Location Of Bridge Research Articles

Prediction of mechanical behavior of reinforced concrete bridges following a fire based on the fire dynamics simulator–kriging model

AbstractThe performance degradation and degree of damage of bridge materials are more extensive at the fire source compared to other bridge locations. The traditional finite‐element model (FEM) modification method leads to a large error and is unable to achieve a good correction effect. In addition, as the traditional static load test method is used to evaluate the bearing capacities of bridges postfire, the risk of bridge damage, or collapse‐induced by secondary loading—remains unaddressed. To solve these problems, this paper proposes a modified FEM of a bridge following a fire based on the fire dynamics simulator (FDS)–artificial intelligence algorithm. The static behavior of a bridge is predicted using the modified FEM. First, a numerical simulation of a bridge fire is conducted using the FDS to obtain the temperature field distribution and determine the influence ranges of local design parameters of the bridge at the fire source. Second, a response surface model with a high fitting accuracy is constructed to modify the initial FEM by using the artificial intelligence algorithm proxy model together with dynamic load test results for the bridge postfire. Finally, the static behavior is predicted using the updated model. In this study, an actual hollow girder bridge postfire is taken as the research object, and the static behavior prediction results obtained via the proposed method are compared with the static loading test results. The results indicate that the response‐predicted value of the modified FEM is close to the measured value of the bridge postfire.

Evaluasi Struktur Jembatan Gantung Pejalan Kaki Dumpoh, Magelang Jawa Tengah

The bridge analyzed is a suspension type with a function as a pedestrian bridge. The bridge has a total span of 53.75 m and a width of 1.8 m, steel construction with wooden deck. The service life factor, damage to the bridge frame, and overload are certainly a problem for this bridge structure. Evaluation of the structure using survey data from existing measurements at the bridge location, then analyzed using the SAP2000 program. The result is that all tower frames, girders, main cables, hangers, and bridge decks, the nominal capacity is still able to withstand the ultimate load. However, the deflection in the middle of the bridge span is 0.72 m and has exceeded the allowable deflection (L/200). So based on the results of the evaluation of the Dumpoh suspension bridge structure, the cross-sectional strength of the frame is still safe, but the stiffness of the deflection value does not meet.

Factors prompting and deterring suicides on the roads.

In addition to the devastating impact on the individual and their families, suicides on the roads can cause distress and harm to other people who might be involved in a collision or witness an attempt. Despite an increased focus on the characteristics and circumstances of road-related suicides, little is known about why people choose to end their lives in this way. The aim of the current study was to investigate the factors prompting and deterring the decision to attempt suicide on the roads. We conducted a secondary analysis of survey data, as well as seven in-depth qualitative interviews. Participants had lived experience of suicidal ideation or behaviour at a bridge or road location. We also carried out an online ethnography to explore interactions in different online communities relating to this method of suicide. Participants perceived a road-related suicide to be quick, lethal, easy and accessible and to have the potential to appear accidental. The proportion of participants who described their thoughts and attempts as impulsive appeared to be higher than had been observed with other method choices. The potential impact on other people was a strongly dissuasive factor. Measures designed to prevent access to potentially lethal sites may be particularly important, given that many participants described their thoughts and behaviour as impulsive. In addition, fostering a culture of care and consideration for other road users may help to dissuade people from taking action on the roads.

A visual condition assessment of a reinforced concrete railway bridge subject to alkali silica reaction (ASR) deterioration in Johannesburg

In the 1940’s, a reinforced concrete (RC) railway bridge located in central Johannesburg was constructed using Witwatersrand Quartzite, at the time, unknown to be an alkali-silica reactive aggregate. The bridge currently displays signs of distress in the form of severe map-cracking. This study presents preliminary results of a series of tests that have been conducted to characterise the severity of alkali silica reaction (ASR) deterioration in the bridge. Twelve concrete cores were extracted for testing from various locations of the railway bridge, which displayed varying degrees of distress. A visual assessment was conducted globally on the entire structure as well as locally (using modified damage rating index (DRI) approach) on the extracted cores. The findings showed that there was extensive map-cracking present on all thirteen railway bridge elements examined, revealing signs of distress in the bridge. Even elements that were sheltered from exposure to direct rain, such as the underside of three arch surfaces, also exhibited extensive map-cracking. Furthermore, the modified DRI method was a useful technique to assess and compare the relative extent of damage of concrete taken from various locations of a RC structure, using local images of the cylindrical surface of the concrete cores.Graphical

Field Monitoring and Analysis of Abutment Foundation Behavior for a Curved Integral Abutment Bridge under Thermal Loading

The construction of integral abutment bridges (IABs), including semi-IABs, has increased substantially in the past two decades, partly because of reduced construction and maintenance costs. However, temperature-driven lateral movements, associated with the elimination of expansion joints, lead to a complex interaction between the bridge structure and the soils behind and under the abutment, which could result in soil densification, void formation, and settlement in the approach slab. The bridge's structure, geometry, and location all play an essential role in how the IAB responds to those movements. In addition, if the IAB is curved, it brings more complexity to its behavior. Nonetheless, there has been very little research on the behavior of curved IABs to date. This study investigates the behavior of a newly constructed curved IAB via field monitoring and numerical simulation. Field measurements included the backfill pressure, horizontal translation, and rotation imposed on the abutments during seasonal thermal fluctuations. The abutments rotate and translate toward backfill in summer and away from it in winter because of thermal expansion and contraction of the superstructure. Such thermal movements contributed to the increase in the lateral pressure to 85 kPa in the first year and to 140 kPa in the second year of monitoring. This implies that irreversible deformation may occur during seasonal temperature changes, supported by the monitored displacements. The bridge curvature, different skew angles at both ends, and the abutment geometry resulted in different movements and backfill pressures at each corner. A numerical simulation is also performed to provide more insights into the behavior of the curved IAB with more seasonal temperature cycles.

Drive-By Fleet Monitoring to Detect Bearing Damage in Bridges Using a Moving Reference Influence Function

This paper introduces a new bridge damage indicator, the moving reference influence function (MRIF), to detect bridge bearing damage using deflections inferred from vehicle accelerations. Recently, vehicle acceleration has been used to find the apparent profile (AP) of a bridge when a vehicle passes. This AP consists of bridge profile elevations and bridge deflection components. To describe the relationship between these deflection components and load, a MRIF is proposed for the first time in this paper. An error minimization process is used to find the MRIF and the road surface profile on the bridge. The vehicle acceleration signals used in the paper are assumed to be collected from a partially instrumented vehicle fleet. In the fleet, only the first axle acceleration is collected from each vehicle. To simplify the minimization process, both the MRIF and the bridge profile are represented by kernel density functions. The results show that the bridge profile can be accurately obtained and that bridge bearing damage can be identified from the MRIF. Both area and skewness of the MRIF are damage sensitive and can be used together to find the location and severity of bridge bearing damage.

The thermal assessment of GFRP reinforced concrete bridge decks in fire scenarios

If a concrete structure survives a fire, several questions can arise regarding the safety of the structure and the extent of repair. This paper combines the results of a set of comprehensive material tests on various Glass Fibre Reinforced Polymer (GFRP) reinforcing bars at high temperatures with heat transfer analysis to approximate the extent of the fire-induced damage. The paper discusses the most common fire types in bridges (i.e., hydrocarbon fire and pool fire) occurring at various locations of bridges. A simple guideline for quick assessment of the GFRP reinforced concrete bridge decks is proposed, enabling the bridge authorities and practitioners to make an informed preliminary decision following a fire incident. This paper provides a quick visual inspection method to approximate the level of damage to GFRP reinforcing bars and correlate their mechanical properties to the available information on the post-fire residual properties of GFRP bars. The limitations of this method are presented in section 6. The paper outlines one example to show how to use the method and the information from the paper to determine the reliability and the conditions of GFRP bars at key locations. The findings of this example indicate that GFRP bridge decks can retain sufficient strength although the long-term performance of the bridge must be assessed carefully.

Application of bridge weigh-in-motion system in bridge health monitoring: a state-of-the-art review

Bridge health monitoring (BHM) has grown as an essential component of the maintenance paradigm in any transportation network around the world. The mostly used visual inspection method has limitations such as inspector bias, inaccessibility in remote areas, need for human physical presence at the bridge location, etc. On the other hand, vibration-based BHM methods require artificial excitation to the bridge. This motivates researchers to explore potential alternatives for BHM. The bridge weigh-in-motion (B-WIM) system has emerged as a promising alternative with the potential to augment traditional BHM techniques. The advantages of B-WIM systems are durability, portability, easy installation, etc. In addition to weight estimation of passing vehicles, it provides other structural informations that are helpful for bridge assessment. It also overcomes the limitations of pavement-based WIM systems. Most importantly, a B-WIM system uses the same components as a standard BHM system, making BHM a by-product and economical compared to a standalone BHM system. With the development of B-WIM theory, recent researches have revealed the feasibility of B-WIM system for BHM. However, the applicability of the B-WIM system for BHM in any type of bridge and condition is limited. Through the fundamentals of B-WIM theory, this paper reviews the existing bridge response-based BHM methods that involved B-WIM algorithm. The findings are discussed in order to identify the remaining challenges and provide insight to the future aspects.

Experimental Study On 3D Acoustic Emission Source Location of Concrete Based On Sparse Least-Squares Support Vector Regression

In order to further prove the effectiveness of the sparse least-squares support vector regression (S-LS-SVR) method in damage detection, the authors used the S-LS-SVR model to locate actual damage sources of concrete. The data from acoustic emission testing (AE) are generated and filtered by the pullout test of reinforcement in concrete, and the three-dimensional coordinates of real-time damage sources in the failure process are provided through the model. The S-LS-SVR method is compared with the Newton iterative method and improved exhaustive method for positioning speed, positioning data utilization, and positioning accuracy. The results show that S-LS-SVR is superior to the two other time difference of arrival–based positioning methods in positioning speed, positioning data utilization, and positioning accuracy (data utilization is slightly lower than the improved exhaustive method). The location method based on S-LS-SVR provides the possibility for the application of AE technology in intelligent damage location of bridges, dams, and other service structures.

Multifactorial Evaluation of Spatial Suitability and Economic Viability of Light Green Bridges Using Remote Sensing Data and Spatial Urban Planning Criteria

Multi-faceted stresses of social, environmental, and economic nature are increasingly challenging the existence and sustainability of our societies. Cities in particular are disproportionately threatened by global issues such as climate change, urbanization, population growth, air pollution, etc. In addition, urban space is often too limited to effectively develop sustainable, nature-based solutions while accommodating growing populations. This research aims to provide new methodologies by proposing lightweight green bridges in inner-city areas as an effective land value capture mechanism. Geometry analysis was performed using geospatial and remote sensing data to provide geometrically feasible locations of green bridges. A multi-criteria decision analysis was applied to identify suitable locations for green bridges investigating Central European urban centers with a focus on German cities as representative examples. A cost-benefit analysis was performed to assess the economic feasibility using a case study. The results of the geometry analysis identified 3249 locations that were geometrically feasible to implement a green bridge in German cities. The sample locations from the geometry analysis were proved to be validated for their implementation potential. Multi-criteria decision analysis was used to select 287 sites that fall under the highest suitable class based on several criteria. The cost-benefit analysis of the case study showed that the market value of the property alone can easily outweigh the capital and maintenance costs of a green bridge, while the indirect (monetary) benefits of the green space continue to increase the overall value of the green bridge property including its neighborhood over time. Hence, we strongly recommend light green bridges as financially sustainable and nature-based solutions in cities worldwide.

Implementation of Non-Contact Temperature Distribution Monitoring Solutions for Railway Vehicles in a Sustainability Development System Transport.

The implementation of temperature sensors represented by thermal imaging cameras is becoming increasingly rational. It is playing an important role in the socio-economic environment, in industry, scientific-research work. The main objective of the work is to assess the quality of the railway vehicles in exploitation and their thermal insulation, localise thermal bridges, and the tightness of the body using the FLIR-E6390 thermal inspection camera. An integration of test methods (research methods) was used including a diagnostic method based on a thermographic study integrated with the system approach method and system failure mode effects analysis (SFMEA). The scientific-research work included studies of seven types of railway vehicles in exploitation. A number of conclusions were reached. Specifically providing implementation of innovative and non-contact temperature distribution monitoring solutions for railway vehicles in a sustainability development system transport. Demonstrated the disparities between the different types of vehicles. Next, the identification of critical elements of their thermal insulation, the location of thermal bridges, and the tightness of the body of the rail vehicles, particularly the doors and inter-unit connections. The study covered the state of consumption of stationary electricity (for non-traction needs), implementing innovative indicators for stationary electricity consumption of railway vehicles as a new approach.

Investigation of human β-defensins 1, 2 and 3 in human saliva by molecular dynamics.

Human β-defensins present in saliva have a broad spectrum of antimicrobial activities that work against infections in oral cavity. To provide a better understanding of these molecules' properties and functions at the molecular level, we have investigated and compared the important structural properties of human β-defensin-1, -2 and -3 using molecular dynamics simulations. Our results have shown that human β-defensin-3 has a more flexible structure in water than the other two because of its high hydrophilicity, low β-sheet content and high repulsive forces between its charged residues. Moreover, we found that the location of the salt bridges is important in protein's stability in water. Molecular dynamics simulations of human β-defensins 1, 2 and 3 revealed that the hbd-3 is more flexible in water than hbd-1 and hbd-2.

Movement dynamics of gibbons after the construction of canopy bridges over a park road

Abstract Gibbons (Hylobatidae) are species highly adapted to tree-top living. Thus, their movement can be compromised due to the negative impact roads have on canopy habitats. In this study, we built two single-rope artificial canopy bridges and a ladder bridge at two out of five locations where a group of white-handed gibbons (Hylobates lar) in Khao Yai National Park, Thailand were known to cross a main park road. We compared road crossing frequencies, home-range characteristics, and other ad libitum observations during the periods before and after bridge installation. After bridge construction was complete, the group took 10 weeks to use the single rope bridges to navigate over the road. During 442 group follow observation hours and 539 bridge observation hours, 131 crosses over the road were observed. The adult female usually crossed the road first, and the group showed a clear preference for the single-rope bridges over the ladder bridge (92 crossings versus 5). Gibbons crossed the road approximately once a day and crossed mostly at the bridge locations both before and after bridge construction. There were not significant changes in crossing rates from before (crossing between the tree branches and on the ground) to after bridge installation at both the places where bridges were installed (crossing using the bridges). Nonetheless, with more crossings being in the bridges than on the ground after bridge installation, crossings were presumably safer. These findings suggest that gibbons will cross a road on the ground, risking predation, encountering people, or being hit by a vehicle, but artificial canopy bridges provided a safer crossing option since gibbons no longer crossed on the road or jumped across wide gaps at the two locations where bridges were constructed. Maintaining canopy connectivity over roads using artificial bridges logically improves home range connectivity, potentially gene flow, and safety of canopy dwellers. However, connecting areas which were not previously connected should be considered carefully. The new connection could disrupt group dynamics, particularly for species that defend territories, such as gibbons.

RASIO DAYA DUKUNG TIANG PANCANG TUNGGAL BERDASARKAN DATA KALENDERING DENGAN DATA TEST PDA

Pile bearing capacity can be obtained from static and dynamic approaches. Calculation of the carrying capacity of the pile statically is by approaching it through the technical properties of the soil. Meanwhile, the dynamic method is to analyse the ultimate capacity with data obtained from pile driving data. The research was conducted using calendaring data to get the carrying capacity ratio based on a dynamic approach. Carrying capacity based on calendaring data is calculated using five methods, namely Hilley, ENR, Danish, and Navy-Mc.Key, and Janbu. The results of these calculations, then a coMParison of the ratio to the carrying capacity of the PDA test is carried out. The research was carried out at two locations: the Gempol-Pasuruan toll road construction project and the Widuri Bondowoso Bridge. The results of the calculation of the carrying capacity for the ultimate Q at the Gempol-Pasuruan toll road location, the Danish method, which is close to the PDA test results with a ratio of 1.1132 (P1-2) 0.8911 (P3-5), for Qijin at the Gempol-Pasuruan toll location, the method Danish is close to the PDA test results with a ratio of 0.7421 (P1-2), 0.5940 (P3-5). The calculation results for the ultimate Q at the Widuri Bondowoso Bridge location, the ENR method is close to the PDA test results with a ratio of 1.7260 (P1-19), 1.2553 (P2-17), for Qijin at the Widuri Bondowoso Bridge location. This Hilley method is close to the PDA test results with a ratio of 1.0489 (P1-19), and 0.7625 (P2-17).

Integrated Top-Down and Bottom-Up Mass Spectrometry for Characterization of Diselenide Bridging Patterns of Synthetic Selenoproteins.

With the rapid acceleration in the design and development of new biotherapeutics, ensuring consistent quality and understanding degradation pathways remain paramount, requiring an array of analytical methods including mass spectrometry. The incorporation of non-canonical amino acids, such as for synthetic selenoproteins, creates additional challenges. A comprehensive strategy to characterize selenoproteins should serve dual purposes of providing sequence confirmation and mapping of selenocysteine bridge locations and the identification of unanticipated side products. In the present study, a combined approach exploiting the benefits of both top-down and bottom-up mass spectrometry was developed. Both electron-transfer/higher-energy collision dissociation and 213 nm ultraviolet photodissociation were utilized to provide complementary information, allowing high quality characterization, localization of diselenide bridges for complex proteins, and the identification of previously unreported selenoprotein dimers.

Impact of Hydrological Conditions on the Isotopic Composition of the Sava River in the Area of the Zagreb Aquifer

The Zagreb aquifer is the main source of potable water for the inhabitants of the City of Zagreb and Zagreb County. It presents a strategic water reserve protected by the Republic of Croatia. All previous studies related to the definition of the groundwater–surface interaction in the study area have been made based on the isotopic composition of the Sava River from the location of the Domovinski Most bridge, which is located downstream of most pumping well fields. In 2019, a new monitoring station was established at the Podsusedski Most bridge, at the entrance of the Sava River into the Zagreb aquifer, approximately 23 km upstream of the Domovinski Most bridge. Within this research, water isotope data (δ2H, δ18O, deuterium excess) from both Sava River and groundwater sites were used along with hydrologic data to examine the extent to which hydrologic conditions affect the isotope signature and whether the interaction between groundwater and the Sava River causes a change in the isotopic composition of the Sava River. In addition, δ18O amplitudes were estimated for different time periods, as well as the mean residence time for the hydrological year 2019/2020. For that purpose, different statistical methods were applied to the new monthly data for six years for the Domovinski Most bridge and two years for the Podsusedski Most bridge. The δ18O amplitudes vary from 0.22 to 1.86 depending on the time interval and hydrological conditions, while the mean residence time for the hydrological year 2019/2020 was estimated to be about 2.5 months.

“Ah Lai’s Crossing” – Malaysia’s first artificial road canopy bridge to facilitate safer arboreal wildlife crossings

Abstract Roads negatively affect wildlife populations globally, causing habitat fragmentation that can facilitate mortality by access to forest for poaching and wildlife collisions with vehicles. Primate habitats are vulnerable to fragmentation exposing them to anthropogenic threats. Endangered dusky langurs (Trachypithecus obscurus) in Malaysia are often found in urban areas and have been frequent victims of vehicle collisions. To mitigate the hazardous impact of a busy asphalt road on wild dusky langurs in Teluk Bahang, Penang, we built the first artificial road canopy bridge in Malaysia in February 2019 to assist arboreal wildlife to move between habitat fragments more safely. Four days after the bridge construction, the first long-tailed macaque (Macaca fascicularis) was recorded via a camera trap crossing the bridge, and plantain squirrels (Callosciurus notatus) and dusky langurs first crossed one and eight months later, respectively. The bridge was upgraded from a single-firehose rope to a double-rope in August 2020 to assess the effectiveness of the two designs. In total, 2128 animal crossings comprising three mammal species were recorded between March 2019 and May 2021. Plantain squirrels crossed the bridge most frequently with 2075 crossings, long-tailed macaques crossed 32 times, and dusky langurs 21 times. There was a significant difference in bridge use according to species between the two designs (Chi-Square, p < 0.001). Since the construction of the bridge, the rate of previously frequently reported primate roadkills near the bridge location has dropped to zero. This successful pilot project has spurred the efforts to implement more canopy bridges country-wide to support primate conservation efforts and better protect arboreal wildlife from the negative impacts of linear infrastructure.

Stability of line shapes in inkjet printing at low substrate speeds

Line formation control plays a critical role in inkjet printing stability for its high relevance to industrial processes. The present study describes experiments for depositing droplets of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) solutions using high-speed imaging technology. The line printing dynamics and ink drops coalescence were analyzed. Two stability criteria are proposed for the stability of the printed line at low substrate speeds, including the continuity criterion derived from the volume conservation and the bulging instability determined by the ratio of the transported flow rate and the applied flow rate. Stable printed lines are bound by the two stability criteria and equipment limitation, represented in a parameter space bound by the normalized drop spacing, p*, and the normalized substrate speed, UT*. We then discuss the changes of the normalized critical substrate speed between the stable and bulging regions UT1* and between the stable and discontinuous regions UT2* under a fixed injection frequency. Finally, the reasons for the formation of different printed line shapes are demonstrated by observing the coalescence processes of an impacting droplet and a sessile printed line. The relationship between the location of the liquid bridge and the drop spacing is discussed for determining the line shapes.

Case analysis of thermal defect detection of near-zero energy building envelope based on infrared thermography

The thermal performance of the envelope structure is one of the important components of the performance design of near-zero energy buildings. Minimizing envelope heat loss is the key to improving building energy efficiency. A necessary first step in the building envelope optimization process is the assessment of its actual thermal performance. This paper summarizes the application status of infrared thermography in thermal defect detection of building envelopes and common forms of thermal defects in near-zero energy buildings. Taking a near zero energy building in Shenyang area as the target object, an efficient and non-destructive infrared thermal image measurement method is applied to determine the thermal defect rating of the building from both qualitative and quantitative aspects. The results show that the building has high thermal performance. The temperature field distribution of the building envelope could be quickly obtained by using the infrared thermal imaging instrument. In this way, it can accurately identify the location of thermal bridges and air tightness defects, and provide an efficient and accurate detection method for building energy-saving diagnosis and evaluation.

Damage Location of Beam Railway Bridges Using Rotation Responses under Moving Train Loads

Detection of potential damage is of great significance for aging railway bridges. In this paper, a damage location method for beam railway bridges based on the rotation response to operational train loading is presented. The method is based on deformation area analysis of the operational rotation response of bridges to the passage of trains. The theoretical basis of this method is elaborated. The calculated deformation curvature area difference ratio (CADR) change is used to identify damage in bridges. To obtain the curvature area, a technique is proposed for the curvature area calculation. The results are presented in terms of the damage condition extracted from each ratio, which was obtained by dividing the deformation area from the current interval to the sum of the areas from all the intervals. The location of damage was identified by observing the magnitude of the changes in the CADR. Finite element models were utilized to verify the method. The influences of train-track-bridge interaction and environmental temperature changes were considered. The calculation process is given for the application of the proposed method to the damage location of railway bridges. Thereafter, vehicle-bridge models with different parameters are investigated. The results show the capability of the method.