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European research program SBRI attempted to reveal the costs caused during the service life of a bridge, direct costs for the building owners as well as indirect costs for the users. The principal results of SBRI should make it possible to better take account of the true costs of a
central pier, by taking into account the risks in phase of construc...
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This paper investigates the structural behavior of composite bridge girders subjected to hogging moment. Such composite girders are widely used in accelerated bridge construction. However, the ultimate moment capacity at the negative moment region is highly affected by the contribution of the reinforcing steel embedded in the concrete deck slab tha...
Corrosion of reinforcing steel in bridge decks decreases life expectancy of bridge superstructure, leading to costly and frequent maintenance or replacement. The use of glass fiber reinforced polymer (GFRP) bars as internal reinforcement is a viable option for the replacement of deteriorated concrete bridge deck slabs due to steel bar corrosion. Th...
Corrosion of reinforcing steel in bridge decks decreases life expectancy of bridge superstructure, leading to costly and frequent maintenance or replacement. The use of glass fiber reinforced polymer (GFRP) bars as internal reinforcement is a viable option for the replacement of deteriorated concrete bridge deck slabs due to steel bar corrosion. Th...
Citations
... It is, of course, possible to apply corrosion protection to all horizontal surfaces of the lower longitudinal and transverse I-beams. However, the use of an inclined plate forming a triangular box on the lower flange of the I-girder has many advantages, so that it is often used for painted bridges [16], because it also: helps resisting impacts for overpass bridges, prevents pedestrians or animals from advancing on the lower flange, avoids buckling of the web and improves the transfer of shear forces, stiffens the bottom flange with a nondeformable triangular box. ...
... Some references can be found in [16] and [17] for the use of a box at the bottom flange. Recent studies by the Chinese University of Tongji [18] even suggest that a box may also be of economical interest for the upper flange. ...
This is the new version of the preprint issued in 2023 with
- new regard from USA on weathering steel bridges
- new regard from France on weathering steel bridges
In addition, some precisions were given regarding the FEM calculation of the fatigue resistance of weathering steels that is reduced by the chancroid notches due to the patina formation.
Of course, the use of weathering steels is economical during the construction phase and avoids transport and application of chemicals, but it must be done with precautions in case of double I-girders bridges carrying heavy motorway traffics.
The examples of pits and chancroid notches show that the calculation of the stress concentration factors, i.e. the modified stresses, is important for the correct calculation of bridges with regard to fatigue. Again, the condition of the surface is critical in terms of sensitivity to fatigue cracking.
Misunderstanding this important point has led some people to encourage the use of a discontinuity of bridge stiffeners, and the use of cope holes at transition points as well as the use of weathering steel without precaution.
However, there is no need to add new statements in the Eurocodes to obtain a common use of the presented results, then Clause 7.1(5) of the 2011 French National Annex to EC3 1-9 and the future Eurocode 3 Part 1-9 codify the use of the Hot Spot and Effective Notch methods to calculate the modified stresses.
... The conception of this type of hanger is also related with their high fatigue resistance associated with a low cost. These hanger also offer a resistance in compression [27], in fatigue when the right feature of Figure 18 is used [28] and it has been shown in [29] that the specific tensioned hanger cross geometry of Figure 17 is not at risk of fatigue inducing resonance under wind loading. ...
... It is, of course, possible to apply corrosion protection to all horizontal surfaces of the lower longitudinal and transverse I-beams. However, the use of an inclined plate forming a triangular box on the lower flange of the I-girder has many advantages, so that it is often used for painted bridges [27], because it also: helps resisting impacts for overpass bridges, prevents pedestrians or animals from advancing on the lower flange, avoids buckling of the web and improves the transfer of shear forces, stiffens the bottom flange with a non-deformable triangular box. ...
... Some references can be found in [27] and [37] for the use of a box at the bottom flange. Recent studies by the Chinese University of Tongji [38] even suggest that a box may also be of economical interest for the upper flange. ...
The fatigue damage of steel bridges is prone to occur under a large amount of heavy traffic and be a worldwide problem leading to serious disasters. This communication will discuss the importance of the correct evaluation of the fatigue category of resistance for the safety and durability of bridges. Although much attention is usually rightly paid by engineers to the effects of traffic, on the other hand the effect of stress concentrations which modify the category of detail of the tables of the Eurocode is still very poorly known. We will deal with multiple examples to illustrate the question: the replacement of the cylinder head of the François I bridge in Le Havre at the very beginning of the 80s is an excellent example of an approach to the calculation of stress concentration factors by finite elements, which made it possible to solve the fatigue problems of this movable bridge. On the other hand, the cracking of the bridges of Chamousset where a then forbidden constructive arrangement was nevertheless built shows that the question is not a view of the mind: If the problem had not been identified and the bridge put under annual surveillance for the hot spots concerned, the two bridges could have collapsed. Today, Clause 7.1(5) of the French National Annex to EC3 1-9 has put manufacturers under the obligation to take into account stress concentration factors since 2011. Several features will be reviewed, such as for example the thickness transition zones with and without cope hole, the anchorages of hangers, the studs under tension and bending, the bottom cuts of the vertical stiffeners that actually do not help regarding fatigue, and the interruptions of guide rails. Finally, the effects of corrosion, in particular the case of the weathering steels when used in the transition zones will be discussed in detail using models using the "Effective Notch Stress Method" based on tests carried out on samples for the Academy of Sciences of the Czech Republic by Ludwig Kunz. Of course, the aging of weathering steels in case of birds droppings is not considered in this study. Even without birds droppings, the fatigue resistance of some weathering steels details has to be reduced considering the Clause 7.1(5) of the French National Annex to EC3 1-9 when compared to the categories given by the tables of the Eurocodes for painted details.
... It is, of course, possible to apply corrosion protection to all horizontal surfaces of the lower longitudinal and transverse I-beams. However, the use of an inclined plate forming a triangular box on the lower flange of the I-girder has many advantages, so that it is often used for painted bridges [16], because it also: helps resisting impacts for overpass bridges, prevents pedestrians or animals from advancing on the lower flange, avoids buckling of the web and improves the transfer of shear forces, stiffens the bottom flange with a nondeformable triangular box. ...
... Some references can be found in [16] and [17] for the use of a box at the bottom flange. Recent studies by the Chinese University of Tongji [18] even suggest that a box may also be of economical interest for the upper flange. ...
A new version of this paper is available in 2024 with
- new ragard from USA on weathering steel bridges
- new ragard from France on weathering steel bridges
In addition, some precisions were given regarding the FEM calculation of the fatigue resistance of weathering steels that is reduced by the chancroid notches due to the patina formation.
Of course, the use of weathering steels is economical during the construction phase and avoids transport and application of chemicals, but it must be done with precautions in case of double I-girders bridges carrying heavy motorway traffics.
The examples of pits and potholes show that the calculation of the stress concentration factors, i.e. the modified stresses, is important for the correct calculation of bridges with regard to fatigue. Again, the condition of the surface is critical in terms of sensitivity to fatigue cracking.
Misunderstanding this important point has led some people to encourage the use of a discontinuity of bridge stiffeners, and the use of cope holes at transition points as well as the use of weathering steel without precaution.
However, there is no need to add new statements in the Eurocodes to obtain a common use of the presented results, then Clause 7.1(5) of the 2011 French National Annex to EC3 1-9 and the future Eurocode 3 Part 1-9 codify the use of the Hot Spot and Effective Notch methods to calculate the modified stresses.
... A list of references, which can be regarded as "background documents" for the design of composite dowels, is appended to this document. The references cover: design guidelines and technical approvals [10,12,13], experience, practical applications (examples of bridges built using composite dowels) [14][15][16][17][18][19][20][21][22][23], research papers (including PhD theses) and project reports [1,3,7,9,11,15,[24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57]. The above list, compiled from the point of view of the researchers in Poland, and the list of papers referenced in [8], compiled from the point of view of the researchers in Germany, provide a broad overview on the design of composite dowels (the first bridges with composite dowels were designed in the two countries). ...
Investigations leading to an evaluation of the ultimate strength of a clothoid-shaped continuous shear connection are presented. This paper follows a study by the authors, in which the behaviour of puzzle-shaped composite dowels was evaluated. Owing to its good fatigue, elastic and ultimate strength, the modified clothoidal dowel shape (MCL) is now most commonly used for the continuous connector. A method of evaluating the strength, stiffness and ductility of the dowel is described. The method is based on experimental studies and FE analyses of the dowel's steel part and concrete part. A mechanical model of the dowel's steel part, based on numerical analyses, is presented. Push-out tests were carried out on specimens differing in the thickness of connectors. The test results and the results yielded by other methods are compared and discussed. The research done by the authors provided the basis for the evaluation of the ultimate limit state (ULS) of composite dowels used in the construction of many road and railway bridges, and for the development of the current design rules.
... All upper connections to the arches are the same. More details are in [5] and [11]. ...
p>The roads represent an important heritage. Even more than corrosion, the fatigue is the principal aging process that affects the durability of steel bridges. Several examples illustrate in the article the importance of affecting a right consideration to the fatigue design of bridges.
Details that may appear as accessory to most of the usual bridge designers may be in fact of a crucial importance. It is in particular the case of the welded joints. The fillet joints are much more sensible to the fatigue stresses and should be avoided when there is a doubt, because their evaluation is very complicated. If the designer of a bridge uses such attachment in the project for tender, he has to verify the relevance regarding fatigue because the time for such studies is generally not available during the execution studies.
Calculation FEM techniques are used to evaluate the stress modified by the concentration factor that has to be taken into account for the fatigue design. For bridges, many fatigue details are classified in the Eurocode 3 ( part 9 ) from tests. But some details that cannot be found in the Eurocode, and must however be studied and evaluated by computation. The article presents an example where the fatigue class of the detail regarding longitudinal stresses is evaluated thanks to a FE-modelization according to the 2008 IIW Fatigue Recommendations at the location of the attachment of different types of hangers.</p
The European research programme SBRI attempted to reveal the costs caused during the service life of a bridge – direct costs for the bridge owner as well as indirect costs for users. The principal results of SBRI should make it possible to take better account of the true costs of a central pier by considering the risks in the construction phase and those that may threaten the highway overpass during its service life.
CEREMA has developed two economic solutions to reach the objective of avoiding the central pier: The solution implemented at Ko Wé Kara in New Caledonia is a steel‐concrete composite tied arch bridge with innovative and economic details: innovative radial hangers made of welded plates, and
innovative reinforcement against accidental impact of over‐height vehicles.
One other possible solution is the composite steel‐concrete gantry bridge. The European research programme PRECOBEAM allowed the use of tests and experimental projects to finalize a new system of connection to lower the cost of this type of structure: a strip along which the cutting line of the steel dowels is made in a clothoid shape (CL), which improves the fatigue resistance. CEREMA introduced this innovation in its research programme.
A composite structure can take various forms. It can associate, for instance, the steel web of a beam directly with a concrete flange. It can also constitute a composite deck with a bottom plate stiffened by connecting CL‐shape indented strips. An outstanding project of this type in New Caledonia is described in detail. Of course, this type of bridge is an integral bridge and the article includes some recommendations for the design and construction of integral bridges.
