Georadiolocation survey of bridge structures: field research methodology, processing and interpretation of materials. Part 1 – massive foundations of bridge pier

Abstract

Introduction: Inspection of bridge structures (bridges, overpasses, etc.), designed for the transfer of transport routes and various communications through water barriers, roads, etc., is aimed at clarifying their design characteristics and technical condition, which determine not only the very possibility of further operation of objects, but also their maintainability [1–4]. In relation to elements of bridge structures that are directly inaccessible for studying, located below the surface of the earth, under a layer of water, ice, asphalt, etc., the only source of information about their design is survey data using geophysical methods, among which the most universal and informative is georadiolocation [1–3, 5–8]. It is important to note that the georadiolocation method is among those recommended by GOST [1] for use when inspecting the foundations of bridge pier. The article, divided into 2 parts, is devoted to the georadiolocation inspection of bridge structures. In the first part the assessment of massive foundations of shallow and deep foundations is considered. Part 2 of the article presents materials concerning the specifics of examining pile foundations, visible parts of pier, transition slabs, as well as retaining and cabinet walls Methodolog: The content of the article is illustrated by materials obtained by the authors as a result of georadiolocation examination of the foundations of various bridge structures. These works were aimed at establishing the types and geometric characteristics of foundations, and were also involved in assessing their bearing capacity. Results and discussion: The materials presented in the article indicate that ground georadiolocation is a fairly effective, and often the only, tool for solving a number of important problems related to the inspection of elements of bridge structures located both above and below the surface of the earth. The inductive method of exciting electromagnetic fields and measuring their parameters, relatively unaffected by surface conditions, allows conducting research without direct contact with both the studied object and the surrounding environment. The wave pattern obtained in the process of ground penetrating radar profiling, accompanied by a developed mechanism for processing radargrams, facilitates the process of identification and subsequent interpretation of informative sections of the record, and also allows to trace the spatial dynamics of changes in the electromagnetic properties of the studied objects. Conclusions: The results of the study suggest that the georadiolocation method can be considered the most universal and effective means of studying the design parameters and technical condition of buried parts of bridge structures. The ability to choose research methods and equipment, as well as approaches to interpreting materials, allows to optimize their implementation for the solution of the specific problems. At the same time, if the continuous profile measurements, which, in most cases, are most preferable, are impossible, a georadiolocation survey can be carried out by discrete point soundings.