A simple procedure to estimate the local displacement demands in regular frame-type structures that respond in elastic limits is described. Given the spectral displacement and beam-to-column stiffness ratio, the procedure estimates the maximum ground story and maximum interstory drifts along the height of the structure. A total of 145 near-fault ground motions recorded on dense-to-firm soil sites are used for the evaluation of the procedure. The approximate drift demands computed from this procedure and the exact results from 27,550 response history analyses are used for calculating the error statistics. The calculations show that the procedure can be used with confidence for frames with fundamental periods between 0.3 and 1.5 s when they are subjected to near-fault records without pulse. The approximations are in good agreement with the exact response history results of near-fault records with pulse when the fundamental period to pulse period ratio is less than 1.5. The performance of the new procedure is also compared with other approximate methods that are employed for similar purposes. The method can be useful for preliminary design of new structures or rapid assessment of existing buildings.

An effective step for seismic risk mitigation in large urban areas under high seismic risk is to identify the most vulnerable buildings that may sustain significant damage during a future earthquake. Once they are identified properly, existing seismic risks may be reduced either by retrofitting such buildings, or by replacing them with new buildings in view of a particular risk-mitigation planning strategy. A fast and simple seismic risk-assessment procedure for vulnerable urban building stocks is proposed in this study. It is basically a sidewalk survey procedure based on observing selected building parameters from the street side, and calculating a performance score for determining the risk priorities for buildings. Statistical correlations have been obtained for measuring the sensitivity of damage to the assigned performance score by employing a database consisting of 454 damaged buildings surveyed after the 1999 Düzce earthquake in Turkey. The results revealed that the proposed screening procedure provides a simple but effective tool for selecting those buildings that have significant damage risk. These buildings have to be subjected to a more detailed assessment for a final decision on their seismic risk level.

PrefaceModern performance based earthquake engineering addresses design, evaluation, construction, maintenance and decommission of structures and requires that their performance during an earthquake can be predicted with a known degree of accuracy. In this framework the importance of residual displacements is twofold: On one hand they represent a significant source of damage affecting mainly the serviceability and the repairability of the structure. On the other hand, after an earthquake, residual displacements are often the only measurable indicator of the shaking occurred during the earthquake. In the framework of a pre-earthquake design or assessment process, the expected residual displacements need to be predicted; while during a post-earthquake assessment the actual residual displacements can be measured.Within his present doctoral dissertation, Mr. Yazgan developed and validated against experimental evidence a new and original methodology to improve the estimate of maximum deformations occurred during an earthquake taking into account both observable damage and measurable residual displacements. The methodology is based on the Bayesian probabilistic theory and, as a particular novelty, explicitly considers model error. To estimate model error Mr. Yazgan carried out a very extensive study on the numerical modelling of structures under earthquake, which also allowed the formulation of practical modelling recommendations. The quantification of model error is of course of fundamental importance also for any realistic pre-earthquake prediction of residual displacements.The thorough and comprehensive work presented by Mr. Yazgan allows a deep understanding of the challenges relevant to the use of residual displacements in the seismic performance assessment of structures and his developments represent a new effective way to achieve this important goal. Zurich, January 2010Dr. Alessandro Dazio SummarySafety assessment of damaged structures is a pivotal part of the post-earthquake recovery process. As a result of the deformation histories that have occurred during the damaging earthquake, the key structural properties of the columns, beams and walls that contribute to the seismic resistance change. The key structural properties include stiffness, strength and deformation capacity. An accurate estimation of the residual key structural properties is crucial in identifying vulnerability of the damaged structure.These residual structural properties are known to be strongly dependent on the maximum deformations that have occurred. A new post-earthquake assessment method is developed following this premise. After an earthquake, the maximum deformations experienced by a damaged structure can be estimated using the developed method.The essential idea behind the method is to probabilistically estimate the experienced maximum deformations based on the post-earthquake residual displacements and the visible structural damage. The major uncertainties related to the estimated maximum deformations are explicitly treated in the me...

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