| This dissertation describes the formulation of an alternative seismic design methodology known as Direct Displacement-Based Design. The design procedure is based on the realization that displacement is of paramount importance in earthquake engineering, and that current procedures, which are based on forces, check displacement rather than design directly for it. By basing design on displacement, we obtain structures that are designed for uniform levels of risk as displacement is an excellent indicator of damage. Additionally, the displacement-based design approach considers inelastic behavior directly, which is in contrast to current force-based procedures thus resulting in more dependable estimations of response during larger earthquakes.; The research described first considers the design of single degree of freedom systems such as single column bridges. This is then followed by analytical as well as experimental verification of the direct displacement-based design procedure. Experimental verification was obtained through the use of dynamic shake table testing of two-column reinforced concrete bridge supports. The last portion of this research describes how the procedure is applied for more complex multiple degree of freedom systems such as multispan bridges. Analytical verification was obtained through the use of dynamic inelastic time history analysis.; Based on the results presented in this dissertation, it is concluded that for the classes of structures considered, direct displacement-based design provides a comprehensive design approach whereby a bridge structure achieves defined performance levels across a wide range of earthquake intensity. |
