Hasil untuk "Bridge engineering"

Jiang Liu, Zefan Liu, Zhiyuan Ma et al.

Current bridge design codes specify combination coefficients for wind–temperature joint actions, yet few studies have addressed these for bridges in plateau canyon regions. This study investigates the joint actions and combination coefficients for Haihuang Bridge, which is in a plateau canyon region surrounded by mountains. Using long-term structural health monitoring data, trivariate normal copulas and Con-KRP were applied to estimate joint probabilities of wind speed and air temperature in different directions. The combination coefficients range from 0.68 to 0.92 for temperature actions and 0.56 to 0.75 for wind actions, obtained based on the principle that bivariate Con-KRP equals univariate Con-KRP. Significant differences in the joint actions are found in different directions. Furthermore, the combination coefficients in the plateau canyon region are much larger than those in the subtropical coastal plain region, indicating a need for further study on the regional difference.

Anni Li, Zhonglin Chai, Karin Jandeleit-Dahm et al.

Kidney organoids, as three-dimensional microstructures derived from human pluripotent stem cells or adult stem cells, precisely simulate the cellular heterogeneity, spatial conformation, and some physiological functions of human kidney units in vitro. Kidney organoids are three-dimensional microstructures derived from human pluripotent stem cells (hPSCs). They precisely simulate the cellular heterogeneity, spatial conformation, and key physiological functions of human kidney units in vitro. This technology, by replicating the interaction network between the glomerulus and renal tubules, provides an unprecedented window for observing the dynamic development and pathological processes of human kidneys. This technology replicates the interaction network between the glomerulus and renal tubules. It thereby provides an unprecedented window into human kidney development and disease. Based on the strong similarity between organoids and native organs, as well as the human genetic information they carry, both iPSC-derived and patient-specific organoids have demonstrated significant value in kidney disease modeling, drug toxicity testing, and the development of regenerative treatment strategies. This review systematically elucidates the key advancements in the field of kidney organoids, including optimized strategies for stem cell-directed differentiation, innovations in culture systems driven by biomaterials engineering, technological breakthroughs in disease model construction, and applications of organoids in drug screening platforms and regenerative medicine. Additionally, it analyzes translational challenges such as the lack of vascularization, insufficient functional maturity, and obstacles in standardized production. These insights will deepen the understanding of kidney pathological mechanisms and propel organoid technology towards substantial clinical therapeutic applications. This review summarizes how convergent technologies in stem cell biology and bioengineering aim to bridge this functional gap. We examine the use of advanced organoids in disease modeling and drug discovery. We also highlight their current limitations. Our focus is on the core translational bottlenecks: vascularization, long-term maturation, and scalable production. Overcoming these hurdles is essential to transform kidney organoids from a research tool into a platform for precision medicine and regenerative therapy.

Yanguo Sun, Tianyi Zhang, Mingshui Li et al.

A significant aerodynamic interference effect exists between parallel bridges. In this study, a proposed long-span cable-stayed bridge, near which is an existing truss-arch bridge, was considered as the background. The wind characteristics at the proposed bridge site and the wind-induced responses of the bridge deck were investigated with and without the influence of an upstream bridge. The results showed that under aerodynamic interference of the upstream bridge, the downstream bridge site exhibited a noticeable change in the mean wind speed profile within the height range of the main girder and arch. The turbulence intensities significantly increased, especially for <i>u</i> and <i>w</i> components. The integral scales decreased remarkably, and the wind speed spectra redistributed toward higher frequencies. For the wind-induced responses, the mean displacements of the downstream bridge all decreased; in contrast, the buffeting and peak displacements all increased in both the maximum single cantilever state and the completed state, while the variation in buffeting response was much more significant and dominated the peak response. Moreover, under the interference of the upstream bridge, the buffeting displacement spectra redistributed toward high frequencies. This research acts as an effective tool for achieving secure bridge design and finding a better balance between design constraints.

Fangyuan Li, Luda Li

Based on recent research findings and an analysis of the literature on Precast concrete (PC) small box girders, this paper presents a systematic discussion of the optimization design, materials, and prestressing techniques for PC small box girder structures. The study analyzes and summarizes the optimization design of PC small box girders in terms of diaphragms, prestressing tendons, cross-sectional dimensions, and materials. It synthesizes the impact of these optimization methods on the mechanical performance of PC small box girders. Furthermore, the current research status of retard-bonded and external prestressing technologies is discussed in detail, along with a summary of the mechanical properties of small box girders utilizing these techniques. Finally, several future research directions are proposed on the basis of the current state of research.

Imran Haider, Muhammad Yaqub, Inamullah Inam et al.

Abstract The use of recycled aggregate (RA) as a partial or full replacement of natural aggregate (NA) is a suitable method of concrete production that has positive impacts on the environment. However, recycled aggregate concrete (RAC) has relatively lower strength and durability than that of normal concrete. To improve concrete performance, silica-fume (SF) was added with 2.5% increment up to 7.5% and metakaolin (MK) is added with a 2.5% decrement from 15 to 7.5%. The concrete with 50% RA, 10% MK and 5% SF showed notable advancement in performance after 28 days of curing. At 28 days of curing, the concrete samples had 31.5 MPa compressive strength, 5.7 MPa splitting tensile strength, and 10.6 MPa flexural strength, a strength improvement of 5.19%, 16.47%, and 8.52% over control concrete. Ultrasonic pulse velocity (UPV) indicated a 16.13% increase alongside a 20.87% reduction in water absorption which confirmed stronger bond performance and better durability of modified concrete. RCA content influences acid resistance negatively when reaching 75% RCA shows maximum deterioration. In addition, the fire resistance of such concrete resulted in higher performance at different temperature conditions for the concrete. This is due to the small particles of silica fume and metakaolin which acted as major factors and led to performance enhancements by filling in the concrete matrix gaps. The combination provides affordable, sustainable construction alternatives. Experiments show that SCMs can produce high-performance recycled concrete for modern building construction.

Yong Deng, Yazhou Zhang, Xianming Shi

Abstract This study introduces human-swarm interaction (HSI) strategies to enhance bio-inspired swarm intelligence (SI) algorithms, addressing inherent limitations of the traditional monkey algorithm (MA) such as premature convergence and computational inefficiency in complex search spaces. We propose three HSI integration strategies involving intermittent, persistent, and parameter-setting interactions within the HSI to augment emergent behaviors and refine the MA’s intrinsic optimization mechanisms. Validation through seven benchmark functions (one unimodal and six multimodal) across seven dimensions demonstrates the HSI-MA’s ability to resolve complex, multidimensional optimization problems with statistically significant (p < 0.05) superior accuracy and stability compared to the original MA and four baseline SI algorithms, achieving 85% dominance in test cases while reducing iterations by an order of magnitude. Further evaluation on five engineering design problems reveals the HSI-MA outperforms 36 state-of-the-art optimizers in 70% of scenarios, confirming its enhanced precision and efficiency in practical applications. In contrast to conventional fusion-based approaches, the HSI framework preserves the original algorithm’s theoretical foundations while systematically integrating human intelligence to enhance structural adaptability and operational efficiency.

Jin Mao, Hao Yuan, Lun Xiong et al.

In order to foster a more sustainable and eco-friendly trajectory for the construction industry, while concurrently mitigating environmental pollution and energy inefficiency, it is imperative to cultivate an environmentally conscious building and urban environment. Under the background of Carbon Peak and Carbon Neutrality, the green building rating system has become a research hotspot in the field of green building. This paper systematically summarizes the research progress of the GBRS in weight setting, indicator setting, and the evaluation process, and creatively proposes the following three directions for future research: (1) Weight determination methods based on machine learning or deep learning models, and reasonable weight allocation by mixing multiple evaluation methods. (2) Setting dynamic evaluation indicators, strengthening interdisciplinary research and regional consideration, and introducing a life cycle assessment to solve the problem of setting indicators in the existing evaluation system. (3) Combine building information modeling with GBRS to realize the automation and intelligence of evaluation and improve the comprehensiveness and accuracy of evaluation.

Preeti Agarwal, Deepak Kumar Singh

AbstractThis study employs the finite element-based CSiBridge v.20.0.0 software to examine the response of a single-cell prestressed box-girder bridge subjected to Indian loading conditions. The analyses is carried out on a simply supported bridge considering the specifications of Indian Road Congress (IRC) 6:2017, IRC 18:2000 and IRC 21:2000. An existing model of prestressed skewed bridge is validated with the published one. A convergence study is conducted for determining the model’s mesh size. An extensive parametric study is carried out to gain a better understanding of the response of a skewed prestressed bridge. The parameters variables are: Skew angle (0°, 10°, 20°, 30°, 40°, 50°, and 60°); Span (35, 40, 45, 50, 55, and 60 m); and Span-depth ratio (10, 12, 14, 16 and 18). The results of this study are presented as ratios of Bending moment, Shear force, Torsional moment, and Vertical deflection. Finally, equations for estimation of these ratios for different span and span-depth ratio are also deduced from the statistical approach so that the results of skewed bridges may be evaluated directly. It is determined that the skewed bridge outperforms the straight bridge because of its higher span-depth ratio, which results in less bending moment development. Evidence suggests that the skewness may help to lessen the prestress load’s dominance. The findings of this study may be helpful to engineers and designers in the analysis and design of prestresssed skewed box-girder bridges.

Memduh Karalar, Gülşah Çufalı

In this study, the effect of the variation of the arch form in thickness and height on the bridge was investigated as a numerical analysis. For this purpose, the historic Antik Iscehisar Bridge located in the Iscehisar district of Afyonkarahisar in the Aegean Region was elected as a numerical application. The bridge was subjected to its own weight and moving load as a static analysis. For dynamic analysis, the effect of 10 different fault movements with historical character obtained from The Pacific Earthquake Engineering Research Center (PEER) on the bridge was investigated. The areas of principal stress and deformation resulting from the applied analyses were determined. Contour diagrams, tables, and charts were given in a comparative manner based on the results of the analysis applied to the bridge. At the end of the analysis, it was observed that the displacements decreased as the arch thickness increased under its own weight in the bridge. In addition, under the influence of live loads and earthquakes, it was observed that the displacements decrease as the arch thickness increases. A seismic reliability assessment was made using the performance criteria provided in this study. If the security level is below what it should be, reinforcement applications can be designed. Accordingly, future maintenance and monitoring planning can be made.

Shangkai Liu, Cheng Cheng, Ruiqiang Zhao et al.

Metal Magnetic Memory (MMM) exhibits the advantage of not requiring embedded sensors or external excitation, making it suitable for inspecting ferromagnetic components in engineering structures. This study introduced MMM into stress detection of steel strands. Graded tensile tests were conducted on the steel strands to investigate the correlation between Self-Magnetic Flux Leakage (SMFL) signals and stress levels. Different spatial detection positions with varying Lift-Off Values (LOV) and Rotation Angle Values (RAV) were set to examine the distribution of spatial SMFL field under load. Furthermore, a magnetic characteristic parameter <i>A_N</i> was proposed to assess the stress level of the steel strands. The results indicate that the rate of change in the middle region of the SMFL curve was lower than that at the beginning and the end. Additionally, with increased applied load, the SMFL curve exhibited systematic variations, and the dispersion of the normal component curve gradually decreased. By utilizing the magnetic characteristic parameter <i>A_N</i>, the stress in the steel strands can be calculated, with the parameters determined based on LOV and RAV. This achievement expanded the nondestructive testing methods for steel strands and holds significant research value.

Junhong Yin, Menghao Wang, Ruijie Zhang et al.

Numerical analysis of collision is an important aspect of bridge seismic research. This paper introduces precise integration to the numerical analysis of seismic collision. Firstly, the collision forces of four contact element models were expressed in a unified form, including linear spring model, Kelvin-Voigt model, Hertz model, and Jan-Hertz-Damp model, and then the precision integration formula was derived for solving the collision force. Next, a collision time search method was proposed under the linear acceleration hypothesis, and the seismic collision was divided into a collision phase and a non-collision phase. Different time steps were adopted for the two phases. This strategy was verified by comparing simulation results with the data of theoretical analysis and shaking table test. The results show that precision integration ensures the accuracy of numerical calculation for bridge structure collision under seismic action, and achieves a high calculation efficiency; the contact element model and model parameters should be selected reasonably to analyze seismic collision of bridges; the Jan-Hertz-Damp model of contact elements boasts the highest simulation accuracy among the commonly used models.

Yang Liu, Gang Tian, Shijun Wang et al.

Hydraulic properties (such as soil–water characteristic curves (SWCC) and hydraulic conductivity function (HCF)) play an important role in evaluating the stability of unsaturated soil slopes. Loess soils are widely distributed in Gansu Province in China, and most of them are in unsaturated conditions due to the deep groundwater table (G.W.T). In this study, twenty-eight sets of data published in the literature were analyzed to develop the upper and lower bounds of the SWCC for loess soil in Gansu. The variation of HCF for the loess soil was estimated from the upper and lower bounds curve developed in this study. Subsequently, numerical analyses incorporating scenarios considering different SWCCs, HCFs, and rainfall conditions were conducted for investigating the effects of those factors on the rainfall-induced slope stability. The results of analyses indicate that the infiltration plays an important role in the rainfall-induced slope stability. Higher permeable soil leads to a larger infiltration amount, which, in turn, results in a lower safety factor. In addition, the effect of the hydraulic property on the rainfall-induced slope stability decreases with the increase in slope angle.

Adriana Dias, Salem Nezami, José Silvestre et al.

Recycled aggregates (RAs) have been playing an important role in replacing natural aggregates (NAs) in concrete production, thereby contributing to a reduction in the extraction of natural resources and the promotion of a circular economy. However, it is important to assess the global impacts of this replacement, in both environmental and economic terms. In this study, an overview of the impacts of the production of natural and recycled aggregates is presented, using the life cycle assessment (LCA) methodology. Through this methodology, products with the same function are compared and information about the best solutions is given, considering their environmental and economic impacts. Studies with data collected from specific producers were compared, as well as environmental product declarations (EPDs) and generic databases, regarding the production of natural and recycled, coarse and fine, and rolled and crushed aggregates. This study intends therefore to provide the environmental and economic impact comparison at the global level through LCA from different data sources. According to this literature review, the best and worst environmental results are assigned to lower and higher transport distances, respectively. Regarding EPDs, the lowest environmental impacts are related to recycled coarse aggregates and the highest to natural coarse crushed aggregates. In terms of generic databases, the results are similar, with the lowest impacts associated with natural fine rolled aggregates and the highest to natural coarse crushed aggregates. In what concerns the economic impacts, in general, recycled aggregates are associated with the lowest costs. However, these results are highly dependent on transport distances and costs.

Kang Yang, Youliang Ding, Hanwei Zhao et al.

The bridge influence line (IL) reflects the response of a certain section due to varying load positions. As a result, IL has a wide application prospect in damage identification and condition assessment. Up to date, studies regarding IL have been focused on the structure condition evaluation. A feasible and practical method for damage identification is still not yet available. The present paper proposes a comprehensive damage identification methodology based on IL under a moving vehicle is composed of data pre-processing, IL extraction, and damage detection. Firstly, a thorough review of existing IL identification methods based on signal processing is provided. Then three quasi-static IL identification methods based on measured data are discussed. Consequently, the study proposes a two-stage damage identification approach for simply supported bridges with equal span length. Also, the effectiveness of this approach is verified through field tests on a real girder bridge. At last, conclusions are drawn, and potential issues for the application of the proposed method in practice are discussed.

Peishuai Chen, Peishuai Chen, Peishuai Chen et al.

In geotechnical engineering, vertical drainage is the most economical method for accelerating the consolidation of a large area of soft ground. In this study, we analyze the viscoelasticity of the soil and the actual drainage conditions on the top surface of the soil, and then we introduce continuous drainage boundary conditions and adopt a fractional derivative model to describe the viscoelasticity of the soil. With the use of a viscoelasticity model, the governing partial differential equation for vertical drains under continuous drainage boundary conditions is obtained. With the application of the Crump numerical inversion method, the consolidation solution for vertical drains is also obtained. Further, the rationality of the proposed solution is verified by several examples. Moreover, some examples are provided to discuss the influence of interface drainage parameters on the top surface of soil and the viscoelasticity parameters of soil on the consolidation behavior of vertical drains. The proposed method can be applied in the fields of transport engineering to predict the consolidation settlement of a foundation reinforced by vertical drains.

Yolanda Gu, Jim Pierrepont, Catherine Stambouzou et al.

Prosthetic impingement is important to consider during total hip arthroplasty planning to minimise the risk of joint instability. Modelling impingement preoperatively can assist in defining the required component alignment for each individual. We developed an analytical impingement model utilising a combination of mathematical calculations and an automated computational simulation to determine the risk of prosthetic impingement. The model assesses cup inclination and anteversion angles that are associated with prosthetic impingement using patient-specific inputs, such as stem anteversion, planned implant types, and target Range of Motion (ROM). The analysed results are presented as a range of cup inclination and anteversion angles over which a colour map indicates an impingement-free safe zone in green and impingement risk zones in red. A validation of the model demonstrates accuracy within +/- 1.4° of cup inclination and anteversion. The study further investigated the impact of changes in stem anteversion, femoral head size, and head offset on prosthetic impingement, as an example of the application of the model.

Mehdi Ebadi Jamkhaneh, Mohammad Ali Kafi, Ali Kheyroddin

In current international practice, composite construction is gaining importance in industrial buildings and in particular in high-rise buildings. Partially encased composite (PEC) columns are one of the recent developments in composite column. Using composite columns have several advantages such as an increased speed of erection compared to reinforced concrete (RC) columns, a more cost-effective design, smaller cross-section dimensions for similar axial resistance, and a better resistance to fire and local buckling than for steel only columns in compare with traditional RC or steel only columns. One of the proper sections for columns is a cross-sectional shape that can be used in these columns. In this paper, experimental and numerical studies are carried out on three PEC columns under pure compression load. The main difference between the specimens is in the reinforcement details of the concrete. Parameters studied in numerical work, details of reinforcement, failure mode, width to thickness ratio of steel flange and distance and transverse link diameter. The results are presented in the form of axial load-displacement curves. Also, the values of experimental work were compared with the relations between the two European and Canadian regulations, which indicated that the Canadian code was conservative. The results were developed in a numerical section after validation with a laboratory specimens and the load-bearing capacity and deformation were evaluated. The evident buckling pattern in the specimens was the kind of rupture of the welds of the links and the local buckling of the flange plate between the two links. Also, the bigger interval between the two links caused an early local buckling in the specimen.

Madjid Gholhaki, Omid Rezayfar, farzaneh ahmadnejad

Nowadays, Steel plate shear walls have been considered as the lateral load resisting system in buildings in increasing the strength and stiffness of structures in two sections of seismic reconstruction and improvement. In this paper, the shear strength and stiffness of a stiffened steel plate shear walls under various stiffeners configuration horizontal, vertical and combined structures with finite element method has been studied and finally the proposed equations for determining the unstiffened equivalent thickness of the steel plate The proposed model is used to design a stiffened steel plate shear wall using the proposed equations of the plate frame interaction method. The results indicate a acceptable prediction of the capacity and stiffness of the stiffened steel shear walls using proposed equations and the error rate has been less than 15%.Nowadays, Steel plate shear walls have been considered as the lateral load resisting system in buildings in increasing the strength and stiffness of structures in two sections of seismic reconstruction and improvement. In this paper, the shear strength and stiffness of a stiffened steel plate shear walls under various stiffeners configuration horizontal, vertical and combined structures with finite element method has been studied and finally the proposed equations for determining the unstiffened equivalent thickness of the steel plate The proposed model is used to design a stiffened steel plate shear wall using the proposed equations of the plate frame interaction method. The results indicate a acceptable prediction of the capacity and stiffness of the stiffened steel shear walls using proposed equations and the error rate has been less than 15%.

Zaharah Allah Bukhsh, Irina Stipanovic, Sandra Skaric Palic et al.

Optimisation of maintenance planning is an essential part of bridge management. With the purpose to support maintenance planning, a multi- objective decision-making model is introduced in this paper. The model is based on multi-attribute utility theory, which is used for the optimisation process when multiple performance goals have to be taken into account. In the model, there are several parameters, which are freely chosen by the decision maker. The model is applied to the inventory of 22 bridges, where four Key Performance Indicators were determined for four performance aspects:  reliability, availability, costs and environment. A sensitivity analysis is performed by changing risk tolerance parameter and attribute weights to determine the robustness of the model. The Multi-Attribute Utility model and sensitivity analysis presented in this paper will help decision-makers to examine the robustness of the optimal solution by dynamically changing the critical parameters.

Marko Ožbolt, Tatjana Rukavina, Josipa Domitrović

Thickness of the pavement structure layers represents an important data for the implementation into the database of roads already constructed, during the pavement strengthening design, particularly if the appraisal of the bearing capacity of the pavement structure is done by means of the Falling Weight Deflectometer, during reconstruction of pavements or during control of the newly constructed roads. If reconstruction is carried out by procedures of recycling of the existing pavement the details about the thickness of asphalt layers are important not only when determining the depth of the intervention but also when designing asphalt mixture. During quality control of the newly constructed road sections the Ground Penetrating Radar (GPR, georadar) can be used as the instrument for fast and efficient determination of the thickness of layers. Measuring is done at speeds that approx correspond to the speeds of traffic flow, so that disturbance of traffic is minimum, whereby the safety of participants in traffic and measuring personnel is increased. The paper presents several examples of determining the thickness of layers of road pavement structures by the non-destructive GPR method. The obtained results were compared to conventional methods of determining thicknesses that are used in Croatia, i.e. coring or data obtained by surveying methods during construction of the pavement structural layers. Measurements were done on completely new and existing roads of different age having the asphalt pavement.