Abstract:
Local scouring around bridge foundations is a major reason for
bridge collapse worldwide. It occurs due to the formation of vortices around
bridge foundations as a result of changing the unidirectional approach flow
into the three-dimensional field in an erodible channel bed, leading to the
development of a scour hole in its vicinity. In the present work, two different
techniques were applied for a full characterization of the scour hole
geometry developed in a sand bed flume experiment by means of a Kinect
sensor and a close-range photogrammetry. These advanced survey and
sensor technologies offer efficient techniques of deriving point clouds and
Digital Elevation Models (DEMs), respectively. The potential, limitations
and results of both techniques are herein examined and conveniently
compared, including a description of measurement devices, reference points
and respective software. Reliable and accurate estimates of the topographic
representation of the scour hole and inherent features were obtained. The
design of the bridge pier used, with a 0.14 m wide rectangular round-nose
concrete column (henceforth termed as oblong pier), replicates the typical
shape used in the 19th and 20th centuries, and are the most common in
Portugal.
