Roadway Bridges Research Articles

Bridge Quality Appraisal Methodology: Application in a Reinforced Concrete Overpass Roadway Bridge

AbstractBridge quality control plans and asset management systems are often integrated in collective frameworks used by authorities nationally and internationally. Similarities among these framewor...

Prestressed CFRP-strengthening and long-term wireless monitoring of an old roadway metallic bridge

This paper presents an application of prestressed carbon fiber-reinforced polymer (CFRP) plates for the strengthening of metallic girders of a roadway bridge in Melbourne, Australia. The study also describes the application of a wireless sensor network (WSN) system for long-term structural monitoring of the retrofitted bridge girders. A flat prestressed unbonded retrofit (FPUR) system was developed to apply prestressed CFRP plates to the steel girders of the Diamond Creek Bridge (122 years old), which is subjected to daily passenger and heavy vehicles. The first section explains the results of sets of static and fatigue tests performed in the laboratory to examine the efficiency of the proposed FPUR system prior to its installation on the bridge. The second section presents details of different aspects of the CFRP strengthening of the bridge girders, fatigue design criteria, and layouts for short- and long-term monitoring. For the short-term measurements, the bridge was loaded with a 42.5-ton semi-trailer before and after strengthening. The CFRP plates were prestressed up to approximately 980 MPa (≈38% of the CFRP ultimate tensile strength), which resulted in about 50% reduction in the maximum tensile stress in the bridge girders. The third section discusses the development, installation, and preliminary results of the WSN system used to monitor the pre-stress level in the CFRP plates. The results of the short- and long-term measurements in this study show that the FPUR system is very effective for flexural and fatigue strengthening of bridge girders. Finally, a set of recommendations for long-term structural monitoring is provided.

Fatigue life evaluation of a composite steel-concrete roadway bridge through the hot-spot stress method considering progressive pavement deterioration

Steel and composite steel-concrete bridges are subjected to random traffic loads along their life cycle which generate significant dynamic impacts. The road-roughness of asphalt pavements is one of the most important aspects that contributes to the significant increase of the stress amplitudes and hence to serious load-induced fatigue concerns. In this context, welded joints are well known as the weakest points in bridges, since they are prone to stress concentrations leading to initiation of fatigue cracks being in current design codes evaluated using primarily the nominal stress method (NSM). However, a more accurate stress definition, which considers the complexity of the stress field at the welds, becomes necessary mainly in old roadway steel bridges that are often subjected to out-of-plane stresses. In this paper, the hot-spot stress method (HSM) is used to evaluate the fatigue life of a welded joint subjected to distortion induced-fatigue, considering the vehicle speeds and a progressive deterioration model for the road pavement. The welded joint was modelled by solid elements and was integrated with a 3D dynamic bridge model using the sub modelling technique. Besides the importance of considering the bridge-vehicle dynamic interactions with the pavement road-roughness, the dynamic amplification effects on local stresses and the relatively high scatter found in the fatigue lives considering global and local approaches show that a detailed local stress definition is fundamental to evaluate the fatigue performance of existing roadway bridges. The effects of the annual traffic increase rate on the fatigue life are also discussed.

Standardization of quality control plans for highway bridges in Europe: COST Action TU 1406

In Europe, as all over the world, the need to manage roadway bridges in an efficient way led to the development of different management systems. Hence, nowadays, many European countries have their own system. Although they present a similar architectural framework, several differences can be appointed. These differences constitute a divergent mechanism that may conduct to different decisions on maintenance actions. Within the roadway bridge management process, the identification of maintenance needs is more effective when developed in a uniform and repeatable manner. This process can be accomplished by the identification of performance indicators and definition of performance goals and key performance indicators (KPI), improving the planning of maintenance strategies. Therefore, a discussion at a European level, seeking to achieve a standardized approach in this subject, will bring significant benefits. Accordingly, a COST Action is under way in Europe with the aim of standardizing the establishment of quality control plans for roadway bridges.

Accelerating construction of roadway bridges using alternative techniques and procurement methods

Approximately a quarter of the bridges in the United States are classified as either functionally obsolete or structurally deficient by the United States Department of Transportation (USDOT). As such, transportation agencies are challenged to handle the increasing need of upgrades with limited resources. Accelerated Bridge Construction (ABC) can reduce the construction duration and can decrease the environmental and socio-economic impacts of repair and upgrade activities by minimizing traffic disruptions. As several states are using accelerated construction techniques, a standard guideline would be highly beneficial for these agencies in developing or improving the ABC decision-making process. As problems are often project specific, a decision tool can assist in determining the viability of ABC over traditional construction methods and in selecting appropriate construction and contracting strategies on a case-by-case basis. This paper presents findings of a recent survey with regards to utilization of ABC strategies by state Departments of Transportation (DOTs), and a decision support framework which consists of three models: (1) Analytical Hierarchy Process (AHP) based ABC vs. traditional construction decision-making model; (2) ABC alternatives selection model; and (3) procurement method and contract selection model. The paper also discusses the use of ABC in New York State and describes a New York State bridge project to validate the AHP model.

Integration of Light Rail on the I-90 Floating Bridge across Lake Washington

Installing light rail transit across a floating roadway bridge presents many unique challenges, foremost of which is how to design the multidimensional moving joints at both ends of transition spans between the fixed and floating structures. A technical solution to this technical challenge has been proposed, analyzed, modeled, designed, and prototype tested in the context of the East Link Extension, a light rail transit project being carried out by Central Puget Sound Regional Transit Authority (Sound Transit). Described are the planning, execution, and results of a full-scale prototype testing program of the proposed Curved Element Supported Rail (CESuRa) Track Bridge System, based on the relationship of curved rail supports in two independent planes that adjust in response to the movements of the Interstate 90 (I-90) Bridge. The prototype CESuRa track bridges performed as expected; the information gathered and lessons learned will greatly benefit the final design, the production track-bridge fabrication, and the installation process. Also discussed is the anticipated performance of these track bridges on the I-90 structure in conjunction with the proposed direct fixation track system, fixed rail anchors, and sliding rail expansion joints to be strategically located across the 1.1-mi I-90 Bridge. Built in 1989, the I-90 Bridge is the fifth-longest floating bridge in the world and carries three westbound and two reversible lanes of traffic between Seattle and Mercer Island, Washington. The bridge will be reconfigured to carry four westbound lanes, and the reversible lanes will be converted to light rail transit.

Time variant natural frequencies of a roadway bridge under stochastic vehicle flow

A general framework for investigating the on-load frequencies of roadway bridges under stochastic traffic flows was developed. The cellular automaton (CA) model was adopted to develop the stochastic traffic flow. The on-load natural frequencies of the bridge are analyzed statistically. The results show that the on-load frequencies of bridge are less than the corresponding natural frequencies of the bridge. For higher or lower traffic occupancies, the fluctuation of on-load natural frequencies of the bridge becomes smaller than that under the middle range of traffic flow densities. A linear relationship exists between the mean frequency difference and the traffic flow density, with the mean slope of regression lines for the first four natural frequencies being 0.0844. There is a stronger linear relationship between the mean frequency difference and the total traffic weight, with the mean slope being 0.482. Based on traffic flow density or total traffic weight on the bridge, it is possible to make an estimate of the effect of traffic flows on the on-load frequency of a reinforced concrete continuous beam bridge using the regression relationships.

Pier Stiffness and Bridge Collapse Mechanism

일반설계에서 탄성거동을 전제로 구조물을 설계하는 것과 달리 내진설계는 구조물의 소성거동을 규명하고 조정하여 붕괴를 방지하는 것이 목적이다. 일반교량의 경우에 요구되는 붕괴방지수준은 교량의 특정한 구조부재의 소성거동으로 낙교를 방지하여 지진발생 이후에 긴급차량의 통과를 가능하게 하는 것이다. 이러한 소성거동은 연결부분 또는 교각기둥에 제한되고 각 경우에 적절한 조치가 요구된다. 도로교설계기준은 교각기둥에서 소성힌지를 형성하여 연성붕괴기구를 구성하는 설계방식과 함께 철근콘크리트 교각을 하부구조로 하는 교량을 대상으로 연결부분의 항복을 이용하여 취성붕괴기구를 구성하는 연성도 내진설계를 부록으로 제시하고 있다. 이 연구에서는 철근콘크리트 교각기둥과 강재받침으로 설계된 일반교량을 선정하고 연성붕괴기구와 취성붕괴기구를 모두 고려한 붕괴방지 설계절차 및 도로교설계기준에 요구되는 수정사항을 제안하였다.While structures are designed within elastic range by other designs, plastic behavior of structures should be verified and controlled in order to prevent structural collapse by the earthquake resistant design. No Collapse Requirement for typical bridges is to avoid falling down of superstructure by way of plastic behavior of certain structural elements and to operate emergency vehicles after earthquake. Such plastic behavior is restricted to connections or pier columns and appropriate measures are required for each case. Earthquake Resistant Design part of Roadway Bridge Design Code provides design processes for Ductile Collapse Mechanism by forming plastic hinges at pier columns. Also for bridges with reinforced concrete piers ductility-based design processes are provided as an appendix constructing Brittle Collapse Mechanism with connection yielding. In this study, a typical bridge with steel bearing connections and reinforced concrete piers is selected and No Collapse Design procedure considering both Ductile and Brittle Collapse Mechanism is proposed together with revisions required for the Earthquake Resistant Design part.

Identifying and evaluating the effective parameters in prioritization of urban roadway bridges for maintenance operations

Bridges are considered one of the most important traffic arteries, particularly in metropolises. In accordance with big cities traffic, severe structural damages, or damages caused by the destruction of a roadway bridge, have harmful effects on metropolis management and make appropriate repair operations very difficult. Different bridge management and maintenance systems in various countries have included efforts to resolve these problems. Encountering with the limitations in funds allocated to the maintenance operation and facing various deteriorating in the current urban bridge conditions, we need a proper and effective model to prioritize bridges for repairing and maintenance. An appropriate model for this prioritizing needs a proper database and a supportive decision-making system to process the data, which is based on several parameters. These parameters should not be such little that raise the prioritizing errors and should not be such numerous that encounter analysis process with complexity. In this paper, the parameters of prioritizing the urban roadway bridges to repair and maintenance operation are identified and classified through investigation of codes, regulations, guidelines and applied research carried out in various countries; then, through analysing the experts’ judgements using the classical statistical tests, a comprehensive evaluation and ranking of these parameters is presented.

Seismic Vulnerability of the Italian Roadway Bridge Stock

This study focuses on the evaluation of the seismic vulnerability of the Italian roadway bridge stock, within the framework of a Civil Protection sponsored project. A comprehensive database of existing bridges (17,000 bridges with different level of knowledge) was implemented. At the core of the study stands a procedure for automatically carrying out state-of-the-art analytical evaluation of fragility curves for two performance levels—damage and collapse—on an individual bridge basis. A WebGIS was developed to handle data and results. The main outputs are maps of bridge seismic risk (from the fragilities and the hazard maps) at the national level and real-time scenario damage-probability maps (from the fragilities and the scenario shake maps). In the latter case, the WebGIS also performs network analysis to identify routes to be followed by rescue teams. Consistency of the fragility derivation over the entire bridge stock is regarded as a major advantage of the adopted approach.

Between East and West: Poland’s Pioneering Bridges

Poland’s earliest notable river crossing was built in Warsaw in 1573, but the country’s contributions to bridge engineering did not end there. In more recent times, Poland birthed the first iron bridge on the European mainland, the first welded roadway bridge in the world, and continental Europe’s first long-span lattice truss bridge, parts of which miraculously survived World War II.

Effects of shape factor on the behaviour of elastomeric roadway bridge bearings and benefits of circular bearing cross section

Elastomeric bearings can support steel and concrete bridge girders. Layered bearings with steel plates are typical and they provide the lateral flexibility to accommodate longitudinal girder movement and the necessary vertical stiffness to vertical support reactions. Elastomeric bearings also replace existing roadway bridge girder supports. Mechanical behaviour of elastomeric bearings strongly relates to the incompressible character of the elastomer material. Incompressible character of elastomers, allows elastomer-bearing design through confining unbound surfaces and limiting surface deformations. A particular character of elastomeric bearings known as the shape factor ( S ) represents the difference in stiffness of two elastomeric bearings that have same cross sectional areas but different cross sectional shapes. Through an advanced finite element-modeling program, this study evaluates and compares the behaviours of rectangular and circular steel layered elastomeric bridge bearings under the application of vertical and lateral loads.

No Collapse Design for Typical Bridges

Abstract The purpose of earthquake resistant design for typical bridges is the No Collapse Design and the Earthquake Resistant Design Part of Roadway Bridge Design Code provides a design process to construct the Ductile Failure Mechanism for the bridge structure. However, if it is not practical to provide the Ductile Failure Mechanism due to structure types or site conditions, the Brittle Failure Mechanism is an alternative way to get the No Collapse Design. As well as the existing design process constructing the Ductile Failure Mechanism, the Earthquake Resistant Design Part provides a ductility-based design process as an appendix, which is prepared for bridges with reinforced concrete piers. According to the new design process, designer determines a required response modification factor for substructure and transverse reinforcement for confinement therefrom. In this study, a typical bridge with steel bearing connections and reinforced concrete piers is selected for which the existing as well as the ductility-based design processes are applied and different results from the two design processes are identified. Based on the results, an earthquake resistant design procedure is proposed in which designers should consider the two design processes.

Assessment of vehicular live load and load factors for design of short-span bridges according to the new Egyptian Code

The new Egyptian Code (ECP-201:2012) introduces new vehicular live loads (VLL) and new load combinations for the design of roadway bridges. The new VLL and load combinations introduced in ECP-201:2012 are fundamentally different than those presented in previous versions of the code. The impact of these new loads and load combinations on the design of new bridges or the structural safety of the existing bridges that have been designed according to ECP-201:2003 or ECP-201:1993 has not been fully addressed for the different bridge deck systems. Three different bridge deck systems, i.e. concrete I-shaped girders, composite steel plate girders, and concrete box-girders with different spans were numerically modeled using two-dimensional grillage analogy. The bridge decks were analyzed under main gravity loads using VLL according to ECP-201:2012 and ECP-201:2003. The internal forces of individual load cases, total un-factored load combination, and total factored load combination of ECP-201:2012 and ECP-201:2003 were compared.The study shows that concrete box-girders designed according to ECP-201:2012 and ECP-201:2003 using the ultimate limit state method yield almost the same demand. Despite the increase in the VLL of ECP-201:2012, and consequently the live load forces, concrete I-shaped girder bridges will be subjected to less total factored internal forces in comparison to ECP-201:2003 This is attributed to the interaction between the live to dead loads ratio and the load combinations. Design of composite steel plate girder bridges according to ECP-201:2012 using the allowable stress design method yields over designed sections.

Spectral Analysis of the Structures due to Traffic

The paper deals with spectral analysis of two selected roadway bridges loaded with traffic seismicity due to road and railway traffic. The frequency parameters were obtained from computing model via FEM software. Spectral parameters comparison between theoretical and experimental results was realised. The traffic means effects on soil in frequency and amplitude domain was necessary for bridge spectral analysis.

Fatigue-safety assessment of reinforced concrete (RC) bridges: application to the Brazilian highway network

During the assessment programme of Brazilian roadway bridges, it was noticed that two girder-slab reinforced concrete bridges, with cantilever girders on extremity spans, were a common structural solution adopted 40 years ago in Brazil. Particularities intrinsic to these systems like significant displacements expected on cantilevers associated with soil embankment settlement in bridge entrance can take to a sudden change in slope grades near its ends, provoking sometimes high impact factors. Besides that, traffic and axle load increase has been of concern because these bridges were designed with different scenarios 40 years ago. Therefore, these facts can affect the structural performance of these structures in face of 100 years life required on most current codes for new bridges. So, in this article, a safety assessment to this assembly of bridges is performed. For this study, a simulation model has been developed, which includes the most significant sources of uncertainty in the definition of traffic action and structural response of bridges. Database provided by dynamic tests of these bridges were used for this performance-based assessment. As a result, reliability indexes to fatigue and ultimate limit state of bending are calculated and compared with target values as specified by codes.

Electrical resistivity imaging of unknown bridge foundations

ABSTRACTUnknown bridge foundations pose a significant safety risk due to stream scour and erosion. Records from older structures may be non‐existent, incomplete or incorrect. We evaluate 2D and 3D electrical resistivity imaging (ERI) as a means to reliably identify the depth of unknown bridge foundations. A survey procedure is described for mixed terrain/water environments in the presence of rough terrain. Some electrodes are installed on the stream banks while others are adapted for underwater use. Tests were conducted at five field sites, including three roadway bridges, a geotechnical test site and a railway bridge, containing drilled shafts and spread footings of both known and unknown depth extent. The 2D data acquisition was carried out in the dipole‐dipole configuration. The 2D ERI method resolved the shape and depth extent of the larger bridge foundations but, with less accuracy, the shape and depth extent of the smaller foundations. The 3D ERI method is time‐consuming and does not add sufficient additional value over 2D ERI to become a practical tool for unknown bridge foundation investigations. The 2D ERI method is a cost‐effective geophysical method that is relatively easy to use by bridge engineers.

일반교량의 내진성능 확보를 위한 기본설계

Structural elements of typical bridges are superstructure, connections, substuctures and foundations and earthquake resistance is decided with the failure mechanism formed by substuctures and connections. Therefore earthquake resistant design should be carried out in the basic design step where design strengths, e.g. design sections for structural elements are determined. The Earthquake Resistant Design Part of Korean Roadway Bridge Design Code provides two basic design procedures. The first conventional procedure applies the Code-provided response modification factors. The second new procedure is the ductility-based earthquake resistant design, where designer can determine the response modification factors. In this study, basic designs including the two design processes are carried out for a typical bridge and supplements are identified in view of providing earthquake resistance.

Simultaneous Vehicle Crossing Effects on Fatigue Damage Equivalence Factors for North American Roadway Bridges

In many design codes for roadway bridges, fatigue design involves passing a load model over an influence line for a critical location on the bridge and then determining the resulting nominal stress range. For fatigue design in the finite-life domain, this stress range is then multiplied by a damage equivalence factor to account for differences in the fatigue damage because of the load model and the expected real traffic. In general, the effects of simultaneous vehicle crossings are not considered in the calibration of the damage equivalence factor. In this paper, fatigue design procedures in the U.S., Canadian, European, and Swiss codes applicable for the design of steel or aluminum roadway bridges are first reviewed. A simulation-based study, conducted to investigate the effects of simultaneous vehicle crossings on the damage equivalence factors for North American roadway bridges, is then presented. Based on the results of this study, recommendations are made for amplifying the North American damage equivalence factors in cases where the effects of simultaneous vehicle crossings are expected to be significant.

A condition assessment method for roadside assets

Infrastructure condition assessments provide key information for monitoring the quality of infrastructure, planning and budgeting of maintenance and rehabilitation activities and establishing performance goals. Although the literature is rich in condition assessment methods for roadway pavement and bridges (and to some extent for traffic signs), it is lacking such methods for roadside assets. This paper describes the development and validation of a condition assessment method for 12 roadside asset types and maintenance activities that are related to roadway safety, drainage, cleanliness and vegetation. These assets and maintenance activities are located in the area between the outside edges of the outside shoulders and the right-of-way boundaries. On divided highways, the median is also included. The developed condition assessment method consists of a set of performance standards, a visual inspection procedure to assess compliance with these standards and a statistical analysis procedure to determine the roadside level of service. To test and validate the developed method, it was applied to five highway corridors in Texas, USA, representing different climatic conditions, topography, traffic volume and population density (urban vs. rural). These field trials provided insights into the developed method, including practicality, reproducibility and probability distribution function which best represents the sample unit score.