Les resultats de l' evaluation d' un prototype danois de deflectographe a grande vitesse (HSD : High Speed Deflectograph) sont presentes. Cet appareil mesure, a l' aide de deux velocimetres laser, la vitesse de deformation verticale de la chaussee au passage d' un poids lourd integre au trafic. Une etude numerique effectuee avec le logiciel Alize montre qu' une relation existe entre la pente deduite des mesures du HSD et la deflexion maximale mesuree par les appareils traditionnels. Cette relation depend de la plate-forme de la chaussee. Sur differentes sections tests variables en structures et en longueurs, la pente du bassin de deflexion a ete estimee par le HSD. La repetabilite de l' appareil a ete estimee et les resultats obtenus ont ete compares a ceux des appareils de reference (FWD et deflectographe Flash). Il est montre que le HSD realise des mesures repetables et qu' il est apte a detecter des differences significatives de niveau de deflexion. (A). (Titre en anglais : Evaluation of a Danish prototype for a high-speed deflectograph (HSD)). EVALUATION OF A DANISH PROTOTYPE FOR A HIGH-SPEED DEFLECTOGRAPH (HSD). The results from an evaluation of a Danish High-Speed Deflectograph (HSD) prototype are presented herein. This device serves to measure, thanks to two laser velocimeters, the vertical deformation velocity of pavement when traversed by a truck traveling in regular traffic flow. A numerical study, using the Alizé software, reveals the presence of a relationship between the slope deduced from HSD measurements and the maximum deflection measured by means of conventional instruments ; this relationship depends on the pavement platform. On test sections varying in both structure and length, the slope of the deflection basin has been estimated using the HSD device. The repeatability of HSD application has been assessed and results were compared with those from reference tools (FWD and Flash deflectograph). Findings demonstrate that HSD yields repeatable measurements and is indeed able to detect major differences in deflection level.
Samenvatting