New Method for Identifying Internal Forces of Hangers Based on Form-Finding Theory of Suspension Cable

Abstract

Tensions in the hangers of suspension bridges are vital for quality control during their construction and health monitoring and maintenance during service. Hence, accurate and efficient estimation of the tensions in hangers is very important. A novel method for identification of the tensions in hangers is proposed in this paper. Different from other methods, this new method identifies the tensile forces in hangers by only using the measured coordinates of the main cables of the bridge, which is convenient and economical to implement in practice. This method is developed based on form-finding theory and a new catenary element for form-finding of suspension cables established in this paper, which are derived by considering the force equilibrium equation of an infinitesimal segment of suspension cable. The method is applied in a case study for Aizhai Bridge. The results show that, compared with the other methods, the proposed method is accurate and efficient. More importantly, the proposed method can identify the tensions in hangers with shock absorbers in cases in which the vibration-based method does not work. In addition, the proposed method can identify the internal forces in all hangers of the suspension bridge simultaneously.