International Journal of Civil Engineering最新文献

Composite trough beam with corrugated steel web wrapped with steel plate (CTBCS) is a trough beam composed of several components, which has a good application prospect in rail transit system. As CTBCS is composed of several components, the bond slip between the interfaces of the components can cause additional displacement. In order to study the bond slip effect of CTBCS, the calculation formulas of additional displacement caused by bond slip effect were first derived theoretically, and the accuracy of the formulas were verified by comparing theoretical results with simulated results. Then, the proportions of different kinds of displacements to the total displacements were studied, among which the bending displacement accounts for the largest proportion of the total displacement, about 55%-70%, the shear displacement and the bond slip displacement account for about 30% and 2%-10% respectively. Finally, the influence of beam parameters on bond slip displacement was analyzed, the study results show that the influence of different beam parameters on the bond slip effect varies, and the influence of the thickness of steel plate is negligible. The analysis results of this paper can provide data support for the selection of beam parameters in the design process of CTBCS.

In the study, flexural performances of FRP reinforced concrete (RC) slabs with different fiber and bar surface properties were investigated. Glass fiber reinforced polymer (GFRP), Carbon fiber reinforced polymer (CFRP), Aramid fiber reinforced polymer (AFRP) and Basalt fiber reinforced polymer (BFRP) steel reinforcements were used in the reinforcement of the slabs. A total of 27 slabs were produced in the dimensions of 1100–1100–100 mm and with the same reinforcement ratios as FRP and steel reinforcement and were tested with the four-point flexural test method. The flexural strength, moment capacity, toughness and ductility values of the slabs were calculated by determining their flexural behaviour, and the average values were compared. In the comparison, the behaviour of the FRP RC slabs was analysed by taking the steel RC slabs as reference. The effects of FRP fiber type and bar surface properties on slab behaviour were evaluated. The bending load-carrying capacity of AFRP and GFRP RC slabs with ribbed surfaces was 4% higher than those with sand-coated surfaces. In addition, the bending load-carrying capacity of BFRP and CFRP RC slabs with sand-coated surfaces was 13% and 16% higher than those with ribbed surfaces, respectively. The type of failure in slabs varies based on the type of reinforcement and the surface properties of the reinforcement. Three types of failures have been identified: flexural failure, shear failure, and flexural-shear failure. The ductility performance of steel RC slabs has been determined to be the highest, with a value of 9.45. When comparing toughness, sand-coated FRP bars exhibit toughness levels 8–40% higher than ribbed ones. Among the FRP RC slabs, sand-coated CFRP RC slabs provide the greatest contribution to flexural load-carrying capacities.

The effectiveness of load-reduction techniques often diminishes due to creep behavior observed in geomaterials, as loess backfill is used, the load reduction rate of high-filled cut-and-cover tunnels (HFCCTs) after creep will decrease by 10.83%, posing a threat to the long-term stability of deeply buried structures such as HFCCTs. Therefore, a geotechnical solution is crucial to ensuring sustained effectiveness in load-reduction strategies over time. This study utilizes a finite-difference method to examine three promising measures for mitigating creep effects. Our analysis focuses on the time-dependent changes in earth pressure atop the cut-and-cover tunnel (CCT) and the internal distribution of cross-sectional forces, including bending moment, shear force, axial force, and displacement. Results indicate that the creep behavior of load-reduction materials significantly influences the internal force distribution. Furthermore, sustained load reduction is achieved when utilizing low-creep materials like dry sandy gravel as backfill soil, which needs to be borrowed from other sites. Additionally, integrating concrete wedges with load-reduction techniques facilitates a more uniform stress distribution atop CCTs.

In this study, geothermal energy has demonstrated significant potential as a sustainable and renewable energy resource for space conditioning. However, developing nations like India have not yet adopted this technology for space heating and cooling, despite experiencing satisfactory seasonal variation in ambient temperatures in many places. Furthermore, the thermo-mechanical behavior of geothermal energy piles in the specific soil and climatic conditions of the area has not been investigated. The present study aims to numerically explore the thermo-mechanical response of a geothermal energy pile in the local soil under the climatic conditions of Jamshedpur, a city in Eastern India. The study analyzed the shear stress at the interface of the pile and adjacent soil, the displacement of the pile head, middle, and toe, and the volumetric strain of the soil. The results of this study was validated and compared with previous studies and found a good agreement with it. The maximum displacement for mechanical loading was observed to be 16 mm in sand and 11.4 mm in layered soil, respectively, for an L/d ratio of 15. Under thermo-mechanical loading, the change in displacement was 0.7 mm in sand and 0.4 mm in layered soil. The maximum shear stress was developed at the toe, reaching 60 kN/m² for L/d = 15. The obtained results reveal an encouraging outcome and help in gaining confidence in constructing geothermal energy piles.

The Southern Corridor within the Belt and Road Initiative (BRI), traversing Iran, signifies a potential link between China and Europe. Although not yet operational, it’s poised for competition with its well-established counterparts: the Trans-Siberian, Middle, and Traditional Maritime Corridors. This study evaluates the competitiveness of the Southern Corridor compared to these rivals, with a noteworthy focus on the Southern and Middle Corridors, which have not previously undergone quantitative evaluation alongside the Trans-Siberian and Traditional Maritime Corridors. The methodology is grounded in Multi-Criteria Decision-Making (MCDM). The study initiates by identifying factors that influence the performance of freight transit corridors, determining their relative importance through consultation with a panel of experts. Precise weights of these factors are calculated using the Fuzzy Delphi Analytical Hierarchy Process (FDAHP). Subsequently, the Technique for Order of Preference by Similarity to the Ideal Solution (TOPSIS) is applied to assess the relative performance of the four corridors. Additionally, scenario planning, with a specific emphasis on the Southern Corridor, is conducted. The results reveal that the Traditional Maritime Corridor secures the top position with an impressive performance index of 0.7203. The Trans-Siberian, Middle, and Southern Corridors follow as the second, third, and fourth-ranked options, with performance indices of 0.4056, 0.2864, and 0.2662, respectively. Furthermore, the scenario planning outcomes demonstrate the significant potential for performance improvement in the Southern Corridor, particularly through enhanced geopolitical stability and the elimination of intermodal operations. These measures are pivotal in enhancing the competitiveness of the Southern Corridor, positioning it favorably against the Trans-Siberian Corridor.

The current investigation examines the influence of footing shape, the base area of footing (A), the mass of footing-machine assembly (m), and eccentric force settings (m_ee) on the dynamic response and performance of machine foundation systems. Five different footing configurations are employed to perform field block vibration tests involving three square, one circular and one rectangular footing. The experiments are performed at the geotechnical field laboratory of IIT Kanpur, India (N26°30′59.0892″, E80°13′51.6888″). The accuracy and reliability of the experimental results are endorsed by the results obtained from the mass-spring-dashpot (MSD) analysis. In addition, an artificial neural network (ANN) model is created to anticipate the dynamic behaviour of the soil-foundation system. A thorough parametric study demonstrates the efficacy of the developed ANN model. It is revealed from the investigation that the stiffness (k) and the damping ratio (D) of the soil for square foundations increase by 7% and 3%, respectively, with a 40% increase in A. Similarly, the circular foundation exhibits 7 and 3% higher k and 4 and 3% higher D than those obtained for square and rectangular foundations, respectively. For square foundations, a 24% enhancement in m leads to a 42 and 4% increase in k and D, respectively. In contrast, for circular and rectangular foundations, a 13% increase in m results in a 27 and 19% increase in k and D, respectively. In this study, experimental testing, analytical validation, and ANN modelling provide insight into the response of machine foundations under various operating conditions. The results of this study can be utilized to optimize the design of machine foundations.

This study concentrated on producing limestone calcined clay calcium sulfoaluminate cement by replacing portland cement in limestone calcined clay cement with calcium sulfoaluminate cement, with the goal of increasing the early strength of limestone calcined clay cement. The mineralogy and microstructures of hydrating pastes were investigated using x-ray diffraction and scanning electron microscopy. Heat evolution was studied using isothermal calorimetry. Strength development and workability were assessed on mortar samples. The 1 day strengths of limestone calcined clay calcium sulfoaluminate cement samples exceeded those of limestone calcined clay cement by ~ 30–80%, though its strength gain slows significantly after 1 day due to the lack of calcium silicates, affecting pH and clay dissolution. Despite this, the strength development of limestone calcined clay calcium sulfoaluminate cement, when adjusted for CO₂ emissions, is comparable to limestone calcined clay cement. Additionally, limestone calcined clay calcium sulfoaluminate cement provides a 10–15% higher flow and exhibits a lower heat of hydration beyond 12 h, while maintaining a production cost similar to that of limestone calcined clay cement.

This study established a finite element model to assess the impact of various transverse strengthening techniques on the Xiuzhen River Bridge, a prestressed concrete box-girder bridge. On-site experiments validated the effectiveness of the finite element model. Five different strengthening techniques, namely, adding steel or concrete diaphragms (ASD or ACD), adding composite truss (ACT), strengthening bridge deck (SBD), and setting transverse prestress (STP), were compared. The results demonstrated a significant reduction in the deflection of the bridge using these techniques. SBD technology exhibited the highest deflection reduction rate at 47.91%, and STP technology achieved a maximum reduction rate of 53.92% in the presence of initial bridge damage. In addition, these techniques notably improved the lateral integrity from the load distribution factor (LDF). However, relying solely on the LDF cannot discern the most effective strengthening method. Therefore, a combined LDF and Kullback–Leibler divergence method was proposed to comprehensively analyse the relative entropy (RE) between different models. The results highlighted that SBD technology significantly reduced the RE of the bridge by 82.94%. In the presence of initial damage, ACT technology demonstrated significant stability in reducing the RE, with a sensitivity of only 10.98%. For newly constructed bridges, SBD technology is notably effective; however, for existing bridges, ACT technology may be a reasonable choice. Additionally, an investigation of failure modes emphasized that all the models exhibit similar failure modes, with initial damage and the implementation of different techniques primarily affecting cracking and ultimate load rather than significantly altering the overall failure mode.

Sandstones exhibit a complex, stress-dependent behavior characterized by nonlinearity and inelasticity. This study delves into the mechanical properties of sandstone through two distinct triaxial compression experiments: monotonic and cyclic tests, under confining pressures ranging from 0 to 20 MPa. Based on plastic strain analysis, two stress-dilatancy models were developed to describe nonlinear plastic dilatation behaviors. The introduction of the “plastic dilatancy line” concept, derived from comparing plastic dilatancy stresses with crack damage strengths, marks a significant advancement in understanding sandstone’s inelastic models. It was found that the plastic flow directions are not perpendicular to the yield surfaces marked by the characteristic strengths. This indicated that the non-associated flow rule is suitable to describe the macroscopic plastic deformations of sandstone. Furthermore, it was identified confining pressure as the dominant influence on sandstone failure, with cyclic loading modes playing a secondary role. An increase in confining pressure shifts the macroscopic failure modes from splitting-tension to mixed shear-tension, and ultimately to shear failure. Scanning Electron Microscope (SEM) analyses indicated that loading–unloading (L–U) cycles induce more significant mineral grain fragmentation compared to monotonic testing, thereby markedly decreasing sandstone’s failure strength due to accumulated damage from grain-crushing. Additionally, the dip angles of dominant fractures in samples subjected to cyclic tests are typically smaller than that in monotonic tests. This investigation not only sheds light on the complex mechanical behaviors of sandstones but also provides a vital theoretical and practical framework for future research in this field.

This paper investigates the potential use of the International Roughness Index (IRI) in generating optimal rehabilitation plans at the network-level. The IRI data used in the study was obtained using the portable vehicle-mounted IRIMETER-2 profilometer, which is a product of Englo LLC, Tallinn, Estonia. An optimum rehabilitation model is proposed to minimize the average IRI value at the network-level subject to variable and budget constraints. The model mainly focuses on using major rehabilitation strategies that can produce a major improvement in pavement condition. An alternate maximization model that can use other pavement condition indicators, such as the present serviceability index (PSI) and pavement condition index (PCI), is also presented. The PSI and PCI can be estimated from the IRI using correlation models. The proposed optimum models are linear in form and can easily be solved using the proposed cost-effectiveness ratio. The sample results presented for a 27.1-km suburban highway indicate the reliability of using the IRI data to generate optimal rehabilitation plans. A statistical uncertainty analysis of IRI measurements produced a mild impact on optimal solutions derived using ten independent IRI tests and 99% confidence level. The uncertainty analysis has also indicated that the use of a single IRI test provides results that are statistically indifferent from those obtained using ten IRI tests.