Research on Parametric Vibration of a Steel Truss Corridor under Pedestrians Excitation Considering the Time-Delay Effect

With the development of the Steel Truss Corridor (STC) toward long-span and gentle development, human-induced vibration often causes large lateral vibration problems and time-delay effects of the STC, which will have a non-negligible impact on the dynamic performance of the STC. In this paper, the parametric vibration model proposed by Piccardo is improved, and the nonlinear dynamic equation of the STC is established considering the longitudinal–lateral walking force coupled parametric vibration with the time-delay effect. Taking the Millennium STC as an example, the mechanism of lateral vibration under the time-delay effect is discussed by the numerical calculation method, and the influence of the time-delay effect on its dynamic response is analyzed. The results show that: considering the time-delay effect, when the frequency ratio θ/2Ω = 1, the value of the time-delay coefficient has no effect on the critical number of STCs in the parametric resonance region. As θ/2Ω moves away from 1, the more significant the effect. When the STC begins to excite the parametric resonance phenomenon, the existence of the time-delay effect will change the time for the STC to reach a stable amplitude and suppress the lateral vibration of the STC. When the STC generates parametric vibration, the value of the time-delay coefficient has no effect on the nonlinear dynamic response of the STC. For STCs in both the nonparametric resonance region and the critical region, there is a pair of staggered critical bifurcation time-delay coefficients, which increase or decrease the vibration response.