Earthquake Simulation Tests On Light Wood Frame Construction With Unsymmetrical Openings

Light wood frame constructions are widely used in residential houses and low buildings in North America. Until now most of the researches were based on the nail failure tests and wood member failure tests. And the anti-seismic analysis based on the whole models were seldom discussed. Based on the shake table test of seismic simulation of light wood frame construction which is widely used in North America, a comprehensive analysis and judgement were conducted according to the different model status and intensity levels of earthquake simulation waves.The shake table test is based on full size two-story light wood frame construction, with 6m×6m size in plan. There are two 1.2m×1.2m(width×height) windows in east and west lateral of each story and a 1.2m×2.1m(width×height) opening in the middle of north lateral of the first story. The height of the opening was kept 2.1m unchanged and the width increased gradually as the test proceeded. According to the size of opening and direction of excitation, the whole tests are devided into five phases. During each phase different intensity levels of excitations(Three typical earthquake waves with maximum amplitude varied from 0.1g,0.2g to 0.4g ) were carried out. Between each intensity levels the white noise frequency sweep test were carried out so as to monitor the variation of translation and torsion frequency.The frequcncy identifications and comprehensive analysis at different model status and intensity levels of earthquake wave simulation tests were accomplished, along with the data process of acceleration response,relative displacement variations,relative movement between oriented strand boards,anchor bolt response. Highlights of the thesis were focused on the torsion analysis under unsymmetrical model status by means of white noise frequency sweep. The transfer functions were obtained by trying different window function and curve fit algorithms, also the transfer functions after the subtraction and addition of acceleration data at the same height in time domain. The comparison and analysis works of transfer functions at different model status and intensity levels of earthquake wave simulation tests was done so as to identificate the translation and torsion frequency in X and Y direction. The first and second order translation mode in different model status and torsion mode in unsymmetrical status were drawn.The further discussion cast light on the first,second order translation frequency and torsion frequency variation influenced by the opening ratio. Take quantitative analysis of the damage level at different opening ratio and the critical point of yielding state. A comprehensive analysis of the failure of nails,anchor bolts response,relative displacement response,large displacement and acceleration amplitude response were made to obtain the failure mechanism. The conception of critical opening ration of unsymmetrical wood structure was proposed to provide regerence on the design of light wood structure. The prediction of wood model analysis was made in combination with with failure mechanism of structure and nails.