Complex Bridge Research Articles

A Revit-Midas/Civil conversion approach for bridge superstructures analysis

In this study, a model conversion method that combined Revit with Midas Civil software was proposed to improve the modeling efficiency and accuracy of finite element calculations for a large bridge structure. The secondary development program was established using the Visual Studio 2022 platform, which was used to convert the model information. A model conversion interface was created by extracting, screening, and then sorting the geometric information of the business information model and generating a Midas Civil Text file. This interface served as a link between Revit and Midas Civil, specifically for the bridge superstructure. The feasibility and reliability of the proposed model conversion method was confirmed using a single-box three-cell Box-girder bridge. The results demonstrated that the model conversion method transfered the Revit model information successfully to a Midas Civil structural analysis model, thereby significantly enhancing the efficiency and accuracy of the finite element modeling of a complex bridge superstructure.

Diiron azadithiolate models with bulky bridgehead moiety: Synthesis, structure and electrochemistry

To further explore the function of azadithiolate (ADT) bridges in diiron complexes and to develop new biomimics for the active site of [FeFe]-H2ases, here a new model complex [Fe2{(μ-SCH2)2NCHPh2}(CO)6] (1), featuring a bulky bridgehead (CHPh2) was prepared by condensation reaction of [Fe2(μ-SCH2OH)2(CO)6] and NH2CHPh2. The corresponding monophosphine-substituted diiron azadithiolate complexes, [Fe2{(μ-SCH2)2NCHPh2}(CO)5 L] (2–7) [L = PPh3, PPh2(2-C5H4N), PPh2(C6H11), P(C6H4–4-CH3)3, P(C6H4–4–OCH3)3, P(2-C4H3O)3], were prepared via the one-pot method that involves [Fe2(μ-SCH2OH)2(CO)6], phosphine ligand and NH2CHPh2. The diphosphine-substituted complexes, [Fe2{(μ-SCH2)2NCHPh2}(CO)5(κ1-dppm)] [dppm = CH2(PPh2)2] (8), [Fe2{(μ-SCH2)2NCHPh2} (CO)4{(κ2-Ph2P)2NCH2C6H5}] (9), [Fe2{(μ-SCH2)2NCHPh2}(CO)4(μ-dppm)] (10) and [Fe2{(μ-SCH2)2NCHPh2}(CO)4{(μ-Ph2P)2NCH2Ph}] (11) were synthesized using either Me3NO-assisted oxidative decarbonylation reaction or thermal reaction. All the new complexes were fully structurally characterized by elemental analysis, spectroscopies, and particularly for 2–10 by X-ray crystallography. Furthermore, the electrochemical and electrocatalytic properties of these model complexes were investigated by cyclic voltammetry, demonstrating their ability to catalyze the reduction of protons to produce H2 when acetic acid was used as the proton source.

System Fragility Analysis of Bridges Based on Response Variables Dimensionality Reduction

Earthquake resistance of bridge structures is an important part of ensuring the functionality of transportation network systems. The structural system of a bridge is composed of multiple components, and the damage of different components may affect the function of the bridge, while the system seismic fragility analysis provides an effective way to evaluate the overall seismic performance of the bridge. In the past, the failure probability of a system is often estimated by the correlation between components, but the complex correlation between components brings certain difficulties to the actual calculation. In this paper, an efficient, accurate and universal method of system fragility analysis is proposed. This method decouples the correlation between components from the perspective of relative damage, adopts the critical demand-to-capacity ratio as the response variable of the system, realizing the dimensionality reduction of the response variables and simplifying the system fragility analysis from high-dimensional fragility analysis to one-dimensional fragility analysis. This methodology offers a viable solution to the challenges posed by the wide estimation of fragility boundaries in the boundaries estimation method and the complexities involved in analyzing correlation of components in the joint probability method. Comparison with traditional methods indicates that the proposed method exhibits high efficiency and convenience, making it suitable for practical engineering applications in system fragility computation. The proposed method holds great potential for future applications in the field of complex bridge structure fragility analysis, large-scale regional seismic damage prediction, rapid assessment, and beyond.

Exploring the properties and applications of complex fuzzy cut vertices and bridges

Exploring the properties and applications of complex fuzzy cut vertices and bridges

Numerical Investigation of Flow and Scour around Complex Bridge Piers in Wind–Wave–Current Conditions

A sea-crossing bridge is typically constructed in a marine environment with complex piers, and is susceptible to severe scour at the foundation. This study presents a numerical investigation on flow and scour around a complex pier, specifically focusing on a real-world sea-crossing bridge in China. A comprehensive CFD model incorporating hydrodynamic, free surface, sediment transport, and morphological models is employed for numerical modeling. Additionally, a wind shear stress model is considered to accurately simulate wind generation. The validation of the CFD model is achieved through comparison with experimental data of scour around a cylinder, demonstrating its capability to accurately replicate scour morphology and the temporal evolution of scour depth. Subsequently, the validated model is utilized for full-scale simulation of scour around the complex bridge pier under different wind, wave, and current conditions. The results indicate that compared to single piers with uniform cross-sectional shapes, flow patterns around complex piers are much more complicated. Scour predominantly occurs around the first row of group piles, while downstream piles experience less scour due to the sheltering effect from upstream piles. Furthermore, it becomes evident that the current exerts greater influence on pier scour than waves and wind, while the latter two factors primarily influence the superstructure of the bridge.

The PfRCR complex bridges malaria parasite and erythrocyte during invasion.

The symptoms of malaria occur during the blood stage of infection, when parasites invade and replicate within human erythrocytes. The PfPCRCR complex1, containing PfRH5 (refs. 2,3), PfCyRPA, PfRIPR, PfCSS and PfPTRAMP, is essential for erythrocyte invasion by the deadliest human malaria parasite, Plasmodium falciparum. Invasion can be prevented by antibodies3-6 or nanobodies1 against each of these conserved proteins, making them the leading blood-stage malaria vaccine candidates. However, little is known about how PfPCRCR functions during invasion. Here we present the structure of the PfRCR complex7,8, containing PfRH5, PfCyRPA and PfRIPR, determined by cryogenic-electron microscopy. We test the hypothesis that PfRH5 opens to insert into the membrane9, instead showing that a rigid, disulfide-locked PfRH5 can mediate efficient erythrocyte invasion. We show, through modelling and an erythrocyte-binding assay, that PfCyRPA-binding antibodies5 neutralize invasion through a steric mechanism. We determine the structure of PfRIPR, showing that it consists of an ordered, multidomain core flexibly linked to an elongated tail. We also show that the elongated tail of PfRIPR, which is the target of growth-neutralizing antibodies6, binds to the PfCSS-PfPTRAMP complex on the parasite membrane. A modular PfRIPR is therefore linked to the merozoite membrane through an elongated tail, and its structured core presents PfCyRPA and PfRH5 to interact with erythrocyte receptors. This provides fresh insight into the molecular mechanism of erythrocyte invasion and opens the way to new approaches in rational vaccine design.

Dynamic response analysis for bridges subjected to moving vehicle loads by using the analytical dynamic stiffness method

This paper presents a highly efficient and accurate analytical method for the dynamic analysis of subjected to moving loads. Bridges with complex cross section and considering damping are modelled as plate built-up structures by the dynamic stiffness method with few degrees of freedom. Different moving loads with time-varying amplitudes travelling at different speeds can be modelled semi-analytically: The moving vehicle loads with varying amplitude are transformed into the frequency-wavenumber domain by the analytical sine transform combined with the fast Fourier transform; then the time-spatial domain dynamic response of the bridge is computed by the associated inverse transforms from the frequency-wavenumber domain response of the dynamic stiffness model. The most commonly used box girder railway bridge is taken as an example, and the results of both free vibration and dynamic response subject to moving train wheel loads computed by the proposed method are validated well by the finite element software ANSYS. The proposed method uses about 1.2% time of that taken by the ANSYS but achieves a similar level of accuracy. The proposed method can serve as an efficient alternative tool of modal and dynamic response analysis for the design and optimization of a wide range of complex bridges.

Experimental investigation of local scour around complex bridge pier of sea-crossing bridge under tidal currents

To study the process of local scour around the large-scale complex bridge pier under tidal currents, local scour experiments were carried out using the pile group-cap of the Hong Kong-Zhuhai-Macao Bridge (HZMB) as prototypes. The geological conditions at the bridge site were explored and the sampled soil was experimentally analyzed to determine the model sand. Based on the long-term observation data of tidal currents at the bridge site, a harmonic analysis of tidal currents was conducted to obtain the hydrodynamic characteristics of the tidal currents. Then a flume experiment of local scour around the large-scale pile groups under tidal currents was carried out. Research results indicate that the tidal currents velocity at the HZMB site exhibits the characteristic that the falling tide velocity is greater than the rising tide velocity. The frequency of the flow direction in the N and S directions is more significant. The tidal currents at the bridge site belong to the irregular semi-diurnal tide. The maximum depth of scour under tidal currents occurs on the side with highest velocity in the rising and falling tide process, and its value is slightly lower than the value under unidirectional flow. The duration of equilibrium scour under tidal currents is longer than under unidirectional flow. The shape of the equilibrium scour pit under tidal currents has changed from a circular arc shape on the upstream side to a saddle shape with deep ends and shallow middle, and has formed a longer sedimentation zone at both ends of the rising and falling tides compared to the situation under unidirectional flow. The size and layout of the pile foundation have a significant impact on the shape of the scour pits that achieve equilibrium scour.

Behavior evolution and deformation prediction of RC beams with double openings under fatigue loading

In the design of complex high-speed railway platforms, bridges, and other transport hub structures, openings need to be made in the reinforced concrete (RC) beam web due to the laying of pipeline lines. The performance degradation caused by the openings is a concern for the RC beam under fatigue load. To study the fatigue performance of RC beams with double openings, six RC beams with double openings were designed, with the load level ratio, location of loading points, and number of fatigue cycles as changing parameters. Fatigue tests were carried out under repeated loads. The stress state and failure mode of RC beams with double openings under fatigue load were studied, and the influence of various parameters on the fatigue performance of beams with double openings was discussed. The deformation compatibility model of opening and mid-span deformation was proposed, and the deformation evolution law of double-opening RC beam is analyzed based on the model. The results indicate that under cyclic loading, the fatigue failure modes of double opening RC beams are inclined cracks in the upper and lower beams of the opening and cracks in the corner of the opening. The specimen with a maximum load limit of 0.7Pu and a load position acting on the middle of the opening undergoes fatigue failure. The double opening RC beam has a fatigue life of at least 410000 cycles under a load level of 0.5Pu. After the fatigue test, the remaining ultimate bearing capacity, flexural stiffness, and ductility of the RC beams deteriorate with the increase of load level. The residual performance of the specimen after fatigue is even worse when the load is located in the middle of the opening. Increasing the fatigue cycle to 410000 cycles has an impact on the remaining ultimate bending moment of about 7% and the remaining flexural stiffness and ductility degrade by about 25%. Based on existing research results, a fatigue deformation prediction method for RC beams with double openings was proposed, with an error of less than 7%.

The Effect of the Piles Cap Elevation on Local Scour around Complex Bridge Piers

The Effect of the Piles Cap Elevation on Local Scour around Complex Bridge Piers

Equivalent estimation method (EEM) for quasi-distributed bridge-deflection measurement using only strain data

Deflection is a crucial parameter for bridge health monitoring procedures. In this paper, an equivalent estimation method (EEM) is proposed for quasi-distributed deflection estimation using onboard strain data. Leveraging the installation of the self-designed sensing bar on the bridge girder, an equivalent analysis model is established. An innovative inverse finite element method (iFEM) is employed to discretize the model and to establish a strain-deflection transformation matrix. Then, quasi-distributed bridge deflections are estimated by reconstructing the deformed shape of the equivalent analysis model. The present model is simple and independent of the typology of bridge structures, making the EEM sufficiently general to analyse complex bridges. The EEM framework is computationally fast, powerful, and robust for real-time applications since iFEM enables deformation predictions by simple matrix–vector multiplication without a priori loading and material information. Experimental validation cases have been performed, and they demonstrate the excellent quasi-distributed sensing capability of the EEM.

System fragility evaluation of a curved highway bridge structure considering multi-direction seismic excitations

This paper presents the impact of varying the input seismic excitation directions on the system fragility of a geometrically complex highway bridge structure. The traditional approach of fragility derivation in the principal loading directions (longitudinal and transverse) results in an under/overestimation of the system fragility. To reduce such errors, the contribution of all major vulnerable components to the system fragility in the critical loading direction must be considered. For this purpose, a series of nonlinear time-history analyses were conducted for a testbed configured geometrically curved highway bridge structure in Japan. Shear strain, ductility, and distortion strain were considered as engineering demand parameters for bearings, concrete pier, and steel piers, respectively. The demand dependency among the components was considered using the correlation coefficient matrix for fragility estimation. Subsequently, fragility functions with respect to the input loading directions were generated for the bridge components and system to quantify their sensitivity to seismic input excitation directions. The results show that the component fragility is significantly influenced by the input excitation direction. A relative comparison of the system fragility for different loading directions indicated that a 150° loading direction yielded a higher fragility demand. The findings suggest that the critical fragility assessment should not always be decided only along the principal loading directions.

Effect of sacrificial piles on local scour around complex bridge piers

Sacrificial piles are used to minimize or remediate the local scour around existing bridge supports. This study evaluates the impact of using sacrificial piles on the scour around complex bridge piers. An experimental model is used to simulate nine different scenarios of sacrificial piles. Different numbers, arrangements, and distances of the sacrificial piles are studied. A large diameter sacrificial pile was also considered to evaluate the diameter’s effect. The results show that sacrificial piles are very effective in reducing scour around complex piers. An effective sacrificial piles arrangement should include an intermediate pile aligned with the center line of the complex pier. The scenario of three collinear piles in the transverse direction of the flow gave the best efficiency as it reduced the maximum scour depth by 63 % compared to the base case. On the other side, increasing the diameter of a single sacrificial pile enhanced its efficiency.

Mn(III)–Salen Complexes with Metallophilic Interactions

We synthesized a series of five novel Mn–salen-based compounds (1a–1c, 2a, 2b) through the reaction between precursor chloride complexes and potassium silver/gold dicyanide. The prepared compounds were structurally and magnetically characterized. Our findings revealed that all the Mn(III) central atoms exhibited an axially elongated coordination polyhedron, leading to the observation of axial magnetic anisotropy as indicated by the negative axial magnetic parameter D, which was determined through fitting the experimental magnetic data and supported by theoretical CASSCF/NEVPT2 calculations. Furthermore, we observed magnetic-exchange interactions only in compounds with a special supramolecular topology involving O–H···O hydrogen-bonded dimers. In these cases, the weak magnetic exchange (J/cm−1 = −0.58(2) in 1b and −0.73(7) in 2b) was mediated by the O–H···O hydrogen bonds. These findings were further supported by BS–DFT calculations, which predicted weak antiferromagnetic exchanges in these complexes and ruled out exchange interactions mediated by diamagnetic cyanido metallo–complex bridges. Additionally, we investigated the observed Ag···π (1b) and Au···Au (2b) interactions using QT–AIM calculations, confirming their non-covalent nature. We compared these results with previously reported Mn–salen-based compounds with metallophilic interactions arising from the presence of the [Ag/Au(CN)2]− bridging units.

Rapid evaluation of the high-speed railway bridge vertical deformation threshold and train operation safety performance based on the virtual track inspection method

This study proposes a method for analyzing the impact of bridge deformation on the train-track-bridge coupled dynamics from the perspective of dynamic track geometry. First, with the static mapping geometry and the superposition of random track irregularities are used as excitations, a mapping analytical model between bridge foundation deformation and dynamic track geometry is established by combining the vehicle-track-bridge dynamics model and the virtual track inspection model. Second, after analyzing the effect of bridge foundation deformation on the ratio of dynamic and static extremums of the second derivative, the mapping relationship among the amplitude of the bridge deformation, the second derivative of the dynamic track geometry and the vehicle dynamic response is obtained. Finally, based on the driving safety indicators, a threshold determination method applicable to different bridge deformation patterns is proposed. This method, when combined with modern track detection technology, allows for rapid evaluation and is adaptable to complex bridge deformation scenarios.

Advances in Methodology for Fatigue Assessment of Composite Steel–Concrete Highway Bridges Based on the Vehicle–Bridge Dynamic Interaction and Pavement Deterioration Model

Fatigue cracking is one of the most prominent causes of mechanical failure limiting the service life of existing steel and composite steel–concrete bridges and is among the central concerns of structural and bridge engineers. In this context, the current work presents some recent advancements in an existing methodology for fatigue analysis developed by the authors throughout the years. The methodology is specifically devoted to the fatigue assessment of composite steel–concrete bridges employing the local hot-spot S-N approach and a coupled vehicle–pavement–bridge system considering progressive pavement deterioration with stochastically generated roughness profiles. Two different methodologies were used to solve the dynamic equilibrium equations: the modal superposition method to solve the bridge dynamic equations and a direct integration method to solve the vehicle dynamic equations. From a computational point of view, the present approach is more efficient and detailed than previous versions, as it allows a significant reduction in the analysis time and the use of complex bridge and vehicle finite element models. In this regard, a case study of a highway composite steel–concrete bridge spanning 40 m was selected in order to demonstrate the usefulness of the presented improved methodology by carrying out a fatigue analysis. The results of this investigation (displacements and stresses) are presented, aiming to verify the factors that directly influence the structural response and, consequently, the service life of steel–concrete composite highway bridges.

Research on coupled vibrations between the low-to-medium speed maglev train and a long-span continuous beam bridge

This study investigates the strong coupling vibration between low-to-medium speed maglev trains and the track beam, which results from unique transmission principle of the trains. The research focuses on the impact of train parameters on the dynamic response of the car-bridge system, using a long-span continuous beam bridge as the background. Initially, a multi-body dynamics model of maglev trains was established based on the theory of maglev force equivalence as stiffness and damping. Subsequently, the solid element available in ANSYS was employed to construct a finite element model of the large-span bridge. In SIMPACK, the train-bridge coupled system was established to evaluate the dynamic response of the coupling system under various working conditions. The results indicate that the equivalent models of maglev train demonstrates excellent control performance. The vehicle parameters of weight and speed do not significantly affect the bridge vibration characteristics. However, the lateral dynamic behavior of the bridge increases significantly when the train velocity reaches 160 km/h. The operation of double-line trains in opposing directions can result in more complex bridge vibrations, with a greater dynamic response observed. Therefore, the analysis of the coupled vibration of the car-bridge system under complex operating conditions is required in the design phase. Analyzing the coupled vibration of train-bridge systems during the design phase is crucial for ensuring the safe and efficient of maglev trains.

Modified Wild Horse Optimizer for Constrained System Reliability Optimization

The last few decades have witnessed advancements in intelligent metaheuristic approaches and system reliability optimization. The huge progress in metaheuristic approaches can be viewed as the main motivator behind further refinement in the system reliability optimization process. Researchers have intensively studied system reliability optimization problems (SROPs) to obtain the optimal system design with several constraints in order to optimize the overall system reliability. This article proposes a modified wild horse optimizer (MWHO) for SROPs and investigates the reliability allocation of two complex SROPs, namely, complex bridge system (CBS) and life support system in space capsule (LSSSC), with the help of the same process. The effectiveness of this framework based on MWHO is demonstrated by comparing the results obtained with the results available in the literature. The proposed MWHO algorithm shows better efficiency, as it provides superior solutions to SROPs.

Parametric nonlinear modelling of 3D masonry arch bridges

Detailed modelling of masonry arch bridges and viaducts presents unique computational challenges. Not only do such structures exhibit complex nonlinear behaviour, but they are also difficult to describe within a consistent computational framework for high-fidelity simulations, due to the range of interactive components with varying geometric characteristics. This paper presents a novel parametric model design tool for the generation of detailed 3D FE meshes of realistic masonry arch bridges and viaducts. This tool has been developed according to a modular description as an add-on component within the Rhino – Grasshopper environment. It allows for modular complex bridge assemblages with independent definition of the key viaduct parts, including arch barrels, spandrel walls, piers as well as multi-layered fill. Moreover, new parts can be seamlessly introduced into the framework due to its modular nature. Notably, as all components are geometrically addressable, it is possible to further enhance the model generation tool by adding non-standard routines to create more complex geometry than that allowed by the current parametric definition. Importantly, the developed strategy enables variable fidelity model generation, where different segments of an analysed viaduct can be represented by meso‑ and/or macro-scale masonry descriptions at different levels of detail. This approach further enables the consideration of initial damage in the brick/blockwork, which is a very common feature of many existing masonry bridges and viaducts.

Synthesis, Characterization, Antimicrobial and Antimalarial Activities of 5-((2- phenylacetoxy) carbonyl)-1H-pyrazole-3-carboxylic Acid and its Ce(III), Pr(III) and Nd(III) Complexes

In the past decade, the lanthanoid coordination chemistry was one of the most focused areas of research due to their wide applications as catalyst, magnetism, luminescence and diagnostic tools in biological studies. In this study, novel pyrazole; 5-((2-phenylacetoxy) carbonyl)-1Hpyrazole-3-carboxylic acid derivative and its lanthanoid complexes are designed and tested for potential antimicrobial and antimalarial activities. The binuclear ligand bridge complexes were obtained by the interaction of the ligand with the lanthanide salts. The compounds were characterized by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, UltravioletVisible spectroscopy, Fourier Transform infrared (FT-IR) spectroscopy, Mass spectrometry (MS), Elemental analysis and Magnetic susceptibility measurements. The in vitro antimicrobial assay was done by Agar well diffusion method and in vivo antimalarial studies were performed based on Peter’s method. The results were analysed using one way analysis of variance (ANOVA). The antimicrobial and antiparasitic effects of these compounds were found to be dose-dependent and they showed greater effects at higher doses.&nbsp