Displacement Design Approach for Reinforced Concrete Structures Subjected to Earthquakes: Fid-Bau Portal

Displacement Design Approach for Reinforced Concrete Structures Subjected to Earthquakes

X. Qi / J. P. Moehle

From an analytical study of the characteristics of inelastic displacement response of single-degree-of-freedom (SDOF) systems subjected to earthquake ground motions, it is observed that the displacement response can be characterized in two period ranges, divided by the characteristic period of the ground motion. Methods are established by which elastic analysis can be used to estimate the peak displacement response in both period ranges. Therefore, a design displacement response spectrum can be constructed for a given earthquake. The spectrum provides a measure of the expected inelastic displacement using a linear model. The method of estimating the displacement of inelastic SDOF systems is extended to estimate the peak lateral displacement of multi-story frame structures. A study of the deformation capacities of reinforced concrete frame members and subassemblages is conducted to relate the details provided in reinforced concrete beams and columns to the maximum inter-story drift capacity. It is concluded that the required details for reinforced concrete members can be assessed primarily on the basis of displacement considerations. A new displacement-based seismic design approach is outlined. It is concluded that more efficient control of the seismic performance of buildings can be achieved using the displacement design approach. The importance of structural stiffness in resisting earthquake excitations is highlighted in the application of the displacement approach.