Study On Seismic Behavior Of Stack-like Structure Under Vertical And Horizontal Earthquake Actions

The destruction of a structure under earthquake action is very complicated, which is usually considered as the result of the cooperation of horizontal, vertical, and torsional ground motions. According to the traditional seismic engineering research, horizontal seismic force plays a dominant role. However, earthquake records and damages show that vertical earthquake actions are sometimes powerful, giving rise to the destruction of a structural system. So, further studies on vertical earthquake actions are significant to the reliability of seismic design, and have practical value to a certain degree.The paper enumerates a number of earthquake damages examples relative to vertical component, presents a research of the amplitude, frequency spectrum, and response spectrum of vertical ground motion, and addresses a comprehensive review of the methods in calculating horizontal and vertical earthquake forces and structural responses.A chimney is modeled by ANSYS program. Based on the modal analysis results, the author analyzes some parameters affecting the vertical dynamic behavior and proposes empirical formulae to estimate vertical modal periods for stack-like structures. Vertical seismic time history analysis are undertaken under two natural seismic records, El-Centro Wave and Taft Wave, and compare with that calculated by means of response spectrum method.The paper describes the method in analyzing the seismic response of stack-like structure under the horizontal and vertical earthquake actions and conducts a dynamic time history analysis to a chimney under horizontal and vertical earthquakes, considering geometrical nonlinearity. Additionally, the author studies structural seismic behavior under both horizontal and vertical earthquakes, and the effects of vertical earthquake actions on the structural performance.