Though an underwater inspection of the timber piles supporting abridge at denton, maryland, indicated reasonable soundness of the timber, the bridge failed. Laboratory tests indicated a substantial reduction in material strength during the life of the piling. A nondestructive procedure for estimating the strength of in-service piles was therefore needed and was developed under the maryland highway planning and research program. The procedure is an ultrasonic wave propagation method in which the in-place strength of a timber pile is correlated with the wave velocity normal to the grain and the in-place unit weight of the pile. The relationship was developed and verified by testing yellow pine piles from 11 bridges in maryland. The technique has been extended to the determination of the condition of piles supporting different types of structures. The nondestructive technique as developed for testing timber piles for bridges is presented. The type of data collected, information needed for data interpretation, equipment description, and factors that affect testing are included, as well as the conditions under which the method can be usedand its limitations. The types of decay occurring in timber piles, determined by comparing the behavior of timber piles supporting bridges, asphalt tanks, and buildings, are discussed. It is concluded that the technique can be used in all three cases if the causes and types of deterioration and the limitations of the ultrasonic techniqueare understood. This paper appears in transportation research record no. 1331, Integrity testing of foundations 1991
Samenvatting