Interference effects on aeroelastic responses and design wind loads of twin high-rise reinforced concrete chimneys

Abstract

Twin chimney arrangement is a typical layout for power stations. The most unfavorable wind-induced responses of twin chimneys usually overwhelm those of the corresponding isolated chimney due to interference effects. The present paper investigates the aeroelastic responses and design wind loads of twin high-rise reinforced concrete chimneys through wind tunnel tests with L/D varying from 2 to 6 (L being the center-to-center spacing and D being the mean diameter). The results from rigid and aeroelastic model tests are analyzed and compared with the codes. It is revealed that the most unfavorable response interfered by the upstream chimney is inferred to be induced by the vortex impingement resonance at critical wind velocity when L/D = 3. It is also found that the interference factor nominally specified in ACI 307-08 is feasible with a modest conservation in the lock-in regime (Ud/UCr = 0.8–1.6). When the design wind velocity is far beyond the critical wind velocity (Ud/UCr ≥ 2), the interference factor can be reduced, which is not covered by the codes. An empirical formula is proposed for this situation which leads to an economic practical design considering the aeroelastic interference effects.