Capacity Of Bridges Research Articles

A hybrid method for damage detection and condition assessment of hinge joints in hollow slab bridges using physical models and vision-based measurements

The simply supported slab bridge is a typical perfricated reinforced concrete bridge. Under the influence of increasing vehicle loads and natural environmental erosion, the hinge joints between slabs suffer from damage that cannot be easily evaluated, which brings negative effects on the load carrying capacity of bridges. In the present study, a hybrid method for damage detection and condition assessment of hinge joints in hollow slab bridges using physical models and vision-based measurements was proposed. The stiffness reduction of hinge joints is taken as the damage degree and condition level of the inspected hinge joints. An analytical model of a simplified spring-mass system was firstly built to demonstrate the applicability of using the relative displacement ratio as the damage index of hinge joints. The relationship between the relative displacement ratio and the stiffness reduction of hinge joints was then studied thoroughly through a parametric study on finite element models considering different damage levels of hinge joints. Thresholds of the relative displacement ratio were defined to classify the damage states of hinge joints. The damage index of target hinge joints can be calculated from the actual data provided by using computer vision-based multi-camera and multi-point displacement measurements. Lastly, the application of a real-life bridge under normal traffic was demonstrated to verify the feasibility of the quantitative evaluation of the service status of joints in hinged-slab bridges. It indicated that the proposed method could evaluate the damage degree of joints quantitatively, effectively and economically.

Effects of groove clearance size on gap bridging capacity in PWLBW of Ti6Al4V alloy sheet assembled in butt joint configuration: Numerical simulation and experimental assessment

In laser tailor-welding of metal sheets, it is difficult to keep the assembly clearance fixed due to plate specification deviation, tooling error, and thermal deformation. In this paper, the influence of clearance size on gap bridging capacity and in turn the seam appearance quality was investigated for thin Ti6Al4V alloy plates, configured by an improved pulse wave laser beam welding (PWLBW) scheme. The welding experiment and the numerical simulation were performed at 1.2 mm-thick workpieces assembled in a butt joint with a reserved clearance. With the clearance size enlarged from 0.2 mm to 0.4 mm, the gap bridging type changes from bilateral to unilateral, which results in the failure of the keyhole to rebound during the pulse interval, and causes an obvious reduction in metal bridge area at the cross-section. As the clearance increases further, a through-cavity geometry is generated between the weld spots and finally preserved within the solidified weld bead, indicating a poor overlapping effect. The dynamics of the weld pool, including thermal cycle, Marangoni convection, and molten metal flow rate are exquisitely sensitive to the change in clearance size. The clearance size during assembly and welding processes should be controlled below 0.4 mm to attain seam integrity, continuity, and sound tensile property.

The impact of adding the Northern sea route to the Belt and Road Initiative for Europe: A chain cost approach

In this paper, the possibility of adding the North Sea Route (NSR) route to the Belt and Road Initiative (BRI) is researched whereby the main aim is to determine if it is possible to set up a container service via the NSR route that could attract cargo from the existing maritime routes via Suez and the land route. In order to make the analysis, a model which is able to calculate the total generalised chain cost for a supply chain is used and updated.This analysis shows that it is possible to set up such a competitive service compared to the land bridge and the Suez Canal Route (SCR) for cargo that has a high value of time. For these specific cargo types, it is possible to attract cargo for the NSR from the SCR at equal costs, but with an average time saving of 10%. Comparing the BRI or land bridge to the SCR, there is a cost increase of 20% and a time decrease of almost 65%. Considering the rather strict limitation in capacity, it should be noted that a single NSR service of eight 5,400 TEU vessels already offers around half the capacity of the land bridge. The uncertainty in arrival times, however, would remain an issue in the NSR service, but with ice diminishing, this risk will decrease as well.

Increasing Inventory Rating Factor of Steel Truss Bridge Through Orthotropic Steel Deck Panel Application

Currently, 18,648 bridges with a total length of 510,366 km have been constructed in Indonesia, but only 86% are in good condition, while the rest are damaged. Steel truss bridge damage generally occurs on the RC decks, and its repair is often implemented through deck replacement or redecking using Orthotropic Steel Deck (OSD) panel. In Indonesia, this method has only been applied limitedly at the Citarum I Bridge in 2009 and the Cisadane Bridge in 2013, while the effect on the existing steel truss bridge is unknown. Therefore, this study aims to evaluate the steel truss bridge performance after OSD panel redecking through numerical modeling. The design process of the OSD panel was carried out by micro-modeling on ABAQUS CAE using shell elements with a mesh size of 50x50 mm and pinned boundary conditions. In this stage, the materials were assumed to be elastic with small deformations. The evaluation of steel truss bridge performance was performed on the A-class steel truss bridge Bina Marga design standard with a 60 m span by comparing the existing bridge inventory rating factor (using RC decks) to OSD panel redecking, which is an indicator of bridge self-weight reduction. Based on the structural macro-model developed using SAP2000, the bridge self-weight reduced the axial tension and compression forces on the steel truss bridge mainframe by 20.6%-24.6% and 20.5%-24.5%, respectively. Consequently, this increased the inventory rating factor by 9.3%-9.5%. In other words, using the OSD panels lighter than the existing RC decks increases the steel truss bridge capacity to resist the live load or vehicle rating throughout its service life.

Displacement-based blast-resistant evaluation for simply-supported RC girder bridge under below-deck explosions

An increasing trend of the intentional and accidental explosions has been threatening the safety of bridges. At present, the blast-resistant evaluation for the simply-supported RC girder bridge under below-deck explosions was conducted by numerical simulations. Firstly, by comparisons with three series of field explosion tests on the reduced-scale RC piers/columns and bridge, the adopted finite element (FE) analysis approach was validated. Then, the refined FE model of a typical two-span prototype bridge was established, and 24 explosion scenarios with three typical explosion sources specified by Federal Emergency Management Agency (FEMA) were numerically simulated. The influence of pier designs on the local damage of pier and global response of bridge was further examined, and it derives that, (i) for compact sedan and sedan bombs, increasing the concrete grades is the most feasible way and decreasing stirrup spacings are also recommended, while increasing pier diameter does not definitely enhance the blast resistance; (ii) for the cargo van bomb, the abovementioned pier designs are not effective to prevent bridge collapse. Finally, the linear relationship between the mass loss of pier and vertical displacement of bridge deck was established, and thus the traffic capacity of the post-blast bridge can be practically evaluated by analyzing a single pier instead of the whole bridge.

МЕТОД РЕКОНСТРУКЦІЇ БАЛОЧНИХ МОСТІВ БЕЗ ЗУПИНКИ ЇХ ЕКСПЛУАТАЦІЇ УЛАШТУВАННЯМ НОВОЇ ЗБІРНО-МОНОЛІТНОЇ ПРОЛІТНОЇ БУДОВИ

The article contains the method of reconstruction of an emergency bridge structure by installing a new span construction without stopping its operation taking into account difficult engineering and geological conditions of construction site on the example of bridge which is situated at the state significance road M-21, near the village Pultovtsy of Vinnitsa region. Have been reviewed the technical condition of short and medium-length beam bridges, which span structures are a system of string-concrete prestressed bridge beams which are often operated in Ukraine.
 Have been described methods for increasing the capacity of bridges, which were used in Soviet times. Have been proved the systemic nature of defects and damages of prefabricated string-concrete spans and bridge structures after widening. Have been described the rational ways to strengthen such bridges. Have been proved the low efficiency of their reinforcement by standard methods due to the critical corrosive wear of the reinforcing prestressed fibers of the main beams. Have been chosen the optimal method by replacing the superstructure from the considered methods.
 Have been proposed a precast-monolithic structural scheme of the bridge with increased carrying capacity according to modern requirements.Have been developed an analytical and finite element model of the stress-strain state of reinforced precast-monolithic bridge structure, taking into account the difficult engineering and geological conditions of the construction site.
 Have been proven the needed to strengthen existing pile foundations. Have been developed a constructive scheme for strengthening the bridge supported by installing additional rows of piles.
 Have been planned to be erected the construction of a new superstructure and additional rows of piles to strengthen the foundations of bridge supports in two stages without stopping of bridge structures exploitation but only with partial blockage of traffic. Have been proposed an effective technological installing diagram for this.

An overarching framework to assess the life-time resilience of deteriorating transportation networks in seismic-prone regions

This study develops a comprehensive framework to assess the resilience of transportation networks consisting of deteriorating bridges subjected to earthquake events. For this purpose, the structural capacity of highway bridges is estimated during their service life using a set of detailed finite-element models that simulate the progress of deterioration. The developed models take into consideration the main environmental stressors and determine the extent of capacity loss as a function of time. Based on the degraded state of structural components, seismic fragility analyses are performed to obtain a probabilistic evaluation of the extent of damageability of the existing bridges under seismic events. Since each transportation link normally consists of a number of bridges, the state of damage in the individual bridges is mapped to the corresponding links and a scenario-based approach is employed to estimate the resilience of the entire transportation network. To demonstrate how the consequences of structural degradation can be integrated into the developed framework, the large-scale transportation network of Los Angeles and Orange counties is investigated under a series of aging and earthquake scenarios. The outcome of this study indicates how the estimates associated with the functionality measures of a transportation network can be improved if the age factor is properly integrated into the framework used for resilience assessment.

Experimental-Numerical Study on the Flexural Ultimate Capacity of Prestressed Concrete Box Girders Subjected to Collision

Precise evaluation for flexural ultimate capacity of bridges which are subjected to the collision of over-height trucks is essential for making decisions on corresponding maintenance, strengthening or replacement. When the span of a cross-line continuous bridge with a double-box girder was hit by an overly high vehicle, the concrete floor of one girder was severely damaged, and part of the prestressed strands and reinforcements in the girder were broken. After the double-box girder was removed and separated into two single box girders, the ultimate flexural capacity of both box girders was studied by destructive tests, and a comparison was made between the damaged and undamaged girders. Moreover, finite element analysis was conducted to simulate the failure process. The results show that the flexural bearing capacity of the damaged box girder decreased by 33%, but it was still 1.07 times greater than the design bearing capacity, which basically meets the design requirements. Also, the damaged box girder showed a desirable serviceable limit state for three-axle vehicles and five-axle vehicles, but showed an undesirable serviceable limit state for six-axle vehicles. This study shows that repairing or strengthening the damaged span may be better than demolishing and rebuilding the whole superstructure bridge.

A Modified Fiber Bridging Model for High Ductility Cementitious Composites Based on Debonding-Slipping Rupture Analysis

Modified micromechanical bridging model is established with consideration of the fiber rupture effect at debonding and slipping stages. The bridging model includes the debonding and slipping rupture of fibers and establishes the fiber/matrix interfacial parameters (friction τ 0 , chemical bonding force G d , slip-hardening coefficient β ). A different interfacial bonding can cause fiber rupture. The influence of the interfacial conditions on the fiber rupture risk was investigated. In the modified bridging model, the effective bridging stress, the debonding rupture stress, and the slipping rupture stress were clearly identified. Finally, single-fiber pullout tests with different embedded lengths were carried out to validate the bridging model. The relationship between the fiber bridging stress and the crack opening predicted by the bridging model was consistent with the experimental results. This modified micromechanical bridging model can be used to quantitatively calculate the actual fiber bridging capacity and to predict the ductility of the high ductility cementitious composites reinforced by different types of fibers.

Evaluation on the performance of magnesium phosphate cement-based engineered cementitious composites (MPC-ECC) with blended fly ash/silica fume

To develop magnesium phosphate cement-based engineered cementitious composites (MPC-ECC) that can be well used for rapid building repair, this study explores the influence of blended fly ash/silica fume on the compressive strength, direct tensile properties, and micromechanical properties of MPC-ECC. And the relationship between two pseudo strain-hardening indices (PSHσ and PSHJ) and ultimate tensile strain is established. The micromechanical analysis indicates that the blending of 30% fly ash and 10% silica fume significantly improves the fiber bridging capacity and fiber bridging complementary energy; however, the blended fly ash/silica fume reduces the tensile cracking strength, elastic modulus, and fracture toughness of the matrix. In addition, the blended fly ash/silica fume increases the compressive strength, up to 41.67 MPa, and also improves the tensile properties of MPC-ECC. The strain hardening behavior is more improved as the fly ash/silica fume content increases. Besides, the ultimate tensile strain and the pseudo-strain hardening indices are positively correlated, showing that the pseudo-strain hardening indices can be used to design MPC-ECC with specific ultimate tensile strains. To ensure that the MPC-ECC achieves an ultimate tensile strain of above 3%, PSHσ and PSHJ are recommended to reach 2.12 and 21.32, respectively, or more at the same time.

Analysing local failure scenarios to assess the robustness of steel truss-type bridges

Many of the steel bridge collapses occur in truss-type bridges. This is, in fact, the focus of this study involving an assessment of the robustness of this type of structures based on an actual bridge that the authors had extensively monitored and controlled. Robustness was assessed by means of computer simulations of various Damage Scenarios (DSs) to analyse the structural bridge capacity to efficiently activate Alternative Load Paths (ALPs). The computational models have been previously validated with the results of load tests on the bridge and a laboratory test on a full-scale bridge span. The DSs have considered a series of non-simultaneous failures in different elements. The results indicate that the structure is capable of not triggering a disproportionate collapse after each of the DSs with the help of the efficient activation of ALPs that required the contribution of other elements with extra-strength capacity as well as from the superstructure and the joints working under bending moments. The results were used as the basis for practical recommendations for: i) the design of new steel bridges and the retrofit of existing ones and ii) monitoring the structure for the optimal position of sensors to predict local failures that could spread to the rest of the bridge.

A Model Test of the Dynamic Stiffnesses and Bearing Capacities of Different Types of Bridge Foundations

With the rapid development of traffic infrastructures in developing countries, the evaluation demands for the vertical capacities of in-service bridges are increasing. The feasibilities of the transient response method (TRM) and index of dynamic stiffness for evaluating pile foundations are proven. However, their applicability to other types of bridge foundations must be investigated, and the correlation between the dynamic and static stiffnesses is also needed for analysis. In the present study, model tests were performed in a laboratory for various types of bridge foundations. A total of eight foundation models were fabricated for three types of bridge foundations. Both TRM and static loading tests were applied on each model. The influence of the foundation constraint state was tested as well. The results show that there is an obvious correlation between the dynamic and static stiffnesses and that the index of dynamic stiffness can reflect the foundation bearing capacity. Accordingly, the TRM can be employed to evaluate different foundation types, including spread, caisson, and pile foundations.

Load carrying capacity of masonry arch railway bridges at the serviceability limit state

This article focuses on masonry arch railway bridges. The main topic is the algorithm, which was developed for the purpose of a non-linear arch bridge analysis. The sensitivity analysis of the input parameters of the calculation was carried out. Subsequently, the study was carried out for the comparison of four calculation methods. For this comparison, a set of arch bridges were chosen. Two methods used commercial software, and the other two methods were developed. One of the developed algorithms uses a simple linear calculation. The second developed algorithm uses an iterative approach to handle material and geometrical non-linearity. The first commercial software method uses 2D non-linear models, the second method is a limit collapse analysis using the software LimitState:RING. These three methods were developed to handle the SLS (serviceability limit state) criteria, and their results were compared to the result of LCC at the ULS (ultimate LS) using LimitState:RING.

Chemistry and Applications of Organosilanes – An Overview

Organofunctional silanes are hybrid materials of silanes having attracted greater attention since the last decade owing to its versatile properties and wide range of applications. In this review, we have summarized the types of organosilanes (RnSiX4-n), their reactions, and applications. Organosilanes usually have two reactive groups, organofunctional groups and hydrolyzable alkoxy groups, which undergo hydrolysis and condensation. Silanols (Si-OH) and siloxane (Si-O-Si) structures are formed by hydrolysis and condensation reactions, respectively. In general, organosilanes acts as excellent binding agent due to its bridging capacity through (Si-O-Si) bond linkage with metal surfaces. From the extensive literature survey carried out, we understand that the silanes are synthesized without comprehending the reaction kinetics mechanism. In the past few decades, significant advances were witnessed in the development of various organofunctional silanes, which were used in a wide range of research areas based on its bifunctional characteristics.

Correlation of flaw structure and cracking behavior in SHCC with X-ray CT scanning technique

Strain Hardening Cementitious Composites (SHCC) are materials featuring multiple cracking and strain hardening behavior. The variation of SHCC’s tensile performance, especially the tensile strain capacity, has long been a puzzle for civil engineers who seek broader infrastructural application of this advanced material. The tensile performance of SHCC is governed by the random distribution of flaw size and fiber content, but the correlation between them has not been comprehensively studied. The present work reconstructed the flaw structure of a number of SHCC specimens utilizing X-ray CT scanning technique and established the cracking strength distribution for each specimen based on a modified fracture mechanics model. The distribution was correlated with the bridging capacity of the cross-section with the least fibers and an index η indicating the fractions of cross-sections that can undergo cracking was proposed. The index was found to correlate well with the number of cracks in a tensile test and provides a new approach to evaluate SHCC’s potential to achieve saturated multiple cracking. Finally, artificial flaws in different sizes were added to tailor the flaw structure in order to facilitate the multiple cracking of SHCC, and design suggestions based on the above findings were provided.

Rapid Evaluation of Load-Carrying Capacity of Long-Span Bridges Using Limited Testing Vehicles

Load testing is usually used to evaluate the load-carrying capacity of long-span bridges in their service life. However, a large number of calibration trucks should be arranged in complicated loading patterns to deform bridges during load testing, which is labor-intensive and time-consuming. Aiming to solve this problem, this paper proposes a rapid bridge load-carrying capacity evaluation method using limited testing vehicles. The methodology includes three steps: influence line identification from limited vehicle exciting responses; influence line correction based on prior information of the bridge; and influence line–based bridge load-carrying capacity evaluation. To apply this method in engineering practice, standardized truck passage routines are designed. An application example involving a 1,280-m long-span suspension bridge is presented at the end of this paper. The truck routines, extracted bridge influence lines, and predicted load-carrying capacity of that bridge are presented based on the proposed methods. The testing results are also compared with standard load testing conducted 12 years ago to evaluate bridge performance changes. The outcomes of this paper provide a workable and economical method for long-span bridge load-carrying capacity evaluation.

A Novel Elastomer-Based Inclinometer for Ultrasensitive Bridge Rotation Measurement.

Bridge deformation consists of cross-section rotation and deflection, which are crucial parameters for bridge capacity evaluation and damage detection. The maximum value of deflection usually happens at mid-span while for rotation it happens at two-ends. Therefore, compared with deflection, rotation is more convenient for in-situ measurement since the bridge pier can be the reference point. In this study, a high-precision inclinometer for bridge rotation measurement was conceptualized, designed, and validated. The proposed inclinometer converted the small rotation of bridge section into the deformation of an elastomer. Strain gauges were then utilized to measure the elastomer deformation and thus the bridge rotation can be obtained. The dimensions and modulus of the elastomer were designed and chosen based on the theoretical analysis. Characteristics of the inclinometer were calibrated in lab and in-situ experiments at an in-service bridge were conducted to validate its feasibility and robustness. Test results showed that the proposed inclinometer had excellent performance in resolution and accuracy, which indicate its great potential for future bridge health monitoring.

Long-term evidence on induced traffic: A case study on the relationship between road traffic and capacity of Budapest bridges

Reducing urban road congestion by infrastructure development promises lower travel times, reduced pollution and wider economic benefits. However, besides advanced transport infrastructure affecting existing traffic, it also induces new demand, which tends to be underestimated. This phenomenon is well-known for interurban roads, especially for motorways, but the literature is scarce on real-life data for urban areas. Most analyses on induced traffic were carried out on relatively short time periods. Therefore, this paper studies 55 years in an urban environment and shows how capacity provision induced extra traffic. Furthermore, it could also be demonstrated that scaling back capacity diminishes travel demand. Most of the analyses on induced traffic concentrated on just a handful of countries; therefore, evidence from a country that emerged from middle income to high income provides new insights for other developing nations and cities.

Isolation design and numerical calculation of isolated rubber bearing in continuous beam bridge in high seismic intensity area

The stability of bridges in the face of earthquake hazards has always been the focus of construction engineering. At present, a large number of bridge construction has begun to use isolation rubber bearings to increase the seismic capacity of bridges. However, in the face of high-intensity earthquake disasters, the seismic performance of the bridge is gradually unable to meet, the main reason is the lack of relevant research on the seismic performance of the bridge in high seismic intensity area. Therefore, this study will explore the changes of the bridge in the face of high-strength earthquake, and try to use high damping rubber bearings for the isolation design of the bridge. By establishing the finite element model of continuous bridge combined with isolation rubber bearing, the numerical calculation of bridge element is carried out on this basis, and the isolation effect of isolation rubber bearing is analyzed. The results show that the compression resistance and shear resistance of the isolated rubber bearing are strong. Under the influence of different seismic waves, the maximum displacement of the bearing is 0.131 m and the maximum horizontal force is 389.6 kN, which are lower than the allowable value of the bridge, and the overall seismic performance of the bridge has been significantly improved, which can play a good theoretical support in the construction of continuous bridges in high seismic intensity areas.

Multiple Earthquake Effects on Vulnerability of Horizontally Curved RC Bridges

ABSTRACT Bridges subjected to mainshock–aftershock sequences experience significant damage as a result of repeated shaking. Therefore, neglecting the effects of multiple earthquakes may lead to a considerable underestimation of bridges seismic vulnerability. The uncertainties in modeling bridge structural systems as well as the representation of seismic loads significantly affect the bridge vulnerability, especially for horizontally curved bridges, where complex loading conditions exist. In this study, fragility curves for horizontally curved bridges are developed for both mainshock only and mainshock–aftershock sequence cases. The seismic response of a typical four-span horizontally curved reinforcement concrete box-girder bridge is evaluated using the cloud analysis method and the effects of uncertainties on the probability of failure of the bridge components are examined and quantified using the Latin hypercube sampling technique. The results from this investigation indicate that considering the mainshock only could significantly underestimate the damage level even by around 50% and that incorporating uncertainties could change the bridge capacity by more than 45% of its estimated value.