Research On The Influences The Pedestrian Incentive Load Has On The Seismic Performance Of Reinforced Concrete Frame Teaching Building

Traditional researches on the seismic performance of frame construction had invariably ignored the influence of human, or treat it as live load or additional quality. However, these assumptions cannot precisely reflect the influence of human on the seismic performance of structure. In order to investigate the influences of the pedestrian incentive load on the seismic performance of.reinforced concrete frame teaching building, the ambient vibration test method was used to determine several frequencies, vibration modes and damping ratios of the structure, and the influence of human on the dynamic characteristics of the structure was obtained. After that, the influence of human on the seismic performance of the structure was discovered. The following studies were finished in this thesis:Firstly, the ambient vibration test method was used to determine several frequencies, vibration modes and damping ratios of the frame teaching building when it under three different working conditions(condition with human in but none move, condition without people in, condition when the structure under pedestrian incentive load). 9 tests have been done on this building, each working condition corresponding to 3 tests.Secondly. Matlab was used to analyse the data acquired from the ambient vibration test and the following 4 analytical steps has been done:1) Data preprocessing has been done to eliminate the interference and noise;2) Filter and resample the acquired data;3) Analysed the acquired data to obtain its auto-power spectrum and cross-power spectrum, then the frequencies and vibration modes of this structure was obtained;4) NEx T method and STD method have been used to get the damping ratios of this teaching building. After the 4 above steps, the wanted results was acquired. The results shows that the natural frequency of the structure barely changes when it under three conditions mentioned above, but they still show little distinctions as follows. The natural frequency of the structure under condition with human in but none move is minimum, the natural frequency of the structure under condition of pedestrian incentive load has been changing in small ranges, but its average value is the maximum. As to the damping ratio of the three conditions, the damping ratio is maximum when the structure under condition with human in but none move, and the d amping ratio is minimum when the structure under condition without human in.Finally, Incremental Dynamic Analysis(IDA) method has been used to assess the seismic performance of this teaching building when it under three different working conditions, similarly, there are four steps:1) Established the finite element model of this teaching building in PERFORM-3D and inputted the acquired dynamic characteristics data into the model. 2)The El-Centro earthquake wave was taken as an example to detailedly show the procedure of IDA. 3) Selected several different earthquake waves and used the same procedure of IDA as above, then several IDA curves was acquired. 4) Maked detailed statistical analysis on these IDA curves, the three different curves with tantile of 16%, 50% and 84% was achieved. And the wanted results can be obtained by comparing these IDA curves. This thesis has acquired the following results: When the strength of earthquake is small, the IDA curves of the structure under three different conditions is mostly coincide with each other. In this case, the seismic performance of the structure is barely changes. However, with the increasing of the strength of earthquake, the three IDA c urves gradually separate from each other, which shows that the structure under condit ion without human in is the first one reach each performance status because its damping ratio is minimum. The structure under pedestrian incentive load is the second and the structure under condition with human in but none move is the last. From the a nalysis results we can obviously see that, in the structure with human inside, the moving of people has some disadvantageous influences on its seismic performance. This kind of influence can be ignored when the strength of earthquake is small. But with the increasing of the strength of earthquake, the disadvantageous influences will be more and more obvious, which should be paid attention to.