| Popis: |
Nondestructive methods are increasingly being used in the USA for evaluation of our aging infrastructure. One of the areas of concern is he determination of conditions of unknown bridge foundation. Foremost is the need to determine the foundation depth, followed by foundation type, geometry, and subsurface conditions. Recently, a comprehensive evaluation was made of potential NDT technologies that have relevance to this problem in the NCHRP 21-5 project 'Determination of Unknown Subsurface Bridge Foundations'. This paper presents the test results of a research study on the applicability of using borehole-based nondestructive test (NDT) techniques for the determination of unknown subsurface bridge foundations. The results included in this paper are from the three borehole-based NDT techniques of parallel seismic test, borehole sonic test, and borehole radar test. The parallel seismic method was found to have the broadest application to the investigations of concrete, timber, and steel bridge substructures. |
