Aspects of modeling reinforced concrete bridge structures for dynamic time history analysis

This thesis consists of analytical studies of reinforced concrete bridges under seismic loads. A new shear-flexural element for modelling the response of non-ductile reinforced concrete bridge columns subjected to biaxial seismic loading is developed. The effect of column behavior in the seismic response of bridges and the reliability of retrofitting are examined. The modeling effects of joints and abutments are also studied in this dissertation. In addition, the response of restrainers is studied and compared with current Caltrans Design Procedure.; In the element development, a conceptual model is adopted to accommodate the non-linear reinforced concrete behavior. The biaxial flexural behavior is simulated by using member end moment-rotation relationships. A biaxial failure surface model is proposed for non-ductile shear failure behavior. The numerical examples and their comparison with experimental results show the validity of the model developed for the non-linear reinforced concrete behavior. Associated with a separator joint element developed by Ricles, the new analytical method is used in the I-5/I-605 separator time history analysis. The analytical results agree quite well with the damage observed after the Whittier Narrows Earthquake.; Analytical studies which take into account different modeling of hinges and abutments are performed. It is shown that the details of modelling the expansion joints and abutments have a significant influence on the earthquake response of complex geometry bridge.; In the restrainer study, a series of analyses with different parameters are performed. The results from non-linear time history analysis is compared with predicted restrainer deflection from the current Caltrans Design Procedure. It is found that the Caltrans method cannot predict the restrainer maximum displacement very well and leads to a conservative design in terms of the restrainer number. The best estimate of joint response involves the difference in absolute maximum displacement of two frames acting as independent non-linear oscillators.