Orthotropic Steel Bridge Decks Research Articles

Structural response of orthotropic bridge deck depending on the corroded deck surface

The possibility of the occurrence of orthotropic-steel-bridge-deck corrosion damage is usually not considered in its maintenance due to the deck’s anti-corrosion coating or painting. The severely corroded surface of an orthotropic steel bridge deck was reported, and fatigue crack occurred on the corroded deck plate, related to severe corrosion damage. Researches on and reinforcement of orthotropic steel bridge deck damage consisting of a corroded deck surface and corrosion damage, however, are rarely conducted. Thus, in this study, the structural responses of an orthotropic steel bridge deck with a corroded deck surface were analytically evaluated to examine the effect of the corrosion on the structural behaviors. Three-dimensional FE analysis models were constructed using two corrosion surface models as a mean corroded-surface model and a corroded surface model to consider the corrosion level of the deck surface. The stiffness change of the asphalt pavement was also considered according to the seasonal temperature change. In the case of the corroded-surface model, a high stress concentration was appeared because of the surface roughness of the corroded deck surface with reduced deck thickness. Their stress levels were evaluated that it can develop the fatigue crack on the orthotropic bridge deck surface compared with the fatigue category suggested in the IIW, AASHOTO and JSSC.

윤하중 시험과 유한요소해석을 통한 강상판 교면포장의 거동분석 연구

PURPOSES: The objective of this study is to analyze and evaluate the behavior of orthotropic steel bridge deck pavement using three-dimensional finite element analysis and full-scale wheel load testing. METHODS: Since the layer thickness and material properties used in the bridge deck pavement are different from its condition, it is very difficult to measure and access the behavior of bridge deck pavement in the field. To solve this problem, the full-scale wheel load testing was conducted on the PSMA/Mastic bridge deck pavement and the deflection of bridge deck and horizontal tensile strain on top of pavement were measured under the loading condition. Three-dimensional finite element analysis was conducted to predict the behavior of bridge deck pavement and the predicted deflection and tensile strain values are compared with measured values from the wheel loading testing. RESULTS: Test results showed that the predicted deflections are 10% lower than measured ones and the error between predicted and measured horizontal tensile strain values is less than 2% in the critical location. CONCLUSIONS: The fact indicates that the proposed the analysis is found to be accurate for estimating the behavior of bridge deck pavements.

Design a Thermosetting Asphalt Mixture for Surfacing on Orthotropic Steel Deck Bridge

According to Superpave mix design method, a thermosetting material (Epoxy Asphalt mixture) was designed for surfacing on orthotropic steel deck bridge. Firstly, based on the thermosetting feature, the viscosity increasing law of EA binder was studied by Brookfield test. Then, some characteristic indexes of EA mixture, such as the prior mixing time and the reserved time, were determined according to the viscosity increasing law and recommended viscosity range for mixing and compaction. Finally, using these characteristic indexes, an EA mixture with 3.0% air voids was designed by volumetric mixture design procedure of Superpave method. The results show: 1) different from other asphalt mixtures, the characteristic indexes of end mixing time and reserved time should be applied in EA mixture design because of the thermosetting character of EA binder; 2) the EA mixture designed by Superpave method in this paper has a higher EA binder content than that designed by conventional Marshall method.

Test Method to Assess Bonding Characteristics of Membrane Layers in Wearing Course on Orthotropic Steel Bridge Decks

For the adequate characterization of the adhesive-bonding strength of various membranes and surrounding materials on orthotropic steel decks and for the collection of the necessary parameters for finite element modeling, details of the membrane adhesion test (MAT) are introduced. Analytical constitutive relations of the MAT device have been derived from the same methodology used by Williams (1997). Furthermore, through the use of the experimental data obtained from the MAT, the ranking of the bonding characteristics of various membrane products is demonstrated, as is the role of other influencing factors, such as test temperatures and types of substrate.

Evaluation on Applicability of Stress Relief Hole for Improvement of Fatigue Stress Capacity of Steel Structural Details

강교량에는 외력에 대해 저항하는 부재의 좌굴 등의 변형을 구속시키기 위한 여러 상세부들이 존재한다. 이들 상세부는 상호 교차하는 부재들로 구성되고 제작의 용이성, 용접결함의 원천적 배제 및 응력집중을 완화시키기 위해 스켈럽을 이용해 왔다. 본 연구에서는 교차부에 발생되는 응력집중으로 상세범주 D등급 이하를 갖게 되는 강교량 상세부의 피로저항 능력을 상세범주 C등급 이상으로 개선시키는 방안으로 응력완화홀(SRH)을 제안하였다. 적절한 크기 및 위치의 SRH 효과를 확인하고 이를 강바닥판교의 U-rib와 가로보 교차부에 작용시켜 SRH에 의한 피로저항능력 개선 가능성을 확인하였다. In steel bridges, there are several details that constrain the deformation such as buckling by external forces. Most of these details which are composed of the intersection members have scallops in order to exclude the weld defects inherently and to get the ease of fabrication and also to decrease the stress concentration. In this study, stress relief hole (SRH) near stress concentration zone with detail category D or under is proposed as a method to improve the resistance on the fatigue crack initiation to detail category C. And the effects of the appropriate size and location of SRH were examined and the applicability to improve the fatigue resistance of the floorbeam web and the rib wall at rib/floorbeam intersection in the orthotropic steel deck bridge was evaluated.

Analysis of Five-Point Bending Test for Multilayer Surfacing System on Orthotropic Steel Bridges

The French five-point bending (5PB) test provides a laboratory-scale test that allows studying the fatigue resistance of surfacing systems on orthotropic steel deck (OSD) bridges. The surfacing structure for OSD bridges in the Netherlands is mostly a multilayer system: top porous asphalt (PA) layer, guss asphalt (GA) layer, steel deck, and two membrane layers. In this paper, an analytical solution for the 5PB test setup is presented first. To understand better the influence of geometrical, mechanical, and structural parameters on the performance of the typical multilayer surfacing system of OSD bridges in the Netherlands, the 5PB test specimens with five structural layers have been investigated. The parametric study was performed at the numerical platform CAPA-3D, which was developed at the Section of Structural Mechanics of the Delft University of Technology. The thicknesses of the top PA layer, middle GA layer, and the steel plate were varied. The influences of the mechanical properties of both top and bottom membrane layers were studied. The sensitivities of those influence factors were evaluated by examination of the maximum tensile stress at the top surface of the PA layers and the strain distributions through the entire thickness of the specimen at two cross sections.

Finite Element Analysis on Mechanical Behavior of Orthotropic Steel Bridge Deck in Balinghe Bridge

Orthotropic plate participates in bridge structure as a part of steel box girder, while in Balinghe Bridge it is used as bridge deck directly to endure the wheel load [1]. In this paper it’s studied systematically the mechanical behavior of orthotropic steel bridge deck in combination with the deck model of Balinghe Bridge, and shows the positions emerging fatigue cracks to provide the basis for future health monitoring and put forward some suggestions.

State of the Art of Asphalt Surfacings on Long-spanned Orthotropic Steel Decks in China

Abstract Reliable and durable asphalt surfacing systems still are desired for long-spanned orthotropic steel bridges according to national and international reports on distresses in deck pavement. Based on ten-year research works, this paper presents a brief review and discussion of the practices and experiences of deck pavement on long-spanned steel bridges in China, including issues of typical surfacing materials and their properties, main distresses in asphalt surfacing, and the basic characteristics of asphalt surfacing on orthotropic steel bridge decks. It is concluded that the behaviours of deck pavement on orthotropic steel bridge decks under truck loads are complex as a result of geometric and material-dependent nonlinearity, coupling the global dynamic effects of the whole bridge system. More efficient computational techniques are still desirable for coupling global effects with local responses, counting the interfacial effects and interactions, and evaluating the effect of the predominant distress of fatigue cracking and de-bonding on the service life of this type of structure.

Comparison Study on Crossbeam Web Cutout of Different Shapes for Orthotropic Steel Bridge Deck

For orthotropic steel bridge deck (OSD), principle tensile stresses near the end of joint of crossbeam web and longitudinal rib and at the edge of crossbeam cutout are dependent on the shape of crossbeam cutout to a great extent. They are results of many factors, among which bending-shearing effect and in-plane supporting effect are in-plane factors, unsymmetrical loading effect and relative longitudinal deformation effect are out-of-plane factors. Comparison study on stresses at some fatigue sensitive regions of orthotropic steel deck with six types of crossbeam web cutout indicates that the top height of cutouts determines the distance between the end of joint and the neutral axis, which affects the bending effect seriously, and the area of cutouts determines the shearing effect. When OSD system is affected by bending-shearing effect, increasing the top height decreases the principle tensile stresses near the end of joint but increases the stresses at the edge of cutout, and increasing the area increases the principle tensile stresses both near the end and at the edge of cutout. When the top height of cutouts increases, the contact area between crossbeam web drops, then the principle tensile stresses near the joint produced by in-plane supporting effect increases. When the side width of cutouts increases, the constraint effect of the crossbeam web to longitudinal rib decreases, then the principle tensile stresses near the joint produced by out-of-plane effects decreases. Generally, OSD system with stiff cutouts behaves well when affected by in-plane effects, and OSD system with flexible cutouts behaves well when affected by out-of-plane effects.

Structural Stress Analysis of Trough to Deck Plate Weld in Orthotropic Steel Bridge Decks

A comparative study among five methods to calculate the structural stress of the trough to deck plate joint in orthotropic steel deck was carried out. The five methods used are surface stress extrapolation method (SSE), Haibach method, Xiao and Yamada method and CAB method. FEM analysis shows the five methods are mesh sensitive. Structural stress calculated using element type solid95 is larger than that of solid45. For fine and medium mesh model, structural stress calculated by Haibach method is larger than other methods, which means a lower fatigue life. Structural stress calculated by Yamada method is lower than other methods, which means a higher fatigue life than that calculated by other methods. For coarse mesh model, structure stress calculated by quadratic extrapolation method is larger than other methods, and, structural stress calculated by Yamada method is much lower than other methods.

A New Approach for the Free Vibration of Steel Bridge Deck with Stiffeners

Based on energy principle, the free vibration of orthotropic steel bridge deck is investigated. The orthotropic steel bridge deck considered to be a stiffened plate. Both longitudinal stiffeners and transverse diaphragms are considered to be beam elements according to the equivalent principle of mass and rigidity. Besides, the plate is analyzed according to classic thin plate theory. The mode shape functions are expressed by the product of two independent beam functions. During the derivation of frequency equation, the lateral flexural effect of both the plate and stiffeners is considered. Besides, the eccentricity and torsion of stiffeners are taken into consideration, as well as the membrane strain energy of the plate. The results of the present approach are validated by the published example. At last, a stiffened plate with three classical boundary conditions is studied. The results show good agreement with the FE software ANSYS. Besides, it is observed that the eccentricity of stiffeners has a greater influence on lower frequencies than the higher, and the dynamic rigidity of stiffened plate can be increased efficiently by increasing the thickness of longitudinal stiffeners or reducing the distance between neighboring stiffeners. But the latter is more efficient.

Structural monitoring of a strengthened orthotropic steel bridge deck using strain data

Orthotropic steel bridges have experienced early fatigue cracks at several welded connections in the steel deck plate. One of the possible strengthening systems to enlarge the fatigue life of the existing decks consists of bonding a second steel plate to the existing deck. This renovation technique was for the first time applied on the orthotropic deck of the movable bridge Scharsterrijn. This article describes the results of the structural monitoring carried out to evaluate the short-term and long-term performance of the strengthening system. Static and dynamic controlled load tests were carried out using a calibrated truck. Strain history measurements were recorded continuously during 1 year from the normal traffic running on the bridge. The short-term measurements show significant decrease of the stress level at the bridge deck after the renovation, especially at the deck plate details. The stresses at the welds between the deck plate and the stiffener web reduce approximately 55% at the deck plate side and 35% at the stiffener web side. Due to this reduction, the fatigue life of these welds is expected to increase 11 times at the deck plate side and 3.6 times at the stiffener side. The long-term measurements do not show significant changes in the stress level at the bridge deck during the year of monitoring. The strengthening system has demonstrated good performance reliability to prolong the life span of the movable orthotropic bridges.

Effective Notch Stress Method for Fatigue Evaluation of Welded Joints in a Steel Bridge Deck

Effective notch stress, as an approach to evaluate the local stress at a notch (weld toe or root), is defined as the total stress assuming linear-elastic material behavior. This method can be effectively used to evaluate the fatigue performance of welded joints. In this study, finite element analysis results using the effective notch stress method were correlated with fatigue test results of rib-to-deck welded joints in a steel orthotropic bridge deck. Effective notch stress approach provided a good correlation with the crack pattern observed in the full-scale fatigue test. A higher effective notch stress at the critical weld toe than at the weld root was consistent with the dominant crack pattern observed at the weld toe during testing. The effective notch stress at the toe on the deck plate was about 80% higher than that on the rib; no cracks at the weld toe on the rib in the testing were observed. Maximum effective notch stress at the weld root occurred on the upper side of the root notch, which indicates that cracks are more likely to propagate into the deck plate, not into the weld metal. This is also consistent with the observed crack pattern in which the crack from the root propagated upward into the deck plate. No such crack pattern, propagating into the weld metal, was observed in the testing.

주행차량에 따른 개단면 강바닥판 교량의 국부거동 특성

The orthotropic steel deck bridge made by using relatively thin steel plate, and structural members such as transverse and longitudinal ribs, cross beam, etc. in the bridge are fabricated with complex shape by welding. Therefore, the possibility occurring deformation and defects by welding is very high, and stress states in the welded connection parts are very complex. Also, the fatigue cracks in orthotropic steel deck bridge are happening fromthe welded connection parts of secondary member than main member. However, stress evaluation for main members is mainly carried out in the design process of the bridge, detailed stress evaluation and characteristic analysis is not almost reviewed in the structural details which fatigue crack occurred. For the orthotropic steel deck bridge with open ribs which has been serviced for 29 years, in this study, the cause of fatigue crack is investigated and the fatigue safety of the bridge is examined based on fieldmeasurement by the loading test and real traffic condition. Also, structural analyses using gridmodel and detailed analysis model were carried out for the welded connection parts of longitudinal rib and diaphramthat fatigue crack occurred. Additionally, the behavior characteristics due to running vehicles were investigated by using influence area analysis for these structural details, and the occurrence causes of fatigue crack in the target bridge were clarified.

Investigation of mechanical properties of thin epoxy polymer overlay materials upon orthotropic steel bridge decks

The paper is focused on development of response and fatigue models of thin epoxy polymer overlay materials. Test data indicated that epoxy binder-steel bonding exhibited a strong temperature dependency. Fatigue models on epoxy binder-steel bonding and epoxy polymer concrete were developed using the power-law equation. Response models of epoxy binder and its concrete were properly established by using the Prony series. The developed response models could be served for finite element simulations on epoxy polymer concrete overlay upon orthotropic steel bridge decks. When the material stress or strain in the overlay is computed, life prediction becomes available by using the fatigue models.

Fatigue Tests of Overlapping Details for Orthotropic Steel Bridge Decks and Transverse Beams of Stay Cables

Rail-cum-road cable-stayed bridge with single cable plane is eccentric under moving load, overlapping details for orthotropic steel bridge decks and transverse beams of stay cables are in typical complex space stress condition. A fatigue test is performed to evaluate anti-fatigue performance of overlapping details under the combination of highway and light railway loads. A 1:1 model is adopted for the overlapping details, where a fatigue loading test for 2×106 cycles is carried out. Its test results show: the structural stress level is low, no crack is found on the test model after cyclic loading for 2×106 cycles, then load amplitude is gradually increased and no crack is found after cyclic loading for 4.25×106 cycles, finally a result is obtained that no fatigue crack will be found on the overlapping details for orthotropic steel bridge decks and transverse beams of stay cables within design life, because fatigue strength requirements are satisfied.

Fatigue Tests of Overlapping Details for Orthotropic Steel Bridge Decks and Transverse Beams of Stay Cables

Rail-cum-road cable-stayed bridge with single cable plane is eccentric under moving load, overlapping details for orthotropic steel bridge decks and transverse beams of stay cables are in typical complex space stress condition. A fatigue test is performed to evaluate anti-fatigue performance of overlapping details under the combination of highway and light railway loads. A 1:1 model is adopted for the overlapping details, where a fatigue loading test for 2×106 cycles is carried out. Its test results show: the structural stress level is low, no crack is found on the test model after cyclic loading for 2×106 cycles, then load amplitude is gradually increased and no crack is found after cyclic loading for 4.25×106 cycles, finally a result is obtained that no fatigue crack will be found on the overlapping details for orthotropic steel bridge decks and transverse beams of stay cables within design life, because fatigue strength requirements are satisfied.

Modelling and fatigue life assessment of orthotropic bridge deck details using FEM

The fatigue life estimation of orthotropic steel bridge decks using the finite element method is most frequently associated with the application of the structural hot spot stress approach or the effective notch stress approach, rather than the traditional nominal stress approach. The application of these approaches to a welded joint with cut-out holes in orthotropic bridge decks, where it is not easy to distinguish the non-linear stress caused by the notch at the weld toe from the stress concentration effect emanating from the hole in the detail, was investigated. The results of the finite element calculations were compared with the results of the fatigue tests which were carried out on full-scale specimens. The results of the finite element analyses revealed that the structural hot spot stresses obtained from the shell element models were unrealistically high when the welds were omitted. Moreover, the way in which the welds were represented had a substantial influence on the magnitude of the hot spot stress. The results of the analysis when using the effective notch stress approach showed that the agreement between the estimated fatigue life using this approach and the fatigue life obtained from the fatigue tests was good.

Basic Performance of the Composite Deck System Composed of Orthotropic Steel Deck and Ultrathin RPC Layer

Fatigue damage in a conventional orthotropic steel bridge deck system poses a formidable challenge to bridge engineers all over the world because of ever-increasing heavy traffic volumes and higher wheel loads over the past decade. An effective solution may be to enhance the stiffness of the bridge deck to reduce the fatigue stress amplitude of its components. This paper proposes an innovative composite bridge deck system that consists of an orthotropic steel deck stiffened with a 45-mm reactive powder concrete (RPC) layer. Based on the analysis of HuMen Bridge in China (a suspension bridge with a conventional orthotropic steel bridge deck system with span length of 888 m) and two types of full-scale model tests, a comparison investigation is conducted between a conventional orthotropic deck system where the asphalt wearing course has been ignored and the proposed orthotropic deck system that includes an integral concrete wearing course, and the proposed composite bridge deck system proves to be considerably effective in reducing the stress range caused by service vehicle loads when applied to long-span steel suspension bridges. The thin RPC layer can be reliably integrated with the deck plate through stud shear connectors, and no shrinkage cracking occurs on the surface of the RPC layer that is cast on the deck plate. The fact that the tensile stress of the RPC layer is up to 42.7 MPa before cracking occurs demonstrates that cracking will not appear in the RPC layer under service vehicle loads. The analysis, which is investigated on the premise that the dead load weight of the bridge deck of HuMen Bridge is approximately the same for the two different deck systems, demonstrates that the stress of the orthotropic steel deck is significantly reduced with the application of the proposed composite deck system. Analysis with a three-dimensional finite-element model indicates that the transverse tensile stress of the deck plate is reduced by 71%, while that of the connection between the deck plate and the longitudinal troughs is reduced by 72%. This indicates that the risk of causing fatigue cracks in the steel bridge deck system can be considerably reduced during the entire life cycle of the bridge.

Special Issue on AASHTO-LRFD Bridge Design and Guide Specifications: Recent, Ongoing, and Future Refinements

The AASHTO Load and Resistance Factor Design Bridge Design Specifications (LRFD Code) were introduced in the early to mid1990s as an eventual replacement for the AASHTO Standard Specifications for Highway Bridges (Standard Specifications). The LRFD Code is effectively modernizing bridge design practice in the United States as an ever-increasing number of engineers and state departments of transportation become familiar with and use its provisions. The LRFD Code is also structured in such a way that updating it is more straightforward than the Standard Specifications had become over time. Since introduction of the LRFD Code, the document has undergone numerous significant revisions. Making it much more userfriendly was one reason for this. However, incorporating the results from recently completed research projects also played a very significant role in a number of the revisions. Research is still being conducted, has recently been completed, or may be proposed in the near future that could further refine the LRFD Code in the coming years. This special issue of the Journal provides highlights of some of these efforts over a broad range of bridge engineering topics. The first paper offers several perspectives on the LRFD Code by an author (Tobias) from a state department of transportation. It provides an overview of the Code’s history, the mechanisms associated with revision, and current and future research topics that could or should be addressed. Other reliability-based AASHTO manuals and guide specifications are also discussed in the paper, along with the processes by which researchers and practitioners can effect future refinements for most AASHTO structural publications. The other papers contained in this issue are sequentially grouped into general categories that include extreme events, foundations, bridge decks, loads and load distribution, prestressed and posttensioned concrete members, effective flange width, bridge piers, and bridge rating. Several of the subjects briefly discussed in the first paper are also discussed in more and varied detail in subsequent papers of this special issue. These include, but are not limited to, papers entitled “Evaluation of Combination Rules for Orthogonal Seismic Demands in Nonlinear Time History Analysis of Bridges” by Bisadi and Head, “Calibration of Live Load Factor in LRFD Bridge Design Specifications Based on State-Specific Traffic Environments” by Kwon et al., “Framework for Simplified Live-Load Distribution Factor Computations” by Puckett et al., and “Full-Scale Testing of Pretensioned HighStrength Concrete Girders with Debonded Strands” by Kim et al. The research described in several of the included papers has already had recent significant impacts on the LRFD Code and/or other AASHTO manuals and guide specifications. These include the papers entitled “Performance of Bridge Columns Subjected to Blast Loads. I: Experimental Program” by Williamson et al., “Performance of Bridge Columns Subjected to Blast Loads. II: Results and Recommendations” by Williamson et al., “Proposed Revisions to AASHTO-LRFD Bridge Design Specifications for Orthotropic Steel Deck Bridges” by Kozy et al., “Bridge Rating Using System Reliability Assessment. I: Assessment and Verification by Load Testing” by Wang et al., and “Bridge Rating Using System Reliability Assessment. II: Improvements to Bridge Rating Practices” by Wang et al. Other papers in this special issue not cited above may have a future influence on the LRFD Code and/or other AASHTO structural publications by functioning as a contribution to the marketplace of ideas. As described in the first paper, it is very common for research published in archived journals, conference papers, and project reports to provide “shape, substance, and a coalescing of concepts and methods in particular subject areas over time, which commonly affects how AASHTO ballots (proposed revisions) are formulated.” Some of these papers include “Evaluation of AASHTO-LRFD Design Methods for Thermal Loads in FixedFlexible Twin-Walled R/C Bridge Piers” by Schultz et al., “Proposed Modification of AASHTO-LRFD for Computing Stress in Unbonded Tendons at Ultimate” by Harajli, and “Unified Approach for LRFD Live Load Moments in Bridge Decks” by Higgins et al. The contributing authors, guest editors (Dennis Mertz and John Kulicki), reviewers, and chief editor of the Journal (Anil Agrawal) all deserve acknowledgment with regard to their contributions to this special issue of the Journal.