Study Of Vibration Response For Large-Span Floor Under Stochastic Crowd Load

Modern structure becomes more and more suitable to its users esthetic sense with the development of new materials and construction technology. Large-span, light, soft, low-damping buildings continue to spring up, however, study of vibration response and control for large-span floor under crowd load is not perfect enough because of the randomness of crowd load, which make it significant to research the vibration response of structure under stochastic crowd load. This paper started with the randomness of crowd load, and stochastic crowd load curves are generated, meanwhile structural response is analyzed. The main research contents and conclusions in this paper are as follows:1. Based on the research achievement of our team, characteristic parameters for statistical crowd walking are determined. Quantities of statistical walking curves are generated with Monte-Carlo method and structural response is analyzed using time-domain analysis. The response under statistical walking load are compared with determined walking load, which is lower when the excitation has resonant frequency, and higher with other frequency, but the error between maximum structural response is within 20% under unfavorable load.2?The floor has the maximum response when stride frequency is 2.3 Hz. When comparing the measured results with Finite Element Simulation data which includes the interaction among people and structure, the error is only 17.51%. After using Monte-Carlo method to calculate the response under statistical walking load, maximum structural response are analyzed which obey the lognormal distribution?3. Research on the correlation between equivalent synchronous pedestrian number under statistical crowd walking condition with total number, damping ratio, Stride frequency. When the crowd density< 1 person/m2, Equivalent synchronous pedestrian number is proportional to the square roots of total number, also to the square roots of damping ratio. It has no correlation with Stride frequency. The expression of equivalent synchronous pedestrian number is determined Neq=8.8·(N ?)0.5.4. A large number of RMS accelerations response spectrum curve is generated. The standard response spectrum curve model is created along with the determination of relative parameters based on the probability. Calculation steps are provided. Response spectrum method is used to test floor statistical vibration response. Reliability of the response spectrum method is verified by comparing with the measured results, when one people walks, the error is10.5%, when seven people walks, the error is 24.5%5. Large-span floor under stochastic crowd is researched taking the example of large cantilevered roof of museum Minhang. The structure response under statistical walking load along with response under determined walking load, results using response-spectrum method are compared with the measured value, all are consistent.