The Steady-State Response Spectrum of Bridge Structures under Statistical Steady Traffic Flow Loads

The study of the statistical law of the response spectrum of bridge structures under the action of random traffic flow loads can not only evaluate the service performance of bridge structures, but also verify the rationality of the design load taking and provide a reference basis for the control of bridge traffic flow. In this paper, the moving vehicle loads are simplified to moving constant forces, and the statistical characteristics of displacement response spectra and acceleration response spectra of an assembled hollow-slab girder bridge under the action of statistical steady-state traffic flow loads, as well as their spatial distribution laws over the whole bridge, are investigated based on the existing statistical distribution model of traffic flow parameters, which are obtained by Monte Carlo simulation for random traffic flow loads. The results show that with the increase of statistical samples, the mean, standard deviation, and probability density of the steady-state response spectrum estimator of each monitoring point gradually converge, and its convergence value is only related to the random traffic flow load model and the bridge structure characteristics; the convergence values of the mean and standard deviation of the response spectra are parabolically distributed along the longitudinal direction of the bridge; the response spectrum estimator of different precast beams at the same cross section are different due to the different loads transferred laterally. The statistical properties of the response spectrum estimates are not affected by accidental external factors, and can be used as indicators to determine the operating conditions of the bridge structure and the magnitude of the traffic flow on the bridge deck, providing a reference basis for the health monitoring of the bridge structure.