Bridge Type Research Articles

Structural Health Monitoring of Typical Urban Bridges in the Netherlands Combining Collapse Simulations and Monitoring Data

Bridges play a vital role in the European transport network, and their preservation is of utmost importance. Despite many centuries- old bridges still being in use in European cities, their structural integrity may be compromised due to factors like material degradation, increased traffic loads, extreme events, or slow deformation phenomena. It is essential to regularly assess the current conditions of these structures and monitor their evolution over time to enable timely intervention when necessary. This study presents the first results of a multidisciplinary methodology for the Structural Health Monitoring (SHM) of typical urban bridges in the Netherlands, combining numerical simulations using the Applied Element Method (AEM) with monitoring data derived from various sensing sources. These sources range from standard in situ techniques to satellite remote sensing using Synthetic Aperture Radar Interferometry (InSAR). The methodology is applied to a representative bridge of Amsterdam canals. The nonlinear analyses have led to a numerically predicted crack pattern consistent with on-site observations. The simulated damage progression until collapse identifies critical points of the bridge to be kept under control with monitoring activities.

Model Updating of different Bridge types using ambient vibration and OMA identification.

Structural Health Monitoring (SHM) to date is an increasingly crucial issue in civil engineering. Many structures like bridges and viaducts nowadays are often older than their design life and show signs of structural deterioration that can potentially affect structural safety. One of the most popular monitoring techniques is dynamic monitoring under environmental vibrations using Operational Modal Analysis (OMA) techniques.OMA needs f.e.m. models that can simulate structural behavior under the real conditions and that can be used for interpretation of monitoring data and for possible damage detection.The study proposes a model updating for two different bridges: a girder and box deck one. After an OMA identification using ambient vibration, through the modal parameter identified, modal updating is performed on f.e.m. models, changing only few essential parameters. All the f.e.m. models are made with beam elements.The study highlights that even a simple f.e.m. model of the structure can describe accurately the dynamic and in general the structural behavior of a complex structure such as bridges and viaducts. The authors also show the differences between a f.e.m. model developed for the design and or verification and a f.e.m. model intended SHM. Model updating is performed through the management of a few parameters of the structure like the stiffness of bearing devices between superstructure and substructure, the deformability of foundation soil, the mechanical properties of concrete and reinforcement and the modal masses. The variation in each of these parameters can have a different role on the behavior of the structure.A good reliability of the f.e.m. model can be achieved through the management of a few structural parameters obtaining results that are sufficient for models that have the purpose of interpreting SHM data and are used to perform damage research.

Statistical analysis of existing bridges inspection results and road network risk management

The Italian scenario of road bridges appears particularly singular as most of the road bridges were built around the early ‘70s of the last century. This paper focuses on the peculiar situations encountered during the inspection activities carried out by the National Safety Agency for Safety of Railway and Road infrastructures (Ansfisa). In particular, an analytical picture of the inspection experience conducted by Ansfisa on the A24 and A25 autoroutes is presented. The infrastructure sample analyzed concerns of 549 existing bridges. The performed inspections allowed for obtaining data on the state of conservation of the considered structures. The statistical elaboration of the collected data, allowed for highlighting typical situations of the state of conservations of typical Italian highway bridges, as well as for drawing considerations useful for the planning of random inspection activities and for the management of infrastructural risk at the network.

Nonlinear Response Characterization of Post‐Tensioned R.C. Bridges through Hilbert–Huang Transform Analysis

A novel methodology for the characterisation of the nonlinear behaviour of post‐tensioned r.c. bridges, which exploits the response to heavy traffic travelling during operational conditions, is presented. This type of bridges shows a nonlinear elastic behaviour due to the partial opening of cracks under heavy loads whose entity is related to the intensity of the prestressing force. The properties of this response vary because of material relaxation or damage of the prestressing system. The study exploits the abilities of the Hilbert–Huang transform (HHT) to extract the instantaneous properties of the dynamic response, and a novel procedure to characterise the nonlinear elastic response is presented and investigated through theoretical applications on simplified dynamic systems. A frequency‐amplitude correlation chart is proposed as a visual tool to retrieve useful information on the nonlinear response related to the instantaneous variation of the natural frequency with the response amplitude. With the aim of denoising and eliminating spurious contributions introduced by the local nature of the information extracted through the Hilbert spectral analysis, a probabilistic model is proposed for the result interpretation, through which the probability distribution of the instantaneous natural frequencies conditional to different levels of the response amplitude is provided and potential bridge’s response modifications and anomalous behaviours of the prestressing system can be detected. An extensive parametric analysis is performed to assess the influence of the most relevant parameters governing the problem and verify the effectiveness of the proposed strategy.

Suspension Bridges Versus Cable-Stretched Bridges: A Comparison of Structural Behaviour and Performance

A suspension bridge and a cable-stayed bridge are compared under various loads and environmental conditions in this study. Under live, dead, and seismic loads, the research investigates axial forces, displacements, bending moments, and shear forces using advanced analytical methods and software such as CsiBridge, SAP2000, and Staad Pro. Steel plays a key role in the construction of suspension bridges and cable-stayed bridges, as this study thoroughly compares both types of bridges. Csi Bridge software is utilized in this study to investigate the axial force, displacement, bending moment, and shear strength of these bridges under various loading conditions. Cable-stayed bridges are recognized for their aesthetic benefits and structural efficiency for medium-to-long spans, and suspension bridges for their high tensile strength and durable design. The two bridge types exhibit different shear forces, displacements, and torsional values, underscoring their unique engineering designs.

Diagnostics of Post-Tensioned Bridge Girders Using Distributed Fiber Optic Sensors

In contemporary bridge construction, post-tensioned concrete technology stands as one of the prevailing methods. Over the past several decades, it has been extensively employed in constructing medium-span bridges worldwide. As time has elapsed, many of these structures now demand diagnostic assessments due to deteriorating technical conditions. A promising approach for diagnosing such bridges involves utilizing distributed fiber optic sensing (DFOS) technology. DFOS enables continuous measurements to be acquired along the entire structural length, which is particularly crucial for these bridge types. Its advantages have already been demonstrated in civil engineering applications, notably in contexts related to concrete structures. The paper presents research conducted on post-tensioned beams with curvilinear multiwire prestressing strands. Optical sensors were installed before and after concreting the beams. The main aims were to measure strains, crack widths and beams’ displacements. It also compared results from DFOS-based sensors embedded in concrete during execution (for new structures) to sensors in pre-made near-surface grooves (for existing structures) and to detect defects within one beam using sensors inside the cable duct, analyzing strain data. DFOS measurements were compared with conventional spot techniques, achieving very good compliance. This investigation establishes that a well-structured DFOS-based system, encompassing suitable measurement methodologies, optical sensor configurations, installation techniques, and post-processing algorithms, emerges as a relevant tool for the comprehensive diagnostics of post-tensioned concrete bridges, both the new and existing ones.

Effect of the linking bridge type on the self-assembly behaviour of 2',3'-difluoroterphenyl derivatives.

The self-assembly behaviour and the crystallization kinetics of two liquid crystal compounds containing 2',3'-difluorosubstituted terphenyl as the mesogenic core have been described. Calorimetric studies show that the linking bridge type affects the polymorphism of smectic phases. The CH2O.3 compound with the -CH2O- linking bridge connected with a longer methylene spacer possesses the chiral smectic phase with antiferroelectric properties (SmCA* phase), while the COO.6 liquid crystal with the -COO- linking bridge connected with a shorter alkyl chain forms the chiral smectic phase with ferroelectric properties (SmC* phase). Both compounds crystallize upon slow cooling, while fast cooling causes the vitrification of the conformationally disordered crystal phase. Dielectric measurements reveal the complex relaxation dynamics in the identified thermodynamic states. DFT calculations allow us to estimate the nature of relaxation processes.

Research on the Bridge Type Quadrant Diagram in Build-ing Collaborative System Bridge Diagrams

Research on the Bridge Type Quadrant Diagram in Build-ing Collaborative System Bridge Diagrams

Research on the Bridge Type Quadrant Diagram in Building Superlong-Span Bridges

Research on the Bridge Type Quadrant Diagram in Building Superlong-Span Bridges

Dental Bridge Procedure to Straighten Loose Teeth, A Review

Background: A dental bridge is a treatment that fills spaces or gaps between teeth or fills in missing teeth. Bridges can help restore bite and maintain the natural shape of the face. The procedure for closing or making abutments between the gaping tooth spaces uses dentures (called pontics). Objective: Report and explain the dental bridge process to straighten loose teeth. Materials and Methods: Based on the author's knowledge, this review included theory or case studies from Elsevier, Willey, MDPI, Hindawi Publishing, Dove Press, and Pubmed journals. Several (35 articles) of these manuscripts are then identified for appropriateness with the subjects provided in this study, assessed descriptively, and described based on the manuscript's flow or scientific principles. Results: Pontics are made of porcelain to match the natural color of the teeth. After the pontic is implanted, there is no more space between the teeth. In general, this procedure is needed to: Restore the teeth's ability to bite and chew, Clarify speech when you speak, Maintain facial shape, and Prevent remaining teeth from falling out or shifting positions. Four types of dental bridges are an option to "bridge" the empty dental space: Traditional bridge, Cantilever bridge, Maryland bridge, and Implant-supported dental bridge. Pontic installation through this process must be repeated every 5-15 years, depending on the type of treatment. This paper reports several types of dental bridges that can be used as references to improve understanding of prosthodontics. Conclusion: A dental bridge uses dentures anchored to teeth or implants to replace lost teeth permanently, improving speech, restoring a smile, and preventing tooth loss

Pengaruh Kepemimpinan Tranformasional, Budaya Organisasi, Lingkungan dan Stress Kerja terhadap Rework di Mediasi Oleh Work Motivation pada Pelaksanaan Proyek Konstruksi

During the implementation period as well as during the maintenance period, there was a lot of work improvement, demolition, or in other words there was a lot of rework, where this rework illustrates the poor quality performance of the project implementation. Many aspects at the implementation stage of this construction project can cause product quality failure (non-performance) so that it must be disassembled and reworked, one of these factors is caused by the aspect of human resources. Quality performance problems that lead to rework can be said to often occur in the implementation of construction projects, both in the type of road projects, bridges, buildings, waterworks, and other types of construction projects. Rework causes cost overruns in project implementation which impact on project cost performance, and ultimately affect overall company performance. One of the dominant causes of the rework incident, among other aspects, is human resources. This research uses descriptive research method. The role of human resources is essentially one of capital and holds the most important position in achieving company goals. To achieve the success of a company not only in terms of technological excellence, but the role of human resources is the most important component in achieving company success.

Development of a seismic vulnerability and risk model for typical bridges considering innovative intensity measures

Seismic intensity measures are one of the core parameters for estimating regional bridges’ seismic risk and vulnerability. Using macroscopic seismic intensity indicators to predict and assess the seismic vulnerability of bridges can contribute positively to establishing urban and rural earthquake risk models. However, the developed vulnerability model rarely considers the contribution of instrument intensity to its quantification results and ignores the influence of nondamage bridge samples on the development of bridge risk models and the membership relationship between seismic vulnerability levels, which makes the developed model somewhat localized and uncertain. This study proposes a quantitative method and innovative model considering composite seismic intensity (instrumental and macroseismic intensity) indicators. The model was updated and validated using 300,000 acceleration records monitored by ten seismic stations during the Luding earthquake on September 5, 2022, in China, and the features of seismic motion parameters were analysed. The established empirical vulnerability dataset of bridges during the 2008 Wenchuan earthquake in China was updated and optimized using the developed models and methods. The traditional vulnerability level of bridges has been expanded by adding and refining actual samples (2317 bridges) from different seismic intensity zones. A vulnerability prediction model based on an updated extended bridge database was developed using nonlinear regression methods. A fragility membership index calculation model for estimating the correlation features of bridge vulnerability levels is proposed by combining the probability risk and fuzzy membership correlation algorithm. The traditional method for calculating the seismic vulnerability index has been improved, and a multiparameter bridge vulnerability model validation and rationality analysis have been conducted using the newly developed bridge sample dataset.

Physicochemical differences between camelid single-domain antibodies and mammalian antibodies.

In recent years, single-domain antibodies, also known as nanobodies, have emerged as an alternative to full immunoglobulin Gs (IgGs), due to their various advantages, including increased solubility, faster clearance, and cheaper production. Nanobodies are generally derived from the variable domain of the camelid heavy-chain-only immunoglobulin Gs (hcIgGs). Due to the high sequence homology between variable heavy chains of camelids (VHHs) and humans (VHs), hcIgGs are ideal candidates for nanobody development. However, further examination is needed to understand the structural differences between VHs and VHHs. This analysis is essential for nanobody engineering to mitigate potential immunogenicity, while preserving stability, functionality, and antigen specificity. We obtained the VH and VHH sequences of various camelid and non-camelid mammalian antibodies from public databases and used multiple sequence alignment based on the Chothia numbering scheme. Aligned sequences were subjected to diverse analyses encompassing paratope length, binding prediction, motif, disulfide bridge, salt bridge profiling, and physicochemical characteristic distribution. Logistic Regression coupled with the Boruta - Random Forest algorithm facilitated the comprehensive examination of physicochemical properties. Our findings revealed longer, less variable paratope sequences in VHHs, along with specific antigen binding residues with increased binding potential compared to VHs. Although the VHs showed more heterogeneous noncanonical disulfide bond patterns, the VHHs had a higher number of noncanonical disulfide bridges. Intriguingly, a typical salt bridge between the 94th and 101st positions in the VHs had a very low encounter rate in the VHHs. Surprisingly, we also identified notable differences in the physicochemical patterns of mostly conserved frameworks (FWs), especially the FW2 and FW3 regions, between VHs and VHHs. Our findings point to possible key sites in VHHs as candidate residues for nanobody engineering efforts.

Forecasting and early warning of bridge monitoring information based on a multivariate time series ARDL model

For bridge monitoring data, employing time series analysis to establish mathematical models that can reflect the operational state of a structure and predict its future state is a feasible research approach for bridge condition assessment. Existing studies primarily consider data from a single monitoring point. However, the bridge health monitoring system (HMS) is equipped with various sensors, and the monitoring data obtained from different measuring points are not isolated. Therefore, this study aims to utilize a multi-point, multi-variable perspective. The multivariate ARDL model, which utilizes multiple monitoring time series, is developed and the interrelationships between different measuring points and variables are investigated. Moreover, a method for structural forecasting and early warning that utilizes the ARDL model is developed. For the warning threshold interval, the confidence interval of the predicted values is utilized, and the establishment and dynamic updating of the periodic model is discussed. Finally, based on the health monitoring data of Kunshan Yufeng Bridge, the ARDL model for bearing displacement and temperature monitoring data is established. Using the model, this study explores the long-term and short-term quantitative relationships and the interactions between bearing displacement and temperature variables. Subsequently, forecasting and early-warning analyses are conducted. Compared with the ARIMA model, which is based on a single displacement variable, the forecasting MAE, RMSE, MAPE, and TIC of the ARIMA model are 2.38681, 3.34296, 0.08698, and 0.06215, while these metrics of the ARDL model are only 0.53197, 0.62786, 0.01913, and 0.01138. Apparently, the ARDL model exhibits much higher forecasting accuracy; thus, early warning precision is ensured. The early-warning and assessment method established herein is robust against bridge types or monitoring parameters; thus, it exhibits satisfactory applicability and feasibility.

Node-based wave analysis method for the dynamic response and stiffness of long-span cable-stayed bridges

For dynamic analysis of long-span cable-stayed bridges (LCB) with high flexibility and long force transmission paths, wave analysis method offers unique advantages over modal analysis. However, conducting wave analysis for the entire LCB poses challenges due to the modeling complexity and the substantial computational cost associated with solving numerous wave equations. Therefore, a simple analytical approach for wave analysis of LCB is proposed, which entails the discretization of the entire bridge into waveguides and the subsequent recombination of the regularized local wave propagation models. The feasibility and strategy of solving the global propagation function using local double coordinate systems and specific node-based local wave propagation models are demonstrated. Additionally, based on the geometric and mechanical configuration of nodes in the LCB, local wave scattering and propagation models corresponding to the four standardized nodes types are proposed. A unified Node-Based Wave Analysis (NWA) method for LCB is developed, considering the viscoelastic behavior of cable-stayed beams according to the Kelvin-Voigt model to enhance structural realism. The reasonable damping coefficient in bridge is determined by means of theory and dynamic in situ test of three bridges. Finally, an extended case study is conducted on a typical two-pylon cable-stayed bridge, focusing on the impact of moving loads and material properties on wave characteristics. The results demonstrate the reliability of the proposed NWA method in predicting wave energy distribution, highlighting the suitability of wave analysis for dynamic analysis of LCB. In comparison to undamped structures, it has been found that the presence of damping results in a pair of additional flexural waves with a new dispersion relation in cable-stayed bridges. Furthermore, the study reveals the stiffness enhancement mechanism associated with wave dispersion characteristics in cable-stayed bridges.

Redesign of The Overpass Bridge Structure at Km 839+450 Toll Road Pasuruan-Probolinggo Using Parker Type Truss Bridge

The Overpass Bridge Km 839+450 Pasuruan - Probolinggo Toll Road which is located in Leces District, Probolinggo Regency, East Java has a total span length of 144 meters with a Girder I bridge type. This bridge has 5 spans with 4 pillars. The writer want to redesign the bridge into 2 spans to increase the free space under the bridge overpass. The Parker truss bridge type was chosen because it has the lightest self-weight compared to other types of steel truss bridges. This parker type steel truss bridge is planned with a length of 72 m, a width of 12 m, and a height of 13 m. The bridge is designed for 1 lane which has 2 main lanes and 1 emergency lane. From the analysis carried out, the thickness of the vehicle floor plate is 20 cm with concrete fc 30 MPa and reinforcement Fy 410 MPa. The steel structure uses BJ 41 steel quality with profile dimensions on longitudinal girders WF 300.300.10.15, transverse girder profile dimensions using WF 700.300.13.24, main frame girder dimensions using WF 552.500.50.50 & WF 552.475.25.30, transverse wind ties using WF 294.200.8.12, as well as cross wind ties using the L 250.250.35. For the connection, high-strength bolts of type A325 with Fy 820 MPa are used with a diameter of 24 mm and a connection plate which is L 100.100.10, L 120.120.12, and a 25 mm thick plate. on the main frame connection. The placement of the bridge uses the placement of Typer Elastomeric Bearings coated with steel plates with dimensions of 600x600x150 mm. Steel truss bridge parker type has the advantage that the upperstructure's own weight is lighter than the existing bridge, the difference in weight reaches 33,07 %.

Structural behavior of skewed prestress concrete superstructure

The construction of span-skewed bridges has become widespread worldwide and in Turkey. This article focuses on the structural behavior of simply supported prestressed concrete bridges with varying skewness angles. Specifically, supported I girder pretensioned prestressed concrete bridges are investigated using different models (five models) with skewness angles 0° - 21°- 37.6°- 57°–66.6°. These models are analyzed using the Midas Civil software to analyze and design various bridge components and types through the finite element method. This method employs the most commonly accepted codes worldwide. This research showed that shear forces and bending moments were significantly affected by increasing the degree of skewness angle when it exceeds 37.5°. External I-girders behavior was similar yet inversely proportional behavior. Internal I-girder behavior was also identical but inversely, too.

Seismic response of bridges employing knowledge-enhanced neural networks for the lumped plasticity modelling of RC piers

AbstractTo facilitate seismic analysis of bridges, especially on a regional scale, this study established a parametric finite element model of bridges incorporating simplified component elements. It employs a knowledge-enhanced neural network (KENN) to calibrate the parameters of the lumped plasticity model of pier columns. Along with a database of historical experimental results, the influence of the key characteristics of reinforced concrete columns on model parameters are investigated and formulated as physical laws to supervise KENN training. The developed KENN model was then developed, yielding root mean square errors within the range of [0.027, 0.209]. These errors are slightly larger than those of the purely data-driven neural network, yet the KENN model aligns more consistently with the physical principles. Further, to demonstrate its accuracy and efficiency, the proposed methodology was applied for the rapid seismic response analysis of typical bridges.

Damage scenario analysis of bridges using crowdsourced smartphone data from passing vehicles

AbstractBridge wear and deterioration occur over time under typical operations. Inspections can be resource intensive, infrequent, and sometimes require bridge closure. Instrumented passing vehicles may be used to record vibration responses and extract damage‐sensitive bridge frequency response characteristics. This paper presents a methodology for extracting bridge frequencies from crowdsourced dynamic response data recorded within passing vehicles. Detected bridge frequency changes and a novel point cloud methodology are used to identify critical damage scenarios and estimate remaining life. The use of a novel crowdsourced Welch methodology allows for spectra averaging that reduces the influence of noise and transient events. Numerical and experimental studies illustrate that bridge frequencies can be accurately estimated and that changes in bridge frequency caused by different damage scenarios can be characterized. Numerical examples for the damage scenario analysis, including estimation of remaining life, are provided for two bridge types and three specific damage scenarios.

Shaking table test of the seismic performance for railway simply-supported girder bridge isolated by self-centering bearing

In order to solve the problem of the residual displacement of a railway simply-supported girder bridge and realize the aim of a rapid recovery in traffic after earthquake events, we designed a self-centering seismic isolation bearing and created a typical simply-supported girder bridge model with 1/10 ratio. Three peak ground acceleration (PGA) shaking table tests were performed, with the test procedures further described in detail. The test results show that the bearing provides an overall good self-centering performance. Other than the case of a 0.5 g transverse earthquake, where the bearing remains outside of the sliding surface and therefore cannot be self-centering, all the tests show that the bearing is completely self-centering. At the same time, during all the earthquake scenarios, the main structure of the bridge was not damaged in any discernable way, the longitudinal frequency did not change, and the transverse frequency decreased given that the bearing remained outside of the sliding surface. In addition, it was found that the large bearing displacement in the longitudinal direction may lead to a collision of adjacent girders, resulting in a sharp increase in the acceleration of the girders. In cases without collisions between the girders, the acceleration of the girder is effectively reduced compared with the acceleration of the pier top. The results also show that the pier can be effectively protected by the self-centering bearing, as well as indicating that the reinforcement strain of the pier does not reach the yield value under all tests. Due to the large displacement of the bearing, it is necessary to increase the allowable displacement or install a limiting device. Finally, the finite element model (FEM) of the test model is established, with the calculation results compared with the test results, in this way proving the correctness of the FEM and providing a reference for designing the seismic isolation of the railway simply-supported girder bridge.