Damage identification in cable-stayed bridges based on the behavior of neutral axis under traffic loading

Abstract

A beam’s Neutral Axis (NA) is a parameter that has been utilized to detect damage. Its position depends on the geometry of the cross-section and also a member’s axial loads. Shifts in its position can indicate changes in either load distribution or geometric characteristics. When considering structures such as cable-stayed bridges where the inclined cables induce significant axial forces, the effect of axial loads on NA position is significant. In this research, a simplified analytical model was developed consisting of the key elements of a cable-stayed bridge (beam, cable, and bearing). The model was loaded with a vertical point load representing a vehicle load. The NA position was calculated beneath the load as it moves over the length of the beam. By changing element properties, one can observe how the NA position behaves in different locations of the beam, due to simulated damage in the beam, cable, or bearing. It was found that changes in NA position can capture not only whether damage has occurred, but also in which component of the structure the damage is located (beam, cable, or bearing). This ability to use NA position for damage identification renders it an excellent parameter for monitoring cable-stayed bridges.

Keywords:

• Analytical model
• beam damage
• bearing damage
• cable damage
• cable-stayed bridge
• damage identification
• Neutral axis
• strain sensors
• traffic loading

Data availability statement

Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request. (Codes for calculating the NA position and for the numerical analysis)

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors would also like to acknowledge Delaware Department of Transportation for the financial support, under partnership agreement 1929F, to develop and implement the structural monitoring system.