Experimental and CFD Study of Wind-Induced Response for Bridge Cables with Ice accretion
Cable-stayed bridges are massive structures which rely on their structural elements such as deck girder, towers and stay-cables for their stability. The bridge stay-cables can be considered as the most flexible elements of the cable-stayed bridges, and thus their structural stability integrity is verified for several phenomena which might affect them. Wind and wind/rain induced vibrations for bridge stay-cables were comprehensively studied by researchers worldwide; however recent projects have identified a new type of cable vibrations caused by ice accretion formed around the cable circumference. The current research proposed two ice accretion profiles for inclined bridge cables and has experimentally investigated the wind-induced vibrations of the two models for the bridge stay-cables with ice accretion, under different vertical (inclination) and horizontal (yaw) angles, and for different wind speeds. Initially, three models of the bridge cable with 1.0 cm and 2.0 cm ice profile were tested in the wind tunnel of cross-section 61 cm × 90 cm, and a maximum wind speed of 30 m/s. In total 6 cases with 1.0 cm ice thickness and 3 cases with 2.0 cm ice thickness were investigated and the vertical and torsional oscillatory displacements were recorded for wind speeds from 1.5 m/s to 15 m/s at intervals of 1.5 m/s. The wind-induced vibrations were analyzed and were compared with the response reported for cables without ice and with the rain-induced response for stay-cables. Computational Fluid Dynamics (CFD) simulations were performed to observe the drag, lift and pressure coefficients around the surface of the accreted cable models yawed and inclined at α = 0°, β = 0° and α = 60°, β = 15° under the effect of 10 m/s and 15 m/s wind speed applied for both cases. A verification for galloping divergent instability was conducted based on the Den Hartog formulation and the vertical vibrations obtained from the wind tunnel experiment.
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Université d'Ottawa / University of Ottawa