Application of dynamic testing to structural assessment of bridges is considered in this article. Forced vibration tests were conducted before and after installation of new bearings on a reinforced concrete bridge. The aim of the tests was to assess, from the measured dynamic response, the effects of the repairs on the bridgeis condition as characterized by its dynamic properties. Frequency response functions, natural frequencies, mode shapes, and viscous damping ratios before and after bearing replacement were compared. The response functions were found to give an indication that some changes have occurred in the bridge. The maximum changes in frequency and damping were about 4% and 21% respectively. The results indicated that the vertical stiffness of the new bearings was not as high as was originally envisaged. Modal analysis techniques were used to compute assessment indices which were able to indicate one of the abutments affected by the bearing replacement. The approach adopted could potentially be used for the assessment of any engineering structure. Resume : Liapplication diessais dynamiques pour liOtude structurale des ponts est considOrOe dans cet article. Des essais de vibrations forcOes ont OtO effectuOs avant et aprs liinstallation de nouveaux appuis sur un pont de bOton armO. Le but des essais Otait dianalyser, ‡ partir de la rOponse dynamique mesurOe, les effets de rOparation sur la condition du pont comme caractOrisOe par ses propriOtOs dynamiques. Les fonctions de rOponse de frOquence, frOquences naturelles, fonctions modales et coefficients diamortissement visqueux avant et aprs remplacement des appuis ont OtO comparOs. Il a OtO trouvO que les fonctions de rOponse indiquent que certains changements dans le pont ont eu lieu. Les changements maximums dans la frOquence et liamortissement Otaient de 4% et 21% respectivement. Les rOsultats indiquent que la rigiditO verticale des nouveaux appuis niOtait pas aussi OlevOe que ce qui a OtO envisagO originalement. Des techniques dianalyse modale ont OtO utilisOes pour calculer des indices dianalyse qui ont OtO capables diindiquer une des butOes affectOes par le remplacement diappuis. Liapproche adoptOe pourrait potentiellement Œtre utilisOe pour lianalyse de toute autre structure. Mots clOs : ponts, essais dynamiques, analyse structurale, appuis, analyse modale, intOgritO structurale, contrUle de vibration. (Traduit par la ROdaction)