ABSTRACT
Literature has shown that Neutral Axis (NA) position, as a feature, has high potential for capturing damage in beam-like structures. NA depends on the geometry of the cross-section and the applied loads, so it may capture damage affecting either the characteristics of the examined cross-section or the way that the loads are distributed in the structure, especially when axial loads are developed. For cable-stayed bridges where large axial loads are developed in the girders from the inclined cables, NA position is of special interest. With the relatively low cost to monitor (need for only two strain measurements at a given location) its position, NA could be a very important tool in the evaluation of the condition of different elements of cable stayed bridges. In this research, a simplified analytical model is developed that consists of the basic elements of a cable-stayed bridge (beam-cable-bearing) and is loaded with a moving point load to represent a vehicle load. Solutions are developed to simulate damage in different structural elements and to evaluate the behavior of the NA over the length of the beam. Changes in the position of the NA for different types and locations of damage are investigated. This is the first known attempt to evaluate NA behavior for a beam-cable system and can help in the better understanding of how NA position is expected to change due to damage in a cable-stayed bridge. While the focus here is on cable-stayed bridges the results and understanding may translate to other types of bridges.
