Bridges

Cover of Vibration Mitigation Measures in Cable Stayed Bridges
Vibration Mitigation Measures in Cable Stayed Bridges
  • Publication no: ABC-DES044-11
  • Published: 31 October 2011

Many cable stayed bridges built have suffered from excessive vibration problems due to rain wind phenomenon and/or parametric excitation. The technology of parallel strand stay cables has evolved since its introduction in the early 1990s. Most of these bridges have been retrofitted with cross ties and external or internal dampers.

The aim of this paper is to present an approach, which can be used to assess the vulnerability of a given stay cable to rain and wind induced vibrations and to provide suitable mitigation measures.

A specific case study is presented in this paper using the ANZAC Bridge located in Sydney. The ANZAC Bridge has three spans with a central span of 345m configured with fan shaped cable stays. In the original design the stay cables were to be cement grouted. However, un-grouted parallel strand stay cables were adopted during construction.

Three cases are considered for comparison purposes of rain and wind effects. The first case deals with the cement grouted stay cables as “originally designed”, second case deals with wax filled anchorages “as constructed” and, the last case deals with dampers installed and surface treatment of the stay cables. A specific model calculation for the ANZAC bridge is discussed as a case study.

This paper also discusses the available remedial measures to retrofit the stay cables. The methods provided in this paper can be used for new designs and also in retrofitting existing cable stayed bridges.