Geotextile reinforcement techniques have been widely used in paving works around the world and have proven to be effective in improving pavement performance. This study has focused on using different positions and numbers of geotextile reinforcement sheets between the layers of flexible pavement for rutting reduction. Fitting depth was measured in the field at seven constructed sections of the pavement of the road model. Each section has been strengthened with different reinforcement approaches. All road sections were subjected to a maximum load repetition of 10,000 cycles. The results indicate that using three layers of geotextile beneath each course of the designed road pavement sections (surface, binder, and base) reduced rutting by 96%. Traffic benefit ratio (TBR) has been employed in this study to reveal the behavior of geotextile reinforcement in increasing the service life of the road. TBR values are the load cycling ratio between the reinforced and unreinforced section for the exact recorded rut depth, it has been found to be minimally equal to 4 for the case of using one layer of reinforcement at interface I, and that value keeps growing up for other reinforcement cases.
The use of fiber-reinforced polymer (FRP) composites in retrofitting and strengthening reinforced concrete (RC) slabs has gained substantial attention due to their durability, high strength-to-weight ratio, and ease of application. The objective of this study was to theoretically investigate the flexural behavior of RC slabs strengthened with carbon fiber-reinforced polymer (CFRP) plates applied in different percentages and patterns using finite element methods (FEMs) in comparison with the experiment outcomes available in the literature using the ABAQUS software (version 2020). This study focused on understanding the influence of the CFRP configuration on the structural behavior, including the load-carrying capacity, flexural performance, crack patterns, and failure modes, under static loading on seventeen RC slabs of 1800 × 1800 mm and 150 mm thickness. A comprehensive program was adopted, where RC slabs were strengthened using CFRP plates with different coverage percentages (0.044, 0.088, 0.133, 0.178, and 0.223) and arrangements (unidirectional, cross-hatched, and grid patterns) to evaluate the slabs’ performance under realistic service conditions. After comparison, the results validate that the percentage and pattern of CFRP plates influence the performance of RC slabs. Higher CFRP plate percentages yielded greater strength enhancement, while optimized patterns guaranteed a uniform stress distribution and delayed crack initiation. This study hypothesizes that the flexural strength, stiffness, and failure behavior of RC slabs are significantly affected by the percentage and arrangement of CFRP strengthening, with certain configurations providing superior structural performance. The use of CFRP cross-hatched plates improved the load–deflection behavior, increasing the ultimate loads by 35% (452 kN) while reducing ultimate deflection, with the cross-hatched CFRP specimen showing the highest deflection among all the CFRP specimens. This study provides engineers and practitioners with valuable information on choosing appropriate strengthening plans for RC slabs using CFRP plates, leading to more cost-effective and ecologically friendly structural rehabilitation methods.
Reinforced concrete deep beams are a vital member of infrastructures such as bridges, shear walls, and foundation pile caps. Thousands of dollars and human lives are seriously threatened due to shear failure, which have developed in deep beams containing web openings. This paper investigates numerically the overall behavior of simply supported concrete deep beams reinforced with carbon fiber-reinforced polymer (CFRP) sheets through forty specimens grouped in four groups. The numerical analysis results agreed well with the experimental results in the literature, particularly the visual failure initiation with a failure load difference of nearly 7%. Finite element analyses indicated that the presence of an opening with considerable width reduced the failure load by about 71% compared to the corresponding solid specimens. In addition, the reinforced concrete deep beam samples started to behave differently when the (b/h) ratio increased more than (2.0). The findings showed that the compression stress strut pathway had been disrupted by the web opening leading to stress redistribution, and the structure will behave as two separate members. Thus, the upper web-opening part sustained the most stress, while the part under the web-opening did not show any stress concentration. The numerical stress distribution results showed that the attributed reason is that rebars and openings helped redirect the stresses to the compression strut. Using CFRP sheets with a width of more than 160 mm significantly improved the reinforced concrete deep beam with web-opening due to the increasing confinement to the upper part of the reinforced concrete deep beams with the opening.
1 January 2022 in Journal of the Mechanical Behavior of Materials
Using the ABAQUS software, this article presents a numerical investigation on the effects of various stud distributions on the behavior of composite beams. A total of 24 continuous 2-span composite beam samples with a span length of 1 m were examined (concrete slab at the top and steel I-section at the bottom). The concrete slab used is made of a reactive powder concrete with a compressive strength of 100.29 MPa. The total depth of each sample was 0.220 m. The samples were separated into four groups. The first group involved 6 specimens with shear connectors distributed into 2 rows with different distances (65, 85, 105, 150, 200, and 250 mm). The second group had the same spacing of shear connectors as the first group except that the shear connectors were distributed with one row along the longitudinal axis. The third group consisted of six specimens with single and double shear connectors distributed along the longitudinal axis. The fourth group included six specimens with one row of shear connectors arranged in a staggered distribution along the longitudinal axis. Results show that the optimum spacing was 105 mm in all groups and the deflection in group four fluctuated up and down due to the non-symmetrical distribution of the shear connectors.
This paper presents a numerical investigation for the behavior of simply supported T-section deep beams, which strengthened with Carbon Fiber Reinforced Polymer (CFRP) sheets. The used specimens were (1.8 m length), (450 mm width and 100 mm depth) flange dimensions, and (180 mm width and 360 mm depth) web dimensions. The specimens were divided into four groups. Mainly, the difference between specimens in each group is in the main reinforcement details. The control group consisted of six beams unstrengthen with CFRP, the other groups were similar to the control group but externally strengthened with CFRP sheets, which were (0.131 mm) thickness. In detail, the second group was strengthened with CFRP sheet at the bottom surface of the web. The third group was strengthened horizontally with CFRP sheets at both sides of the specimen's web. The last group was strengthened with three sheets of CFRP; one at the bottom face of the web and the others at the web sides. The results show that using CFRP at the bottom slightly increased the ultimate strength and changed the failure mode from flexural to shear. Using CFRP at the sides significantly increased both flexural and shear strength, while using CFRP at the sides and bottom of the web did not significantly enhanced the ultimate strength in comparison with using CFRP at the sides only.