Birth certificates of bridges – reference condition of new bridges

Abstract

Information on changes in the structure and deviations from normal behavior is important for the predictive maintenance of engineering structures. Changes can be detected by using monitoring and structure inspection. The determination of changes, requires that these changes be compared with a reference condition. The determination of the reference condition currently takes place when changes and damage to the structure are already present. This is where the idea of the birth certificate begins. The birth certificate of a bridge describes the zero measurement of the bridge, which determines the reference condition and the load-bearing behavior of a bridge after its completion on the basis of suitable parameters. Measurements can be repeated at appropriate intervals to detect changes. The concept of birth certificate does not require continuous measurements over the entire life cycle. Relevant parameters are: - Physical: Determination is carried out by equipping the bridge with sensors and performing measurements possibly supported by test loads with the aim of mapping the static and dynamic behavior of the bridge. - Geometric: Creation of a three-dimensional, geo-referenced model of the actually built structure in sufficient detail. - Chemical: Detection of changes that lead to a reduction in durability via investigations of building materials technology. The main objective is to identify a reference condition for detecting and evaluating changes in the behavior and condition of the bridge. In the paper, the background to the creation of the birth certificate, the objectives and the approach in other countries or disciplines are presented. Furthermore, the importance of the reference measurement for the monitoring application in new construction and ideas of a concept for the implementation of birth certificates via the derivation of indicators, are described.