Simplified Dynamic Analysis Of Tall Buildings And High-rise Structures

In recent years, with the construction of various tall buildings and high-rise structures, the dynamic analysis of these structures appears even more necessary and urgent. Based on the principle of equivalent stiffness and equivalent mass principles, the equivalent continuous models of the tall buildings and high-rise structures were established in this thesis. According to the Hamilton principle , the differential equations and their corresponding boundary conditions that controlling the free vibration and forced vibration of the equivalent continuous model were derived, then the problems of structural dynamics were converted to the eigenvalue problems or boundary value problems of ordinary differential equations. Finally, the equations were solved by taking of the ordinary differential equation solver of high efficiency and quality. The specific content of this thesis is as follow:1. According to the characteristics of the tall buildings and the high-rise structures, and based on the traditional continuous analytical method, the high-rise structures were regarded as a generalized Euler cantilever beam with variable mass and stiffness, and the variable section tubular structures for tall buildings were thought as a generalized space Timoshenko cantilever beam with variable section that considering the bending, shear, axial and torsional deformations. These models can be more clearly reflected the mechanical properties of the structures, and have even more practical significance.2. The ODE boundary value problem solver COLSYS and eigenvalue problem solver COLGEN were employed, their corresponding subroutines were compiled by using FORTRAN95, and their speed and accuracy of calculation were verified by solving the problem of free vibration of the tube-in-tube tall buildings.3. The functions describing the variable of the stiffness and mass along the hight of the high-rise structures were found, the equivalent bending stiffness of the high-rise steel tower was derived, and then, the free vibration and the seismic response at the horizontal direction were analyzed.4. The functions describing the variable of the stiffness and mass along the hight of the variable section tubular structures for tall buildings were searched out, then the free vibration analysis was accomplished, and the dynamic response due to the multi-dimensional harmonic loads and multi-dimensional rectangular loads and the impact of blast loads were investigated.The results show that, the method proposed in this thesis is simple and satisfies the precision requirement, and it is considered as a cost-effective method of calculation. It can provide reference for the tall buildings and high-rise structures in structural design, seismic analysis and overall performance evaluation.