Research Of Performance Based Design Method For The Minimum Life-Cycle Cost Of Structures

Based on the performance based design, the designer needs to consider the users' need, such as safety, applicability (including comfort), durability and other aspects, in addition to the satisfied performance character and lesser construction cost. Therefore, the safety and comfortable of construction under different condition (earthquake, wind, temperature, vibration, etc.) will be taken into consideration as the important content. The current seismic design codes in most country aim to ensure people's life, i.e. the three-level earthquake resistant Design-"undamaged under frequent earthquakes , repairable under moderate earthquake, non-collapse under major earthquakes"It makes that the main structure will not collapse under major earthquakes to ensure the life safety, but it induces enormous economic loss due to the failure of useful function under frequent and moderate earthquakes. Wind load will become the decisive horizontal load as the building height increases. It makes the tall building flexible more and more as more aspects, such as the improvement of structure system, the application of gentle material, etc., and wind load affects more continually, dynamic wind loading will induce tall buildings vibration, so it makes the reduction of human comfort become the important factor in designing and controlling tall building.This paper will research the expected cycle life cost of structures including the initial cost and loss expectation from five different performance levels under earthquake effect, i.e. "nearly intact, minor damage, moderate damage, serious damage, collapse" and the comfortable performance under dynamic wind force. Based on reliability theory and random vibration theory, regarding the earthquake and dynamic wind force as random process, using the inter-story displacements and vibration acceleration as the control index of earthquake-resistant safety performance and wind-resistant comfort performance failure, the dynamic reliability of each performance level is calculated using dynamic reliability method, the total failure probability of exceeding the various performance levels is derived by regarding the stories to be of series relation. The structures take place elastic deformation under frequent earthquakes and dynamic wind loading, by using the linear elastic computation theory of the structures and the principles of impulse-response function, the methods of acceleration and velocity impulse function applied in computing the responses of structures...