ABSTRACT
Vibration measurements are an established method for determining the tension force of stay cables. The approach utilizes linearization of the vibration characteristics of stay cables that are structural members exhibiting significant geometrical nonlinearities. Based on measured natural frequencies the cable force can thus be identified. This paper presents measurements that have employed mobile measurement equipment, namely MEMS-based (microelectromechanical systems) acceleration sensors connected to battery-operated microcomputers as well as those integrated in smartphones, and studies the accuracy for tension force measurements. Software written for streamlined measurement processes is linked with nonlinear analyses for predicting the frequency-force relationship. In contrast to traditional monitoring systems that are composed of several individual hardware components, smartphones and tablets can integrate the recording, storage, processing, transfer and visualization of data within one single device. The proposed methodology and implementation is validated on cables of Queensferry Crossing during construction. The technology has shown potential to allow simple yet accurate tension force measurements.
