Study On Wave Passage Effect Of Irregular Frame Structures

With the development of economy and people’s pursuit of the structural function, more and more complex and irregular building structures appeared, this will be a trend of the development of modern architecture. But a lot of earthquake damages show that irregular structures can easily lead to severe torsion damage which lead to huge economic losses. So it is very important to analyze the seismic performance of irregular structures. Although there are a lot of researches on the seismic response of irregular frame structures at home and abroad, the research on the wave passage effect of irregular structures has not been reported. In this paper, a kind of L type irregular structure is studied to study effect of wave passage.Firstly, the dynamic equilibrium equation of the structure under the multi-point excitation is reviewed, and the method of matrix calculation is given which is used to calculate the structure node displacement and internal force caused by the foundation settlement. Computer program is compiled by MATLAB software. For a cross two layer frame structure, the displacement and internal force of the upper structure are calculated by using the program when the right base node has different settlement. The change of the first level of the column axial force and the moment of the beam and the shear force of the beam are compared. The results show that with increase of settlement, the left beam shear force and bending moment increases gradually, the right end of the shear force and bending moment decreases gradually; the left column axial force increases gradually, and right column axial force decreases gradually.Secondly, the vibration mode decomposition response spectrum method without considering torsion coupling, the vibration mode decomposition response spectrum method with considering torsion coupling and the bottom shear method are given according to the Seismic Design of Building. Computer program is compiled by MATLAB software. For the single span two layer frame structure and the L- type irregular frame structure, the shear force of the first floor frame column is calculated by using the program, comparing and analysing the results of the three methods. the results show: for the single span two layers structures, compare to mode-superosition response spectrum without considering torsional coupling, the shear force of some columns increase using mode-superosition response spectrum considering torsional coupling, while others decrease. The shear force of the two columns which are far from the stiffness center are increased, which are close to the stiffness center are decreased. For the L type irregular frame structure, compare to mode-superosition response spectrum without considering torsional coupling, the shear force of some columns increase using mode-superosition response spectrum considering torsional coupling, while others decrease. The three columns of more than11 meters stiffness center increase, other series of columns shear decrease. Comparing base shear method, all of the columns shear force increase when using mode-superosition response spectrum considering torsional coupling.Finally, the finite element software Midas/Gen is used to build the structure of a six story L reinforced concrete frame. Analyzing of the natural vibration characteristics of the structure including periodic and mode shapes, and then the plane irregular structure under the four earthquake of the third kinds of space is studied, comparising the shear force of a frame column under the action of uniform excitation and wave passage excitation.The results show: the shear force of the column may increases also be reduces under the passage wave effect. Compared with the uniform excitation, columns shear in the direction of the wave increase under the action of wave passage excitation, Four seismic waves are the most likely to increased 2.38%, 0.8%,0.41%, 1.19%. Under the action of wave passage excitation, the time of the maximum value of the columns shear are obviously delayed compared with the uniform excitation.