SENSITIVITY OF SEISMIC RESPONSE TO UNCERTAINTIES IN RESTORING FORCE MODEL - A MONTE-CARLO SIMULATION CASE-STUDY

A rigid slab supported by two lateral load resisting elements with ran dom yield strength is used to evaluate the sensitivity of structural r esponse to the uncertainty in the restoring force of these elements. T he input ground acceleration consists of scaled versions of the strong -motion protion of the 1940 El Centro record. The structure is symmetr ic in the elastic range and behaves as a single-degree-of-freedom syst em. However, it can experience translational and torsional vibrations following the first yielding because of the difference between the val ues of the element yield strengths, caused by uncertainty. The dissipa ted energy and the maximum displacement, ductility, and rotation are u sed to quantify the response sensitivity to the uncertainty in the res toring force model. The dissipated energy is the least sensitive respo nse measure. On the other hand, the maximum rotation of the structure can be strongly affected by this uncertainty. Therefore, special desig n measures are needed to limit the uncertainties in this response meas ure.