Seismic Reliability Analysis Of Egyptian Code-designed Structures Under Multi-dimensional Non-stationary Ground Motion

Earthquakes are one of the most dangerous natural disasters on the Earth.Although Egypt is affected by only moderate seismic activity compared to other countries,it has experienced occurring of damaging earthquake effect through its history.Due to the great and rapid spreading of large investment in national projects in recent years,the study of earthquake activity and seismic hazard assessment of Egypt is very important.However,the current basic seismic design codes depend on a uniform hazard spectrum and has exposed to unpredictable levels of risk when applied to structures.Furthermore,all types of engineering structures are simultaneously excited by multiple(horizontal and vertical)ground motion components during an earthquake.As a result,there is an urgent need to estimate current seismic-hazard values and provide this information for application and use in improving seismic design and construction of structures.Based on this,this study revolves around establishing a theoretical and computational framework for real-world application of seismic reliability,essential for assessment of different Egyptian code-designed structures under multi-dimensional non-stationary ground motion.The first part of this dissertation is devoted to propose a framework for a multi-dimensional non-stationary ground motion model based on spectral representation theory and compatible with the Egyptian Seismic Code.Starting from the local simulation of the ground motion process(modulation function,power spectrum,and response spectrum),non-stationary multi-dimensional ground motion using parameters according to the Egyptian Seismic Code have been determined.The numerical simulation results show that this approach can be used for the accurate predictions of the multi-component design ground motions from the target response spectrum and validate the applicability of the target response spectrum approaches for the generation of spectral representation-based multi-dimensional nonstationary ground motion expected for the design responses of structures.Seismic reliability analysis of building structures through the combination of seismic responses and the probability density evolution method based on the multi-dimensional non-stationary ground motion model is then presented.Reinforced concrete frame structures and composite steel-concrete mega structure are the subjects of this part.First,finite element models of these study structures are developed and analyzed to examine both global and local performance of structural system.The random seismic responses are then combined with the probability density evolution method to carry out the seismic reliability analysis of the structures.The results indicate that multi-dimensional earthquake components should be taken into consideration and vertical components cannot be ignored.The probability density evolution method can also provide a new approach for the structural reliability analysis under the excitation of random earthquakes.In the final part of the dissertation,a seismic reliability assessment method for transmission tower-line systems under multi-point non-uniform excitations is proposed.Through the ground motion time history and dynamic time history analysis compatible with the Egyptian response spectrum,the random seismic response and reliability analysis of the transmission tower-line systems under the multi-point non-uniform excitation is carried out,and the influence of the combination of the spatial effect of the ground motion on the structural seismic response is studied.The reliability of transmission tower-line system is shown to be more sensitive to an increase in the intensity of extreme seismic loading than to a wave apparent velocity variation.The results also shown that the proposed probabilistic framework can be used to develop component and system failure probabilities for design purposes of complex structures under extreme seismic loads.The research work presented and the results obtained in this dissertation will contribute to the development of robust reliability-based seismic performance assessment practice for typical engineering structures.It thus lays a solid foundation for seismic reliability analysis of complex engineering structures under extreme earthquake event.