Direct damage controlled seismic design of plane steel degrading frames

A new method for seismic design of plane steel moment resisting framed structures is developed. This method is able to control damage at all levels of performance in a direct manner. More specifically, the method: (a) can determine damage in any member or the whole of a designed structure under any given seismic load, (b) can dimension a structure for a given seismic load and desired level of damage and (c) can determine the maximum seismic load a designed structure can sustain in order to exhibit a desired level of damage. In order to accomplish these things, an appropriate seismic damage index is used that takes into account the interaction between axial force and bending moment at a section, strength and stiffness degradation as well as low cycle fatigue. Then, damage scales are constructed on the basis of extensive parametric studies involving a large number of frames exhibiting cyclic strength and stiffness degradation and a large number of seismic motions and using the above damage index for damage determination. Some numerical examples are presented to illustrate the proposed method and demonstrate its advantages against other methods of seismic design. © 2014, Springer Science+Business Media Dordrecht

An energy-based seismic response evaluation of simple structural systems with simulated ground motions

In recent years, there has been a strong interest on energy-based design and assessment methods for structural systems. The underlying research has been mostly performed using real ground motion records taken from existing earthquakes worldwide. Results may involve bias due to lack of homogeneity of the available ground motion dataset in terms of magnitudes, source to site distances or soil conditions. In this study a large set of ground motion records is simulated within a parametric exercise to investigate the effect of different intensity measures on the energy-based response of simple SDOF structures. To generate simulated records, the stochastic finite-fault methodology which is effective in simulating a wide range of frequencies including those that influence the built environment is used. The simulations are performed on active faults around Duzce city center located on the western segments of North Anatolian Fault zone in Turkey. The simulated records cover a wide range of moment magnitude, source-to-site distances and soil conditions. To assess the response statistics on SDOF models, time history analyses with simulated records are performed. Input energy, damping energy and hysteretic energy are considered as the main output parameters. The results of this study reveal that energy is a more stable parameter than the other response parameters such as displacement and force. However, it is important to dissipate the estimated input energy through damping and inelastic action. Finally, it is believed that conducting parametric seismic analysis based on simulated records yield realistic results since these records provide variability in seismic demand