Tension Identification of Suspenders with Supplemental Dampers for Through and Half-Through Arch Bridges under Construction

Abstract

This paper focuses on the identification of tension in suspenders equipped with supplemental dampers in through and half-through arch bridges. Although the differential equation governing the transverse vibration of beams can be modified to include the restraining actions and energy dissipative features of the damper, ensuing solutions relating suspender tension to suspender frequency can only be expressed implicitly, rendering the approach impractical in real bridge applications. This paper develops a simpler, practical identification method which takes into consideration the influence of the damper. Numerical results relating suspender frequency to suspender tension and damper lateral stiffness can be visualized as a surface plot, which in essence is a signature of the suspender system. Feasibility of the tension identification method is demonstrated using a recently completed 180-m-span bowstring arch bridge. Results are promising because suspender tensions are identified with acceptable accuracy. It is further contended that the proposed method is effective in identifying the tension in suspenders equipped with supplemental dampers at all stages of construction and the process can be readily extended to tension identification during the service life of bridges.