Wave Propagation Analysis Of Super High-rise Building Structure Under Impulse-type Vertical Earthquake

Dramatic difference in distributions of axial stiffness and mass for super high-rise buildings with large amount of core walls and limited peripheral columns would make these buildings more sensitive to longitudinal impulse-type excitations, causing possible substantial damage in link elements between the two lateral resisting components when these buildings are excited by the vertical component of strong near-fault earthquakes. And near fault region, larger value of V/H and velocity of P wave might make more energy be input into structure in a relatively short period. Worse, with later arrival of the horizontal component of the earthquakes, adverse coupled damage in the buildings would occur. It is not desirable to apply vibration mechanics to reflect the impulse effect and depict stress wave-induced damage since it cannot reflect time delay and reflection well of stress waves propagate through floors. In contrast, wave propagation method could consider wave effect fully and is more sensitive to discontinuity.To study the impulse wave effect of high-rise buildings under impulse-type vertical earthquake, in elastic range, typical structural system is simplified as one and two dimensional model, then simplified wave propagation method and spectral element method are adopted. In this dissertation, the following aspects are studied by theoretical and numerical analysis, some important results and conclusions have been achieved as follows:(1) The wave propagation method has been combined with vibration mechanics herein to derive the reflection and transmission coefficients of longitudinal wave propagates through simplified lumped masses at floors in which damping effect is considered. Structural vertical seismic macro response is calculated by simplified wave propagation method, which uses difference time delay and FFT filter.(2) Based on existing SEM. spectral element stiffness matrix of Timoshenko beam is derived. Time delay is considered in the analysis through the modified dynamic equilibrium.(3) Compared with the vibration method, wave propagation method is more targeted in calculating structural vertical seismic response, especially under impulse-type vertical earthquake. The axial force fluctuation and relative movement caused by vertical earthquake can not be ignored. The relative displacement between core walls and columns, i.e. vertical drift in link elements, exists when structures are subjected to vertical earthquake. Significant shear force and bending moment in the link elements caused by the vertical drift could be expected in some cases which are not preferable for design high-rise buildings using this kind of lateral load resisting systems.