Résistance à la fatigue d'un joint modulaire d'expansion pour ponts à multiples barres de support soudées

Sieprawski, Guillaume (2004). Résistance à la fatigue d'un joint modulaire d'expansion pour ponts à multiples barres de support soudées. Mémoire de maîtrise électronique, Montréal, École de technologie supérieure.

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Résumé

De plus en plus, la tendance au niveau du design des ponts est d'éliminer les joints d'expansion de faible capacité de mouvement dans une structure en faveur de joints modulaires d'expansion pour pont (Modular Bridge Joint System (MBJS)). Cependant, ces types de joints sont plus coûteux à l'achat et au remplacement, leur viabilité à long terme doit donc être assurée. L'objectif de cette étude est donc de caractériser la résistance à la fatigue des connexions soudées du joint modulaire d'expansion à multiples barres de support. Il s'agit dans le cadre de ce projet de vérifier qu'elles respectent la catégorie C de résistance à la fatigue, définie par l'AASHTO Bridge Design Code Guidelines. Ces tests ont permis de construire la courbe de fatigue des connexions soudées avec un total de 11 points montrant clairement que le détail a une résistance à la fatigue compatible avec les catégories C et C', définies par l'AASHTO LRFD 1998 Bridge Design Code.

Titre traduit

Fatigue testing of a welded multiple support bar modular expansion joint for bridges

Résumé traduit

lncreasingly, the tendency among bridge design engineers is to eliminate the number of smaller capacity expansion joints in a given structure, in favour of multiple-cell or Modular Bridge Joint System (MBJS) for bridges. These units are considerably more expensive to purchase and to replace, so manufacturers have been asked to find ways to validate the long-term viability of Modular Joints. One area of concern has been the performance of the various Modular Joint designs with respect to fatigue. Several studies have been carried out in this regard, most notably that conducted in the NCHRP for AASHTO (NCHRP 402 and 467 reports).

The main objective of this study is to evaluate the fatigue resistance of the critical details of the multiple support bars modular expansion joint, with welded connections as manufactured by Z-Tech Industries lnc. Structural models (1-D and 3-D) for the analysis of the MBJS test specimen were validated by comparing the experimental strains and stresses at different locations of the structure, with those predicted by the theoretical models. The fatigue performance of the modular joint was evaluated by testing multiple support bars modular joint specimens in accordance with the test procedure recommended by the NCHRP-402 Report. Of particular interest is the fatigue rating of the welded connection detail.

The testing was carried out in conformity with the requirements and guidelines of the procedure outlined in appendix B of the National Cooperative Highway Research Program (NCHRP) Report 402, "Fatigue Design Criteria for Modular Bridge Expansion Joints". ln total, eleven fatigue points were obtained from three identical subassemblies of the modular joint system, which were fabricated in the factory and instrumented in laboratory. Each specimen is made of a center-beam supported by four equally spaced support bars. Support bars are connected to the center-beams by full penetration welded connections. Different load ranges were applied for each specimen in order to obtain sufficient number of points of the experimental fatigue (S-N) curve.

Fatigue cracks of the same type as those reported by NCHRP-402 Report were observed within the welded connection detail. No fatigue crack has been observed elsewhere. The testing allowed ta construct the fatigue curve of the welded connection with a total of 11 points clearly showing that that the detail has achieved a fatigue resistance compatible with Categories C and C' details, as defined by the AASHTO LRFD 1998 Bridge Design Code. Two structural models (1-D and 3-D) were used for the analysis of the joint. The 3-D model was found more accurate than the 1-D. However, given its simplicity and its relative accuracy, the 1-D model is thought to be convenient for preliminary design of such joints.

Type de document:	Mémoire ou thèse (Mémoire de maîtrise électronique)
Renseignements supplémentaires:	"Mémoire présenté à l'École de technologie supérieure comme exigence partielle à l'obtention de la maîtrise en génie de la construction". Bibliogr.: f. [162]-165.
Mots-clés libres:	Barre, Connexion, Contrainte, Expansion, Experimental, Fatigue, Joint, Modele, Modulaire, Multiple, Pont, Resistance, Soude, Support
Directeur de mémoire/thèse:	Directeur de mémoire/thèse Chaallal, Omar
Programme:	Maîtrise en ingénierie > Génie de la construction
Date de dépôt:	02 mai 2011 20:24
Dernière modification:	22 oct. 2016 00:33
URI:	https://espace.etsmtl.ca/id/eprint/688

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