Seismic Collapse Resistant Capacity Analysis Of RC Frame Structures Based On Nonlinear Equivalent SDOF Systems

The collapse of building structure under seismic action will not only results inpersonnel casualty and economic loss, but also brings a great impact to the society, thusensuring collapse resistant capacity analysis of building structures has become the coreobjective of performance-based seismic design. Thestrength and stiffness degradation ofstructural components is the main reason for the collapse and damage of buildingstructures under strong earthquake. Therefore, studying the seismic collapse resistantcapacity, which considersthestrength and stiffness degradation of structural components,is becoming the key content of Performance-Based Earthquake Engineering (PBEE). Inthis thesis, by using the dynamic balance equation and the format conversion betweenacceleration A and displacement D of the capacity spectrum, the pushover curve oforiginal structure is equivalent to skeleton curve of SDOF systems. Based on the finiteelement software OpenSees, modifided I-K model is used as the hysteretic model ofequivalent SDOF systems. By considering the uncertainty of ground motion andstructures, analyze collapse resistant capacity of the equivalent SDOF systems from RCframe structures.The main contents of this thesis are as follows:1. Describe the research progress of collapse resistant capacity at domestic andabroad, and separately analyze the collapse resistant capacity of structure with andwithout consideration of the degradation property of structural components, the collapseresistant capacity of structure based on tests, and the collapse resistant capacity ofstructure based on the equivalent SDOF systems.2. Introduce how the pushover curve of original structure is equivalent to SDOFsystems by using energy method and FEMA method, and the process to model nonlinearequivalent SDOF systems based on OpenSees platform. Then by comparing thehysteretic models of structural components, use the modifided I-K model, whichconsiders the strength and stiffness degradation of structural components, as thehysteretic model of equivalent SDOF systems.3. Make an introduction of the factors influencing collapse resistant capacity ofnonlinear equivalent SDOF systems. Introduce Incremental Dynamic Analysis (IDA)and collapse vulnerability analysis of nonlinear equivalent SDOF systems by separatelyusing methods considering and unconsidering P-? effect, energy method and FEMAmethod, to get median, standard deviation, collapse margin ratio of collapse resistantcapacity of equivalent SDOF systems with consideration of ground motion randomness. 4. Introduce the influence that the uncertainty of the rule has on RC frameequivalent SDOF systems. Based on IDA and collapse vulnerability, analyze equivalentSDOF systems that considers the uncertainty of structural model parameters and groundmotion, then compare median, standard deviation, collapse margin ratio of collapseresistant capacity of the above equivalent SDOF systems with the system which onlyconsiders ground motion.