Study On The Dynamic Response Of Curved Continuous Bridges Under Spatial Seismic Excitation

As a widely-adapted type of continuous bridges in modern transportation, curvedcontinuous bridges are particularly well-fitted in viaduct and interchange withuncommon site condition. In recent devastating earthquakes, a great many continuouscurved bridges suffered from damages and collapses, which severely influenced thearterial traffic and afterward rescues. The bending-torsional effect of curved bridgemay aggravate its dynamic response and failure compared to straight bridge withsame characters. Existing bridge seismic codes give simple rules on the spatial effectsand even less seismic restrictions on curved bridges under non-uniform excitations.Studies on patterns and rules of the seismic behavior of curved continuous bridges indomestic and abroad are mainly theoretical and numerical while response spectrummethod and time history method are widely-used. Therefore, the stochastic characterand the spatial effects of the earthquakes may not be effectively revealed. The shakingtable experiments on scaled model continuous curved bridge are rare in relativeanalysis which can map the accuracy of the numeric results. In all, this paper hasthoroughly studied the response pattern of continuous curved bridge under stochasticvibration while shaking table experiment has been conducted to prove the results.Suggestions have been provided at last as supplement for the existing code ondefining ‘regular bridges’. The main purposes and achievements are listed as follow:1. The paper summarized and Compared the stochastic vibration analyzing methodsconsidering spatial effects. Clough-Penzion PSD modal has been selected aftercomparison. Based on ANSYS, the stochastic vibration analysis has been conductedconsidering the spatial effects.2. The paper analyzed the dynamic characteristics and responses of a4-spancontinuous curved bridge model under random excitation with various geometric andspatial parameters. Results show that different geometric parameters would prominentchange the dynamic responses of specific parts of the bridge, while different spatialparameters affect the bridge thoroughly.3. A1/10scaled model bridge has been designed and tested on the shaking table.Results have been compared with numeric analysis. Site condition effect and thetraveling wave effect are especially considered during the experiment.4. Based on the above studies, American codes and Canadian codes have been bothreferenced for editing and complement the Chinese code about “regular bridges”.