of corrosion increased. Specifically, for the maximal stress equal to 90% of the tensile strength, the corrosion degree was increased by approximately 7.3%, in comparison to the unstressed specimen. In this case, a 7.3% corrosion degree corresponds to a weight loss of 350 g. The theoretical degree of corrosion was calculated using Faraday’s Law, which allowed the prediction of a rough estimate of the corrosion degree obtained with known input data. The experimental results showed that there was no apparent difference in the corrosion morphology of the sample during the same time-dependent corrosion influence at the same prestressing level in the sample with the same electric current value. Full article

(This article belongs to the Special Issue Advanced Technologies in Foundations Engineering and Construction Materials)

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21 pages, 12236 KiB

Open AccessArticle

Analysis of a Large-Scale Physical Model of Geosynthetic-Reinforced Piled Embankment and Analytical Design Methods

by Jozef Vlček, Marian Drusa, Filip Gago and Ján Mihálik

Buildings 2023, 13(6), 1464; https://doi.org/10.3390/buildings13061464 - 04 Jun 2023

Viewed by 1195

Abstract

The piled embankment represents one of the solutions for the realization of a soil body on a compressible subsoil where extended settlement or insufficient stability threatens the serviceability of related structures. Widely adopted analytical design procedures were analyzed: Marston’s formula and Hewlett and [...] Read more.

The piled embankment represents one of the solutions for the realization of a soil body on a compressible subsoil where extended settlement or insufficient stability threatens the serviceability of related structures. Widely adopted analytical design procedures were analyzed: Marston’s formula and Hewlett and Randolph method contained in the British standard BS 8006-1, the German regulation EBGEO and the Dutch regulation CUR 226. Using these recommendations, the theoretical values of the individual parts of the load acting in the embankment and, subsequently, the values of the axial strain or tensile forces in the reinforcement were determined and compared with experimental data obtained from the tests in the large-scale physical model. For the presented case, without subsoil support, CUR 226 with the inverse load, which is recommended in the case of subsoil with low bearing capacity, shows better coincidence with the measured data. Overall, EBGEO and CUR 226 can be considered to be close to the real behavior of the piled embankment. Because of the frequent utilization of geosynthetic reinforcement and possible changes of subsoil parameters during the service life of the piled embankment, a rheological process of its elements should be investigated during the design process. Full article

(This article belongs to the Special Issue Advanced Technologies in Foundations Engineering and Construction Materials)

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27 pages, 9356 KiB

Open AccessArticle

Mechanical Properties of Corroded Reinforcement

by František Bahleda, Jozef Prokop, Peter Koteš and Agnieszka Wdowiak-Postulak

Buildings 2023, 13(4), 855; https://doi.org/10.3390/buildings13040855 - 24 Mar 2023

Viewed by 1521

Abstract

Reinforced concrete (RC) structures are basically composite elements because they consist of two materials—concrete and reinforcement (reinforcing steel bars). From the point of view of the design of new constructions, it is necessary to design them in such a way as to ensure [...] Read more.

Reinforced concrete (RC) structures are basically composite elements because they consist of two materials—concrete and reinforcement (reinforcing steel bars). From the point of view of the design of new constructions, it is necessary to design them in such a way as to ensure their reliability, safety and durability throughout their design lifetime, T_d. However, all elements, including RC members, are affected by the environment in which they are located. An aggressive environment causes degradation of materials. In the case of reinforcement, corrosion of the reinforcement is considered to be the most well-known and at the same time the most serious way of degradation. From the point of view of existing reinforced concrete elements, it is therefore important to know whether and how the corrosion of the reinforcement affects the mechanical properties of the given reinforcement. The mechanical properties of reinforcement are very important when assessing the actual condition of reinforced concrete (RC) elements, to determine the resistance and load-carrying capacity of the elements. Therefore, it is necessary to investigate the effect of corrosion on mechanical properties of reinforcement. The paper reports on the results of an experimental analysis of the effect of corrosion on the change in the mechanical properties of reinforcement. Furthermore, it presents both the redistribution of mechanical properties along the cross-section of reinforcement, produced by various techniques, such as hot-rolling, hot-rolling with controlled cooling from rerolling temperature and cold-rolled as well as the mechanical properties under the action of corrosion. Full article

(This article belongs to the Special Issue Advanced Technologies in Foundations Engineering and Construction Materials)

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15 pages, 13435 KiB

Open AccessArticle

Study of Application of Fiber Reinforced Concrete in Anchorage Zone

by Martin Vavrus and Jakub Kralovanec

Buildings 2023, 13(2), 524; https://doi.org/10.3390/buildings13020524 - 14 Feb 2023

Cited by 4 | Viewed by 1540

Abstract

In the case of post-tensioned or geotechnical structures, the anchorage zone is considered a critical part of the design and construction process. Generally, the failure of the anchorage zone is one of the most common problems. High-bearing stresses create significant transverse tension. For [...] Read more.

In the case of post-tensioned or geotechnical structures, the anchorage zone is considered a critical part of the design and construction process. Generally, the failure of the anchorage zone is one of the most common problems. High-bearing stresses create significant transverse tension. For these reasons, conventional reinforcement, usually in the form of closed stirrups, must be designed. The presented analysis is focused on the possible increase of load-carrying capacity of the anchorage zone with steel fiber-reinforced concrete. Three types of specimens were analyzed. The first type of specimen represented the anchorage zone made from standard reinforced concrete. The second and third series of specimens were designed from fiber-reinforced concrete with two different volumes of steel fibers added into the anchorage zone. The parameters used in the numerical analysis of the anchorage zone were experimentally determined on a set of beam specimens. In the analysis, the anchorage zone was loaded by a node force applied on a steel load distribution plate placed on the top edge of the bloc. The performed numerical study suggests that the load-bearing capacity can be increased by adding fiber-reinforced concrete with a higher volume of fiber (Dramix 3D 55/30, volume of fiber of 110 kg/m³) into the vicinity of the anchorage plate. Full article

(This article belongs to the Special Issue Advanced Technologies in Foundations Engineering and Construction Materials)

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