Torsional ductility spectrum for predicting ductility distribution in simple asymmetric-plan structures

2020-09-01
An analytical procedure is developed for predicting the ductility demands in simple asymmetric-plan structures under earthquake ground motions. The procedure governs regular structures dominated by the lower vibration modes where inelastic response occurs only at the bases of first story columns and at the beam ends, in conformance with the capacity design principles.Torsional ductility spectraare generated for expressing the maximum ductility response of torsionally coupled, generic, single-story, 2-degree-of-freedom inelastic parametric systems. Five parameters characterize the parametric systems: first mode period, uncoupled frequency ratio, stiffness eccentricity, stiff-to-flexible edge strength ratio, and ductility reduction factor. A surrogate modeling approach is developed for converting the properties of the actual systems to those of the parametric system. Mean maximum ductilities of torsionally stiff, equally stiff, and torsionally flexible systems are calculated under a set of design spectrum compatible strong motions for the possible combinations of characteristic parameters. The results obtained from case studies revealed reasonable accuracy of the estimations. The results have indicated that the flexible side frames of torsionally stiff and equally stiff code conforming designs are mainly responsible for providing the intended ductility and energy dissipation capacity whereas the stiff side frames play a secondary role, particularly when the stiff edge is significantly stronger than the flexible edge. However, ductility demands in torsionally flexible systems are significantly larger at both sides compared with torsionally stiff systems.
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS

Suggestions

PREDICTION OF SEISMIC ENERGY-DISSIPATION IN SDOF SYSTEMS
NURTUG, A; Sucuoğlu, Haluk (Wiley, 1995-09-01)
A simple analytical procedure is developed for calculating the seismic energy dissipated by a linear SDOF system under an earthquake ground excitation. The ground excitation is specified by its pseudo-velocity spectra and effective duration whereas the SDOF system is defined by its natural period of vibration and viscous damping ratio. However, the derived relationship for the energy dissipation demand under an earthquake excitation is sensitive neither to the viscous damping ratio nor the ductility ratio w...
Generalized force vectors for multi-mode pushover analysis of torsionally coupled systems
Kaatsız, Kaan; Sucuoğlu, Haluk (Wiley, 2014-10-25)
A generalized multi-mode pushover analysis procedure was developed for estimating the maximum inelastic seismic response of symmetrical plan structures under earthquake ground excitations. Pushover analyses are conducted with story-specific generalized force vectors in this procedure, with contributions from all effective modes. Generalized pushover analysis procedure is extended to three-dimensional torsionally coupled systems in the presented study. Generalized force distributions are expressed as the com...
An improvement to linear-elastic procedures for seismic performance assessment
Gunay, Mehmet Selim; Sucuoğlu, Haluk (Wiley, 2010-07-10)
An improved linear-elastic analysis procedure is developed in this paper as a simple approximate method for displacement-based seismic assessment of the existing buildings. The procedure is mainly based on reducing the stiffness of structural members that are expected to respond in the inelastic range in a single global iteration step. Modal spectral displacement demands are determined from the equal displacement rule. Response predictions obtained from the proposed procedure are evaluated comparatively by ...
Prediction of input energy spectrum: attenuation models and velocity spectrum scaling
Alici, F. S.; Sucuoğlu, Haluk (Wiley, 2016-10-25)
Recent improvements in performance-based earthquake engineering require realistic description of seismic demands and accurate estimation of supplied capacities in terms of both forces and deformations. Energy based approaches have a significant advantage in performance assessment because excitation and response durations, accordingly energy absorption and dissipation characteristics, are directly considered whereas force and displacement-based procedures are based only on the maximum response parameters. En...
System identification of instrumented bridge systems
Arıcı, Yalın (Wiley, 2003-06-01)
Several recorded motions for seven bridge systems in California during recent earthquakes were analysed using parametric and non-parametric system identification (SI) methods. The bridges were selected considering the availability of an adequate array of accelerometers and accounting for different structural systems, materials, geometry and soil types. The results of the application of SI methods included identification of modal frequencies and damping ratios. Excellent fits of the recorded motion in the ti...
Citation Formats
H. Sucuoğlu, “Torsional ductility spectrum for predicting ductility distribution in simple asymmetric-plan structures,” EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS, pp. 0–0, 2020, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/46560.