Inelastic earthquake control of weld failure part II: Probability theory

Active structural control of inelastic response is proposed on an existing building as a method to reduce the risk of steel building weld failure. Pro bability theory of analysis using maximum plastic rotation as the random va riable is performed to study the number of earthquake records needed in ord er to accurately predict the probability of failure. Based on the character istics of the plastic rotation, a new probability density function is devel oped that consists of both discrete and continuous random variables. Forty- nine earthquake ground motion time histories are used in this study, and nu merical simulations show that at least 40 earthquake ground motions are nec essary to accurately predict the probability of failure, which is contrary to the design criteria provided by the Uniform Building Code. The probabili ty density function is then used to design the control system, and in the p rocess the use of structural control is shown to be very effective in reduc ing the risk of weld failure to an acceptable level. Copyright (C) 1999 Joh n Wiley & Sons, Ltd.