Half-circular and half-elliptic edge modifications for increasing aerodynamic stability of stress-ribbon pedestrian bridges

Abstract

A wind tunnel study was conducted to examine the aerodynamic stability of concrete stress-ribbon pedestrian bridges with special reference to the Jomon Bridge. Not popular triangular fairings but half-circular and half-elliptic modified edges on both sides of decks were examined as a fundamental study prior to the Jomon deck model test. The modifications are found to be effective in increasing the critical flutter speed VF as well as suppressing vortex excitation. It was found in the Jomon deck model test that VF was below the design speed for the deck with a conventional cross-section and that VF was greatly increased by the similar edge modifications and a pair of half-circular cylindrical fairings as well. Based on the test results and for some reasons, the half-circular fairing was applied to the actual bridge.